Parallel specification of competing sensorimotor control policies for alternative action options

• Published in: Nature neuroscience Vol. 19; no. 2; pp. 320 - 326
• Main Authors: Gallivan, Jason P, Logan, Lindsey, Wolpert, Daniel M, Flanagan, J Randall
• Format: Journal Article
• Language: English
• Published: New York Nature Publishing Group US 01.02.2016; Nature Publishing Group
• Subjects: 631/378/2629/1409; 631/378/2629/1779; Action potential; Adolescent; Analysis; Animal Genetics and Genomics; Behavioral Sciences; Biological Techniques; Biomedicine; Brain - physiology; Feedback, Psychological; Female; Humans; Male; Movement - physiology; Neurobiology; Neurosciences; Noise - adverse effects; Perceptual-motor processes; Photic Stimulation; Planning; Psychomotor Performance - physiology; Sensation - physiology; Young Adult; Canada; Ontario Canada
• ISSN: 1097-6256; 1546-1726; 1546-1726
• DOI: 10.1038/nn.4214

Several prominent theories propose that, in situations affording more than one possible action, the brain prepares, in parallel, multiple competing movements before selecting one. The authors provide evidence for this idea, showing that individuals simultaneously specify distinct feedback gains, a critical component of control, for competing target options. Recent theory proposes that the brain, when confronted with several action possibilities, prepares multiple competing movements before deciding among them. Psychophysical supporting evidence for this idea comes from the observation that when reaching towards multiple potential targets, the initial movement is directed towards the average location of the targets, consistent with multiple prepared reaches being executed simultaneously. However, reach planning involves far more than specifying movement direction; it requires the specification of a sensorimotor control policy that sets feedback gains shaping how the motor system responds to errors induced by noise or external perturbations. Here we found that, when a subject is reaching towards multiple potential targets, the feedback gain corresponds to an average of the gains specified when reaching to each target presented alone. Our findings provide evidence that the brain, when presented with multiple action options, computes multiple competing sensorimotor control policies in parallel before implementing one of them.