NEURAL CORRELATES OF VISUAL AND MOTOR DECISION-PROCESSES

Recent research has clarified and revealed characteristics of perceptu al and motor decision processes in the brain. A democracy of sensory n eurons discriminate the properties of a stimulus, while competition co ntrasts the attributes of stimuli across the visual field to locate co nspicuous stimuli. Salience and significance are weighed to select an object on which to focus attention and action. Experimentally combinin g neural and mental chronometry has determined the contribution of per ceptual and motor processes to the duration and variability of behavio ral reaction time. Whereas perceptual processing occupies a relatively constant amount of time for a given stimulus condition, the processes of mapping particular stimuli onto the appropriate behavior and prepa ring the motor response provide flexibility but introduce delay and va riability in reaction time.