title: Differences between left- and right-hand reaction time rhythms: indications of shifts in strategies of human brain activity.
abstract: Reaction time (RT) measurements serve as quantitative indices for pilots' cognitive processes of the brain. To examine if laterality exists in the brain hemispheres we measured, by the use of a Pilot Evaluation System (PES), right- and left-hand performance rhythms as indicative of RT to audible and visual stimuli. The tests included sets of simple tasks and complex ones to which a secondary task composed of audio signals was added. The accuracy of recorded reaction time was 27 ms. Seven right-handed males, 27-42 years of age, experienced with the PES flight simulator, were tested every 2 h, nine times daily (starting at 08:00 h) during 3 consecutive days. The results indicated that for simple tasks, the 24 h period of RT rhythm is either exclusive or prominent for both hands. For complex tasks the prominent period of RT is 24 h for the right (dominant) hand and 8 h for the left (non-dominant) hand (right-hand 24 h period Fstat = 140, r2 = 0.62 and 8 h period Fstat = 25, r2 = 0.22; left-hand 24 h period Fstat = 44, r2 = 0.34 and 8 h period Fstat = 100, r2 = 0.54). The findings suggest that a laterality exists in the brain hemispheres with regard to differences in rhythm periodicities. The expression of this laterality is dependent on the task-load level and points to a strategy of linkage and integrity in brain activity.
authors.affiliation: Department of Human Genetics, Sackler School of Medicine, Tel Aviv University, Israel.
authors.forename: Y
authors.initials: Y
authors.lastname: Shub
authors.forename: I E
authors.initials: IE
authors.lastname: Ashkenazi
authors.forename: A
authors.initials: A
authors.lastname: Reinberg
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001921:Brain / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008297:Male; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology*