Prefrontal and motor cortex EEG responses and their relationship to ventilatory thresholds during exhaustive incremental exercise.

PURPOSE: The purpose of this study was to measure the EEG response in the prefrontal cortex (PFC) and motor cortex (MC) during incremental exercise and align these responses with ventilatory parameters. METHODS: The EEG activity at the motor (MC) and frontal cortices was measured during an incremental exercise test (IET) in 11 cyclists (peak oxygen uptake VO2peak 4.1 ± 0.74 (SD) L min(-1)). EEG power spectral densities were calculated for alpha slow (αS) (8-10 Hz), alpha fast, (αF) (10-13 Hz), Beta (ß) (13-30 Hz), and Gamma (γ) (30-40 Hz). EEG data were calculated as % change from eyes open (EO) baseline and a repeated measures analysis of variance (ANOVA) was performed on regions of interest (ROI), time and bandwidth. RESULTS: All EEG activity increased from 50 % Vo2peak to ventilatory threshold (VT) (P = 0.045) and respiratory compensation point (RCP) (P = 0.019) and decreased from RCP to end of exercise (END) (P = 0.04). Significant differences between regions were found at the VLPFC and MC for both αS and αF. αS and αF increased from 50 % VO2peak to RCP (14.9 ± 10.2 to 23.8 ± 15.5 and 18.9 ± 10.6 to 26.12 ± 12.7, respectively) and then decreased to END (23.8 ± 15.5 to 14.4 ± 10.3 and 26.1 ± 12.7, to 17.7 ± 8.8, respectively) (P < 0.01) and concomitantly only decreased significantly in MC in αF from VT to END (P < 0.05). CONCLUSION: There is a decline in the EEG response to exercise in the PFC following the RCP, whilst alpha activity in the MC is preferentially maintained; therefore, changes within the PFC appear to play a role in exercise termination.

Acute electroencephalography responses during incremental exercise in those with mental illness.

Introduction: Depression is a mental illness (MI) characterized by a process of behavioral withdrawal whereby people experience symptoms including sadness, anhedonia, demotivation, sleep and appetite change, and cognitive disturbances. Frontal alpha asymmetry (FAA) differs in depressive populations and may signify affective responses, with left FAA corresponding to such aversive or withdrawal type behavior. On an acute basis, exercise is known to positively alter affect and improve depressive symptoms and this has been measured in conjunction with left FAA as a post-exercise measure. It is not yet known if these affective electroencephalography (EEG) responses to exercise occur during exercise or only after completion of an exercise bout. This study therefore aimed to measure EEG responses during exercise in those with MI. Materials and methods: Thirty one participants were allocated into one of two groups; those undergoing management of a mental health disorder (MI; N = 19); or reporting as apparently healthy (AH; N = 12). EEG responses at rest and during incremental exercise were measured at the prefrontal cortex (PFC) and the motor cortex (MC). EEG data at PFC left side (F3, F7, FP1), PFC right side (F4, F8, FP2), and MC (C3, Cz, and C4) were analyzed in line with oxygen uptake at rest, 50% of ventilatory threshold (VT) (50% VT) and at VT. Results: EEG responses increased with exercise across intensity from rest to 50% VT and to VT in all bandwidths (P < 0.05) for both groups. There were no significant differences in alpha activity responses between groups. Gamma responses in the PFC were significantly higher in MI on the left side compared to AH (P < 0.05). Conclusion: Alpha activity responses were no different between groups at rest or any exercise intensity. Therefore the alpha activity response previously shown post-exercise was not found during exercise. However, increased PFC gamma activity in the MI group adds to the body of evidence showing increased gamma can differentiate between those with and without MI.