Chronic stress impacts visual motion inhibition but exercise induced
arousal does not.
Abstract
It is more difficult to discriminate the direction of large sinusoidal
gratings than small ones, if both are high contrast. This is presumed to
reflect center surround suppression (CSS) within the visual system. CSS
is altered in multiple psychological disorders, and its magnitude has
been linked to overall intelligence. The present study examines the
degree to which two novel factors, physiological arousal and chronic
stress, are related to CSS. Stress was measured through a questionnaire,
while acute arousal was induced through strenuous aerobic exercise. In
both resting and aroused states, participants were presented with a
psychophysical motion discrimination task that quantified CSS as the
difference in accuracy between a small and a large stimulus across six
presentation times. Chronic stress was positively correlated with CSS
for the presentation times where the effect peaked. There was no
difference in CSS or baseline motion perception performance between
exercise-induced aroused states and calm states. The results suggest
that CSS does not vary as a function of acute arousal, but rather on a
longer-term basis in accordance with stress.