Barchi Library, 140 John Morgan Building
Post-doc, Gold/Cohen Labs
University of Pennsylvania
Dual mechanism of motor-goal encoding and decision-making in monkey sensorimotor cortices during biased reach selection
I am presenting my previous work on action selection between reach movements. Action choices can be regarded as competition between motor-goal alternatives. We investigated the effect of prior expectation on motor-goal competition in premotor and parietal motor-planning areas. Monkeys performed a rule-guided reach selection task with graded prior predictability of the rule instruction on instructed trials. Rule predictability induced a graded choice bias on interspersed choice trials despite the priors were neutralized at the moment the decision was required. Graded modulation of neural motor-goal responses mirrored prior-induced choice biases during movement planning. Individual neurons in both brain areas contributed to the biased competition in two complementary ways, either up-regulating when the action prior matched the neurons’ coding direction, or down-regulating in the opposite case, but rarely both. Choice signals in both brain areas reflected reaction time differences, but emerged earlier in down-regulated neurons of the premotor area. Our results suggest a dual mechanism of action goal encoding and action selection process in the fronto-parietal network.
A pizza lunch will be served.