Translational Research
Table of Contents
- Basic and Laboratory Science Initiatives
- The Assessment and Brain Banking Core
- Neurocognitive Heterogeneity in Psychosis: A Dimensional Approach (Katherine Burdick, PhD)
- Genetic and Molecular Determinants of Suicide (Stella Dracheva, PhD)
- Neuronal subtype-specific epigenetic regulation in schizophrenia (Stella Dracheva, PhD)
- Molecular Determinants of Individual Differences in Fear Reactivity and Recovery (Stella Dracheva, PhD)
- Ankyrin-G and the nodes of Ranvier: Mechanisms of disconnectivity in Schizophrenia (Harry Haroutunian, PhD)
- The tripartite neuron, astrocyte, oligodendrocyte unit in Schizophrenia (Harry Haroutunian, PhD)
- Neurofascin and the nodes of Ranvier in schizophrenia (Harry Haroutunian, PhD)
- New Directions in the Genetics of Impulsivity and Aggression (VA MIRECC) (Mercedes Perez-Rodriguez, MD, PhD)
- Borderline Personality Disorder International Genetics Consortium (Mercedes Perez-Rodriguez, MD, PhD)
- Comprehensive assessment of cytokines and NF-κB activation in Schizophrenia Spectrum Disorders (Panagiotis Roussos, MD, PhD)
- An fMRI Study of the Enhancement of Emotion Regulation in Patients with Borderline (Harold Koenigsberg, MD)
- Neuropsychological Assessments (Philip Harvey, PhD)
- Clinical Assessments in the Chronic Psychosis Project (Philip Harvey, PhD; Harry Haroutunian, PhD)
- 5-HT2CR and Suicide (Stella Dracheva, PhD)
- 5-HT2CR and Drug Addiction (Stella Dracheva, PhD)
- Clinical Genetics Research (Jeremy Silverman, PhD)
- Neuroimaging Studies (No PI)
- fMRI of VisuoSpatial Working Memory in Schizotypal Personality Disorder (Harold Koenigsberg, MD, et al)
- A Thalamocentric Approach to the Neuroanatomy of Schizophrenia: A Quantitative Study in Immunocytochemically Identified Thalamocortical Projection Neurons (William Byne, MD, PhD)
- Oligodendrocytes in Severe Mental Illness and Aging (William Byne, MD, PhD)
- Glutamate and Myelin Dysfunction in Elderly Patients with Schizophrenia (Harry Haroutunian, PhD)
- Contribution of Cell Cycle Processes to Myelin Deficits in Schizophrenia (Harry Haroutunian, PhD)
Basic and Laboratory Science Initiatives
The basic science initiatives of the VISN 2 South MIRECC revolve around understanding the neuropsychological and neurobiological factors that contribute to serious mental illness (SMI) in veterans and in the population as a whole. Neuropsychological factors are studied with formal, systematic, and detailed assessments of veterans with SMI at regular intervals, while the centerpiece of the study of neurobiological factors is a well-established Brain Bank. Brain tissues donated to the Brain Bank are fully characterized neuropathologically and are distributed to dozens of VISN 2 South MIRECC and external laboratories performing state-of-the-art neurobiological studies. T he combination of antemortem neuropsychological assessments and postmortem neurobiological studies provides the unprecedented opportunity to relate neuropsychological deficits to their potential neurobiological substrates.Current & Ongoing Projects and Activities Include:
- Continued characterization of glutamine-glutamate-GABA pathway in schizophrenia
- Continued characterization of mRNA and protein expression of ionotropic glutamate receptors and associated transporters and intracellular trafficking molecules in schizophrenia
- Continued study of genome-wide gene expression by microarray to supplement the seventeen brain regions already studied with additional cases and in additional regions
- Continued study of glutamate- and myelin-related gene expression in anatomically defined nuclei within the thalamus and defined cortical and subcortical regions in schizophrenia
- Studies to characterize gene expression in laser assisted microdissections of identified cells in the cortex, hippocampus and thalamus in schizophrenia
- Continued exploration of myelin-associated gene expression in grey vs. white matter throughout the course of human development from less than one through 105 years of age (studies in collaboration with Joel Kleinman)
- Continued efforts to build on recent success to increase autopsy rates at the James J. Peters VA Medical Center
- Continued efforts to build on recent success to obtain brain tissue donations from Suffolk County ME
- Continued development of Brain Bank and associated neuropsychological data warehouse
The Assessment and Brain Banking Core
Brain Bank
The VISN 2 South MIRECC Brain Bank is part of a larger Mental Illness and Alzheimer's Disease Brain Bank directed by V. Haroutunian, Ph.D., and is a joint initiative of the James J. Peters VA Medical Center Psychiatry Service and the Mount Sinai Department of Psychiatry. The MIRECC component of the Brain Bank accepts brain tissue donations from veterans receiving care at the NJ Veterans Health Care Network, VA Hudson Valley Health Care System, and the Northport VAMC. The Brain Bank is supported by multiple grants, including the VISN-3 MIRECC, an NIMH sponsored Mental Illness Clinical Research Center, the Mount Sinai School of Medicine Alzheimer's Disease Research Center, and a Program Project Grant to Study Early Dementia. It currently holds brain tissue specimens from over 1180 cases, many of which are generously donated by families of patients who have participated in neuropsychological assessment and treatment studies. After detailed neuropathological examination, brain tissue specimens are distributed to research laboratories within the James J. Peters VA Medical Center, the Mount Sinai School of Medicine, and over 20 different collaborating laboratories within the United States and abroad. This Brain Bank directly supports the Molecular biology, Neurochemistry and Neuroanatomy basic science projects of the VISN-3 MIRECC.
Neurocognitive Heterogeneity in Psychosis: A Dimensional Approach
Katherine Burdick, PhD
This study aims to identify the clinical and molecular predictors of cognitive dysfunction in psychosis. Converging evidence suggests that individuals with psychosis have neurocognitive deficits that persist even when acute affective/psychotic symptoms are in remission. The evidence further suggests that these neurocognitive deficits impair functioning in social, occupational, and residential settings. To identify the clinical and molecular predictors of cognitive dysfunction, this study incorporates comprehensive clinical and neurocognitive phenotyping and a novel genomic approach capturing common variation across the genome as well as rare structural variation. We are enrolling 300 patients with any psychosis diagnosis. Participants will be paid $150 for completing the project. Ultimately, data derived from this project could serve to 1) elucidate underlying molecular mechanisms of overlap between bipolar disorder and schizophrenia and 2) guide future efforts toward developing novel and effective treatments for these disabling symptoms.Genetic and Molecular Determinants of Suicide
Stella Dracheva, PhD
The study aims to identify biological markers that are associated with high risk for suicide. To date, many conventional genetic association studies have been performed but none have revealed any genetic variants that could be used as reliable predictors of suicide risk. In this study, we propose to use an alternate approach. In particular, our previous studies, as well as studies in other laboratories, have demonstrated that serotonin 2C receptor editing is altered in the prefrontal cortex of suicide victims regardless of their underlying psychiatric illness. Thus, dysregulation of editing constitutes a biological factor that is strongly associated with completed suicide. Serotonin 2C receptor is expressed only in the brain and spinal cord. Therefore, editing cannot be noninvasively measured in living individuals in the areas relevant to suicide (i.e., brain). We hypothesize the existence of single nucleotide polymorphisms (SNPs) that are associated with 5-HT2CR editing. In this study we aim to identify these editing-associated SNPs, which can be used as a proxy for measuring editing in the brain, and therefore, as predictors for suicide risk.Neuronal subtype-specific epigenetic regulation in schizophrenia
Stella Dracheva, PhD
This is a collaborative project with Drs. Byne, Roussos, and others that aims to explore cell-specific (in different sub-populations of neurons) genome-wide epigenetic alterations in schizophrenia. Different subpopulations of cells from postmortem brains of schizophrenia patients and controls are separated by FACS, and the chromatin studied, using different epigenetic assays for DNA methylation and histone modifications.Molecular Determinants of Individual Differences in Fear Reactivity and Recovery
Stella Dracheva, PhD
Over the past two decades, key aspects of the neural basis of fear have been elucidated through studies of Pavlovian fear conditioning, mostly in random populations of animals. However, because most humans with fear/anxiety disorders (e.g., Post-Traumatic Stress Disorder) are believed to represent extremes in the degree of underlying vulnerability, studies in random populations of animals may not be ideal for determining these vulnerabilities. To elucidate molecular networks that characterize individuals with high or low liability to fear/anxiety disorders, we focus in this project on behaviorally identified phenotypes that represent extremes of fear-related behaviors in rats. We use state-of-the art technology [whole transcriptome sequencing (RNA-Seq)] and weighted gene co-expression network analysis to study gene expression differences in particular nuclei of the amygdala among the highest, the intermediate, and the lowest fear reactivity phenotypes. The identified differences will help to pinpoint genes and pathways that characterize individuals with high or low liability to fear/anxiety disorders as well as individuals who are resistant to these disorders.Ankyrin-G and the nodes of Ranvier: Mechanisms of disconnectivity in Schizophrenia
Harry Haroutunian, PhD
This program seeks to elucidate some of the neurobiological mechanisms of the disconnectivity syndrome that characterizes SZ through the genetic and neurobiological study of postmortem human brain and transgenic animal models. The focus is on the nodes of Ranvier abnormalities which we have described that can cause functional disconnectivity by disrupting communication between neurons and brain circuits. The proposed studies address the mechanisms of a specific abnormality in SZ the direct translational and clinical applications of which may reinvigorate stalled drug development that can improve the mental health of our Veterans.
The tripartite neuron, astrocyte, oligodendrocyte unit in Schizophrenia
Harry Haroutunian, PhD
The overarching aim of this project is to use postmortem human brain and animal models to reconceptualize aberrant CNS function in SZ as the consequence of the interdependent dysfunction of tripartite cellular units comprised of neurons, astrocytes and oligodendrocytes where abnormalities in one member of the unit cascade to affect abnormalities in the others.
Neurofascin and the nodes of Ranvier in schizophrenia
Harry Haroutunian, PhD
This program aims to uncover the mechanisms that contribute to the nodes of Ranvier deficits in schizophrenia (SZ) and to determine how these abnormalities affect SZ-relevant behavioral, cognitive, neuroimaging and electrophysiological functions. These aims include: (1) the study of how a newly identified SZ-associated SNP within the neurofascin (Nfasc) gene affects cognitive processes and the expression of Nfasc and other keystone genes and proteins critical to NOR function; (2) exposing the cortical circuits most severely affected; (3) uncovering the direct effects of Nfasc on circuit and synaptic electrophysiology in the hippocampus and on brain anatomy; and (4) localizing the SZ-associated Nfasc abnormality to the NOR vs. the axon initial segment.
New Directions in the Genetics of Impulsivity and Aggression (VA MIRECC)
Mercedes Perez-Rodriguez, MD, PhD
This study examines the genetic underpinnings of core dimensions of Borderline and Schizotypal Personality Disorder, with a focus on impulsivity and aggression. It includes candidate-gene association studies, haplotype approaches, and imaging-genetics paradigms (e.g., "Brain-Derived Neurotrophic Factor and Amygdala Habituation in Borderline Personality Disorder").
Borderline Personality Disorder International Genetics Consortium
Mercedes Perez-Rodriguez, MD, PhD
Project Description: The Principal Investigator, based at the Bronx coordinating site (James J. Peters VA Medical Center), oversees the constitution of the consortium, which plans to perform the first whole-exome sequencing and GWAS in Borderline Personality Disorder, including over 3000 cases and 2000 healthy controls from 11 international sites.
Comprehensive assessment of cytokines and NF-κB activation in Schizophrenia Spectrum Disorders
Panagiotis Roussos, MD, PhD
In this study, we plan to collect peripheral blood from patients with Schizophrenia, their healthy first-degree relatives, and healthy controls, and to examine whether the NF-κB pathway is altered in living subjects, similarly to human postmortem studies in Schizophrenia. We hypothesized that Schizophrenia patients and, to a lesser degree, their unaffected first-degree relatives will present alterations of cytokines plasma levels and corresponding changes in expression levels and transcription activity of the NF-kB pathway.
An fMRI Study of the Enhancement of Emotion Regulation in Patients with Borderline
Harold Koenigsberg, MD
Functional Magnetic Resonance Imaging (fMRI) measures brain activity by detecting changes in blood flow. MIRECC investigators are using this technology to improve treatment for patients with Borderline Personality Disorder (BPD). The intense and rapid mood changes, self-destructive behaviors, and tumultuous relationships in BPD are not only painful for patients to experience but also impair their social functioning. In previous imaging studies, the investigators found that BPD patients are less able than healthy people to quiet the amygdala, the part of the brain that sends emotional alarm signals. To follow up, the investigators trained patients with BPD to distance emotionally from upsetting stimuli in the form of disturbing photographic images. The investigators then used fMRI to determine whether, by applying this skill, patients would succeed in reducing their brain activity to normal levels. The investigators also sought to learn whether, with additional exposure to the same images, brain activity would increase (indicating that sensitivity to them is increasing) or decrease (indicating that sensitivity is decreasing).
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Neuropsychological Assessments
Philip Harvey, PhD
The objective of the VISN3 Assessment Program is to perform state-of-the-art detailed clinical and neuropsychological assessments of SMI-veterans and to make these results available to health care professionals. The Assessment Battery consists of diagnostic reassessment, Assessment of Negative and Positive Symptoms (PANSS), Assessment of Cognition and Function (MMSE, CDR, CERAD Cognitive Battery, supplemented with additional assessments), the Social Adaptive Functioning Evaluation (SAFE) Scale or the Specific Levels of Functioning Scale (SLOF) depending on the residential status of the veteran. In addition to providing support for enhanced clinical care of veterans, this project directly supports the Neurochemistry and Neuroanatomy basic science projects of the VISN-3 MIRECC.
Clinical Assessments in the Chronic Psychosis Project
Philip Harvey, PhD; Harry Haroutunian, PhD
This clinical initiative focuses on diagnostic re-evaluation, symptomatic assessment, cognitive evaluation, and functional appraisal. To date, over 900 assessments and 225 re-evaluations have been conducted at four VISN3 sites, and every VISN inpatient over age 55 has been seen. Recently, the project has received additional federal funding to expand the efforts into longitudinal assessment of functional skills in older community dwelling SMI patients. Expanding on the previous discharge monitoring studies, this five-year project will examine the course of cognitive and functional status, with the goal of identifying points of intervention.
The results of the joint MIRECC-Mt. Sinai study on aging in schizophrenia have been published in numerous refereed scientific journals and have been characterized by reviewers as essentially defining the field of cognitive and functional change in older patients with schizophrenia. These studies have both compared the characteristics of VA and public sector patients, as well as examining the course of functional status in large samples of patients including veterans.
Assessment Examples:- Aging-related changes in cognitive functioning in treatment responsive and treatment refractory samples: Data from this study reveal that the experience of chronic psychotic symptoms may lead to cognitive decline. Moreover, previous data have suggested that even ambulatory patients may experience decline in executive tasks and in information processing capacity. The Boston Naming Test, the Animal Naming Test, Word List Learning, Letter-Number Sequencing, and the Constructional Praxis Test were used to assess differences between a normative sample of older healthy controls, a demographically similar sample of older healthy controls, ambulatory Schizophrenia patients aged 50 to 80, and an institutionalized and treatment refractory sample of patients with Schizophrenia aged 50 to 80.
- The impact of substance abuse: Substance abuse is very common in Schizophrenia, with approximately 50 percent of patients showing at least episodic abuse. Though this is less of an issue for chronic populations, even treatment refractory patients often live in the community. Data from this assessment suggest that dually diagnosed patients experience more overall cognitive decline with aging than do patients with Schizophrenia only, patients with Alcoholism only, and patient controls. Global cognition was the only significant predictor of functional skills in the Schizophrenia/Schizoaffective Disorder plus Substance Abuse group. Symptoms, age, and education did not enter the equation.
5-HT2CR and Suicide
Stella Dracheva, PhD
Results from a large number of studies have implied that a predisposition of people to suicidal behavior is strongly associated with both psychiatric disease and impaired serotonergic function. The serotonergic involvement with suicide appears to be equally strong, regardless of the associated psychiatric disorder. Therefore, brain serotonergic abnormalities may constitute a common basis for suicidal behavior irrespective of the underlying psychiatric illness. The precise nature of serotonergic defects in suicide remains elusive, however. The 5-HT2CR is a plausible candidate which might contribute to suicidal behavior because it has been shown to be widely distributed in the central nervous system and is thought to play an important role in regulating mood and affect. We are currently investigating whether the editing of 5-HT2CR is altered in the victims of suicide compared to people who died by other causes.
5-HT2CR and Drug Addiction
Stella Dracheva, PhD
A large body of evidence supports the hypothesis that 5HT2CRs that are expressed in the ventral tegmental area (VTA) modulate the basal activity of the dopamine (DA) midbrain neurons through the enhancement of the GABAergic inhibitory neurotransmission, and subsequently, control the rewarding effects of psychostimulants and other drugs of abuse (e.g. ethanol and nicotine). Thus, it is plausible that differences in 5-HT2CR function in VTA influence individual differences in sensitivity to drugs of abuse. In our future studies we are planning to investigate whether an individual’s repertoire of the 5-HT2CR isoforms may underlie phenotypic differences in responsivity to drugs of abuse and perhaps predisposition to addiction in rodents and humans.
Clinical Genetics Research
Jeremy Silverman, PhD
Molecular Genetics of Schizophrenia (MGS)Schizophrenia is strongly familial, but both genetic and non-genetic factors seem to be involved in its development.The specific genetic risk factors remain unknown. The first Molecular Genetics of Schizophrenia MGS-1 project, an affected sibling pair study, was completed in August 2003. MGS-II, a genetic association study, began in September 2003 and will run through August 2007 in ten collaborating centers. This NIMH-sponsored study is projected to employ 4,500 patients with Schizophrenia and 4,500 controls in an effort to identify one or more Schizophrenia susceptibility genes. A gene bank for Schizophrenia genetic association studies will also be established.
Consortium on the Genetics of Schizophrenia (COGS):Research is underway to identify the link between certain characteristics called endophenotypes (such as eye movements and verbal memory) in families and the development of schizophrenia. Seven centers are collaborating to examine this relationship between genetic differences and potential endophenotypes. Six endophenotypes in patients with schizophrenia and in their family members were selected for measurement. Analyses will determine whether these endophenotypes reflect the influence of a single common gene or multiple genes.
Key measures of neurophysiological deficits include P50 event related suppression, prepulse inhibition of acoustic startle response, and the antisaccade task for eye movements. Neurocognitive deficits are revealed by poor performance on the Continuous Performance Test (CPT), the California Verbal Learning Test (CVLT) to assess verbal memory, and the Letter Number Sequencing subtest of the WAIS III to measure working memory. Each of these deficits has also been demonstrated in clinically unaffected relatives of patients with schizophrenia, which is evidence that these deficits may reflect part of the heritable risk for the illness. Goals of the study include the establishment of a neurocognitive/psychophysiological laboratory for genetic/family studies in Schizophrenia and other disorders; recruitment of fifteen families with a Schizophrenia proband a year for five years; establishment of a gene bank for 420 pedigrees; characterization of the complex relations among the major endophenotypes in the families; and implementation of a genome scan for Schizophrenia and endophenotypic traits.
Neuroimaging Studies
[No PI]
Understanding of the neuropathology of schizophrenia has been advanced by numerous magnetic resonance imaging (MRI) studies over the past decade, which confirms the presence of structural brain abnormalities in schizophrenia, including volume alterations of the ventricles, frontal lobe, medial temporal lobe, superior temporal gyrus, inferior parietal lobe and subcortical brain regions. Conte Center (Mount Sinai School of Medicine) affiliated studies on Diffusion Tensor Imaging (DTI), Magnetization Transfer Imaging (MTI), and Proton Magnetic Resonance Spectroscopy (MRS) are underway to assess cognitive components and functional outcomes of patients with Chronic Schizophrenia. The studies involve complete cognitive batteries, symptomological assessments, and investigation of brain white matter structures and neurochemicals.
fMRI of VisuoSpatial Working Memory in Schizotypal Personality Disorder
Harold Koenigsberg, MD, et al
As with patients with Schizophrenia, the visuo-spatial working memory of individuals with Schizotypal Personality Disorder (SPD) is impaired. Visuo-spatial working memory (VSWM) affects a wider range of patients with Schizophrenia than does impairment in verbal working memory, and connects to extensive non-human primate work including single-cell recordings. This study was developed with the hypothesis that SPD patients will activate regions in the frontal part of the brain normally used in working memory (called regions BA9/46) less strongly than will healthy volunteers, and that SPD individuals will activate a different region at the very front of the brain (the frontal pole; called region BA10) more strongly than will healthy volunteers, while performing the VSWM task. Preliminary data reveal that SPD patients and healthy controls (HC) show increased activation during the memory maintenance period compared to the control condition. However, HC’s exhibit greater activation in right BA9/46 than do SPD patients, while SPD patients show greater activation in right BA10 than do HC’s. In addition, our findings on ventral prefrontal cortex activation, activation in premotor areas, and parietal cortex activation replicate findings from published literature on spatial memory. Future directions include a comparison of patients with Schizophrenia, SPD, and HC subjects in the same study, employment of a larger sample size, and examination of the effect of working memory load.
A Thalamocentric Approach to the Neuroanatomy of Schizophrenia: A Quantitative Study in Immunocytochemically Identified Thalamocortical Projection Neurons
William Byne, MD, PhD
Schizophrenia is a psychiatric disorder characterized by functional and structural abnormalities in multiple brain regions, all of which communicate with the part of the brain called the thalamus. The thalamus can, therefore, be considered as a communication hub of the brain. Pathology in a given brain region may induce pathology in other regions of the brain with which it communicates. Thus the abnormalities in multiple brain regions in schizophrenia may be causally related by virtue of their communication with the thalamus.
We have, therefore, investigated the thalamus for pathology associated with schizophrenia. Our overarching hypothesis is that pathology will be found in those regions of the thalamus that communicate with other brain regions which are known to be abnormal in schizophrenia. We have identified two large regions (nuclei) of the thalamus that are characterized by decreased volume and cell number in schizophrenia. These nuclei are the mediodorsal nucleus and pulvinar. The present application focuses on the pulvinar, which comprises five separate divisions, each of which has a different pattern of communication (connections) with other brain regions. Identifying exactly which of these divisions are affected in schizophrenia is therefore essential to understanding how the disorder alters brain circuitry. The study employs autopsied human thalami obtained from the Brain Bank, and aims to examine approximately thirty-six specimens (eighteen from patients with schizophrenia and eighteen from comparisons without schizophrenia).
To date there has been no satisfactory unifying hypothesis to explain the multiple functional and neuroanatomical abnormalities associated with schizophrenia. We have adopted an approach to neuroanatomical schizophrenia research which is premised on the unifying hypothesis that some of the multiple brain abnormalities associated with this disorder are etiologically related by virtue of the communication of the affected brain regions with the thalamus. Rather than resulting from multiple lesions independently affecting various functional circuits, multiple functional deficits might be better explained by a lesion in the thalamus where the relevant circuits converge. Because pathology in one brain region may induce pathology in other brain regions with which it communicates, thalamic pathology may also hold a key to understanding why multiple brain regions exhibit schizophrenia-associated structural, cellular, and neuromolecular anomalies.
We have demonstrated a schizophrenia-associated loss of volume in the mediodorsal nucleus and in the pulvinar of the thalamus in both postmortem histological and in vivo neuroimaging studies. Our large scale (N=101) MRI study included neuroleptic naive subjects ranging in age from 18-73 and suggested that the volume loss is independent of neuroleptic exposure and does not progress with age. Our postmortem studies have demonstrated neuronal loss in both of these thalamic nuclei and a loss of dendritic material in two of their prefrontal cortical fields. Both of these thalamic nuclei are comprised of multiple subdivisions which have unique sets of efferent and afferent projections. Understanding which subdivions are affected is, therefore, crucial to understanding how schizophrenia may impair neural circuitry. Current work employs well-characterized material from the Mount Sinai/James J. Peters VA Medical Center Schizophrenia Brain Bank and is aimed at determining precisely which cell types (e.g., glia, projection neurons, interneurons) and which subdivisions of the mediodorsal nucleus and pulvinar are affected in schizophrenia. We are also beginning to examine the thalamus for abnormalities associated with major depression and bipolar disorder.
Oligodendrocytes in Severe Mental Illness and Aging
William Byne, MD, PhD
A variety of approaches suggest deficits of oligodencrocytes or oligodendrocyte/myelin genes in schizophrenia and some other mental illnesses, and there is evidence that these deficits vary with age. This project employs quantitative PCR to examine cell cycle and stage specific oligodencrocyte/myelin gene expression in populations of cells enriched for oligodendrocytes in order to shed light on myelin turnover in mental illness and normal aging. In addition to thalamus, other brain regions are examined to determine the regional specificity of mental illness and age related changes in oligodendrocyte number. We have found that in at least 2 thalamic nuclei, oligodendrocyte number increases after middle age in normal subjects but not in subjects with a history of a psychotic illness.
Glutamate and Myelin Dysfunction in Elderly Patients with Schizophrenia
Harry Haroutunian, PhD
Our studies have shown that it is imperative to think of brain function within frameworks that integrate neurons and glia into functional units. The studies proposed in this Merit funded project is to test the unifying hypothesis that myelin and glutamate abnormalities in schizophrenia are interrelated. Methods used combine molecular neurobiology and laser capture microdissection of specific and identified cell groups. To date, neurons and oligodendrocytes have been dissected from approximately 50% of the planned study cohort. In addition, laminar dissections of cortical specimens have been completed and the study of gene expression of 37 different transcripts associated with ionotropic glutamate receptors and oligodendroglial genes has been initiated.
Contribution of cell cycle processes to myelin deficits in schizophrenia
Harry Haroutunian, PhD
Microarrays and qPCR studies have identified significant deficits in the expression of myelin and oligodendrocyte-related (OMR) genes in schizophrenia. Based on our preliminary studies we hypothesize that terminally differentiated oligodendrocytes reenter the cell cycle and begin executing a pathological program that adversely affects the expression of OMR genes and myelin function. Methods combine molecular neurobiology and laser capture microdissection of identified cell groups.
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