Examining the Effects of Exercise on Pattern Separation and the Moderating Effects of Mood Symptoms

• Published in: Behavior therapy Vol. 50; no. 3; pp. 582 - 593
• Main Authors: Bernstein, Emily E., McNally, Richard J.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.05.2019
• Subjects: Adolescent; Adult; Affect - physiology; Anxiety - diagnosis; Anxiety - psychology; Anxiety - therapy; depression; Depression - diagnosis; Depression - psychology; Depression - therapy; exercise; Exercise - physiology; Exercise - psychology; Female; Humans; Male; Memory - physiology; Middle Aged; mnemonic discrimination; mood; Pattern Recognition, Visual - physiology; pattern separation; Photic Stimulation - methods; Random Allocation; Young Adult; mnemonic discrimination; exercise; pattern separation; depression; mood
• ISSN: 0005-7894; 1878-1888; 1878-1888
• DOI: 10.1016/j.beth.2018.09.007

Aerobic exercise has broad cognitive benefits. One target of interest is enhanced memory. The present study explored pattern separation as a specific memory process that could be sensitive to acute and regular exercise and clinically significant for disorders (e.g., depression) characterized by cognitive-affective deficits and hippocampal impairment. In a within-subjects design, participants (N = 69) attended two visits during which they repeated a behavioral pattern separation task at rest and after an activity (cycling, stretching). Regular exercise habits, demographics, mood and anxiety symptoms, and recognition memory capacity were also measured. More regular exercise predicted better resting pattern separation, t(62) = 2.13, b = 1.74, p = .037. Age moderated this effect, t(61) = 2.35, b = .25, p = .02; exercise most strongly predicted performance among middle-age participants. There was no main effect of activity condition on post-activity performance, t(61) = .67, p = .51. However, with significant heterogeneity in reported mood symptoms and regular exercise habits, there was a three-way interaction between condition, regular exercise, and depression, t(55) = 2.08, b = .22, p = .04. Relative to stretching, cycling appears to have enhanced the benefit of regular exercise for pattern separation performance; however, this was evident among participants with mild to no symptoms of depression, but absent among participants with moderate to severe symptoms. Results have implications for how exercise might protect against declines in pattern separation. Future research should explore exercise’s potential as a prevention tool or early intervention for pattern separation and related clinical outcomes. •More regular exercise is associated with better behavioral pattern separation•Acute exercise enhances this effect but only for those with mild or no depression•Exercise could be most potent as a prevention tool or early intervention