Prefrontal cortex asymmetry and psychological responses to exercise: A systematic review

Background: Studies have shown a relationship between prefrontal cortex (PFC) activation asymmetry and psychological responses to exercise, so that a higher rest activation in left rather than right PFC has been associated with positive psychological responses to exercise such as an improved affect, anxiety and multidimensional arousal states.

Purpose: To review: 1) evidence that PFC activation asymmetry before exercise is associated with psychological responses to exercise; 2) protocols of PFC asymmetry determination.

Methods: A systematic review (SR) was performed on studies retrieved from the PubMed and Web of Science database up to 04-30-2019. Eligibility criteria were: 1) studies investigating participants submitted to aerobic exercises; 2) including cerebral activation measures through electroencephalography (EEG) before the exercise bout; 3) and psychological measures during or after the exercise bout; 4) original studies.

Results: A number of 1901 studies was retrieved from the databases and 1 study was manually inserted. Thereafter, 1858 studies were excluded during the screening stage so that 30 studies remained for the SR. After full reading, 22 studies were excluded and 8 studies composed the final SR. Methodological assessment revealed that 62.5% of the studies showed a low risk of bias, while 34.37% and 3.12% showed either an unclear or a high risk of bias, respectively. Protocols of PFC activation asymmetry used EEG at F3-F4-P3-P4 (3 studies), F3-F4 (2 studies), F3-F4-T3-T4 (1 study), F3-F4-F7-F8-T5-T6-P3-P4 (1 study) and Fp1-Fp2-Fz-F3-F4-F7-F8-Cz-C3-C4-T3-T4-T5-T6-Pz-P3-P4-Oz-O1-O2 (1 study) positions. Most studies (75%) found a higher left PFC activation associated with a greater affect (n = 2), energetic arousal (n = 2), lower anxiety (n = 2) as well as calmness and tired arousal, simultaneously (n = 1).

Conclusions: Although the heterogeneity of PFC asymmetry protocols, reviewed studies showed a low risk of bias, suggesting that a higher left PFC activation is associated with a positive psychological response to exercise.