Neuroscience

J. John Mann, M.D., Chief of Psychiatric Research

DIVISION OF NEUROCHEMISTRY

Beth Brodsky, Ph.D., Research Scientist II
Steven Ellis, Ph.D., Research Scientist V
Michael Grunebaum, M.D., Psychiatrist (Research) II
Yung-yu Huang, M.S., Research Scientist IV
John Keilp, Ph.D., Research Scientist IV
Shuhua Li, M.D., M.P.H., Dr.P.H., Scientist III
Maria Oquendo, M.D., Psychiatrist (Research) II
Stephen Rayport, M.D., Ph.D., Psychiatrist (Research) II
Leo Sher, M.D., Psychiatrist I
Barbara Stanley, Ph.D., Research Scientist VI
David Sulzer, Ph.D., Scientist V
Hadassah Tamir, Ph.D., Research Scientist VI
Mark Underwood, Ph.D., Research Scientist V

DIVISION OF NEUROPATHOLOGY

Victoria Arango, Ph.D., Research Scientist VII, Co-Director
Andrew Dwork, M.D., Pathologist II, Co-Director, Division of Neuropathology
Jonathan Javitch, M.D., Ph.D., Research Scientist V
Suham Kassir, B.Sc., Research Scientist III
Gorazd Rosoklija, M.D., Assistant Professor of Clinical Psychiatry
David Ruggiero, Ph.D., Professor of Clinical Neuroscience
Claudia Schmauss, M.D., Scientist V
Etienne Sibille, Ph.D., Research Scientist II

DIVISION OF BRAIN IMAGING

Ronald Van Heertum, M.D., Medical Specialist II
Ramin V. Parsey, M.D., Ph.D., Psychiatrist (Research) II
Marie-José Bélanger, Ph.D., Research Scientist II
Dileep J.S. Kumar, Ph.D., Research Scientist IV
R. Todd Ogden, Ph.D., Research Scientist V
Norman Simpson, B.S., Research Scientist IV
Malingham Pradhaban, M.B.B.S., Research Scientist II

The Department of Neuroscience spans the research spectrum from basic cell biology to in vivo imaging, molecular genetics and treatment trials. It emphasizes translational research and employs a multidisciplinary approach to psychiatric research to examine the biological substrate of mental illness at multiple levels. The Department is comprised of three divisions that pursue postmortem and in vivo studies of psychiatric disorders. The Neurochemistry Division develops laboratory probes for in vivo clinical and biological studies of the serotonergic, dopaminergic and other monoamine systems, and organizes clinical treatment studies. It also conducts basic studies in single cells, rodents and nonhuman primates. The Division of Neuropathology conducts neuroanatomical mapping and gene expression studies in human, nonhuman primate and rodent brains, postmortem brain studies of psychiatric disorders and provides neuropathology services to the OMH. The Division of Brain Imaging conducts functional and structural brain imaging studies in baboons and human subjects.

Each division is involved with other Departments at NYSPI, The College of Physicians and Surgeons, School of Public Health and the Columbia Presbyterian Medical Center. The Division of Neurochemistry works closely with the Center for Neurobiology and Behavior and the Columbia Genome Center on molecular genetics and with the Irving Center for Clinical Research in clinical inpatient research. The Division of Neuropathology is involved with the Department of Pathology and with the Alzheimer’s Disease Research Center. The Division of Brain Imaging is closely involved with the Department of Radiology.

Division of Neurochemistry
The major areas of clinical investigation for the Division of Neurochemistry have been the biological basis of mood and psychotic disorders, the action of antidepressants and other psychotropics, and risk factors for suicidal behavior. Basic studies have involved studies of the serotonin and dopamine systems and the action of antipsychotics and antidepressants.

Dr. Mann heads the Stanley Center for the Applied Neuroscience of Bipolar Disorders. This Center uses PET scanning to study the neurochemistry of bipolar depression in vivo and the action of antidepressants in the brain. The Center also conducts neurochemical postmortem studies of bipolar disorder that inform the design and goals of the functional imaging studies. The ultimate goal of the Stanley Center is to develop treatment selection guidelines based on actual neurochemical abnormalities of bipolar patients.

Dr. Maria Oquendo coordinates all the clinical/biological studies in the Division. Dr. Ramin Parsey has major responsibility for PET clinical imaging studies. Drs. Michael Grunebaum, Leo Sher and Lawrence Kegeles conduct psychobiological studies of mood and psychotic disorders. Dr. Ainsley Burke trains and supervises the clinical evaluation core research staff.

Dr. Kegeles does studies of the GABAergic system using PET and magnetic resonance spectroscopy. A deficiency of GABAergic function appears to be present in mood and psychotic disorders. Dr Kegeles’ work complements postmortem studies of the GABAergic system being conducted in postmortem tissue by scientists in the Neuropathology Division.

The schizophrenia suicide studies component is directed by Dr. Jill Harkavy Friedman, who has a NIMH grant to support this work. The uniqueness of this study lies in the fact that it is prospective and involves an examination of clinical, cognitive, social, developmental, genetic and neurobiological risk factors in the same patient population.

Neurobiological studies in schizophrenia are supervised by Drs. Lawrence Kegeles and Roberto Gil. Neuropsychological studies of cognitive function and impulsivity are conducted by Dr. John Keilp.

Dr. Barbara Stanley conducts neurochemical and psychological investigations in borderline personality disorder supported by two NIMH grants and an American Foundation for Suicide Prevention grant. One of her NIMH grants supports a parallel group, randomized, double blind study of the efficacy of a psychotherapy called dialectical behavior therapy versus an SSRI medication in the prevention of suicidal behavior in borderline personality disorder.

Dr. Oquendo has received an NIMH grant to conduct a double blind, randomized treatment study comparing lithium and divalproex maintenance treatment on suicidal behavior in bipolar disorder.

Drs. John Mann, Maria Oquendo, and Ramin Parsey have developed methods using Positron Emission Tomography (PET) for visualizing regional brain responses to serotonin activation and serotonin receptors. These techniques allow study of mood disorders, the effect of treatment with medication or ECT, and identification of high-risk patients and the localization of regional brain abnormalities in high-risk patients. These studies have resulted in publications reporting the role of specific prefrontal cortical regions in determining the lethality of suicidal behavior as they mediate the degree of intent and impulsivity which, in turn, determine the medical lethality of suicidal behavior. We have also mapped the brain regions with abnormal serotonin system function on depressed patients. Other studies are in progress examining possible genetic influences on the manifestation of suicidal and self-harming behaviors.

In collaboration with Drs. T. Conrad Gilliam, of the Columbia Genome Center, René Hen of the Center for Neurobiology and Behavior, and Dr. David Brent of the University of Pittsburgh, a candidate gene approach has been adopted, focused on key serotonin and neurotransmitter-related genes. Several key genes have been found to be associated with mood disorders, or substance abuse or aggressive/impulsive traits and others with suicidal behavior. A study of the familial transmission of depression, suicidal acts and impulsive-aggressive traits is underway, funded by NIMH grants to Dr. Mann and Dr. Brent (in Pittsburgh). This study is entering its sixth year of funding and has demonstrated that the familial transmission of suicidal behavior not only requires transmission of a mood disorder but also other factors such as impulsive aggressive traits that are, in turn, partly related to the familial transmission of a reported history of childhood sexual abuse. The studies are also supported by the NIMH funded Conte Center and three other NIH grants to Dr. Mann. The Conte Center is also supporting a microarray approach in animals and postmortem human brain to the detection of altered gene expression that, in turn, can reveal new, previously unsuspected, candidate genes that can be evaluated in our family study.

Dr. Hadassah Tamir and her associates, Kuo-peing Liu, Shu-chi, Hsiung and Mella Adlersberg, have recently been able to demonstrate stimulation-induced enhanced secretion of catecholamines from chromaffin cells. This enhancement is due to increased acidification of storage vesicles, which was also observed in synaptic vesicles.

Stimulation-induced regulation of pH of secretory and synaptic vesicles may represent a new presynaptic mechanism contributing to modulation of secretion and synaptic transmission. In addition, several steps in the transduction pathway leading from extracellular Calcium receptor activation to 5-HT secretion from parafollicular cells were elucidated. They include: Gbeta/gama subunits, phosphoinositide 3-kinase, Akt and atypical PKCzeta. These findings may shed light on the physiological functions that this receptor plays in the brain and other nervous tissues where it is expressed.

Dr. Mark Underwood conducts research into the regulation of serotonergic neurons in suicide and alcoholism. The studies examine serotonergic neurons in the brainstem and define their functional capacity using quantitative morphometric and receptor binding methods. Dr. Underwood is one of the few scientists studying serotonin neurons at the brainstem level in both humans and animals to further elucidate their role in normal brain function and in diseased states. This work is supported by the NIAAA, the NIMH Conte Center for the Neuroscience of Mental Disorders and the Stanley Center. Dr. Underwood is also collaborating with his colleagues to perform imaging studies in rodents in vivo using the newly installed microPET camera in Milstein Hospital. The Department of Neuroscience was the first to perform imaging studies using PET in live rodents at Columbia University.

Dr. Stephen Rayport’s lab continues its focus on the synaptic pharmacology of mesolimbic dopamine neurons. These neurons are in the ventral tegmental area (VTA) of the midbrain and project to the nucleus accumbens (nAcc) where they appear to mediate the rewarding effects of abused drugs as well as positive symptoms in schizophrenia. J. Masson and S. Rayport, in collaboration with R. Hen (Neurobiology & Behavior), have made transgenic mice with fluorescent dopamine neurons, which N. Chuhma and S. Rayport are using to study the synaptic actions of the neuron in the brain slice. With Y. Schmitz and D. Sulzer, they have demonstrated that that the mesoaccumbens projection is intact by cyclic voltammetry and amperommetry. Then, using whole-cell patch recordings, Chuhma and Rayport have shown that VTA stimulation evokes excitatory monosynaptic responses in nAcc neurons. These responses were blocked by the AMPA-type glutamate receptor antagonist CNQX, and reduced by the D2 dopamine agonist quinpirole, consistent with presynaptic inhibition of glutamate release from DA neurons. Taken together, these results demonstrate that DA neurons make glutamatergic synapses in the nAcc in the intact brain. To address the functional role of the glutamate cotransmission, Masson, Rayport and Hen are making transgenic mice where glutaminase, the enzyme that produces neurotransmitter glutamate, is selectively deleted from dopamine neurons. The glutamatergic synapses of dopamine neurons may have novel neuroplastic capabilities. If so, these mice may be less likely to develop drug dependence; another prediction is that they will manifest behavioral changes associated with schizophrenia, given their hypoglutamatergic state.

Dr. David Sulzer's laboratory is pursuing the modulation of dopamine release at the presynaptic level. They have recently identified a role for alpha-synuclein in activity-dependent presynaptic depression of release, the precise role for antipsychotics and amphetamine on depressing release, and the effects of presynaptic metabotropic glutamate and GABA receptors. They have established the first direct recordings of quantal release in the central nervous system, showing the number of dopamine molecules and the temporal kinetics of the release. This approach has demonstrated the first direct evidence that quantal size can be changed in the CNS, and the lab has shown such effects by drugs including L-DOPA and amphetamine, and the growth factor GDNF: indeed, the mechanism of action of these two drugs is in large part explained by these effects. In new work, they have elucidated the effects of dopamine release on plasticity of the cortical-striatal synapse that is thought to underlie the reward pathway, drug dependence, and motor control. They have been examining the effects of dopamine oxidation in neurodegeneration, which appears to underlie the neurotoxicity due to methamphetamine, the biosynthesis of neuromelanin, and possibly in Parkinson's Disease. This work is supported by several NIH, NSF, and private foundation grants.

Division of Neuropathology
The Division of Neuropathology conducts basic and clinical research and participates in postgraduate medical education. It provides a neuropathology service to the New York State Office of Mental Hygiene (OMH). The Neuropathology Division examines the brains of OMH patients obtained at autopsy and it maintains an archival collection of these specimens.

Dr. Andrew J. Dwork and colleagues are searching for neuropathological features of schizophrenia and mood disorders, and for neuropathological correlates of the dementia that is common among elderly schizophrenics. Combining modern and classical neuropathological techniques, they have made several novel observations. They have also developed standardized procedures for the retrospective clinical review of psychiatric hospital records so that neuropathological findings can be compared with clinical data. These projects are supported by grants from NIMH, NARSAD, the Theodore and Vada Stanley Foundation, the American Foundation for Suicide Prevention and the US/Macedonian Joint Fund for Science and Technology. Current projects of the laboratory include: (1) Studies of structural abnormalities of dendrites in schizophrenia and mood disorders. (2) Studies of the neuropathological correlates of dementia in schizophrenia. (3) Collection of brains and clinical data from autopsies of psychiatric patients, suicides, and comparison cases in the Republic of Macedonia. This is a collaboration with several Macedonian institutions: Institute for Forensic Medicine, Psychiatric Hospitals of Skopje, Demir Hisar, and Negorci, and the School of Medicine. (4) Collaborative studies with the Department of Biological Psychiatry on neuroanatomical effects in non-human primate models of electroconvulsive therapy and magnetic seizure therapy.

Dr. Victoria Arango, in collaboration with Drs. Mark Underwood, Hadassah Tamir, John Mann, Suham Kassir and Yung-yu Huang, is conducting a program of postmortem studies of suicide victims utilizing a combination of quantitative receptor autoradiography, in situ hybridization histochemistry and morphometric analysis of forebrain and brainstem nuclei. Dr. Arango is the Director of the Brain Bank of the Conte Center for the Study of Suicidal Behavior. Psychological autopsies, conducted by the Clinical Evaluation and Treatment Core (Dr. Maria Oquendo, Director), are used to obtain detailed clinical information on each case in the Brain Bank. Brain toxicological screens on subjects in the Brain Bank are conducted by Tom Cooper. Dr. Arango and colleagues demonstrated that the reported low serotonergic activity in suicide is not due to a loss of serotonergic neurons or processes in the dorsal raphe nucleus of suicide victims. Dr. Arango and colleagues found that fewer serotonergic cells expressed the gene for the serotonin transporter in depressed suicide victims compared to controls. Less SERT gene expression may be interpreted as a homeostatic mechanism to reduce serotonin reuptake and compensate for lower intrasynaptic serotonin.

Dr. Arango and colleagues replicated their previous report that suicide victims had lower serotonin transporter binding in the orbital prefrontal cortex and that females had lower binding than males.
	More recently, they also determined that subjects with major depression, independent of cause of death, had a widespread loss of serotonergic innervation in all the prefrontal areas studied. A parallel set of postmortem studies is being conducted by the same investigators in alcoholics in order to determine the neurochemical and morphological consequences of acute and chronic alcohol
consumption. A recent study of serotonin 5-HT2A receptors in the prefrontal cortex revealed that alcoholics with a positive family history of alcoholism had significantly lower 5-HT2A receptor binding throughout the prefrontal cortex than subjects without a positive family history of alcoholism, independent of whether the case was a control or an alcoholic. Alcoholics without a family history of alcoholism did not differ from controls without a family history of alcoholism in any brain region examined. Familial alcoholism may be associated with a prefrontal serotonergic abnormality. These studies have identified areas in the brain that control impulsive behaviors such as suicide. They have also revealed fundamental neurochemical differences between suicide victims and mood disorder patients, important in enhancing our understanding as to why some patients are at higher risk for suicide, and indicating new diagnostic and screening possible tests for high suicide risk and new treatment targets. Drs. Arango, Underwood and Mann are supported by the NIMH, the Stanley Foundation and the NIAAA for postmortem human brain research.

Dr. Claudia Schmauss’ research program uses molecular biological and biochemical approaches to study the expression and function of neurotransmitter receptors that are targets for drugs with antipsychotics potencies. A major project in Dr. Schmauss’ laboratory focuses on elucidating the distinct functional properties of two members of the D2-class of dopamine (DA) receptors, named D2 and D3 (the main targets for neuroleptic drugs), by means of analyzing the behavioral and molecular/biochemical phenotypes of mutant mice with a targeted disruption of D2, D3, and D2/D3 receptors. These knockout mice were generated in Dr. Schmauss’ lab, and this lab has published several papers that report results of studies on these mutants. During the past year, studies on these knockout mice have shown clearly that manipulations that selectively target one DA receptor subtype also produce changes in the functions of other DA receptors. For example, Dr. Schmauss’ lab found that D1 receptor function is substantially impaired in brains of mice lacking D2, D3, and D2/D3 receptors. Importantly, these alterations occur in brain regions where DA is known to influence behaviors that are often found to be abnormal in schizophrenia. For example, mice deficient for D2 and D3 receptors exhibit a decreased agonist-stimulated D1-receptor activity in the prefrontal cortex, a structure in which dopamine D1 receptor activity is a critical determinant for performance in working memory tasks. Indeed, mice lacking D2 and D3 receptors were found to have significant impairments in spatial working memory. Most recent experiments investigate the molecular mechanisms underlying the complex regulation of D1 receptor function in the presence and absence of D2 and D3 receptor expression.

Another project conceptualized, designed, and executed in Dr. Schmauss’ laboratory investigates the posttranscriptional processing of the serotonin (5-HT)2C-receptor-encoded pre-mRNA (known as RNA editing) in human prefrontal cortex and mouse forebrain neocortex. These studies identified significant, site-specific alterations in the editing of 5-HT2C pre-mRNA in the prefrontal cortex of depressed suicide victims that result in a predominant expression of a 5-HT2C receptor population with decreased sensitivity to 5-HT. In contrast, mice treated chronically with the 5-HT-selective re-uptake inhibitor fluoxetine (Prozac) exhibit site-specific alterations of forebrain neocortical 5-HT2C pre-mRNA editing that are exactly opposite from those detected in depressed suicide victims and that lead to an increased expression of those 5-HT2C receptor isoforms that are most sensitive to serotonin stimulation. None of these alterations in pre-mRNA editing are due to altered substrate concentration, i.e., the cytoplasmic expression levels of 5-HT2C mRNA are unaltered. These studies provided new evidence for a significant role of alterations in the posttrancriptional regulation of gene expression in psychosis. Most recent studies (submitted for publication) have now elucidated in detail how changes in the synaptic concentration of serotonin affect editing-site preferences in 5-HT2C pre-mRNA.

Dr. Schmauss is the Principal Investigator of a research grant from the National Science Foundation, two RO1 grants of the National Institutes of Health, and a NARSAD Independent Investigator Award.

Dr. Jonathan Javitch’s research focuses on understanding the structural bases for the function of G protein-coupled receptors and neurotransmitter transporters. His group has studied the dopamine D2 receptor, the principal site of action of antipsychotic drugs, and the dopamine transporter, the site of action of the psychostimulants cocaine and amphetamine. They also have a new research project funded by NIDA examining the structure of bacterial transporters that are related to transporters.

Dr. David Ruggiero’s research focuses on experimental models designed to shed light on the pathogenesis of pediatric developmental disorders, particularly the functional maturation of stress-adaptation circuits. The behavioral conditioning of stress adaptation networks is implicated in the etiology of a range of sleep disorders, mood syndromes and autonomic imbalances resulting in central neurogenic hypertension, among other visceral disorders, for example, related to psychoneuroimmunological compromise. Chronic Intermittent Hypoxia (CIH) is a possible cause of a range of pediatric developmental ‘spectrum’ disorders, consequent to intrauterine exposure to vasoconstrictor agents such as nicotine and/or cocaine which are co-abused in jags during pregnancy and established as risk factors for SIDS and infantile autism. Collaborative studies with Dr. A.L. Sica and the late Drs. P.M. Gootman and N. Gootman of Downstate Medical College clarified the critical periods of development of central chemoreceptor circuits in neonatal, Yorkshire swine. These studies corroborate the second week as a critical period and window of vulnerability to stress in infancy. Further studies assessing a long-term impact of CIH on monoaminergic transmitter systems are on-going.

Epinephrine was identified as a key stress regulatory transmitter hormone of a highly collateralized visceral control network that mediates sympathoexcitatory, endocrine and behavioral/arousal components of the first excitatory phase of stress adaptation. Studies of critical or ‘sensitive’ periods predict sustained activation and compromise of epinephrine chemoreceptor networks by chronic homeostatic challenges, such as CIH. Accelerated cell death programs are triggered by a neurotoxic, monoamine oxidase-A metabolite of norepinephrine and epinephrine, as shown in vivo. Collaborative studies with Dr. W. Burke of Washington University demonstrate that this MAO metabolite of catecholamines, 3,4-Dihydroxyphenylglycoaldehyde (DOPEGAL) triggers apoptosis and a loss of central epinephrine neurons. The findings obtained, in vivo, in the laboratory rat may relate to the neuropathology of epinephrine transmitter stress regulatory networks and signs of accelerated cell death programs in SIDS, Alzheimer’s and Parkinson’s disease. Epinephrine neurons are rendered dysfunctional in disorders of development and aging. Insights into these functions were gained by collaborative studies with Dr. E. Golanov of Weill Medical College of Cornell University. These studies characterized the role of central epinephrinergic chemosensors in a neurochemically complex ‘oxygen conserving’ cerebrovasodilator/EEG synchronizer circuit.

Division of Brain Imaging
Ronald Van Heertum, M.D. is the Director of the Brain Imaging Core, and Ramin Parsey M.D., Ph.D. is the Associate Director for the Stanley Center for the Applied Neuroscience of Bipolar Disorders and the Conte Center for the Neurobiological Studies of Suicidal Behavior. The Division supports both these cores. The Stanley Foundation Center was newly refunded this year. Dr. Todd Ogden is the senior brain image analysis statistician and has developed novel innovations in methods and software for kinetic modeling and analysis of PET neuroreceptor binding studies. Dr. Ogden, together with the kinetic modeling expertise of Dr. Ramin Parsey, and the programming skills of Dr. Ashish Ojha, have produced a new software package for analyzing PET and SPECT neuroreceptor binding data. Dr. Marie-José Bélanger, who has a Ph.D. in biomechanical engineering and did her dissertation in brain imaging at MIT, has added valuable expertise in PET physics and signal processing. She has worked with Dr. Parsey on a motion correction software method that will be valuable for time activity studies common in neuroreceptor mapping studies.

The Division is continuing to study unipolar and bipolar depressed subjects before and after treatment with an SSRI or ECT, bipolar depressed subjects, suicide attempters and non-attempters, and healthy volunteers. These studies have generated important new data that for the first time demonstrate that many of our findings in postmortem human brain tissue can be detected in vivo in depressed subjects. In addition, we are continuing our non-human primate PET studies focusing on new ligand development and evaluation, endogenous competition studies, and blocking studies. This year we have introduced the use of the microPET camera and have begun doing rodent PET studies. These have greatly contributed to our development of new PET tracers. That program is funded by the two center grants, and newly awarded grants to Drs. Mann and Dileep Kumar. The chemistry group has been greatly expanded an now includes Drs. Dileep Kumar, Ted Wang, Jaya Prabhakaran and Vattoly Majo, who are an outstanding group of organic chemists. As a result, we have introduced novel PET tracers for the serotonin transporter and other serotonin receptors and are working on additional new ligands. Collaborations have been developed with several groups in neurology and other P.I. investigators using some of our PET tracers. We have continued our structural brain studies with quantitative MRIs of subjects enrolled in the PET studies and have used a voxel based analytic approach to find alterations in brain structure in mood disorders. Our efforts have been greatly assisted by collaborations with the Department of Radiology (Ronald van Heertum, M.D. and Peter Esser, Ph.D.). In collaboration with Dr. De La Paz, Dr. John Keilp has an AFSP grant to study cognitive function with fMR.

During 2001, we continued providing technical support for ongoing imaging studies for Dr. Devanand in the Department of Biological Psychiatry.

New grants in brain imaging in 2001 were obtained by Drs. Mann, Parsey, Attia, Van Heertum and Oquendo. Ongoing funding from NIMH and foundations include two center grants, RO1s, a KO1 award, AFSP, Clinical Trials and NARSAD grants.