The goal of this proposal is to determine the effects of practice on the cortical mechanisms producing sequential hand movements in primates. Although clinical and imaging studies have identified various brain areas related to improvements in performance resulting from practice, the underlying neural mechanisms for such changes are largely unknown. This proposal focuses on three areas in the primate frontal cortex that are commonly considered to play important roles in learning of motor sequence: the prefrontal cortex (PF), supplementary motor area (SMA), and dorsal premotor cortex (PMd). The following hypotheses will be tested: (1) after learning, neuronal activity reflects anticipated location of the next target before it is presented; (2) the PF plays an important role in early stages of sequence learning, and its contribution diminishes as the SMA and/or PMd establish mechanisms for more automatic execution of sequential movements; (3) anticipatory activity in frontal cortex provides a mechanism for timing of sequential movements; (4) spatial and temporal information about sequential movements is processed in parallel by different populations of neurons; and (5) the rate of synchronized spikes is influenced by practice, and carries information about sequential movements.
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