title: Startle neural activity is additive with normal cortical initiation-related activation.
abstract: The current study examined the process of response initiation in a simple reaction time (RT) task using a startling acoustic stimulus (SAS), which has been shown to trigger a prepared movement through an involuntary initiation pathway. The SAS was presented within the RT interval (concurrent with, and 25, 50, 75, 100, and 125 ms following the "go" signal), with the observed response latency used to examine the relative contributions of voluntary and involuntary activation to response initiation. Our results clearly indicate that both voluntary and startle-related initiation activation jointly contribute to the observed RT. The data support a model in which startle-related neural activity is additive with voluntary cortical initiation-related activation. This result also provides indirect support for the hypothesis that both voluntary and SAS-related involuntary activation involve a similar process of response output.
authors.affiliation: School of Kinesiology, University of British Columbia, Vancouver, Canada.
authors.forename: Dana
authors.initials: D
authors.lastname: Maslovat
authors.affiliation: School of Human Kinetics, University of Ottawa, Ottawa, Canada.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Carter
authors.affiliation: School of Human Kinetics, University of Ottawa, Ottawa, Canada.
authors.forename: Michael
authors.initials: M
authors.lastname: Kennefick
authors.affiliation: School of Human Kinetics, University of Ottawa, Ottawa, Canada. Electronic address: tony.carlsen@uottawa.ca.
authors.forename: Anthony N
authors.initials: AN
authors.lastname: Carlsen
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D002540:Cerebral Cortex / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009068:Movement; D011930:Reaction Time; D013216:Reflex, Startle; D014953:Wrist / Q000502:physiology
keywords: Additive model; ECR; FCR; Initiation; Motor preparation; Neural activation; RT; SAS; SCM; Startle; extensor carpi radialis; flexor carpi radialis; reaction time; startling acoustic stimulus; sternocleidomastoid