Peter Strick - US grants

DESCRIPTION (provided by applicant): Our concepts about the cortical control of movement have undergone a dramatic evolution. In the past, the primary motor cortex (M1) was viewed as the sole source of descending command signals to the spinal cord. Other cortical areas and subcortical structures like the basal ganglia and cerebellum were thought to influence the control of movement mainly through their connections with M1. We now know that the frontal lobe contains 6 premotor areas. Each of these cortical areas projects not only to M1, but also directly to the spinal cord. As a consequence, the central commands for movement may originate not only from M1, but also from each of the premotor areas. We now propose to examine four fundamental questions about the organization of the premotor areas: (1) Although all of the premotor areas project to the spinal cord, which of the premotor areas are major sources of descending commands to motoneurons? (2) We have found that output neurons within two premotor areas are connected to motoneurons that control eye muscles. Do these premotor areas create a neural interface between the oculomotor and skeletomotor systems? (3) We have also discovered that output neurons in M1 and in the premotor areas are connected to neurons that control the sympathetic nervous system. Do these motor areas create a neural interface between the visceromotor and skeletomotor systems? (4) Approximately 25% of the corticospinal efferents from the frontal lobe originate from the cingulate motor areas. What is the organization of inputs to these areas from the basal ganglia, cerebellum and spinal cord? Each of these questions will be answered in a separate experiment. However, each question requires a technical approach that is capable of unraveling neural connections within complex, multi-synaptic networks. Thus, we will use transneuronal transport of neurotropic viruses in these experiments because this technique is uniquely capable of defining circuits of synaptically-linked neurons. The results from the proposed studies are likely to have broad implications for concepts about the function of the cortical motor areas in normal movement, their involvement in the motor and non-motor symptoms of movement disorders like Parkinson's disease and their role in the recovery of motor function following brain or spinal cord injury.

The basal ganglia and cerebellum are major subcortical nuclei that have long been regarded as critical to the generation and control of movement. A major structural feature of basal ganglia and cerebellar circuits is their participation in multiple open and closed loops with the cerebral cortex. In the past, basal ganglia and cerebellar output was thought to terminate in a single region of the thalamus and influence a single cortical area, the primary motor cortex. It is now becoming increasingly clear that the output of these circuits is much more widespread than previously suspected. Recently, we used a new tracing technique, retrograde transneuronal transport of herpes simplex virus type 1, to examine some basal ganglia and cerebellar projections to the cerebral cortex. Our results indicated that the output from the basal ganglia and cerebellum directly influences prefrontal areas of cortex, as well as motor areas. We have proposed that the projection to prefrontal cortex provides a means for the basal ganglia and cerebellum to influence frontal lobe functions such as working memory, rule-based learning and the planning of future behavior. We now propose to use the same technique to examine the extent of basal ganglia and cerebellar projections to temporal posterior parietal, and cingulate cortex. Connections with these cortical areas would provide the anatomical substrate for basal ganglia and cerebellar participation in aspects of perception, attention and other higher order cognitive processes. Indeed, damage to these circuits or alterations in their development have been thought to be the anatomical basis of a number of symptoms associated with mental disorders such as schizophrenia, autism and obsessive-compulsive disorder. Thus, the results of the proposed experiments could have important implications for concepts regarding basal ganglia and cerebellar contributions to normal and abnormal behavior.

The present grants of the PI of this collaborative project (P. Strick) are directed primarily for connectivity studies and functional mapping in the monkey brain. Subsequent to the development of human functional imaging with magnetic resonance in 1992, an active collaborative effort has developed on human brain mapping, utilizing the 4 Tesla instrument supported as a BTRR at the University of Minnesota. These human studies are direct extensions of the monkey work and currently focus on 1) identification and somatotopic organization of premotor areas especially in the frontal lobe of the human brain and 2) cognitive role of the cerebellum in the human brain. Abstracts have been presented in 1996 ISMRM and Brain Map meetings on the first topic, and articles in Science magazine has already been published in previous years on the second subject. Classically, the primary motor cortex has been viewed as the "upper motoneuron" or the "final common pathway" for the central generation of movement. According to this concept, the primary motor cortex was the main source of descending commands for voluntary movement. The basal ganglia, cerebellum and cortical areas in the parietal and frontal lobe were thought to influence these commands largely through direct or indirect projections to the primary motor cortex. The results of our recent studies have led us to challenge this concept. We have shown that there are at least 6 premotor areas in the frontal lobe. Each premotor area is somatotopically organized and contains largely separate regions for the control of arm and leg movements. Perhaps more importantly, our results indicate that each of these premotor areas has substantial direct projections to the spinal cord. Furthermore, our data suggests that the corticospinal projections from the premotor areas are involved in the control of both distal and proximal arm movements. These observations raise the possibility that each premotor area is an independent source of central commands for the generation of limb movement. While the many of these areas are identified in the monkey brain, similar exhaustive anatomical identification in the human brain does not exist, especially the six premotor areas that were identified in the frontal cortex of the monkey brain. This issue is currently being pursued as a collaborative project at the high field national research resource at the CMRR, taking advantage of the recent developments in functional magnetic resonance imaging and the advantages of high magnetic fields in cortical mapping. The specific hypothesis tested is that the general cortical region area often referred to as Broca's area (including and near parts of Brodmann's areas BA44, BA45) may significantly overlap with and may be the location of a ventral lateral premotor area (PMv) described in monkey studies . To test this and to discriminate between functional areas, subjects are asked to perform several motor tasks and a covert speaking task. These tasks are: (I) random tongue movement, (II) toe movement, (III) complex instruction guided finger-tapping, (IV) copying of displayed hand shapes and (V) covert speaking task. Task V requires phoneme based word generation. Preliminary results demonstrate that the frontal lobe of humans contains a region that is comparable to the PMv of monkeys and this area lies in a ventral inferior part of BA6, BA44 and BA45. In addition, these studies are being extended to deaf subjects who are native users of American sign language (ASL) where the Broca's areas language and motor functions are further examined. The advantage in this approach is the similarity of the language and motor tasks that can be designed. In previous years we have accumulated a large set of data which we are in the process of analyzing.

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This proposal requests funding for the acquisition of a 3T MRI scanner for human and animal brain imaging for use by a large, multi-disciplinary, dual-university community of users. The instrument is based on a Signa Horizon LX platform, optimized for activation studies. The very high-field strength enhances the signal to noise ratio and contrast for fMRl applications, enables the collection of very high-resolution structural images, and it is equipped for ultra-fast echoplanar imaging (EPI) that enables images to be acquired and processed at the rate of over 10 images per sec.

The scanner would be the centerpiece of a new, inter-university Imaging Institute that brings together researchers in several disciplines at the University of Pittsburgh and Carnegie Mellon: cognitive neuroscientists who study human performance in complex environments, neuroscientists combining single-cell recording and neuroimaging with monkeys, biophysicists interested in advancing MR methods, statisticians with expertise in neuroimaging, and computer scientists interested in the analysis of large-scale databases. The basic science approach aims at an interdisciplinary synergy focused on brain imaging and theoretical integration. The university-supported Imaging Institute will provide a rich infrastructure and appropriate staffing to maximize the benefits of the scanner.

The new instrument will be optimized for assessing a wide range of cognitive processes and will provide an unparalleled opportunity to relate human and animal cognition. The new facility will provide a data rich environment in which the 34 participating investigators (and a total group of 174 potential users) can combine their expertise in biomedical engineering, cognitive psychology, computer science, education, linguistics, statistics, and neuroscience. The investigators include seasoned researchers who can link brain imaging to their established research disciplines, thereby enriching the imaging research.

There are five areas of basic science research: 1. Cognitive processing (of language, problem solving, spatial processing, motor control, and learning); 2. Monkey imaging (of network activity, maturation/learning, activity dependent contrast agents, relation to single neuron activity, and structural imaging); 3. Analysis methods including statistical analysis (noise reduction, hierarchical Bayesian assessment, motion correction) and computer science analysis (machine learning, data mining, and analyzing the content of images); 4. MRI methods development including: fast fMRI imaging, respiratory/cardiac noise reduction, reduction of susceptibility artifact, metabolic and volumetric imaging, animal RF coils and contrast agents; and MR spectroscopy of metabolites; and 5. computational modeling of cognitive function, examining how a variety of computational architectures can simultaneously account for human performance and fMRI patterns.

The facility will provide extensive training and research time (20,000 hours of scanning over the next five years) to undergraduates, graduates, postdocs and faculty, and will infuse the unfolding science into the ongoing educational mission. The training activities include the development of new graduate and undergraduate courses (using a new brain imaging computer classroom), seminars and workshops on brain imaging, a new brain imaging graduate core, and summer undergraduate research traineeships. External training will include workshops, web course materials, software tools, and functional imaging and modeling data sets. Outreach activities include courses for educators, museum shows, web programs, and technology transfer with industrial partners.

The activity would advance the new interdisciplinary science, extending and integrating the growing knowledge in this area into comprehensive theories of brain and mind.

DESCRIPTION (provided by applicant): The classical view is that the outputs from the basal ganglia and cerebellum project to a region of the ventrolateral thalamus that ultimately influences a single cortical area, the primary motor cortex. In contrast, the basal ganglia and cerebellum receive input from multiple areas of the cerebral cortex located in the frontal, parietal, and temporal lobes. This view contributed to the concept that the basal ganglia and cerebellum perform a sensorimotor transformation on the diverse cortical input they receive. The results of this processing are then used to generate and control movement at the level of the motor cortex. New anatomical findings have required a reappraisal of this functional construct. For example, we have shown that the outputs from the basal ganglia and cerebellum project not only to primary motor and premotor areas of cortex, but also to selected portions of prefrontal, posterior parietal and inferotemporal cortex. Thus, it is now clear that the outputs from the basal ganglia and cerebellum influence more widespread regions of the cerebral cortex than previously suspected. In general, we have seen that cortical areas that project to the input stage of basal ganglia and cerebellar processing also are the target of basal ganglia and cerebellar output. This and other observations have led us to hypothesize that a major organizational feature of basal ganglia and cerebellar anatomy is their participation in closed 'loop' circuits with multiple cortical areas. We now propose to test whether this functional architecture extends to other regions of the cerebral cortex that are known to provide input to the basal ganglia and cerebellum. For example, anterior cingulate and orbital frontal cortex are major sources of input to the basal ganglia. Similarly, widespread areas of the posterior parietal cortex which were not examined in our prior studies are major sources of input to the cerebellum. We will use retrograde transneuronal transport of neurotropic viruses to test whether the output nuclei of the basal ganglia and cerebellum project back upon these areas of cortex. It is known that abnormal activity in basal ganglia and cerebellar loops with motor areas of cortex results in hypo-and hyperkinetic movements. Likewise, abnormal activity in loops with cingulate, orbital frontal, and posterior parietal cortex could lead to a broad range of psychiatric and neurological symptoms such as those associated with depression, obsessive-compulsive disorder, Parkinson's and Huntington's Disease. When these loops are functioning normally, they could provide the neural substrate for basal ganglia and cerebellar involvement in cognitive, emotional and perceptual domains. Thus, the results of these experiments could have important implications for concepts regarding basal ganglia and cerebellar contributions to normal and abnormal behavior.

The classical concept of the cortical control of sequential movements is that the premotor areas, particularly those on the medial wall of the hemisphere, are critical for learning and storing the representations of new sequences. According to this view, the primary motor cortex (M1) is thought simply to produce the patterns of muscle activity necessary to implement the plans generated by the premotor areas. Recent data have led to some challenges to this point of view, and raise the possibility that M1 plays a more active role in the acquisition and retention of sequential movements than previously thought. The primary goal of this project is to examine whether practicing sequences of movements actually induces changes in the response properties of M1 neurons, as well as induces changes in the properties of neurons in the premotor areas that project to MI. In preliminary studies, we developed a behavioral task that allows us to examine the processes of motor skill acquisition, performance and retention in monkeys. Next, we recorded the activity of neurons in the arm area of M1 in one monkey that was over-trained to perform sequences of pointing movements- internally generated or visually instructed. Our initial results suggest that, with practice, aspects of learned sequences come to be represented in the activity of M1 neurons. We also used the 14C-2-deoxy-glucose (2DG) technique to image metabolic activity associated with performance of the internally generated movement sequences. The imaging results provide further evidence that long-term practice on sequences alters activity patterns in MI. To further explore the cortical control of sequential movements, we propose to continue our examination of the effects of extended practice on the response properties of M1 neurons and on the patterns of metabolic labeling in MI. Next, we will compare the response properties of M1 neurons with those of neurons in several premotor areas in the frontal lobe that project to it. Finally, we will examine the activity of M1 neurons in monkeys who are at early, middle and late stages of skill acquisition.

[unreadable] DESCRIPTION (provided by applicant): [unreadable] The use of viruses to define the synaptic organization of neuronal circuitry has experienced an explosive growth over the past decade. This experimental approach is the most widely used method to provide a polysynaptic perspective on the functional architecture of the nervous system. Consequently, it has proven to be increasingly popular among neuroscientists whose goal is to define ensemble organization of populations of neurons devoted to specific functions. The goal of this application is to establish a state of the art National Resource Center that will a) serve as a technical and intellectual resource for those interested in using viral transneuronal tracing, b) develop improved transneuronal tracing technologies and make them available to investigators throughout the United States via access to center resources and training, c) serve as a repository for well-characterized reagents essential to the application of the method, and d) stimulate collaborative multidisciplinary studies of mechanisms underlying viral neuroinvasiveness and pathogenesis. Our efforts to establish this National Resource Center are based upon five fundamental tenets. First, there is a general consensus that the method offers a powerful means for functional dissection of neural circuitry, but implementation of the procedures is a costly endeavor beyond the reach of most investigators. Second, recent literature clearly demonstrates that there are valuable and important avenues that can be pursued to improve this technology. A Center would provide the necessary resources and focus to energize this technology development and make it more widely available. Third, there is historical precedent demonstrating that multidisciplinary research in this area rapidly advances the understanding of fundamental principles in multiple fields. A Center would provide the focus and platform for developing such interactions. Fourth, the University of Pittsburgh is the home for a surprising number of investigators who have been influential in the development and application of this methodology and also have productive collaborative relations with other prominent investigators who have been similarly influential. Thus, the Center would be established and successful within a relatively short period of time. Fifth, special facilities already exist at the University of Pittsburgh that meet the unique requirements for the use of alpha herpesviruses and rabies virus in multiple species, including non-human primates. Collectively, these observations support the conclusion that establishment of a Center at the University of Pittsburgh will provide a unique National Resource that will contribute substantially to efforts to improve our understanding of nervous system function and organization. [unreadable] [unreadable]

There is growing evidence that the basal ganglia participate in multiple 'loops' with a wide variety of cortical areas including regions of motor, premotor, prefrontal, orbitofrontal, cingulated, posterior parietal and inferotemporal cortex. These circuits could provide the basal ganglia with the neural substrate to influence motor, cognitive, emotional and perceptual domains of behavior. Likewise, abnormal activity in basal ganglia loops with the cerebral cortex could lead to a broad range of motor and neuropsychiatric symptoms such as those associated with Parkinson's and Huntington's Disease, L-DOPA toxicity, Tourette's syndrome, Attention Deficit Hyperactivity Disorder, Obsessive-Compulsive Disorder and depression. The overall goal of the experiments in this application is to link the specific motor and behavioral symptoms associated with basal ganglia dysfunction to the cortical areas that are responsible for their expression. To achieve this goal we will employ a unique multi-disciplinary approach. We will make microinjections of a GABAergic antagonist, bicuculline, into the external segment of the globus pallidus (GPE). These injections produce reversible dyskinesias, hyperactivity, attention deficits or stereotypes, depending upon the location of the injection site. We propose that the cortical area determines these symptoms, which is the target of the abnormal signals from the GPe. To begin to test this hypothesis we will locate the site in GPe where bicuculline injections produce hyperactivity. Then, we will use a novel neuroanatomical technique-transneuronal transport of rabies virus-to identify the cortical areas that are interconnected with this GPe region. Rabies virus is transported transneuronally in the retrograde direction through chains of synaptically-connected neurons (Kelly and Strick, '00, '03, '04). We will use transneuronal transport of rabies after injections into the hyperactivity site in GPe to define the cortical areas which are the source of input to this region of GPe. In a second set of experiments, we will use transneuronal transport of rabies after injections into the cerebral cortex to define the cortical areas which are the target of output from the hyperactivity site in GPe. Together these experiments should provide the 'proof in principle' that this two stage approach can be used to identify cortical areas that are responsible for the expression of motor and non-motor abnormalities associated with basal ganglia dysfunction. The results of these experiments should provide new insights into the functional neuroanatomy of basal ganglia disorders. As a consequence, our findings could stimulate new therapeutic approaches for dealing with complex problems like dopa-induced dyskinesias and the cognitive and emotional dysfunctions associated with Parkinson's Disease.

DESCRIPTION (provided by applicant): There is growing evidence that the basal ganglia (BG) participate in multiple segregated "loops" with a wide variety of cortical areas including regions of motor, prefrontal, posterior parietal and inferotemporal cortex. These circuits provide the BG with the neural substrate to influence motor, cognitive, emotional and perceptual domains of behavior. We and others have argued that abnormal activity in BG loops with the cerebral cortex could lead not only to motor disorders, but also to the behavioral symptoms associated with neuropsychiatric disorders like Depression, Obsessive-Compulsive Disorder (OCD) and Tourette Syndrome (TS). The overall goal of our experiments is to link the non-motor symptoms associated with BG dysfunction to the cortical areas that are responsible for their expression. The basal ganglia can be subdivided into 3 general territories: sensorimotor, associative and limbic. This application will focus on the associative and limbic territories. Prior studies have shown that microinjections of the GABA antagonist, Bicuculline (BIC) into the associative and limbic territories of the external segment of the globus pallidus (GPe) reversibly evoke abnormal behaviors. The behavior that is evoked depends on the specific site injected within GPe. BIC injections into the associative territory evoke hyperactivity and attentional deficits, whereas injections into the limbic territory of GPe evoke excessive grooming, nail biting, and communicative gestures. We propose that the symptoms produced by a microinjection of BIC are determined by the cortical areas that are the targets of the abnormal signals from GPe. We will use transneuronal transport of rabies virus to identify the cortical areas that are interconnected with behaviorally characterized sites in GPe. We propose two sets of experiments. In the first set of experiments, we will behaviorally define sites in the associative and limbic territories of GPe using BIC micro-injections. Then, we will inject a small amount of rabies virus at the GPe site and allow retrograde transneuronal transport of the virus to label 2nd order neurons in the cerebral cortex. This approach will identify the cortical neurons that provide input to the associative and limbic territories in GPe. In a second set of experiments, we will again use micro-injections of BIC to define specific sites in the associative and limbic territories of GPe. These sites will be marked with micro-lesions. Then, we will inject rabies virus into specific areas of the cerebral cortex and allow retrograde transneuronal transport to label 3rd order neurons in GPe. We will compare the location of these GPe neurons to the marking lesions in GPe. This approach will identify cortical areas that are the targets of output from the associative and limbic territories in GPe. Together these experiments should provide new insights into the cortical areas that are responsible for the non-motor symptoms of basal ganglia dysfunction. This information may lead to new avenues for treatment of complex disorders like Depression, OCD and TS. PUBLIC HEALTH RELEVANCE The proposed studies will define the matrix of interconnections that link the basal ganglia with cortical areas in the frontal lobe. These circuits are essential for normal cognitive and affective function, and they appear to be dysfunctional in a wide variety of neuropsychiatric disorders. Thus, the results of the proposed studies could lead to new avenues for treatment of complex disorders like Depression, Obsessive-Compulsive Disorder and Tourette Syndrome.

The ability to link elementary actions together to perform a meaningful sequence of movements is a key component of voluntary motor behavior. Many of our daily motor tasks (e.g., handwriting, typing, etc.) depend on attaining a high level of skill in the performance of sequential movements. Consequently, the neural basis of skill acquisition and retention is a fundamental problem of systems neuroscience. To explore the cortical involvement in this behavior we will use optical imaging and single neuron recording to define patterns of activity in the primary motor cortex (Ml) and the dorsal premotor area (PMd) as monkeys learn to perform and practice sequences of movements. We will monitor activity at various times in relation to an animal's level of skill acquisition and task performance. The data from optical imaging and single neuron recording are likely to provide fundamental insights into the neural basis of motor skills. However, both techniques are correlational approaches. To test causality, we will make micro-injections of various pharmacolgic agents in M1 and the PMd to disrupt local neuron activity, protein synthesis and ERK signaling. We will determine the effects of these micro-injections on the acquisition, performance and retention of motor skills. Taken together, the proposed studies will provide some novel information on the cortical mechanisms that underlie a critical aspect of human behavior- the acquisition and retention of motor skills. In addition, there is growing evidence that many of the mechanisms of plasticity that are used to acquire new skills may also be available to promote recovery of function following traumatic brain injury or stroke. Thus, the new insights gained from the proposed experiments may suggest novel rehabilitation strategies for restoring motor function. RELEVANCE (See instructions): The proposed work is central to the problem of understanding the mechansims where practice leads to to reorganization of the human motor system in the face of aging, neurodeneration, stroke or brain injury. Understanding these mechansims has an impact on the design of therapies directed at preserving function, developing compensator movements and ultimately, developing novel motor capacity.

The Administration Core will have the staff to manage the administration of the CNRN. Because the Center will use NHPs, its administration will have requirements that go well beyond those of the usual research center. These requirements include arranging for purchase, transport and quarantine of NHPs, tracking daily care and procedures to ensure enrichment and psychological well-being of NHPs, and tracking compliance with personnel training and immunization requirements. Overall, the CNRN is organized to strengthen current research, create new research opportunities, and foster collaborative interaction. As a consequence, the Center will speed the translation of basic science observations into new and improved treatments for neurological disorders. The University has made the substantial investment in infrastructure and faculty to create the CNRN. We are now seeking support for the essential staff to operate the Center.

Facilities and Services. This Core will provide each investigator with access to high-quality histological processing of neural tissue from various regions of the brain and spinal cord. The Core will have staff and equipment necessary for whole-brain histology. Physiological research on the brain and spinal cord requires precise anatomical confirmation of stimulation, recording, injection and lesion sites. This Core will have the expertise to offer complex immunohistological procedures, in addition to conventional neurohistology. The Histology Core will have a state-of-the-art laboratory with 3 microtomes for sectioning NHP brains and two experienced histologists who practice their craft on a daily basis.

DESCRIPTION (provided by applicant): The goal of this application is to establish a Center for Neuroscience Research in Non-Human Primates (CNRN) at the University of Pittsburgh. Each of the Center's six Cores - (1) Veterinary Services; (2) Surgery; (3) Histology; (4) Imaging; (5) Bioengineering, Computing, and Electronics; and (6) Administration - is designed to meet the specialized needs for neuroscience-related research in awake, behaving non-human primates (NHPs). The CNRN has 3 main goals: (1) To support the neuroscience research of current major users of non-human primates; (2) To make resources available to Early Stage Investigators who are setting up labs to work with NHPs; and (3) To enable investigators who work with other model systems to perform proof of principle studies in NHPs. The Center's resources will be available not only to investigators at the University of Pittsburgh, but also to those at our sister institution, Carnegie Mellon University. The CNRN does not overlap or duplicate other facilities within the University. Indeed, certain types of research will only be possible because of the existence of the Center. The Center has 9 NINDS-qualifying research projects directed by 6 separate Principal Investigators. Overall, the Center will serve the needs of faculty in multiple Basic Science (4) and Clinical Departments (11), including 17 heavy users, 6 Early Stage Investigators, and 11 investigators who have expressed an interest in testing their ideas in a NHP model. In summary, the CNRN will be a critical resource for at least 28 scientists with 50 grants (30 of which are NINDS grants) at 2 major institutions, the University of Pittsburgh and Carnegie Mellon University. The Center will serve multiple Centers of Excellence at the University of Pittsburgh including those focused on topics of primary interest to the mission of NINDS, such as Parkinson's and Huntington's Diseases, traumatic brain and spinal cord injury, stroke and the normal and abnormal control of movement.

This proposal requests renewal of postdoctoral training in the Neurobiology of Neurological Disease. This is a 2 year program that currently funds six fellows each year. Due to the success of this program, as well as the large number of qualified candidates and faculty mentors, we seek an increase to cover eight fellows. Our program has five primary goals: 1) To foster understanding of the diseases and syndromes that are of high relevance to NINDS; 2) To ensure that trainees are appropriately mentored in their research and that they acquire the professional skills necessary for independent careers in neuroscience; 3) To afford opportunities for innovative research; 4) To attract underrepresented minorities to postdoctoral training in neuroscience; and 5) To support training of special cases ? individuals whose needs differ from those of the typical training fellow. These special cases may include individuals with computational backgrounds who now seek biological training, as well as young scientists who take on projects that require extended time and effort for completion. Our program requires trainees to be active participants in a two-year course on the ?Neurobiology of Disease.? Many sessions of the course are taught by an academic clinician and a basic scientist, and include patients to illustrate a relevant disease or syndrome that is the topic of the session. The course is spread over two years to cover the full spectrum of diseases and syndromes. This time period also makes it easier to schedule the participation of patients and active clinicians. At least two presentations per year are devoted to critical analysis of clinical research, as well as basic science papers. This allows trainees to discuss issues relevant to experimental design and data analysis. We also provide trainees with a two-step Professional Development Series that is tailored to the specific needs of early- and late-phase postdoctoral fellows in neuroscience. The professional development series includes topics ranging from grant writing to exploring job opportunities and setting up a first lab. Trainees can also take additional courses, as needed, to fill in gaps in their background. At the core of every postdoctoral experience is mentored research in an accomplished laboratory. To oversee this experience we have devised a mentoring program that includes regular review of both the trainee and the mentor. Each trainee has a primary research adviser as well as an individualized Research Advisory Committee. This arrangement has proven to be especially helpful to Early Stage Investigators who have trainees in their laboratories for the first time. Our 49 training faculty supervise 55 postdoctoral trainees. More than half of these trainees are eligible for individual NRSA and/or T32 support. We believe that the quality and breadth of our faculty, the state-of-the-art facilities, and the unique nature of our training program enable us to attract outstanding fellows and provide them with a special experience.

We know almost nothing about the neural basis of the Brain-Body connection. This connection is the circuitry that enables motor, cognitive and affective processing to have a major impact on the function of internal organs such as the stomach, heart and spleen. Inappropriate signals in these networks are thought to contribute to the generation of some prevalent medical illnesses, and to cause the so-called functional and psychosomatic disorders. The experiments proposed in this application will fill a major gap in our knowledge. We will identify the cortical areas that influence, and in some instances control the function of the gastrointestinal (GI), cardiovascular and immune systems. The brain-body connection is based on chains of synaptically-connected neurons. No conventional neuroanatomical tracer is capable of revealing multi-synaptic circuits. To overcome this shortcoming, we developed the use of rabies virus as a transneuronal tracer in non-human primates. We propose to use this unique approach to reveal the complex networks that are responsible for the top-down influence of the central nervous system on the stomach, heart and spleen. There is a growing awareness that many medical symptoms, especially those without identifiable pathology, may be caused by a disturbance in the brain-body connection. This is especially the case for often intractable disorders such as irritable bowel syndrome, stress- and depression-related heart disease, and fibromyalgia. Thus, the information that will come from our studies has the potential to transform the way we view and treat these disorders. In essence, the brain-body connection is a construct that lacks a concrete basic science foundation. The results from the proposed research will establish a structural framework for the brain-body connection and thus, create new opportunities for rigorous research and novel approaches for treatment. This information, because of its all-encompassing nature, will be of interest to many, if not all of the NIH Institutes and Centers.

ABSTRACT Visual learning is critical to the lives of human and non-human primates. Visuomotor association, the assignment of an arbitrary symbol to a particular movement (like a red light to a braking movement), is a well- studied form of visual learning. This proposal tests the hypothesis that the brain accomplishes visuomotor associative learning using an anatomically defined closed-loop network, including the prefrontal cortex, the basal ganglia, and the cerebellum. In our preliminary work we have developed a task that studies how monkeys learn to associate one of two novel fractal symbols with a right hand movement, and the other symbol with a left hand movement. Every experiment begins with the monkeys responding to two overtrained symbols that they have seen hundreds of thousands of times. At an arbitrary time we change the symbols to two fractal symbols that the monkey has never seen. It takes the monkey 40 to 70 trials to learn the new associations. In our preliminary results we have discovered that Purkinje cells in the midlateral cerebellar hemisphere track the monkeys? learning as they as they figure out the required associations. The neurons signal the result of the prior decision. Half of the neurons respond more when the prior decision was correct; the others respond more when the prior decision was wrong. The difference between the activity of these two types of neurons provides a cognitive error signal that is maximal when the monkeys are performing at a chance level, and gradually becomes not different from zero as the monkeys learn the task. The neurons do not predict the result of the impending decision. Although the neurons change their activity dramatically at the symbol switch, the kinematics of the movements do not change at all. This proposal takes this discovery as the starting point for four aims: 1) to use viral transynaptic tract tracing to discover the cortical and basal ganglia regions that project to the cerebellar visuomotor association area. 2) to record from the four nodes of the network as anatomically defined (midlateral cerebellar hemisphere, dentate nucleus, basal ganglia, prefrontal cortex), simultaneously, using multiple single neuron recordings, to see if these areas also have information about the process of visuomotor association 3) to inactivate each node, to see how their inactivation affects the monkey?s ability to learn new associations, and whether the inactivation affects the activity of the neurons at the other nodes. 4) to develop computational methods to analyze the activity of neural activity recorded simultaneously in all four nodes of the network (Aim 2) in the midlateral cerebellar cortex with regard to parameters such as prior outcome and movement, hand, symbol, and the intensity and epoch of the prior cognitive error signal. We will use dimensional reduction techniques to answer questions like whether hand or symbol can be decoded from network activity. We will model how the cerebellum simple spike cognitive error signal might propagate through the network and be used to facilitate visuomotor association learning and the processing of signals in the cerebellum, basal ganglia and cerebral cortex

PROJECT SUMMARY. The demonstration in the late `80s and early `90s that specific strains of herpes and rabies virus are transported transneuronally exclusively at synapses in a time- and direction-dependent fashion opened up a new era in experimental neuroanatomy. Virus transneuronal transport is uniquely able to reveal the cellular composition of multi-synaptic circuits. As a consequence, this technique is providing fundamental new insights into the functional architecture of sensory, motor, cognitive and affective circuits in the central nervous system. The Center for Neuroanatomy with Neurotropic Viruses (CNNV) was created in 2004 to provide the neuroscience community with access to the highly specialized reagents, training and facilities that are necessary to use neurotropic viruses as transneuronal tracers. We document in this application that the CNNV has become an essential national and international resource for an important segment of the neuroscience community. Users of the Center are funded by 15 different institutes of the NIH, by NSF and by private foundations and international research organizations. The Center has established a strong history of providing well-characterized reagents, training and guidance in the use of the method, and specialized biohazard facilities for performing experiments using neurotropic viruses. The Center has served as an essential technical and intellectual resource for those interested in using this novel method. The goal of the Resource Component of this competitive renewal is to continue these essential functions of the Center.

PROJECT SUMMARY. The demonstration in the late `80s and early `90s that specific strains of herpes and rabies virus are transported transneuronally exclusively at synapses in a time- and direction-dependent fashion opened up a new era in experimental neuroanatomy. Virus transneuronal transport is uniquely able to reveal the cellular composition of multi-synaptic circuits. As a consequence, this technique is providing fundamental new insights into the functional architecture of sensory, motor, cognitive and affective circuits in the central nervous system. The Center for Neuroanatomy with Neurotropic Viruses (CNNV) was created in 2004 to provide the neuroscience community with access to the highly specialized reagents, training and facilities that are necessary to use neurotropic viruses as transneuronal tracers. We document in this application that the CNNV has become an essential national and international resource for an important segment of the neuroscience community. Users of the Center are funded by 15 different institutes of the NIH, by NSF and by private foundations and international research organizations. The Center has established a strong history of providing well-characterized reagents, training and guidance in the use of the method, and specialized biohazard facilities for performing experiments using neurotropic viruses. The Center has served as an essential technical and intellectual resource for those interested in using this novel method. The goal of the Resource Component of this competitive renewal is to continue these essential functions of the Center.