Assistant Professor of Psychology
We investigate how neuromodulators - particularly acetylcholine - alter activity in mammalian cortical circuits. It is known that acetylcholine can briefly and selectively boost the strength of sensory input arriving at the neocortex from the eyes, skin, ears, and nose. This boosting enables a preferential processing of sensory data over ongoing internal cortical activity; a process that has been compared to “attending” to the external world (in contrast to, say, “attending” to one’s internal thoughts). In addition to these transient effects, prolonged acetylcholine release into the neocortex triggers massive reorganization of cortical maps and alters the local balance of excitatory and inhibitory activity. These longer term changes have been linked to learning and memory. Current questions being investigated in the lab are: How does the cortical cholinergic system subserve these diverse functions, at a mechanistic level? And what is the relationship between acetylcholine’s short-term (attention-like) and long-term (memory-like) effects?
We use diverse techniques to answer these questions. We make and use a unique combined multi-electrode array that can simultaneously monitor local acetylcholine levels (or levels of other neuromodulators) and the spiking activity of neurons. We also explore the mechanisms by which acetylcholine receptors act within cortical circuits using pharmacological techniques. Both of these techniques are used in in combination with behavioral studies. And finally, to make the crucial connection between structure and function, we examine how acetylcholine receptors are distributed within the neocortex using neuroanatomical techniques at the light, confocal, and electron microscopic levels.