title: Motor preparation in an anticipation-timing task.
abstract: Previous findings from experiments involving anticipation-timing tasks have indicated that a point in time may exist after which a participant is committed to producing a pre-programmed movement. For example, if a "stop" signal is given too long after a "go" signal but prior to movement initiation, the response is often still produced. It has been suggested that a startling stimulus may act to elicit a pre-programmed response in reaction time (RT) tasks without involvement of the cerebral cortex (Valls-Solé et al. 1999). The present experiment employed a startling stimulus to investigate the temporal course of motor preparation during a stop-signal anticipation-timing task. Participants timed a key release coincident with the sweep of a clock hand reaching a target. On some trials, the clock hand stopped prior to reaching the target (meaning participants were to refrain from responding), which was accompanied by either a startling acoustic stimulus (124 dB) or control stimulus (82 dB). Results from startle trials indicate that while some advance preparation of motor circuits was evident, subcortical pre-programming and storage of the motor command in circuits common to the voluntary and startle response pathways was not completed well in advance of response production.
authors.affiliation: School of Human Kinetics, University of British Columbia, Vancouver, BC, Canada. carlsen@interchange.ubc.ca
authors.forename: Anthony N
authors.initials: AN
authors.lastname: Carlsen
authors.forename: Romeo
authors.initials: R
authors.lastname: Chua
authors.forename: J
authors.initials: J
authors.lastname: Timothy Inglis
authors.forename: David J
authors.initials: DJ
authors.lastname: Sanderson
authors.forename: Ian M
authors.initials: IM
authors.lastname: Franks
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D003071:Cognition / Q000502:physiology*; D004576:Electromyography; D005246:Feedback / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D009334:Neck Muscles / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D013216:Reflex, Startle / Q000502:physiology*; D014836:Volition / Q000502:physiology*; D055815:Young Adult