Effect of mental task load on fronto-central theta activity in a deep saturation dive to 450 msw.

摘要: The increase of theta activity (4-7 Hz) in the electroencephalogram (EEG) during deep diving is commonly attributed to pathophysiologic mechanisms underlying high pressure neurologic syndrome. aim this study was clarify whether more precise cognitive aspects condition may be described which occurs a dive. Among 4 divers who were repeatedly examined GUSI 14 dive 450 msw, 3 exhibited pronounced correlation between short-term memory load, as varied by set size Sternberg's search task (MST), and distinct peak band EEG-power spectrum. power greatest fronto-central electrode position (Fz), increased dramatically MST-performance at pressure, failed subside fully 1 day before surfacing. Despite close dependency observed on demands, no consistent with performance measures (mean reaction time errors) found. In one diver, waves similar morphology appeared resting EEG significantly We suggest two alternative explanations for positive interaction load hyperbaric exposure Fz-theta: a) Both factors induce state mental effort or selectivity attention, known accompanied frontal from normobaric studies. b) Pressure abnormally facilitates patterns rhythmical excitations that would occur naturally lesser extent certain activities, learning, repetitive operations.