Buildup of Choice-Predictive Activity in Human Motor Cortex during Perceptual Decision Making

• Main Authors: Donner, Tobias H. (Author), Siegel, Markus (Contributor), Fries, Pascal (Author), Engel, Andreas K. (Author)
• Other Authors: Massachusetts Institute of Technology. Department of Brain and Cognitive Sciences (Contributor), Picower Institute for Learning and Memory (Contributor)
• Format: Article
• Language: English
• Published: Elsevier B.V., 2015-03-26T15:02:31Z.
• Subjects: Article
• Online Access: Get fulltext

 Simple perceptual decisions are ideally suited for studying the sensorimotor transformations underlying flexible behavior 1 and 2. During perceptual detection, a noisy sensory signal is converted into a behavioral report of the presence or absence of a perceptual experience [3]. Here, we used magnetoencephalography (MEG) to link the dynamics of neural population activity in human motor cortex to perceptual choices in a "yes/no" visual motion detection task. We found that (1) motor response-selective MEG activity in the "gamma" (64-100 Hz) and "beta" (12-36 Hz) frequency ranges predicted subjects' choices several seconds before their overt manual response; (2) this choice-predictive activity built up gradually during stimulus viewing toward both "yes" and "no" choices; and (3) the choice-predictive activity in motor cortex reflected the temporal integral of gamma-band activity in motion-sensitive area MT during stimulus viewing. Because gamma-band activity in MT reflects visual motion strength [4], these findings suggest that, during motion detection, motor plans for both "yes" and "no" choices result from continuously accumulating sensory evidence. We conclude that frequency-specific neural population activity at the cortical output stage of sensorimotor pathways provides a window into the mechanisms underlying perceptual decisions.