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Mark F. Dubach PhD Associate Professor mdubach@u.washington.edu Phone: (206) 543-6772 Fax: (206) 685-0305 Site: UW Medical Center Health Sciences Building 1959 NE Pacific Street Box 357330 Seattle, WA 98195 Link to CV Division Psychiatric Neurosciences

Bio Brain Implants in a Basal Ganglia Neurophysiology: We have developed a means of threading a hollow fiber through a given region in brain in such a way that both ends of the loop are available for applying drugs to the brain parenchyma and for sampling the extracellular fluid. In this project we are applying antagonists to D1 and D2 dopamine receptors in the putamen and observing their effect on neuronal activity in the globus pallidus and on performance of a sensorimotor task. This new approach to pharmacology and electrophysiology is relevant to basal ganglia syndromes such as Parkinson's and Huntington's disease. Excitatory Amino Acids and Focally-Evoked Convulsions and GABA-mediated Anticonvulsant Actions and Basal Ganglia: Epilepsy is often linked to damage at a "seizure focus", some part of the brain unique to each patient where the seizure presumably begins and from which it spreads to other regions. But some types of seizure can occur without a discernable focus. One or two structures and pathways may play a key role in most patients and may even be related to the distribution and severity of "focal" seizure effects. The focus of our research in these two closely related projects is a small site near the piriform cortex in nonhuman primates. We have found that direct blockade of GABA receptors at this site can elicit frontal and temporal lobe seizures. We are testing the pharmacological features of this phenomenon by intracranial injection of GABA antagonists and excitatory amino acid antagonists at this site. We are also investigating the functional neuroanatomy of these effects by treating the substantia nigra and the deep layers of the superior calyculus, which are know to modulate seizure development and propagation in rats.