Ultradian rhythms in cognitive functions and their relationship to visceral processes

Visceral and behavioral data were repeatedly sampled over time in 7 men performing tests of eye-hand coordination and of recall. Spectrum analysis of behavioral data showed peaks in the ultradian range which for the group were significantly different from white noise. Relations between visceral and behavioral data were not striking. However, relations between (a) epinephrine and indices of sympathetic tone (i.e., norepinephrine or heart rate) and (b) ongoing performance were positive and the highest of all tested.