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 (β) (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.