Evidence for cerebral asymmetries in a finger sequencing task.
Visual input was lateralized using a specially designed contact lens system. Subjects performed a sequence of two keypresses in response to a light stimulus with either the left or the right hand in a choice reaction time paradigm. Two choice reaction time conditions were used: (A) hand certainty, sequence uncertainty and (B) hand uncertainty, sequence certainty. Reaction time (RT) results indicate that there are no significant differences between the left and right hemisphere in selecting a sequential response in either of the two conditions. Interfinger time (IFT) results show a relative left eye (right hemisphere)-left hand advantage when there was hand certainty, sequence uncertainty and a relative left eye (right hemisphere) disadvantage for both hands when there was hand uncertainty, sequence certainty. The RT results do not support the concept of a center in the left hemisphere for selection of the components of a two-element sequential keypress, prior to movement initiation. However, the IFT results indicate that there are differences in the processing ability of the left and right hemispheres in a sequencing task, after movement initiation.
Sivak
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B
Department of Kinesiology, University of Waterloo, Ontario, Canada.
MacKenzie
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CL
D000328:Adult; D001288:Attention; D004292:Dominance, Cerebral; D005260:Female; D005385:Fingers; D007839:Functional Laterality; D006801:Humans; D008297:Male; D009949:Orientation; D011597:Psychomotor Performance; D011930:Reaction Time; D014794:Visual Fields