Abstracts

Abstracts are listed in alphabetical order by last name of the first author

1. Serotonergic excitation of amygdala projection neurons in the mouse medial prefrontal cortex
Daniel Avesar, Allan Gulledge
Department of Physiology and Neurobiology, Geisel School of Medicine

The prefrontal cortex (PFC) is involved in executive regulation of higher order cognitive tasks and emotional regulation. In rodents, the medial prefrontal cortex (mPFC) has been shown to have a clear role in regulating fear conditioning through specific projections from the mPFC to different parts of the amygdala. We characterized serotonergic responses of mPFC pyramidal neurons projecting to the amygdala, and found these neurons to be excited by serotonin 2A receptors. In recent work we show that mPFC neurons which project to the pons are uniformly inhibited by serotonin through activation of the serotonin 1A receptor, while pyramidal neurons that project to the contralateral hemisphere of the PFC are excited by serotonin 2A receptor activation. Given that mPFC neurons with contralateral projection and amygdala projection are both excited by serotonin, we compared serotonergic responses in these two subpopulations. We find that these two populations partially overlap, but that they have subtle differences in the magnitude of excitatory serotonin responses. Our findings reveal selective serotonergic excitation of cortical-amygdalar projection neurons, demonstrating a cellular substrate for serotonergic regulation of fear responses.

This work was supported by the NIMH (R01 MH83806) and a NARSAD Young Investigator Award.

2. RNAi-mediated knockdown of Nav1.1 disrupts a cognitive neural network
Bender AC, Luikart BW, Scott RC, Holmes GL, Lenck-Santini PP
Departments of Neurology and Physiology and Neurobiology, Geisel School of Medicine

Background: Dravet syndrome (DS) is a childhood-onset epilepsy leading to severe and permanent cognitive impairment. As many as 85% of cases of DS are linked with loss-of-function mutations in the SCN1A gene, coding for the type I voltage-gated sodium channel (Nav1.1). However, the impact of Nav1.1 deficits on cognitive neural networks has not been studied. Here, we use an RNAi approach to investigate the direct effects of Nav1.1 downregulation on specific neural networks in vivo.

Summary of Results: We found that focal Nav1.1 downregulation in the basal forebrain region caused a spatial memory impairment. Continuous EEG monitoring revealed that this effect was not caused by seizures. Rather, the fundamental neurophysiological properties of this network were altered. Specifically, a dysregulation of hippocampal theta frequency was associated with poor spatial memory performance. Secondly, single-unit recordings of basal forebrain neurons in vivo demonstrated that the firing properties of this neuronal population were substantially impacted. The average peak firing frequency was reduced and the average action potential width was increased. These deficits may help explain the dysregulation of hippocampal oscillations and impaired cognitive function. Our results to this point suggest that the loss of function of Nav1.1 in Dravet syndrome may directly impact cognition through mechanisms other than seizures, and that one of these mechanisms may involve alterations in brain oscillations.

We would like to thank Bryan Luikart and Meijie Li, Radu Stan, Mary Jo Mulligan-Kehoe, Christian Dong, Nick Shworak, Allan Gulledge, Alfonso Romero-Sandoval and Pam and Hermes Yeh for their helpful advice and support.

Supported by grants from NINDS to GLH, PPLS, RCS (NS076763, NS074450 and NS073083), and ACB (F31NS077537-01), and by the Emmory R. Shapses Research Fund.

3. Characterizing the Spatial Distribution of Amyotrophic Lateral Sclerosis in Northern New England, USA
Tracie A. Caller, MD, Nicholas C. Field, Xun Shi, PhD, Rup Tandan, MD, Shannon Lucy, Colette Oesterle, & Elijah W. Stommel, MD, PhD
Department of Neurology, Geisel School of Medicine; Psychology, Dartmouth College; Psychology, Eastern Maine Medical Center

Background: The majority of cases of Amyotrophic Lateral Sclerosis (ALS) are not familial, but sporadic. Detailed epidemiology studies can be used to generate hypotheses for disease etiology and potential contributing environmental factors. Geographic disparities in ALS have been identified in other parts of the world, but lack of detailed spatial and demographic data has limited spatial analysis of ALS in the United States.

Objective: To perform a surveillance study of sporadic ALS within the states of Vermont (VT) and New Hampshire (NH), and to determine if spatial variation of ALS exists within this region using novel geocomputational techniques.

Design/Methods: Incident cases of ALS diagnosed 1997-2011 in NH and VT (underlying population 1,942,211 persons) were identified through Dartmouth-Hitchcock Medical Center, Fletcher Allen Health Care, the Muscular Dystrophy Association, and private neurologists. Dwelling addresses at time of diagnosis were geocoded into spatial coordinates using Google Maps API. Landscan Global 2008 and 2000 US Census data were integrated using ArcGIS© 10 software and used to create a high resolution background population layer. The expected number of ALS cases was calculated based on expected disease incidence rates and the background population. A Monte Carlo simulation of the distribution of ALS cases was then performed based on the location of actual cases compared to the location of expected cases.

Results: High resolution maps were created, demonstrating geographic variation in ALS. Spatial analysis revealed several regions with higher than expected ALS incidence.

Conclusions: Our data suggest that ALS occurs at a higher frequency within certain locations. Environmental exposures could play a role in this geographic variation. Detailed surveillance studies and case control studies could help further investigation of environmental influences in the development of ALS. This work was supported by The ALS Association & the Hitchcock Foundation

4. Development of a Self-Management Intervention to Address Cognitive Dysfunction in Epilepsy
Tracie A. Caller, MD, Karen Secore, ARNP, Robert Ferguson, PhD, Robert Roth, PhD, Jonathan Kleen PhD, Faith Alexandre, Rod Scott MD, PhD, Barbara C. Jobst, MD.
Department of Neurology, Geisel School of Medicine; Psychology, Dartmouth College; Psychology, Eastern Maine Medical Center

Rational: Psychosocial comorbidities such as depression and cognitive dysfunction are often neglected in the process of delivering epilepsy care. Limited treatment options and resources with which to intervene represent a major barrier. Our objective was to ascertain the degree of self-reported cognitive symptoms in our epilepsy population and determine if an intervention could be developed to address cognitive symptoms.

Methods: To ascertain the degree of subjective cognitive dysfunction in an outpatient epilepsy population, the 6 questions comprising the cognitive subset of the validated Quality of Life in Epilepsy (QOLIE-31) scale were administered to all adult epilepsy patients over a 3 month period. Seizure frequency, depression symptoms (NDDIE) and overall quality of life (Likert scale of 1-10) were also assessed. Based on the findings, an intervention was developed to address cognitive dysfunction.

Results: Review of 202 patients yielded an average cognitive score of 63 ± 28 on a scale of 0-100 (with 0 indicating very poor subjective cognitive function); 31% scored below 50. Patients with a cognitive score below 50 were more likely to have depression scores consistent with major depressive disorder (38% vs. 11%, p<0.001). and lower reported quality of life (6.4 ± 1.4, vs. 7.5 ± 1.5, p<0.001).

Based on the high prevalence of subjective cognitive symptoms, we developed a self-management program called HOBSCOTCH (HOme Based Self-management and Cognitive Training CHanges lives). HOBSCOTCH utilizes problem solving therapy (PST), widely used in treating depression. Compensatory strategies for enhancing memory in day-to-day life are taught primarily over the phone. Working memory training via a commercially available device (Nintendo, Inc. Brainage®) will be delivered to a subset of patients.

Conclusion: There is a high prevalence of cognitive dysfunction in epilepsy, supporting a clear need for a cost-effective intervention. The feasibility and effectiveness of HOBSCOTCH is currently being evaluated. Our primary outcome is to improve quality of life, with secondary outcomes of self-reported function, subjective memory symptoms, objective memory performance, executive function, and depression.

This work was supported by: Centers for Disease Control & Prevention

5. Putative Circadian Clock Genes in the American Horseshoe Crab, Limulus polyphemus
Chesmore K.N., Simpson S.D., Albanese F.D., Chabot C.C
Biological Science department, Plymouth State University

Daily changes in physiology and behavior are governed by circadian clocks located in several tissues including the central nervous system. In Drosophila, these endogenous clocks are composed of interlocking transcription/translation negative feedback loops consisting of four core genes: period, timeless, clock, and cycle. While this system has been extensively studied in model organisms such as Drosophila, nothing is known about its molecular basis in Limulus polyphemus, an organism known for robust circadian rhythms. Based on the hypothesis that the core mechanisms of the clock are conserved between Limulus and Drosophila, the goal of this study was to identify orthologs of the four core genes in the newly sequenced Limulus genome and transcriptome which was developed using Illumina high throughput sequencing. The genes of interest were identified and annotated using CLC Genomics Workbench and phylogenies were determined using a Maximum Likelihood algorithm. Unique orthologs of clock and timeless genes were identified in the Limulus genome and transcriptome. Unexpectedly both databases revealed additional copies of period and cycle genes. Phylogenetic analysis shows that these genes evolved before the divergence of insecta and chelicerata and indicates that all genes of interest share homology to other invertebrate clock genes. This is supported by conservation of intron/exon structures and amino acid sequences of functional domains, such as the PAS and TIMELESS domains which are responsible for protein dimerization as well as bHLH domains which are involved in transcriptional regulation. Overall, these results suggest a functional conservation of these proteins in the Limulus circadian clock.

This work was supported by: NH-INBRE, NSF, Plymouth State University

6. Refining the serotonergic contribution to central chemosensitivity and thermoregulation
Andrea E. Corcoran, Rachael D. Brust, Russel S. Ray, George B. Richerson, Susan M. Dymecki, and Eugene E. Nattie
Department of Physiology and Neurobiology, Geisel School of Medicine

The involvement of brain serotonergic neurons (5HT neurons) in a remarkably wide range of physiological functions and disorders motivates a deeper examination of their heterogeneity with respect to developmental origin, functional properties, and molecular expression. We are using these characteristics to subdivide 5HT neurons and study the involvement of molecularly defined subtypes in different functions. Here, we are interested in the role of 5HT neurons in central respiratory regulation, particularly in the respiratory chemoreflex (defined as an increase in ventilation in response to elevated CO2 to restore blood gas and pH levels to normal), and thermoregulation. To test this more definitively, we developed a transgenic mouse strain capable of inducibly and reversibly inhibiting 5HT neuron activity in the awake and behaving mouse, building on the Di system developed by Bryan Roth and colleagues (Armbruster et al 2007). We have found that suppressing neuron activity in all 5HT neurons causes a decreased ventilatory response to breathing 5% CO2 (Ray et al 2011). We now continued to apply this approach toward silencing subtypes of 5HT neurons in order to identify those that contribute most to the CO2 respiratory chemoreflex and temperature regulation. Using a dual recombinase (Cre and Flpe)-based intersectional genetic approach we have labeled and manipulated (via Di expression) subtypes of 5HT neurons defined by developmental gene expression differences. Present findings highlight a subset defined by having a history of expression of the transcription factor Krox20 (Egr2) and arising from hindbrain rhombomere 5. In vivo plethysmography confirms the importance of these particular neurons in the ventilatory response to hypercapnia. Using patch clamp electrophysiology we find that this same population (identified by eGFP labeling) is chemosensitive in vitro (increase firing rate in response to a decreased bath pH caused by elevating bath CO2, a property that is not shared among all 5HT neurons). In contrast, other subsets of 5HT neurons do not show similar involvement in respiratory chemosensitivity (defined by having a history of expression of either En1 or HoxA2 transcription factors). This work defines a molecular and developmental 5HT neuron subtype involved in CO2 chemosensitivity and extends our understanding of 5HT neuron biology and its role in a vital homeostatic neuronal network.

This work was supported by the NIH grant PO1 HD036379.

7. Nucleus Accumbens Deep Brain Stimulation in a Rat Model of Binge Eating Disorder
Doucette, W, MacLeod, J, Leiter, J and Green, Al
Department of Psychiatry, Department of Physiology and Neurobiology Geisel School of Medicine at Dartmouth

Background: Binge eating disorder (BED) affects 0.7- 4% of the general population and bingeing behavior is present in up to 30% of dieting obese individuals. Those with BED have binges dominated by sugar and fats, known potent activators of the brain reward circuit. We used a rat model of BED to test the hypothesis that treatment with deep brain stimulation in the nucleus accumbens core (NAc), a crucial component in the brain reward circuit, will decrease bingeing. This hypothesis is based on the following: 1) brain areas thought to be dysfunctional in both addiction and eating disorders include the NAc; and 2) deep brain stimulation in NAc has been shown to decrease alcohol use in animal models of addiction. Methods: Sprague-Dawley rats were implanted with stimulating electrodes in bilateral NAc and then randomized into either a stimulation (N=6) or sham stimulation group (N=4). Rats were given restricted access (2 hrs) to a highly palatable sweet-fat chow and a standard chow and water provided ad libitum. Animals reached a stable baseline of bingeing prior to the treatment phase. The stimulation was constant current (0.2 mA) and high frequency (150 Hz), with a pulse duration of 60 µsec applied during the restricted access period. Results: Pilot data show a statistically significant (p< 0.0005) 25% reduction in bingeing in the active stimulation group compared to the sham control group. Conclusions: Our pilot data suggest that deep brain stimulation within the NAc can decrease binge size in an animal model of BED.

8. Conversion points in long-term multiphasic disease course of Alzheimer disease: Conversion of normal elderly and depressed elderly
Virginia-Olga Beattie Emery, Ph.D.
Department of Psychiatry, Geisel School of Medicine

Alzheimer disease (AD) is not a singular homogeneous disease but a final common endpoint and phenotype. There are a number of disorders that involve long-term multiphasic disease course culminating in AD. AD has a long-term CNS course with points of conversion: pre-AD stages that are identifiable early on. First intervention must occur at these pre-AD stages before final conversion to diagnostic-AD. In this report, research from a series of studies is presented delineating two long-term trajectories leading to AD:(1) normal elderly conversion to AD, and (2) depressed elderly conversion to AD. In explicating normal elderly devolution into AD, two "normal elderly" pre-AD or prodromal stages are discussed: age-associated memory impairment (AAMI) and mild cognitive impairment (MCI). Data are presented involving "healthy" normal elderly (ages 75-95) with the finding that 31% of these elderly have AAMI and another 22% suffer from MCI. Using the same paradigmatic method that documents normal elderly conversion to AD: there is data based explication of age-controlled depressed elderly conversion to AD. The long-term disease progression of major depression without dementia to depressive dementia to final conversion to AD is delineated. Depression is defined as a cognitive syndrome and risk factor for AD. Data are presented showing that depressed elderly perform significantly worse than demographically equivalent normal elderly on cognitive tasks. Depressive dementia is defined as a prepermanent, intermediate-stage dementia in multiphasic disease course between major depression without dementia and irreversible, permanent dementia, such as AD. Modal pattern of depressive dementia and its conversion to AD is described. Population statistics indicate first intervention in AD occurs most often at time of diagnosis of AD. First intervention at time of diagnosis of AD is too late, when by definition, final conversion to AD has already occurred. These disease trajectories of normal elderly and depressed elderly bring into focus long-term, progressive, spectrum features of cognitive deterioration prior to final transformation into AD phenotype. An AD intervention timeline has been developed and is presented. To conclude, AAMI/MCI and depressive dementia represent conversion points in a long-term, multi-stage retrogenic process whereby the elderly person enters a trajectory involving progressive cognitive deterioration and devolution into AD.

Acknowledgment: Manchester Veterans Affairs Medical Center. Department of Internal Medicine, Geriatrics Division

9. A common link between three sporadic amyotrophic lateral sclerosis cases in Annapolis, MD, USA.
Nicholas C. Field, Sandra Banack, PhD, Tracie A. Caller, M.D., James Metcalf, PhD, Paul Cox, PhD, Elijah W. Stommel, M.D., PhD.
Department of Neurology, Dartmouth-Hitchcock Medical Center; Institute for Ethnomedicine, Jackson, WY.

Background: The majority of amyotrophic lateral sclerosis (ALS) cases occur sporadically, and spatial clustering of ALS has been described. A number of environmental triggers have been implicated, including beta-methylamino-L-alanine (BMAA), a cyanobacteria-produced neurotoxin linked to ALS on Guam. The BMAA hypothesis is intriguing since cyanobacteria are present worldwide and could provide a ubiquitous source of BMAA exposure through aquatic food webs. We report a cohort of three ALS patients who lived for a minimum of 10 years on the same street in a suburb of Annapolis, Maryland, USA. Cyanobacteria blooms have been present in the Chesapeake Bay for decades, providing a potential for BMAA exposure through the food web in this region. A questionnaire was used to ascertain possible risk factors for ALS and cyanobacteria exposure to determine if a common environmental risk factor was present.

Methods: The diagnosis of ALS in all 3 cases was confirmed through their regional ALS Center. A questionnaire was completed by a surviving immediate family member of each patient, which ascertained lifelong dwelling history, exposure history, and social history. The questionnaire also assessed recreational water use and potential exposure to cyanobacteria.

Results: We identified 3 confirmed cases of sporadic ALS diagnosed within an 8 year time period, all living on the same street in Annapolis, MD. Other than the close proximity of the 3 cases, review of the questionnaires revealed one striking commonality, which was the weekly consumption of freshly caught Chesapeake Bay blue crabs. Based on the results of the questionnaire, we decided to further investigate a possible link to ingestion of BMAA within the food web by obtaining fresh Chesapeake Bay crabs from the same fish market where the three patients regularly bought crab meat, and testing the crab for BMAA using well-established methods.

Conclusion: The lifelong consumption of blue crab contaminated with BMAA may be a common risk factor for sporadic ALS in all three patients. Other factors may have also contributed to disease development. Further studies are beginning to investigate a link between ALS, cyanobacteria, and seafood consumption.

This work was supported by: Deerbrooke Charitable Trust and private donations to the Dartmouth-Hitchcock ALS Center

10. Functional connectivity of the default mode network and reward circuitry in patients with schizophrenia and co-occurring cannabis use disorder: Effects of cannabis and delta-9-tetrahydrocannabinal
Adina S. Fischer, B.Sc., Susan Whitfield-Gabrieli, Ph.D., Robert M. Roth, Ph.D., Mary F. Brunette, M.D., Alan I. Green, M.D.
Department of Psychiatry, Geisel School of Medicine

Background: Cannabis use disorder (CUD) occurs commonly in patients with schizophrenia (SCZ) and substantially worsens disease course. Available treatments for SCZ are rarely successful in limiting cannabis use. Development of effective treatments will be facilitated by a more complete understanding of the basis of their cannabis use. We theorize that patients with SCZ use cannabis to ameliorate brain reward circuit (BRC) and default mode network (DMN) dysfunction. In the present study we used resting state functional connectivity (rs-fc) to assess the integrity of the BRC and DMN in patients with SCZ and CUD (as compared to controls), and to investigate the effects of cannabis and dronabinol (delta-9-tetrahydrocannabinol [THC]) administration.

Methods: Participants included 12 patients with SCZ and CUD (abstinent from cannabis for > 7 days) and 12 control subjects. Patients completed an fMRI resting scan at baseline, and again (in a double-blind design) after either smoking a 3.6% THC cigarette (n=6) or taking a 15mg dronabinol pill (n=6). Controls were scanned twice, with no intervention made. Seed-to-voxel rs-fc was analyzed using bilateral nucleus accumbens (NAc) seed regions to assess the BRC and default seeds (posterior cingulate, medial prefrontal, and left and right parietal cortices) to evaluate the DMN. In patients, plasma THC concentration, marijuana craving, subjective high, and symptom severity (PANSS) were assessed at baseline and following pharmacological intervention.

Results: At baseline, patients showed decreased rs-fc between NAc and other BRC regions (e.g., orbitofrontal, ventral anterior cingulate, and parahippocampal cortices) as well as hyperconnectivity of the DMN (especially between the medial prefrontal and posterior cingulate cortices) relative to controls. Both cannabis and dronabinol administration increased connectivity within the BRC and decreased DMN rs-fc. Moreover, plasma THC was positively correlated with improvement in BRC connectivity. Subjective high ratings increased following dronabinol and cannabis, but no change in symptom severity or marijuana craving was detected.

Discussion: Our findings indicate that BRC rs-fc is reduced in patients with SCZ and CUD, and that both cannabis and dronabinol increase BRC connectivity. Conversely, patients show DMN hyperconnectivity at baseline that is ameliorated by THC agonists. Study findings support the use of rs-fc to identify connectivity abnormalities and track the effect of pharmacologic agents on this circuitry. If confirmed by subsequent study, our findings suggest that dronabinol might be tested as a potential adjunctive treatment for cannabis use in SCZ.

This study was funded by the National Institute on Drug Abuse [R01DA026799-01].

11. Current source density analysis of spontaneous interictal spikes in vivo
Sean P. Flynn, Pierre Pascal Lenck- Santini, Gregory L. Holmes
Department of Neurology, Geisel School of Medicine

Purpose: Interictal spikes (IIS) are a common observation in both patients and animal models of epilepsy. Although IIS have been well studied in in vitro hippocampal slice preparations, few studies have described spontaneously generated IIS in vivo. In this study we investigated the propagation of spontaneous IIS within the hippocampus and entorhinal cortex (EC) of rats exposed to pilocarpine-induced status epilepticus (SE).

Method: Male Sprague Dawley rats were administered lithium (127mg/kg, i.p.) followed by multiple doses of pilocarpine (12.5mg/kg, i.p.) until the development of SE, defined by continuous stage 4/5 seizure activity. Seizures were stopped 90 min following the initiation of SE, with lorazepam (2.5mg/kg, i.p.). All recordings were completed at least 2 weeks following SE. For in vivo recordings animals were anesthetized with urethane (1.5g/kg, i.p.). A laminar 16-channel silicon probe was lowered into the hippocampus to record from a plane including either CA1-CA3 or CA1-dentate gyrus. Additional EEG wires were placed in the medial EC.

Results: Spontaneous IIS were observed in both the hippocampus and EC in pilocarpine-treated rats under urethane anesthesia. In preliminary analysis we observe 3.0 ± 0.3 IIS per minute within the hippocampus. Current source density analysis of the EEG traces containing IIS, combined with histological verification of probe placement will allow for a detailed description of how IIS enter the hippocampus and EC.

Conclusion: We have demonstrated that spontaneous IIS can be recorded under urethane anesthesia. Detailed analysis of how IIS enter the hippocampus will help illuminate where individual spikes were generated. There is evidence that IIS help establish epileptic foci and negatively affect cognition, thus understanding how IIS are generated in vivo may help guide the development of anti-spike therapies.

12. Fatty acids increase neuronal hypertrophy and spine density of PTEN knockdown neurons
Catherine J. Fricano, Tyrone DeSpenza Jr, Paul W. Frazel, Meijie Li,Gary L. Westbrook, and Bryan W. Luikart
Department of Physiology and Neurobiology, Geisel School of Medicine at Dartmouth

Phosphatase and tensin homolog (PTEN) catalyzes the reverse reaction of PI3K by dephosphorylating PIP3 to PIP2. This negative regulation of downstream Akt/mTOR/S6 signaling results in decreased cellular growth and proliferation. Here we report that knockdown of PTEN in neonatal mice has a more profound impact on neuronal morphology and S6/mTOR signaling than in the adult. The increased sensitivity to PTEN knockdown in neonates could reflect an increase in extracellular factors driving growth. Because circulating fatty acids can promote growth in non-neuronal cell types, we examined the levels of endogenous circulating fatty acids in neonatal and adult mice. Circulating fatty acid levels were increased in neonates and implantation of mini-osmotic pumps delivering fatty acids to adults resulted in neuronal hypertrophy, increased dendritic spine density, and increased levels of p-S6/p-mTOR in PTEN knockdown cells. Our results suggest that circulating fatty acids increase the cell-extrinsic drive of intracellular growth signaling in the brain.

This work was supported by R01 MH097949-01 and Autism Speaks Pilot Grant #7359

13. Activity-dependent secretion of nerve growth factor from neurons: a real-time study
Lan Guo, Bryan Luikart, Hermes H. Yeh
Department of Physiology and Neurobiology, Geisel School of Medicine

Nerve growth factor (NGF) is the prototypic member of the neurotrophin family of secreted polypeptide growth factors. Neurotrophins play pivotal trophic function in the developing nervous system. In addition to its developmental role, neurotrophins are involved in modulation of neuronal plasticity and synaptic functions in the adult central nervous system. The neurotrophins brain-derived neurotrophic factor (BDNF) and NGF are synthesized and secreted by neurons of the hippocampus, via both the constitutive and the regulated pathways. The synthesis of these neurotrophins is found to be regulated by neuronal activity, and various neurotransmitters induce their secretion from neurons. We previously showed that exogenous NGF can modulate GABAergic synaptic transmission in cholinergic neurons of the medial septum; and that NGF can potentially be secreted in the medial septum from hippocamposeptal projections. We hypothesize that NGF secretion from hippocamposeptal axons is activity-dependent, and that this can place it "in the right place at the right time" to regulate neuronal plasticity. In this study, we used a virus-encoded NGF tagged with the pH-sensitive green fluorescent protein super-ecliptic pHluorin (FU-NGF-SEP) in cultured hippocampal neurons to image in real-time the activity-dependent secretion of NGF. pHluorin-tagged proteins are generally quenched in secertory vesicles and unquenched when exposed to extracellular saline, making it an ideal reagent for live imaging of vesicle exocytosis. Using this approach, we have begun to address some unresolved issues regarding NGF secretion from neurons, namely, the time-course, compartment, and kinetics of release events. Under high extracellular potassium stimulation, we observed an increase in the amplitude but not the frequency of NGF-SEP unquenching, which correspond to the opening of fusion pores of NGF-SEP-containing vesicles. Under electrical stimulation, there was an additional trend of increase in event frequency. These "fusion pore opening" events displayed two distinct kinds of decay kinetics unaffected by stimulation. Ongoing studies continue to probe the potential difference in NGF secretion induced by high K+ or electrical stimulation and to confirm the relationship between "fusion pore opening" events and NGF release from neurons.

This study was supported by RO1MH69826 and RO1AA014698

14. Late Onset Rasmussen's Encephalitis: A Report of 4 Cases
Alendia Hartshorn MD Charles Guardia III MD, Vijay Thadani MD PhD, Gregory Holmes MD, Barbara Jobst MD
Department of Neurology, Geisel School of Medicine at Dartmouth

Rationale: Rasmussen's encephalitis (RE) is a rare, progressive form of chronic encephalitis characterized by seizures and hemiparesis. About 10% of cases are late onset, typically occurring in adolescence or early adulthood. Symptoms are often milder with slower progression. We present four cases of late onset RE, with symptoms beginning at age 13 to 23.

Methods: Information was gathered by chart review and included age of symptom onset, initial presenting complaint, MRI results, EEG findings, age of diagnosis, and treatment.

Results: Mean onset of symptoms was 18.3 years (range 13-23). In three cases, seizure was the presenting complaint. In one patient hemiparesis was followed by seizures in one year. Two out of four patients experienced epilepsia partialis continua during the course of illness. In two cases the initial brain MRI showed inflammatory changes and atrophy. The other two cases had initially normal MRI scans and developed hemi-atrophy and diffuse unilateral T2 prolongation consistent with inflammation (16 years from onset of symptoms in both cases). All had EEG findings consistent with partial onset epilepsy. Mean age of diagnosis was 26.5 years (range 20-31) and average time from symptom onset to diagnosis was 8.8 years (range 0-16). Treatment included intravenous immunoglobulin (IVIg) and/or corticosteroids in all four patients. One of the four patients in our report progressed rapidly and was diagnosed in the first year of symptom onset. This patient is currently undergoing treatment with rituximab. To date, none required hemispherectomy.

Conclusions: Late onset RE can present a diagnostic challenge, especially early in the disease. The initial MRI may be normal. Seizures may be suggestive of a partial onset epilepsy. As the disease progresses over decades, the diagnosis is established. The impact of immunosuppressive therapy in RE still needs to be determined in larger studies as compared to the natural course of the disease.

15. Attention deficit caused by early life interictal spikes is improved with ACTH
Amanda E. Hernan, Abigail Alexander, Kyle R. Jenks, Jeremy Barry, Pierre-Pascal Lenck-Santini, Elena Isaeva, Gregory L. Holmes, Rod C. Scott
Department of Neurology, Geisel School of Medicine at Dartmouth

There is a well-described association between childhood epilepsy and pervasive cognitive and behavioral deficits including working memory impairments, ADHD and autism spectrum disorder. However, the precise role of epileptiform discharges in these deficits remains unclear. In order to understand the relationship between frequent epileptic discharges during the neurodevelopmental period and cognition later in life, we developed a model of frequent focal interictal spikes (IIS). Postnatal day (p) 21 rat pups received intracortical injections of bicuculline methiodine into the prefrontal cortex (PFC) whilst EEG was continuously recorded. Within seconds of injection, focal spikes were recorded at the injection site. Injections were repeated in order to achieve 5 days of IIS. Short-term plasticity (STP), behavioral outcomes and therapeutic impact of adrenocorticotrophic hormone (ACTH) were studied. IIS resulted in a significant increase in STP bilaterally in the PFC. In a delayed non-match-to-sample task IIS rats showed marked inattentiveness without deficits in working memory. Rats also demonstrated deficits in sociability. The attention deficits were partially ameliorated by ACTH, despite not altering IIS frequency. We conclude that early-life focal IIS in the PFC have long-term consequences for cognition and behavior at a time when IIS are no longer present. Focal IIS during development can disrupt neural networks, lead to long-term deficits and thus may have important implications in attention deficit disorder and autism. Some of the consequences of IIS may be reduced with pharmacological treatment.

This work was supported by an Investigator-Initiated Grant from Questcor Pharmaceuticals awarded to AEH and GLH. 1R01NS073083 (awarded to GLH), Emmory R. Shapses Research Fund (GLH), R01NS075249 (RCS) and R01NS076763 (PPLS). RCS is funded by Great Ormond Street Children's Charity. EI is funded by State Foundation of Fundamental Research of Ukraine F46.2/001.

16. Impact of valproic acid on cognition.
Adam Jellett, Kyle Jenks, Ali Titiz, Amanda Hernan, Sean Flynn, Rod Scott
Department of Neurology, Geisel School of Medicine

Valproic acid (VPA) is a broad-spectrum anti-seizure drug widely used in childhood epilepsy to control seizure activity. Evidence has suggested that VPA is associated with cognitive deficits in pediatric patients with epilepsy. To address this issue, we investigated the cognitive impact of VPA on rats that received flurothyl-induced early-life seizures. The rats experienced one seizure a day from postnatal day 12-36 and were injected either with VPA (250mg/kg i.p) or saline from P26-P36. Spatial cognition was evaluated at P32 using the Morris water maze. VPA-injected rats performed significantly worse in their latency to reach the submerged platform, had slower swimming speeds, performed more rotations, and had longer distances travelled compared to the saline-injected rats during the first three days of trials. These results show that in animals with continuing seizures, those receiving VPA rather than saline exhibit impairments in both motor and cognitive function. This may have relevance to the treatment of children with intractable epilepsy.

This work was supported by: NINDS

17. Depression, seizure type and polytherapy with AED influence subjective memory in women with epilepsy
Barbara Jobst, MD
Neurology Department, Geisel School of Medicine

Rationale: Memory impairment, a common co-morbidity of epilepsy, significantly impacts quality of life, but treatment options are few. Subjective memory complaints do not necessarily correlate with objective neuropsychological impairment. We examined which factors influence subjective memory complaints in a large well documented patient cohort of women with epilepsy (WWE).

Methods: The National Institute of Health Progesterone Trial randomized 294 women, ages 11-46 years, with focal, poorly controlled epilepsy. In 249 patients, baseline data about subjective memory impairment was available as part of the quality of life assessment (QOLIE-31). Seizure frequency, AED type and epilepsy characteristics were well documented for three months in the baseline phase of the trial. Depression and mood was repeatedly measured by the Beck Depression Inventory (BDI II) and Profile of Mood States (POMS) without treatment intervention over three months. Cognitive complaints were correlated to epilepsy characteristics, AEDs, seizure frequency, BDI II, POMS mood states, body mass index (BMI) using linear regression.

Results: Cognitive complaints were highly correlated with depression (p<0.001) on BDI II and all mood state subscales (p<0.001) on the POMS (tension, vigor, depression, anger, fatigue, confusion). Overall 25.4% of patients showed mild depressive symptoms (BDI II >11) and 14.3 % showed clinically significant depression (BDI II>15). Memory complaints also correlated with seizure type and whether the patient was on mono- or polytherapy with AEDs. Patients with secondarily generalized seizures had more significant memory complaints than patients with focal seizures as their main seizure type (p<0.001). Polytherapy increased cognitive complaints (p<0.05). There was no difference in memory complaints whether patients received enzyme-inducing or non-enzyme inducing AEDs. Seizure type, type of AED therapy and depression were independently related to memory complaints in a multiple regression model.

Memory complaints did not correlate with age, BMI, catamenial seizure pattern or average seizure frequency over three months (p>0.05). Side of seizure onset, unilateral or bilateral seizure onset and temporal or extratemporal seizure onset had no impact on subjective memory (p>0.05).

Conclusion: Depression is a major determinant for cognitive complaints in WWE. Among epilepsy related factors, secondarily generalized seizures, as most severe seizure type, and type of AED therapy were independently associated with subjective cognitive dysfunction. Although the relationship is not proven to be causal, the management of depression may be important in the treatment of memory impairment, a frequent comorbidity in WWE.

This work was supported by: Barbara C. Jobst, Cynthia L. Harden, Rodney C. Scott, Kristin M. Fowler, Andrew G. Herzog for the Progesterone Study Group

18. Using voxel-wise functional connectivity analysis to map interictal epileptiform discharges from simultaneous EEG-fMRI data
Barbara C. Jobst, Junjie V. Liu, Terrance M. Darcey, Erik J. Kobylarz
Department of Neurology, DHMC, Geisel School of Medicine

Purpose: We describe a novel method to map the interictal epileptiform discharges (IED) through voxel-wise functional connectivity analysis of the functional magnetic resonance imaging (fMRI) portion of simultaneous electroencephalography (EEG)-fMRI data. This method measures the local synchronization of fMRI signals and, in contrast to conventional methods, does not require modeling of neural activities or hemodynamic response.

Methods: Simultaneous EEG-fMRI was performed on five patients with focal temporal lobe epilepsy and IED events were detected from the EEG portion of data using conventional methods. The fMRI data was subdivided into time segments of 20 seconds in length, then reorganized and randomized into one set of stitched time series containing the IED events and many sets without IED. Local degree centrality (LDC), a metric of functional connectivity, was computed for each brain voxel to summarize its signal correlations to brain voxels within 14 mm of physical distance. This computation was repeated for each set of stitched time series, yielding one whole-brain LDC map for time with the IED events and many maps for time without IED. A statistical score was then computed for each voxel to detect the voxels with significant LDC value differences associated with the IED events. The fMRI data was also processed separately by conventional methods for comparison.

Key findings: In all five patients, focal regions with significant LDC increases during IED were identified, and their locations were concordant with the simultaneous EEG. In contrast, results from conventional methods were less well defined in two patients, and discordant with EEG in one patient. We illustrated scenarios where LDC increased with IED in regions with highly variant IED-evoked fMRI responses, and where LDC remained unchanged in regions with negative IED-evoked fMRI responses.

Significance: The results suggest that voxel-wise functional connectivity analysis of EEG-fMRI data contributes new knowledge about IED not obtained from conventional analysis, and may help improve the sensitivity and specificity in locating the IED.

This work was supported by: Department of Medicine Seed Funding, Dartmouth-Hitchcock Medical Center

19. The influence of memory on preference-based categorical decision-making dynamics in humans
Kanghoon Jung, Ming Meng and Jerald D. Kralik
Department of Psychological and Brain Sciences, Dartmouth College

The ability to choose among abstract concepts and categories is often taken for granted in human decision-making. The value of abstract categories such as genre of music may guide our choices to maximize emotional reward by selecting the most preferred category among the given options. However, we do not yet fully understand the underlying dynamics of categorical decision-making based on preference, and how the dynamics of socio-emotional rewards, such as beautiful faces, may differ from that of primary appetitive rewards, such as food. In addition, it remains unclear how the heterogeneity of choice categories influences the valuation process.

We examined individuals' choice pattern over five hundred repeated choices among four categories in each of three conditions that manipulated the degree of heterogeneity in the choice categories. In condition 1, participants chose to look at pictures among faces, bodies, animals, and objects; in condition 2, among four different occupations; and in condition 3, among four famous male actors. In each trial, choice was followed by a short presentation of a randomly selected representative picture corresponding to the chosen category.

We found that for all conditions there was no significant preference for a specific category or location across subjects; however, there was a significant difference in choice frequency based on category rank, and the specific pattern in the rank distribution was similar across subjects. In addition, we found a similar pattern in the rank distributions across all conditions, indicating that the valuation process compares alternatives by assigning the values for abstract categories in a common currency that enables people to compare qualitatively different options. Interestingly, subjects exhibited perseveration in their choices by displaying systematic deviations from random choices, attesting to the influence of past reward history on the decision. Examining the impact of category heterogeneity on choice dynamics, we found no significant differences in degrees of goal-directed and habit behavior across conditions, suggesting insensitivity to the heterogeneity of the choice categories. This result suggests that the valuation process prior to decision-making may actively weight preferences according to rank, yielding a similar rank distribution regardless of category heterogeneity. Such a mechanism could simplify decision-making, and provide a heuristic to valuate heterogeneous categories. This study provides insight into the underlying goal-directed and habit systems in categorical decision-making and how the interaction of these systems is reflected in choice behavior.

20. Deconstructing Clozapine: Toward medication for alcoholism in schizophrenia
Jibran Y. Khokhar, Ph. D., Jill MacLeod, Ph.D., Amanda Adams and Alan I. Green, M.D.
Department of Psychiatry, Geisel School of Medicine at Dartmouth

Introduction: Alcohol use disorder occurs commonly in patients with schizophrenia (~35%) and dramatically worsens their clinical course. While most antipsychotics do not lessen alcohol use in patients with schizophrenia, the atypical antipsychotic clozpine (CLOZ) does, although the mechanism by which this occurs is unknown. Since CLOZ's toxicity severely restricts its use, understanding its mechanism of action, as tested in this study, may lead to development of new drugs, safer than CLOZ, which could limit alcohol use in this population. We have hypothesized that CLOZ's ability to decrease alcohol drinking in patients with schizophrenia relates to its weak blockade of the dopamine (DA) D2 receptor (D2R) coupled with its potent blockade of the norepinephrine (NE) α2 receptor and its ability to release NE in the brain. CLOZ's ability to modulate glutamatergic signaling may also play a role in its ability to reduce alcohol intake. We have deconstructed the effects of CLOZ, and assessed the effects of CLOZ-like agents, in the Syrian golden hamster – an animal model of alcohol drinking in schizophrenia. Methods: Hamsters were acclimated to alcohol drinking and then treated chronically with medications. Clozapine Deconstructed: Hamsters received vehicle, CLOZ (2-4 mg/kg), raclopride (2 mg/kg) clonidine (0.16 - 0.64 mg/kg), guanfacine (0.01-1.0 mg/kg), m-NBP (0.1-0.25 mg/kg), D-serine (1.35-2.7 g/kg) either alone or in combination with CLOZ. Clozapine Reconstructed: Hamsters received low doses of haloperidol (0.02 mg/kg) and risperidone (0.2 mg/kg) either alone or in combination with desipramine (1-5 mg/kg). Results: Raclopride (potent DA D2/D3R antagonist) and clonidine (non-specific NE α2 receptor agonist) both lessened the ability of CLOZ to suppress alcohol drinking whereas guanfacine (NE α2a receptor agonist) and m-NBP (NE α2c receptor agonist) did not alter CLOZ's effects on alcohol intake. D-Serine (NMDA receptor co-agonist) potentiated the alcohol intake reducing effects of CLOZ. The addition of desipramine (DMI, NE reuptake inhibitor) increased the ability of both haloperidol and risperidone to limit alcohol drinking, more than DMI alone. Conclusions: These data suggest that CLOZ's ability to decrease alcohol drinking depends, in part, on its weak DA D2R blockade, its potent NE α2 receptor antagonism, its NE reuptake antagonism, and, potentially, on its ability to modulate glutamatergic function in the brain. Further study of the mechanism of action of CLOZ will help develop new pharmacotherapeutic agents that can safely limit alcohol use in patients with schizophrenia.

This work was supported in part by National Institute for Alcoholism and Alcohol Abuse (NIAAA) Grant 1R01AA018151-02 (AIG)

21. Epigenetic regulation and its potential role in the Sudden Infant Death Syndrome
Stella Y. Lee, Bryan W. Luikart and Eugene E. Nattie Jr.
Department of Physiology and Neurobiology, Geisel School of Medicine

This work was supported by: P01 HD036379: Nattie, E.E. Project PI; Kinney, H.C. Program Director

22. Handwriting Electromyography as a Tool for Parkinson's Disease Diagnosis
Stephen L. Lee, Michael Linderman, Valery I. Rupasov, Mikhail A. Lebedev, Joseph S. Erlichman, James C. Leiter
Dept of Neuroethics, Norconnect, Inc., Ogdensburg, NY; Dept of Basic Research, Norconnect, Inc., Ogdensburg, NY; Dept of Neurobiol., Duke Univ., Durham, NC; Dept of Biology, St. Lawrence Univ., Canton, NY; Dept of Neurology, Dartmouth Medical School

Objectives: We examined electromyographic (EMG) activity recorded from hand muscles during handwriting in 6 healthy younger subjects, 6 elderly healthy subjects and 7 elderly patients with diagnosed Parkinson's Disease (PD). We tested the hypothesis that temporal interactions between hand muscle groups would deteriorate during handwriting in PD patients.

Methods: Each subject wrote the number '3' approximately 400 times. The ensemble statistics of these handwriting trials was used to evaluate the probability distribution function in the time domain for hand EMG signals. Correlation between EMGs was evaluated using Pearson correlation functions.

Results: Time-dependent correlations of the EMG signals differed between subject groups. Young healthy subjects had the highest correlations and autocorrelations for all EMG signals. The correlations persisted over longer time intervals for the younger normal subjects. The cross-correlations and autocorrelation magnitudes were lower for elderly normal subjects, but their temporal characteristics were unaffected. In elderly subjects with PD, EMG correlations were attenuated the most. Moreover, correlations persisted over shorter time intervals.

Conclusions: Analysis of EMG signals recorded during handwriting may serve as a simple tool to monitor and diagnose PD. The reduction in correlations between muscle groups during handwriting may reflect the general deterioration in the coordination of motor activities, indicative of PD.

This work was supported by: NSF Grant No. IIP-0848523 Amendment No. 006 Proposal No. IIP-1048430

23. Role of peripheral mitogen activated protein kinase phosphatase-3 (MKP-3) at the side of surgical incision in the resolution of postoperative pain in mice.
Brenna Liponis (a), Daniel L. Alvarez (a), Sladjana Skopeldj (a), Madhurima Saha (a), E. Alfonso Romero-Sandoval (a,b)
(a) Geisel School of Medicine at Dartmouth, Department of Anesthesiology, Lebanon, New Hampshire. (b) Presbyterian College School of Pharmacy, Department of Pharmaceutical and Administrative Sciences, Clinton, South Carolina.

Background: MKPs are the main regulators of mitogen–activated protein kinase (MAPK), such as ERK and p38. MKP-3 limits inflammatory processes by preferentially dephosphorylating p-ERK, but also p-38. The clinical relevance of our studies is that MAPKs, such as p38 are part of the pathophysiological mechanisms of acute postoperative and chronic neuropathic pain in humans. We have observed that following paw incision (a model of postoperative pain) in MKP-3 KO mice, p-ERK (but not p-p38) is persistently expressed in skin surrounding the surgical incision. This finding was observed in parallel to persistent pain-related behaviors in these mice. We hypothesize that this persistent peripheral p-ERK expression due to a lack of MKP-3 activity/expression is responsible for the development of persistent postoperative pain.

Methods : Wild type (WT, B6129SF2/J) and MKP-3 knockout (KO, B6129X1-Dusp6 TM1Jmol/J) male and female mice (50-60 days old) underwent unilateral plantar hind paw incision (post-operative pain model). Mechanical allodynia was assessed using von Frey filaments and up-down statistical method, measuring 50% paw withdrawal threshold. Paw inflammation was studied by measuring the paw perimeter before and after surgery. Skin ERK phosphorylation was measured by Western blot analyses and using total ERK and beta actin as the loading control. Cell infiltration at the surgical incision was determined using immunohistochemistry. Peripheral pharmacological p-ERK inhibition was also performed in MKP-3 knockout mice.

Results: Following paw incision, both WT and MKP-3 KO groups displayed mechanical allodynia (pain-related behavior), which resolved normally by postoperative day 7 in WT mice, but persisted for up to 12 days after surgery in MKP-3 KO mice. Paw incision induced paw inflammation. Even though paw inflammation resolved in both groups by postoperative day 12, paw inflammation resolution was delayed in MKP-3 KO vs. WT mice. Cell infiltration was enhanced on postoperative day 1-7 and returned to basal levels at postoperative day 12 in WT mice. A similar dynamic was observed in incision cell infiltrate in MKP-3 KO mice. However, MKP-3 KO mice displayed higher numbers of infiltrating cells than in WT mice at base line and each time studied. Based on our observations of persistent expression of p-ERK in MKP-3 KO mice, we administered PD035901 (25 nmol, 5 ul, a MEK inhibitor that block the phosphorylation of ERK) into the incised paw, next to the surgical incision on postoperative day 12. This intervention reduced p-ERK expression in the incised paw skin, and blocked postoperative-induced hypersensitivity in MKP-3 KO mice.

Conclusions: Our data demonstrate that peripheral MKP-3 is pivotal for the normal resolution of acute postoperative allodynia, presumably by regulating peripheral p-ERK. Our results suggest that a disruption in MKP-3 signaling leads to persistent postoperative pain.

Future Directions: To determine the levels of peripheral MKP-3 and p-ERK in a model of persistent postoperative pain, and promote the induction of MKP-3 expression using nanotechnology and gene therapy to prevent the development of persistent postoperative pain.

This work was supported by: James O. Freedman Presidential Scholarship (BL); Trygve E. Myhren 1958 Tuck 1959 Undergraduate Research Fund (DA); Rita Allen Foundation & American Pain Society 2011 Pain grant (AR-S), and Hitchcock Foundation (AR-S).

24. Are Neuronal Representations of Fearful Scenes in the Ventral Visual Pathway Size-invariant?
Zhengang Lu, Bingbing Guo, Ming Meng
Department of Psychological and Brain Sciences, Dartmouth College

Visual processing of fearful scenes provides important cues for human to avoid potential dangers. Using functional Magnetic Resonance Imaging (fMRI), we demonstrated that brain activation in fusiform gyrus (FG) and lateral occipital complex (LOC) correlates with the levels of fearfulness of the scenes (Guo et al., 2012, SFN). However, if this activity represents affective perception of the fearful scenes, it should be invariant to manipulations of low-level stimulus features as long as the manipulation would not alter perceived fearfulness of the scenes. In a factorial design we used fMRI to measure brain activation corresponding to participants observing natural scene pictures with 5 levels of fearfulness x 2 image sizes (small: 200x200 pixels, large: 600x600 pixels). Participants viewed each fearful scene for 2s in a random order and were asked to judge the scene presented was scary or not. By using intact fearful scenes versus scrambled scenes, regions of interests (ROIs) were functionally localized in FG and LOC in each participant with separate scan runs and different stimuli set that was not used in the main experimental runs. Consistent with previous findings, a GLM analysis indicated that there is a linear relationship between brain activation in LOC and FG with the levels of fearfulness. More interestingly, large fearful scenes led to greater MR activity in both LOC and FG than small fearful scenes. Apparently, low-level visual features, such as image size, would actually influence the representations of fearful scenes in LOC and FG. These results may question the thought of functional roles of these brain regions.

This work was supported by NARSAD Young Investigate Award to Ming Meng

25. Morphine-potentiated blood-brain barrier dysfunction in the LP-BM5 murine AIDS model
Virginia D McLane, Ling Cao, Colin L Willis
College of Osteopathic Medicine, University of New England, Biddeford, ME; Graduate School of Biomedical Sciences and Engineering, University of Maine, Orono, ME

Human immunodeficiency virus (HIV)-1 infection can induce neurocognitive disorders ranging from mild cognitive deficits to dementia. Opioid abuse accelerates the onset of these deficits and increases central nervous system (CNS) viral load in HIV-1 patients. Under normal conditions, the blood-brain barrier (BBB) restricts the passage of blood-borne compounds such as the HIV-1 virion from the vasculature into the CNS. Proinflammatory cytokines (tumor necrosis factor-α, interleukin-1β, RANTES, etc.), matrix metalloproteases, and reactive oxygen species modulate BBB permeability, allowing increased access of peripheral virions and infected cells to the CNS. Opioids such as morphine facilitate the glial inflammatory response to HIV proteins, thus increasing expression of cytokines such as RANTES and IL-6.

We hypothesize that morphine potentiates blood-brain barrier breakdown and subsequent viral entry through enhancement of the proinflammatory response during HIV-1 infection. To test this, we have applied neurochemical and pharmacological strategies to a well-established LP-BM5 murine acquired immunodeficiency syndrome (MAIDS) model. Following chronic morphine administration, we assessed changes in cytokine expression, CNS viral load, and BBB permeability of LP-BM5-infected mice through the use of Luminex assay, quantitative real-time PCR and immunohistochemistry. Surprisingly, we observed a significant decrease in CNS RANTES expression following morphine treatment in infected mice, while TNF-α and IL-1β did not change. Nonetheless, BBB dysfunction persisted in morphine-treated, LP-BM5-infected animals. Our results indicate that elevation of RANTES correlates with LP-BM5-induced BBB dysfunction. However, chronic morphine treatment abolished this response, suggesting there may be a novel pathway for morphine-potentiated blood-brain barrier dysfunction in HIV infection.

26. Methotrexate Toxicity presenting as Foix-Chavany-Marie Syndrome, Case report
Barbara L. Nye MD, Jonathan Marehbian MD and Timothy Lukovits MD
DHMC, Department of Neurology, Geisel School of Medicine at Dartmouth

The setting of acute onset of neurological symptoms, stroke is high in the differential diagnosis. In patients that have been recently treated with chemotherapeutic agents, specifically methotrexate; methotrexate-induced leukoencephalopathy should be considered in the differential diagnosis. CT of the head is usually normal, where MRI of the brain is revealing of DWI hyperintensity and ADC map correlate but does not respect the vascular territories that would be expected in an ischemic event. Both the neurological symptoms and the DWI abnormalities have been reported to resolve within hours to days. We present a case of methotrexate-induced leukoencephalopathy presenting as Foix-Chavany-Marie Syndrome and a 24-year-old male recently treated with methotrexate for his acute lymphocytic leukemia.

27. Sex-Specific Effects of Anabolic Androgenic Steroids and Interactions with Ethanol in the Expression of Anxiety-Like Behavior
Marie M. Onakomaiya, Joseph G. Oberlander, Donna M. Porter and Leslie P. Henderson
Department of Physiology and Neurobiology, Geisel School of Medicine

Anabolic androgenic steroids (AAS) are synthetic derivatives of testosterone taken illicitly by adolescents and adults of both sexes to improve athletic performance and body image. Chronic AAS exposure is reported to produce adverse behavioral effects, most notably on aggression, anxiety and reproductive behaviors, in both human subjects and in animal models. Our data indicate that the ability of chronic AAS to alter the expression of anxiety-like behaviors differs significantly in male versus female mice. Specifically, chronic exposure throughout adolescence to a mixture of three commonly used AAS augments generalized anxiety-like behaviors in female mice as measured by the acoustic startle response (ASR) and on the elevated plus maze. This behavioral outcome arises from increased levels of corticotropin releasing factor (CRF) and CRF-dependent changes in neural transmission in the extended amygdala of females. Surprisingly, chronic exposure of male mice to AAS throughout adolescence does not significantly enhance generalized anxiety, nor does this treatment significantly alter CRF levels in the extended amygdala. These results suggest that sex-specific differences in the effects of AAS on the expression of anxiety may reflect fundamental differences in CRF-mediated signaling in the extended amygdala in the male versus female brain.

Human studies have shown a significant covariance of AAS and alcohol use, and both drugs modulate the expression of anxiety via CRF-dependent mechanisms in the extended amygdala. To ascertain if sex-specific differences were also evident in the interactions of AAS and alcohol, we assessed ethanol consumption, anxiety-like behaviors, and CRF levels in male and female mice. Female mice exposed to AAS consumed less ethanol at all tested concentrations (3% to 15%) and had a lower preference for ethanol at the higher concentrations (10% to 15%), suggesting a significant interaction between these drugs in females. Neither ethanol consumption nor preference was affected by AAS exposure in male mice. Chronic ethanol consumption significantly decreased ASR amplitudes, consistent with the reported anxiolytic actions of alcohol, but with no significant difference between male and female mice. Similarly, chronic exposure to ethanol modulated CRF levels in the extended amygdala by decreasing CRF peptide in the bed nucleus of the stria terminalis and increasing CRF mRNA in the central amygdala, in both males and females. These data indicate that chronic ethanol consumption lowers anxiety in both sexes, potentially through CRF-mediated activity and, thereby, negates the sex-specific differences in anxiety imposed by AAS alone. Our data also suggest that in female but not male mice, a comparable reduction in the expression of anxiety may be achieved by lower alcohol consumption in AAS-treated versus control mice.

Funding was provided by NIH grant R01-DA14137

28. Placental Serotonin receptor HTR2A Methylation is associated with Infant Neurobehavioral Outcomes
Alison G. Paquette, Corina Lesseur, David Armstrong, Devin Koestler, Allison Appleton, Barry M. Lester, Carmen Marsit
Department of Pharmacology and Toxicology, Geisel School of Medicine at Dartmouth

Serotonergic tone modulates neuronal developmental events including cell division, neuronal migration, and cell differentiation. Serotonin is synthesized within the placenta during crucial developmental periods and stimulation of the placental serotonin receptor HTR2A causes placental cell growth and division. The genes involved in the serotonin response pathway are targets of epigenetic changes, particularly DNA methylation. Maternal and environmental factors have been associated with variation in methylation of other genes as well as in neurobehavioral development. This study analyzed placental promoter methylation of the serotonin receptor, HTR2A, and examined the relationships between this epigenetic variation and neurodevelopmental outcomes in a human population. Participants were infants (N=444) enrolled in the Rhode Island Child Health Study, an ongoing, healthy infant birth cohort in Providence, Rhode Island. Placental tissue, extensive maternal and infant clinical characteristics and exposure histories were collected, and infants are assessed using the NICU Network Neurobehavioral Scales (NNNS). Genotypes for SNP rs6311 and HTR2A promoter methylation was analyzed through quantitative bisulfite pyrosequencing . The HTR2A promoter region showed considerable variability within the studied population, and methylation was significantly higher (P<0.05) in males and was marginally higher in infants who mothers smoked during pregnancy, but was not associated with genotype of SNP rs6311. After controlling for confounding variables, HTR2A methylation was negatively associated with infant quality of movement (P=0.05), and positively associated with infant attention (P=0.00013), and smoking appeared to modify this relationship. These results suggest that methylation of the HTR2A gene can be environmentally modulated and plays an important role in infant neurodevelopment assessed through NNNS. Further research is needed to define the role of the HTR2A receptor within the placenta and the broader role of the placental serotonin pathways in infant neurodevelopment.

This work was supported by NIH-NIMH R01MH094609, NIH-NIGMS P20GM103537, NIH-NCI P30CA23108

29. Single unit recordings during virtual navigation tasks in patients with epilepsy
Ashlee A. Robbins, Ali S. Titiz, Rod C. Scott, Pierre-Pascal Lenck-Santini, Barbara Jobst, Gregory L. Holmes
Department of Neurology, Geisel School of Medicine at Dartmouth

Spatial navigation tasks are often used in experimental neuroscience to evaluate the mechanisms of learning and memory. These tasks allow for insight into alterations in episodic memory that occur in the pathological brain. The Morris Water Maze tests spatial navigation by training rodents to find a hidden platform in a tank of opaque water. Animals must use spatial cues placed around the tank in order to locate the platform. Animal models of epilepsy and seizures demonstrate significant impairments in this task. In the present study, we are investigating if patients with epilepsy demonstrate similar deficits in spatial navigation by utilizing a using a virtual Morris water-maze (vMWM) task that we developed using the "Source Engine" (Valve™). A coin chasing task was also developed as a correlate of pellet chasing in rodents. This task was designed to encourage patients to spatially sample a virtual environment in order to evaluate if recorded cells may respond to a given place field. Similar to studies in animals we show that epilepsy patients display a significantly reduced performance (be more specific about what the performance is) in the vMWM when compared to controls. We hypothesized that this spatial navigation deficit may be due to impairments in single cell firing patterns in the hippocampus or surrounding structures. This study is characterizing single unit activity recorded from patients while performing both coin chasing and vMWM tasks.

This work was supported by NIH (R01-NS074450)

30. Multimodal MRI performance comparison between 1.5T and 3.0T in recurrent GBM
Lara J. Ronan, MD; Thomas Hampton, PhD; Clifford Eskey, MD; Camilo Fadul,MD
Department of Neurology, Department of Radiology, DHMC

Glioblastoma multiforme is the most common primary brain tumor. CE MRI is gold standard to determine response to treatment/tumor recurrence. We hypothesized that multimodal MR techniques providing tissue signatures obtained at 3T will be more accurate than 1.5T to characterize tumor recurrence.

Materials and Methods: We prospectively acquired multi-parametric MR variables from GBM patients with pathologically confirmed recurrence. We compared the values of signatures acquired at 1.5T and 3T, to evaluate the predictive strength with the differing MR machines. Correlations between MRS ratios Cho/Cr,NAA/Cr,Lip/Cr, total metabolites T-NAA and T-Cho, ADC ratio and CBV were determined.

Results: The confidence intervals for mean ADC, CBV and MRS were similar with both machines. There was poor correlation between metabolite variables on either 1.5T or 3.0T MRI.CBV shows a trend towards higher accuracy with the 3.0T MRI.

Conclusion: We were unable to discern a clear benefit to the use of 3.0 T MRI in the tissue characterization using ADC ratio and MRS. over the standard 1.5 T machine in common clinical use. A trend towards better accuracy with the 3.0 T MRI was seen for CBV. A larger sample may determine if statistically significant.

Support: Norris Cotton cancer Center developmental Funds 2009-2011

31. Role of the Innate Antiviral Response of Trigeminal Ganglia Neurons in control of Herpes Simplex Virus Replication
Pamela Rosato and David Leib
Microbiology and Immunology, Geisel School of Medicine

Herpes Simplex virus type 1 (HSV-1) is a persistent pathogen that cycles between an acute/lytic infection and a latent state within sensory neurons of the trigeminal ganglia (TG). The factors needed for control of latency and thus prevention of disease pathology remain largely unknown. Mouse and human studies show the importance of the innate antiviral response for controlling HSV-1 replication and disease, however, little is known about this response in neurons. We hypothesize that innate immunity of TG neurons is a critical factor in the control of acute HSV-1 replication and the establishment and maintenance latency. Using cultured trigeminal ganglion (TG) neurons derived from adult mice, we measured HSV-1 replication in wild-type (WT), and STAT1-deficient neurons, a critical IFN signaling molecule, in the presence and absence of exogenous IFNβ. Surprisingly, we saw no difference in HSV-1 replication between neurons lacking IFN signaling and WT cells, regardless of addition of exogenous IFNβ. Moreover, vesicular stomatitis virus (VSV), a highly IFN-sensitive virus, also replicated to high titers in both WT and STAT1-deficient neurons. Upon IFNβ pre-treatment, however, we observed a 1000-fold decrease in VSV replication in WT neurons, demonstrating that despite the failure of intrinsic IFN responses to control virus infection, these neurons are highly responsive to IFN. Infection of TG neurons with a more IFN-sensitive HSV-1 strain lacking γ34.5, showed 100-fold reduction in viral replication, and this reduction was dependent on the presence of Stat1 and exogenous IFNβ. These data show that mature TG neurons are capable of mounting an effective antiviral response upon exposure to exogenous IFNβ but that HSV-1 can combat this response through γ34.5. Moreover, our data indicate that the intrinsic IFN response of TG neurons is incapable of controlling virus replication. Ongoing experiments are examining the implications of these results with respect to the establishment and maintenance of HSV-1 latency.

This work was supported by: NIH/NEI T32AI007519, RO1EY09083

32. The neural correlates of disorientation in head direction cells
Michael E Shinder and Jeffrey S Taube
Psych and Brain Sciences, Dartmouth College

Head direction (HD) cells in the limbic system are active when the animal is facing a particular direction in the environment. Further, the HD signal correlates with the animal's perceived orientation in that environment. The accuracy of the HD system output requires continuous and accurate updating by head movement signals from the vestibular system. This dependency implies that when the vestibular system fails, HD cells will lose their heading representation. Current experiments to determine neural correlates of disorientation in HD cells exploited the sensory detection limitations of the vestibular sensory apparatus. The vestibular hair cells detect head acceleration as inertial forces bend their cilia. Head-restrained rats were rotated at constant velocity to produce continually changing head direction in the absence of head acceleration. While recording in the anterodorsal thalamus, rats underwent constant velocity rotations in the light and dark, and in both directions. Each rotation was analyzed separately, and individual conditions were repeated four times to create average responses. Initially, the directional responses were maintained for 3 cycles of 180°/sec rotation (6 sec) ipsilateral to the recorded HD cell (i.e. rightward head rotation while recording in the right thalamus). In the light and dark, the directionally tuned response produced a Rayleigh value of 0.9, had a peak firing rate (PFR) that was 90% of the first cycle response, and displayed cycle-to-cycle drifts of the preferred firing direction (PFD) of about 20° (21 cells recorded in the dark, 12 in the light). However, contralateral rotational responses differed in the light and dark. While HD responses in the light were the same as those during ipsiversive rotation, HD responses in the dark had early signs of deteriorating directional tuning with a PFR at 80%, Rayleigh values at 0.8, and PFD shifts of 45° - twice the shift seen in other conditions. Over time all HD cell responses displayed deteriorated directional tuning. After 12 sec of rotation, ipsiversive rotation in the light and dark, and contraversive rotation in the light continued to behave similarly. The PFR fell to below 50% of the initial value, the Rayleigh value was about 0.6, and cycle-to-cycle PFD shifts were ~40°. Contraversive rotation in the dark also continued to display larger losses in tuning with a PFR at 40%, Rayleigh r at 0.5, and cycle-to-cycle PFD shifts of ~60°. Continual rotation progressively reduced all direction-specific firing and accuracy during disorienting spins. Cell firing after this stage was characterized by low random firing with occasional short bursts. Vision improved directional tuning, but only for the HD response when rotation stimulated the contralateral vestibular pathway. Disorientation can be represented as a breakdown of the integrity of the HD system, and exposes neural mechanisms that contribute to normal HD accuracy.

This work was supported by: NIH DC009318

33. A Novel Approach for the Treatment of Episodic Ataxia Type 2 using Zonisamide
Shital Shah, DO; Stephen Lee, MD
Department of Neurology, Geisel School of Medicine

Introduction: Episodic Ataxia Type 2 is a rare autosomal dominant disorder characterized by episodes of ataxia and vertigo. It occurs as a result of mutations in the CACNA1A gene. Treatment is limited to acetazolamide and 4-aminopyridine.

Case Presentation: A 27-year-old woman with Episodic Ataxia Type 2 with two to three episodes per week did not tolerate acetazolamide due to a drug rash. Zonisamide was prescribed due to its carbonic anhydrase activity with successful results.

Conclusion: The treatment for Episodic Ataxia Type 2 is limited to acetazolamide and more recently 4-aminopyridine. Zonisamide was prescribed in this patient because of its similar mechanism of action to acetazolamide via carbonic anhydrase inhibition. Given the positive result in this patient, further studies investigating the use of zonisamide should be considered to provide another treatment approach for those intolerant to acetazolamide.

34. Mitogen activated protein kinase phosphatase-3 (MKP-3) drives the resolution of postoperative allodynia in mice by regulating spinal p-p38
Sladjana Skopelja, Madhurima Saha, Elena Martinez, E. Alfonso Romero-Sandoval
Geisel School of Medicine at Dartmouth, Department of Anesthesiology

Background: The mechanisms that drive normal resolution of acute postoperative pain are not completely understood. We postulate that a disruption of these physiological processes underlies the transition from acute to chronic post-surgical pain. Spinal mitogen activated protein kinases (MAPKs), such as p38 and extracellular signal-regulated kinases (ERKs), are pivotal in acute and chronic pain models in rodents and in humans. We hypothesize that a dysregulation of a major MAPKs regulator, MAPK phosphatase (MKP)-3, drives the transition from acute to persistent postoperative pain.

Methods : Unilateral plantar hindpaw incision (post-operative pain model) was performed on wild type (WT, B6129SF2/J) and MKP-3 knockout (KO, B6129X1-Dusp6 TM1Jmol/J) male and female (50-60 days old) mice. Mechanical allodynia was assessed using von Frey filaments and up-down statistical method measuring 50% paw withdrawal threshold. Spinal and peripheral p38 phosphorylation, p-ERK phosphorylation, and MKP-3 expression were measured by Western blot analyses, using beta actin as the loading control. Pharmacological p-p38 inhibition was also performed in MKP-3 knockout mice.

Results: Mechanical allodynia that develops in both WT and MKP-3 KO mice after paw incision surgery resolved normally by postoperative day 7 in WT mice, while persisting 12 days after surgery in MKP-3 KO mice. In WT mice, spinal p-p38 peaked at postoperative day 5 and returned to normal levels by days 7-12 after surgery, in accordance with changes in spinal MKP-3, which was enhanced from days 5-12 after surgery. Spinal cord p-p38 (ipsilateral to paw incision) increased significantly at postoperative day 5 and remained elevated up to day 12 after paw incision in MKP-3 KO mice. At the periphery (i.e. paw incision site) p-p38 levels in both WT and MKP-3 KO mice remained elevated until postsurgical day 7 and subsided at day 12 after surgery. While MKP-3 levels in WT mice increased at days 7 and 12, corresponding to a reduction in p-p38 expression, lack of MKP-3 in KO mice appeared to correspond to persistently high levels of p-ERK instead of p-p38, at the periphery. Pharmacological inhibition of spinal p-p38 at postoperative day 12 reduced postoperative-induced hypersensitivity in MKP-3 KO mice.

Conclusions: Our data demonstrate that MKP-3 drives the resolution of acute postoperative allodynia by regulating spinal rather than peripheral p-p38 levels, and possibly via peripheral p-ERK regulation. Therefore, our study suggests that MKP-3 signaling is pivotal in the development of persistent postoperative pain.

Future Directions: To develop plausible mechanisms of MKP-3 induction, in perspective to the temporal relationship between p-p38 and MKP-3 levels, as means of preventing the development of persistent postoperative pain.

This work was supported by: Rita Allen Foundation & American Pain Society 2011; Pain grant (AR-S), and Hitchcock Foundation (AR-S); Ph.D. Program in Experimental and Molecular Medicine, Dartmouth College.

35. Maternal ethanol consumption transiently increases Cajal-Retzius cells during corticogenesis
Alexander G.J. Skorput, Danny Wong, Hermes H. Yeh
Dept. Physiology & Neurobiology, Geisel School of Medicine, Lebanon, NH 03756

Cajal-Retzius (CR) cells are among the earliest generated neurons in the embryonic cerebral cortex. They synthesize and secrete a number of factors that regulate radial and tangential migration of immature cortical neurons. Cajal-Retzius cells are depolarized by GABA, which has also been shown to influence neuronal migration. Abnormal migration of cortical neurons leads to cortical malformations and cognitive deficits, including Fetal Alcohol Spectrum Disorder (FASD). Here we hypothesize that ethanol exerts its effects on cortical migration in part by altering CR cell disposition. We report that, in the neonatal offspring, moderate maternal ethanol consumption increases the number of CR cells and diminishes their responsiveness to GABA.

Time pregnant Ebf2-GFP dams (GENSAT) were fed a liquid diet with or without 2% ethanol beginning on E9.5-E10.5, corresponding to the start of CR cell birth. The maternal blood-alcohol level (BAL) averaged 24+ 6 mg/dL, and this was comparable to the BAL in the embryos through birth (P0). Beyond P0, BAL became undetectable in the offspring, despite continued maternal ethanol consumption. GFP+ CR cells in the marginal zone of the prefrontal cortex (PFC) and somatosensory cortex (SSC) were counted in 30µm fixed-frozen coronal sections. In both cortical regions, ethanol-exposed neonates (P0, P2) exhibited ~33% more CR cells relative to controls. This increase in CR cell number was transient, insofar as it was no longer apparent by P4. Interestingly, at P6, counts of CR cells revealed a decrease in the PFC, but not in the SSC, of the ethanol-exposed group compared to controls, suggesting a cortical region-selective effect. Patch clamp analysis of CR cells revealed a reduced apparent potency of GABA in ethanol-exposed vs. control pups at P3 that was absent at P8.

Our results to date indicated that gestational exposure to ethanol increases the number of CR cells and alters their pharmacological properties in the neonatal cortex. These alterations in CR cell fate/function may be an important early contributor to the neurodevelopmental abnormalities in FASD. Ongoing studies are extending our initial observations to examine aspects of migration and circuit formation associated with CR cells in the developing cortex.

Funding was provided by PHS RO1 MH069826

36. Anti- N-methyl-D-aspartate receptor encephalitis: a patient with refractory illness after 25 months of intensive immunotherapy
Alissa A. Thomas, Paula Rauschkolb, Nuria Gresa-Arribas, Alan Schned, Josep Dalmau, Camilo E. Fadul
Departments of Neurology/Neuro-Oncology, Geisel School of Medicine

BACKGROUND: N-methyl-D-aspartate receptor (NMDAR) antibody encephalitis is an autoimmune encephalitis that can be paraneoplastic and usually responds to treatment. It is quickly becoming the most common paraneoplastic encephalitis.

CASE REPORT: We present a case of a 39 year old woman who developed psychiatric symptoms that progressed to encephalopathy, seizures, autonomic instability, and hyperkinetic movements. The patient was found to have an ovarian teratoma and serum and cerebrospinal fluid NMDAR antibodies. Despite resection of the teratoma and treatment with immunosuppressive therapy, the patient progressed to a minimally conscious state. She was supported medically in our institution for 25 months. During her hospitalization she was treated with multiple immunosuppressive agents. With each treatment we analyzed the serum and cerebrospinal fluid for NMDAR antibodies. While there was some initial reduction in the serum antibodies, the spinal fluid antibodies remained persistently elevated. The patient did not have any clinical improvement and eventually died after the family decided to withdraw care.

CONCLUSIONS: As far as we know, this case represents the longest active treatment without improvement of a patient with anti-NMDAR encephalitis. The patient had persistently high cerebrospinal fluid and serum antibody titers, which may be of prognostic significance.

This work was supported in part by grants from the National Institutes of Health RO1NS077851, Fundació la Marató TV3, and Fondo de Investigaciones Sanitarias (FIS, PI11/01780) (Josep Dalmau).

37. Diagnosis of Non-Epileptic Seizures at First Encounter: Does Gender Matter?
Alissa A. Thomas, MD, Julie Preston, Rod Scott, PhD, Krzysztof Bujarski, MD
Department of Neurology, Geisel School of Medicine

Rationale: Non-epileptic seizures (NES) are paroxysmal events of altered behavior that outwardly resemble epilepsy but are caused by psychiatric disease. Diagnosis of suspected NES can be made in the outpatient clinic prior to video EEG monitoring by identification of specific NES risk factors and specific elements of seizure semiology from the clinical history. Since psychiatric disease often presents differently in women and men, we questioned whether gender-specific differences exist in NES risk factors and semiology. Such differences can be used to improve the outpatient diagnosis of suspected NES.

Methods: Male and female patients were identified from a video EEG monitoring database. Seizure semiology for each patient was analyzed de novo and categorized into one of three established semiology clusters. In addition, patients' medical records were reviewed and data on possible risk factors was obtained.

Results: 86 patients were included in the analysis (59 women, 27 men). Among female patients, seizure semiology was classified as major motor in 39%, minor motor in 22%, and non-motor in 42%. Among male patients, seizure semiology was classified as major motor in 41%, minor motor in 22%, and non-motor in 37%. There were no significant differences between men and women in any of the semiology clusters. Analysis of NES risk factors showed significantly higher rate chronic pain female patients as compared to male.

Conclusions: Our results support the use of the same "semiology criteria" for the outpatient diagnosis of suspected NES in both female and male patients.

38. Ictal and postictal MRI for the localization of seizure onset
George P. Thomas, Jay Liu, Kris A. Bujarski, Erik J. Kobylarz, Vijay M. Thadani, Karen R. Richardson, Barbara C. Jobst
Department of Neurology, Geisel School of Medicine

BACKGROUND-Presurgical localization of seizure onset zone in intractable focal epilepsy frequently relies on ictal SPECT, but the technetium tracer is becoming difficult to acquire. Breakdown of the blood-brain barrier might be a component of seizure physiology (Alvarez, V., P. Maeder et al, 2010), suggesting that gadolinium enhanced MRI might be useful in seizure onset zone localization. We sought to determine the feasibility of ictal contrast-enhanced MRI to localize seizure onset zone.

METHODS-Subjects with intractable focal epilepsy undergoing VEEG monitoring received gadolinium within 30 seconds of seizure onset, followed by MRI (MPRAGE, DWI, FLAIR and T2W) within 2 hours. Each subject also underwent inter-ictal contrast-enhanced MRI at least 24 hours after ictal MRI.

We examined inter-session differences in individuals. Using SPM5, ictal images underwent a 3D affine-only alignment to the inter-ictal images. Next the images were smoothed with a 3mm FWHM Gaussian filter. The ictal images were then subtracted from the inter-ictal images, and the resulting data were visually inspected for focal differences with regard to location of seizure onset based on EEG.

RESULTS-Four subjects completed the study. It was feasible to inject gadolinium ictally and perform MRI within 2 hours of the seizure. We found no focal difference in MRI signal in any sequence between the sessions.

CONCLUSION-Ictal contrast-enhanced MRI does not appear to be useful in localizing seizure focus and is not an alternative to ictal SPECT. Breakdown of the blood brain barrier during single seizures might not be consistently sufficient to lead to changes in MRI imaging.

39. Firing properties and reactivation of hippocampal place cells in rats with epilepsy during sleep
Ali Titiz, Pierre-Pascal Lenck-Santini, Rod C. Scott, Gregory Holmes
Department of Neurology, Geisel School of Medicine

Purpose: Memory consolidation is thought to occur by the reactivation of neural activity during the waking period in the following sleep period. We hypothesize that this process is impaired in the lithium-pilocarpine model of epilepsy in rats.

Method: A cohort of rats (4 controls and 7 epileptics) were tested in the Morris Water Maze task (MWM) and a reaction-to-novelty task (RNT) to study spatial memory. This was also used for Timm staining for mossy fiber sprouting and Cresyl violet staining for the thinning of the cell layers to confirm epileptogenesis. Another cohort (4 controls and 4 epileptics) was trained to run clock-wise in a circular maze for 15 mins (RUN, >20 turns) followed by a rest period for 1 h (POST). We recorded multiunit activity and local EEG in the CA1 layer of the hippocampus, EMG, and the rat's location throughout the experiment.

Results: Rats with epilepsy showed impaired performance in both the MWM and the RNT tasks. Cells recorded from epileptic rats showed increased firing rates in all three states during POST. Place cells recorded from epileptic rats showed lower coherence, higher out of field firing rate, and larger place fields than controls. Real-time analysis of reactivation showed no differences between the groups in the strength and number of replay events as well as the maximum correlation coefficients. As sleep was decompressed to look for reactivation at smaller time scales, epileptic rats were found to consistently have an increased number of reactivation events across multiple decompressions.

Conclusion: In this study, we present the first evidence of the disruption of the reactivation of neuronal networks during sleep in epilepsy. Rats with epilepsy displayed higher number and strength of reactivation events than controls. This effect persisted across multiple time scales, indicating a system-level increase in reactivation.

40. Steroid responsive cervico-medullary lesion: A unique presentation of isolated central nervous system sarcoidosis
Yoshie Umemura, Alissa Thomas, Lara Ronan
Department of Neurology, Geisel School of Medicine at Dartmouth

Sarcoidosis is a systemic, idiopathic, granulomatous disease that affects multiple organs. Neurosarcoidosis is an uncommon variant of this disease, affecting about 10% of patients with systemic sarcoidosis. In less than one percent of sarcoid patients, the disease presents as isolated neurosarcoidosis. It may affect any part of the nervous system, mimicking other neurological diseases, and making diagnosis challenging. Biomarkers are often unreliable, so a high index of clinical suspicion and a therapeutic trial of steroids is necessary to make the diagnosis. Here we present a 59 year old man with history of diabetes who presented with bilateral hand numbness, progressing over 6-7 months to profound truncal and appendicular weakness, numbness, and ataxia. Magnetic resonance imaging revealed a diffuse, invasive cervico-meduallary lesion. After careful exclusion of infectious diseases and malignancy, the patient was challenged with steroids and responded with a dramatic improvement in his symptoms. He was diagnosed with isolated neurosarcoidosis. This case illustrates a rare presentation of a rare disease, including the initial presentation, diagnostic evaluation, and treatment plan.

41. Normal sensitivity to facial identity in the face-selective area in right anterior inferotemporal lobe despite the loss of right fusiform face area
Hua Yang, Tirta Susilo, Bradley Duchaine
Department of Psychological and Brain Sciences, Dartmouth College

Multiple face-selective cortical regions have been identified in humans, but the function of each region and the relationship between them remains unclear. We addressed this issue by examining the effect of a lesion to a posterior region in the face network on the functioning of a more anterior region. Galen is a 30-year-old right-handed male who became prosopagnosic after a surgery to remove a cerebral arteriovenous malformation (AVM) in his right occipito-temporal cortex. A structural scan revealed lesions on the right side extending from the temporal lobe to the occipital lobe, as well as a small part of right cerebellum. A localizer scan showed that Galen's right fusiform face area (FFA) was missing due to the lesion. Other face-selective areas were present including bilateral occipital face area (OFA), bilateral posterior superior temporal sulcus (pSTS), bilateral anterior STS (aSTS), and left FFA. Most importantly for the current study, bilateral regions in Galen's anterior inferotemporal cortex (aIT) also showed a face-selective response. We used fMRI-adaptation to investigate the sensitivity of Galen's aIT to facial identity. On each trial, two different images of the same celebrity or two different age- and sex-matched celebrities were presented. While being scanned, Galen and nine control participants judged whether pairs of images showed the same celebrity, and as expected, Galen's discrimination ability was significantly worse than the controls. The control group showed significant repetition suppression for the same identity pairs in right aIT. Surprisingly, Galen's right aIT showed repetition suppression comparable to that seen in the controls. This finding indicates right aIT can preserve its face-selectivity and continue to represent identity information despite of the loss of the right FFA.

This research is supported by the Hitchcock Foundation. We thank Galen for his interest and participation.