Alteration of cognitive functions during extended wakefulness: role of the brain functional asymmetry
Volf, N.V.
Aviakosmicheskaia i Ekologicheskaia Meditsina 30(5): 45-48
1996
ISSN/ISBN: 0233-528X PMID: 8974600 Document Number: 461634
The study was aimed at looking into the effects of prolonged wakefulness on the activities predominantly governed by the left or right hemisphere. To this end, the subjects were requested to fulfill tests of manual/verbal interaction (1), establishment of similarity through the names of two tachistoscopic letters (2), evaluation of spatial proportions when using the right or left hand (3). The experiment was run with 16 male-subjects eight of which were tested following sleepless night whereas the other eight subjects had a normal night rest. In test 1, the deprived subjects exhibited lower tapping rate of both right and left hands than their counterparts; this fact may point to deteriorated function of anterior hemisphere compartments. The fact that under the effect of competing verbal activity both groups slowed down tapping by either hand at the same rate speaks in favor of immutability of the relative activation of anterior compartments of the right and left hemispheres, maintenance of the norm-specific basal profile of functional asymmetry after sleep deprivation. During prolonged sleep deprivation, test 2 displayed dominance of the right hemisphere in correct identification of letters which was not the case in the control. In deprived subjects test 3 showed overestimation of the left part of space when determining line lengths. Hence, results of experiments 2 and 3 suggest a relative activation of the caudal compartments of the right hemisphere during long wakefulness.