EEG Correlates Of Approach Behavior: Does Anticipated Exercise Intensity Influence Pre-exercise Frontal Alpha Asymmetry?

Abstract

Increased alpha activity (8-12 Hz in EEG) indicates a relaxed state, whereas a decrease in activity indicates an increase in cognitive activity. Previous studies have reported a greater reduction in alpha activity in the left vs. right frontal lobe after moderately-intense exercise, but not after light or intense exercise. This relatively greater left cognitive activity has been linked to improved motivational disposition and approach related behavior. PURPOSE: To examine the influence of the anticipated exercise intensity on pre-exercise cognitive activity and motivational disposition. METHODS: Twenty-two healthy, adults (8 females, 25-35y, 1 left handed) were monitored with continuous EEG, recorded at the F3 and F4 sites, while at rest (15s) and prior (15s) to a uni-lateral (right), isometric contraction (plantar flexion, 15s) corresponding to 20, 40, 60, 80, and 100% of individualized maximum voluntary contraction, in randomized, counterbalanced order. Continuous EEG data was subject to off-line fast fourier transformation (FFT) analysis using a series of 1.0s Hanning windows with 10% overlap (NicoleteOne, Viasys, Wisconsin, USA). Eye blinks were manually excluded from analysis. Absolute alpha activity (μV2) was natural log transformed to obtain normality. Motivational disposition was indexed by comparing hemispheric alpha activity to derive the frontal asymmetry index (FAI) computed as lnF4-lnF3 (right-left). RESULTS: Alpha activity decreased linearly as anticipated exercise intensity increased (ANOVA; F (5,100) = 2.67, p = 0.03; linear trend p = 0.02). Alpha prior to the 100% effort was significantly lower than at rest (bonferonni, p = 0.03). There was no statistical difference in motivation disposition and no gender differences. CONCLUSION: Given the inverse relationship between alpha activity and cognitive resources, this study demonstrates that pre-exercise frontal lobe function (i.e., executive planning of movement) is increased when the anticipated exercise intensity is greater. However, the results further indicate that a concurrent improvement in motivational disposition (e.g., approach related behavior) is not present. Future studies should investigate whether pre-exercise cognitive activity is influenced by the anticipated type of exercise, the intensity, or duration.