A promising model to study the neural mechanisms of motor plasticity is conditioned response learning which is a simple form of associative learning. The eye-blink reflex has been widely adopted for physiologic studies of the mechanisms of conditioned response learning. Recently, a significant advancement in the study of the conditioned eye-blink has been made. Using the in vitro brainstem-cerebellum preparation from the turtle, the neural correlates of the conditioned eye-blink response can be generated entirely in vitro. Thus the cellular mechanisms underlying this type of motor learning will be more accessible for study than has previously been achieved using whole animal preparations. As an initial step in studying the mechanisms of acquisition and execution of learned motor responses in vitro, the goals of Dr. Joyce Keifer are: 1) to examine sites of convergence of conditioned and unconditioned afferent inputs using activity-dependent dye uptake and extracellular recordings; and 2) to assess which of these sites of convergence are essential to the generation of the conditioned response using reversible lesions. These highly exploratory studies will provide a significant advance in our understanding of the cellular bases of synaptic integration underlying motor control learning, which is of global relevance to processes fundamental to behaviorally adaptive motor control.
