title: A supramodal accumulation-to-bound signal that determines perceptual decisions in humans.
abstract: In theoretical accounts of perceptual decision-making, a decision variable integrates noisy sensory evidence and determines action through a boundary-crossing criterion. Signals bearing these very properties have been characterized in single neurons in monkeys, but have yet to be directly identified in humans. Using a gradual target detection task, we isolated a freely evolving decision variable signal in human subjects that exhibited every aspect of the dynamics observed in its single-neuron counterparts. This signal could be continuously tracked in parallel with fully dissociable sensory encoding and motor preparation signals, and could be systematically perturbed mid-flight during decision formation. Furthermore, we found that the signal was completely domain general: it exhibited the same decision-predictive dynamics regardless of sensory modality and stimulus features and tracked cumulative evidence even in the absence of overt action. These findings provide a uniquely clear view on the neural determinants of simple perceptual decisions in humans.
authors.affiliation: Trinity College Institute of Neuroscience and School of Psychology, Trinity College Dublin, Dublin, Ireland.
authors.forename: Redmond G
authors.initials: RG
authors.lastname: O'Connell
authors.forename: Paul M
authors.initials: PM
authors.lastname: Dockree
authors.forename: Simon P
authors.initials: SP
authors.lastname: Kelly
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000293:Adolescent; D001307:Auditory Perception / Q000502:physiology*; D003657:Decision Making / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D055815:Young Adult