Tracing the neural trajectories of evidence accumulation and motor preparation processes during voluntary decisions

Abstract

Voluntary decisions have previously been described by where they arise in the brain and how actions corresponding to one’s choice are prepared. However, the processes by which these internally guided decisions are formed and translated into action remain unclear. We tested whether neural signatures of evidence accumulation and motor preparation—established in perceptual decision-making—are also observed during voluntary decisions. Forty-nine adults made voluntary (free choice between two options) and forced (single specified choice) decisions while electroencephalography was recorded. To isolate decision formation from action selection, all responses were made with a right-handed keypress. A..