Associate Professor of Bioengineering
The Clark Lab
Brain and Behavior
Neurobiology of Disease
A.B. 1975, Brown University; Ph.D. 1982, University of California, Irvine; Postdoctoral Fellow, 1982-1984, Columbia University
Bio-based neuroprostheses; electrophysiological, cellular, and computational analyses of neuronal information processing and plasticity in simple systems (Aplysia and Hermissenda)
Dr. Clark's research uses physiological and computational approaches to investigate neural function, dysfunction, and treatments. Ongoing neuroprosthesis research uses high-count Utah Slanted Electrode Arrays implanted in peripheral nerves to reanimate paralyzed muscles, and to control and provide feedback from artificial limbs. Because the array electrodes are in close proximity to nerve fibers, it is possible to record or stimulate small groups of neurons very selectively. Combined physiological and computational modeling studies using the eye of the marine mollusk Hermissenda as a simple model system investigate the role of contextual spike-timing codes and subcellular-level noise, which paradoxically improves, rather than degrades, systems-level encoding of light intensity. His laboratory also explores synapse-specific plasticity and its underlying mechanisms, using the marine mollusk Aplysia.
Butson, C.R., and Clark, G.A. (2008) Mechanisms of noise-induced improvement in light-intensity encoding in Hermissenda photoreceptor network. J. Neurophysiol., 99:155-165.
Guan X., Clark G.A. (2006) Essential role of somatic and synaptic protein synthesis and axonal transport in long-term synapse-specific facilitation at distal sensorimotor connections in Aplysia. Biol. Bull., 210:238-254.
McDonnall D., Clark G.A., Normann R. (2004) Selective motor unit recruitment via intrafascicular multielectrode stimulation. Can. J. Physiol. Pharmacol., 82:599-609.
McDonnall, D., Clark, G.A., Normann, R.A. (2004) Interleaved, multi-site electrical stimulation of cat sciatic nerve produces fatigue-resistant, tremor-free motor responses. IEEE Trans. Neur. Sys. Rehab. Eng., 12:208-215.
Clark, G.A. (2002) Regulation of synaptic efficacy. In: International Encyclopedia of the Social and Behavioral Sciences, J.L. McClelland and R.F. Thompson (eds.), Oxford, England, Elsevier Science.
Schultz, L.M., and Clark, G.A. (2001) Post-light potentiation at type B to A photoreceptor connections in Hermissenda. Neurobiol. Learn. Mem., 76:7-32.
Clark, G.A. (2001) The ins and outs of classical conditioning: Maxims from a mollusk. In: Model Systems and the Neurobiology of Associative Learning, J.E. Steinmetz, M. Gluck, and P. Solomon (eds.), Lawrence Erlbaum Associates.
Fost, J.W., and Clark, G.A. (1996) Modeling Hermissenda: II. Effects of variations in type-B cell excitability, synaptic strength, and network connectivity. J. Comput. Neurosci., 3:155-172.