1987 — 1989 |
Baizer, Joan Susan |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Behavioral Functions of Association Cortex @ State University of New York At Buffalo
Much is now known about the simple, passive analysis of sensory stimuli by each sensory system. However, the cognitive processes which depend on these stimuli, including learning and memory, object recognition, and integration of stimuli from several modalities, are still largely mysterious. Nor is it known how the brain combines incoming sensory information about the environment with stored information about past experience, and with information about the organism's motivational state to program appropriate behavior. The long-term goals of this research are to understand the neural mechanisms underlying perception, learning, and sensorimotor integration. The focus of the present proposal is on the contribution of visual association cortex, traditionally known as areas 18 and 19, or prestriate cortex, to these higher cognitive processes underlying behavior. In macaque monkey, an area known as "V4" or the "V4 complex" occupies the prelunate gyrus and adjacent buried cortex of the lunate and superior temporal sulcus. Data from visuotopic mapping studies in this region suggest that there are several topographic subdivisions. Studies of single-cell response properties suggest that the area is functionally heterogeneous. The Aims of the present proposal are to investigate the relation between the functional mosaic and visual topography in the V4 complex, and to see if topographic subunits are distinguished by functions, connections or myeloarchitecture. Response properties of single neurons in this cortex will be studied in the awake behaving monkey. Animals will be trained on a number of different tasks, so responses of neurons in different behavioral contexts may be compared. The first Aim is to study classical receptive field properties of neurons. The second Aim is to evaluate the nature and extent of surround-mediated response modulation in these zones, to assess their contribution to object recognition. The third Aim is to study the effects of shifts of attention on neuronal responses. Finally, the fourth Aim is first to examine projections from V2 to two of these topographic zones, AL and PM, to see if different cell groups in V2 send input it them, and second to see if these two zones may be distinguished on the basis of myeloarchitectonics.
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0.958 |
2003 — 2004 |
Baizer, Joan Susan |
R03Activity Code Description: To provide research support specifically limited in time and amount for studies in categorical program areas. Small grants provide flexibility for initiating studies which are generally for preliminary short-term projects and are non-renewable. |
Methylphenidate &Gene Expression in the Rat Brain. @ State University of New York At Buffalo
DESCRIPTION (provided by applicant): The long-term objectives of this research are to understand the changes in neuronal structure and function that may be caused by long-term use of ethylphenidate. ADHD/ADD is a common disorder affecting as many as 6% of schoolchildren. The ADHD/ADD population is at risk for school failure, difficulties with interpersonal relationships, and later substance abuse. ADHD/ADD is best treated by a combination of medication and behavior management. The most commonly prescribed drug used to treat ADHD/ADD is methylphenidate, Ritalin. Methylphenidate is a highly effective drug for treating impulsivity, hyperactivity, and inattention, the symptoms of ADHD, and seems to be safe. Abuse, tolerance and sensitivity are not major clinical concerns in its use. At present, we do not understand all of the mechanisms by which methylphenidate exerts its beneficial effects, nor do we know what neuronal changes may result from its use. There is concern about the potential effects on the brain and behavior of its long-term use, and especially over whether its use can affect the likelihood of later substance abuse. One reason for this concern is that Ritalin binds to the dopamine transporter and increases dopamine levels in the brain. Other psychostimulant drugs, amphetamine and cocaine, also increase dopamine levels, and these drugs are major drugs of abuse. A single dose of those drugs cause short-tem changes in expression of the Immediate Early Genes. Chronic use results in a complex pattern of changes in the expression of the IEG's and other genes. These changes in gene expression are thought to mediate the changes in behavior underlying addiction. We have found that a single dose of Ritalin results in expression of the Immediate Early Gene c-fos in the rat brain. We wish now to analyze the effects of chronic Ritalin use on gene expression, using the techniques of immunohistochemistry and DNA Microarray technology. Knowledge of the effects on gene expression will allow a more direct comparison of the effects of Ritalin on the brain with the effects of amphetamine and cocaine, provide more information about its mechanisms of action and allow more informed predictions about the long-term consequences of its use.
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0.958 |