Chronic stress impacts visual motion inhibition but exercise induced arousal does not.

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.