A supramodal accumulation-to-bound signal that determines perceptual decisions in humans

• Published in: Nature neuroscience Vol. 15; no. 12; pp. 1729 - 1735
• Main Authors: O'Connell, Redmond G, Dockree, Paul M, Kelly, Simon P
• Format: Journal Article
• Language: English
• Published: New York Nature Publishing Group US 01.12.2012; Nature Publishing Group
• Subjects: 631/378/1697; 631/378/2649/1409; Accuracy; Acoustic Stimulation - methods; Adolescent; Animal Genetics and Genomics; Auditory Perception - physiology; Behavioral Sciences; Biological Techniques; Biomedicine; Brain; Decision making; Decision Making - physiology; Female; Humans; Male; Motion Perception - physiology; Neurobiology; Neurons; Neurosciences; Perception; Photic Stimulation - methods; Physiological aspects; Properties; Psychomotor Performance - physiology; Reaction Time - physiology; Signal processing; Signal Transduction - physiology; Young Adult; United States; New York; United States > US
• ISSN: 1097-6256; 1546-1726; 1546-1726
• DOI: 10.1038/nn.3248

This study uses EEG in humans to isolate and track an evolving, domain-general decision signal, which varies with accumulated evidence, but is independent of overt actions. 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.