Parallel Specification of Competing Sensorimotor Control Policies for Alternative Action Options

摘要

Recent theory proposes that the brain, when confronted with several action possibilities, prepares multiple competing movements in advance of deciding between them. To date, psychophysical supporting evidence for this idea comes from rapid reaching tasks in which individuals, under cases of target uncertainty, launch initial movements in between competing targets, consistent with multiple prepared reaches being executed simultaneously. Reach planning, however, involves far more than specifying movement direction(s); it requires the specification of sensorimotor control policies that set feedback gains shaping how the motor system responds to errors induced by noise or perturbations. Here we show that the feedback gains for reaches toward multiple potential targets correspond to an average of the gains on trials in which the targets are known in advance. These findings provide evidence that the brain, when presented with multiple action options, computes multiple competing sensorimotor control policies in parallel prior to instituting one of them.