The effects of a startle on awareness of action.
The execution of a ballistic movement within a reaction time task paradigm is significantly speeded up when an unexpected startling auditory stimulus (SAS) is delivered together with the imperative signal. Using Libet's clock, we investigated whether acceleration involves also the subjective appraisal of the time of task execution. In trials containing the SAS, reaction time shortened to 68.7% of control values. However, subjective judgment of task execution remained a similar time with respect to the imperative signal as in control trials. The dissociation between task execution and its subjective perception indicates the existence of separate circuits for action execution and action awareness.
Unitat d'EMG, Servei de Neurologia, Hospital Clínic, Departament de Medicina, Universitat de Barcelona, IDIBAPS (Institut d'Investigació Biomèdica August Pi i Sunyer), Barcelona, Spain.
M T
MT
Sanegre
J M
JM
Castellote
P
P
Haggard
J
J
Valls-Solé
D000161:Acoustic Stimulation; D000328:Adult; D001307:Auditory Perception / Q000502:physiology; D001364:Awareness / Q000502:physiology*; D004525:Efferent Pathways / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000502:physiology; D009068:Movement / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology*; D013216:Reflex, Startle / Q000502:physiology*; D013998:Time Perception / Q000502:physiology*