title: Neural basis of adaptive response time adjustment during saccade countermanding.
abstract: Humans and macaque monkeys adjust their response time adaptively in stop-signal (countermanding) tasks, responding slower after stop-signal trials than after control trials with no stop signal. We investigated the neural mechanism underlying this adaptive response time adjustment in macaque monkeys performing a saccade countermanding task. Earlier research showed that movements are initiated when the random accumulation of presaccadic movement-related activity reaches a fixed threshold. We found that a systematic delay in response time after stop-signal trials was accomplished not through a change of threshold, baseline, or accumulation rate, but instead through a change in the time when activity first began to accumulate. The neurons underlying movement initiation have been identified with stochastic accumulator models of response time performance. Therefore, this new result provides surprising new insights into the neural instantiation of stochastic accumulator models and the mechanisms through which executive control can be exerted.
authors: Center for Integrative & Cognitive Neuroscience, Vanderbilt Vision Research Center, Department of Psychology, Vanderbilt University, Nashville, Tennessee 37240, USA.
authors: Pierre
authors: P
authors: Pouget
authors: Gordon D
authors: GD
authors: Logan
authors: Thomas J
authors: TJ
authors: Palmeri
authors: Leanne
authors: L
authors: Boucher
authors: Martin
authors: M
authors: Paré
authors: Jeffrey D
authors: JD
authors: Schall
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000222:Adaptation, Physiological / Q000502:physiology*; D000818:Animals; D005074:Evoked Potentials, Visual / Q000502:physiology; D005403:Fixation, Ocular / Q000502:physiology; D007266:Inhibition, Psychological; D016014:Linear Models; D008253:Macaca mulatta; D008297:Male; D008959:Models, Neurological; D009068:Movement; D009474:Neurons / Q000145:classification / Q000502:physiology*; D009483:Neuropsychological Tests; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology*; D012438:Saccades / Q000502:physiology*