Breath hold task induces temporal heterogeneity in electroencephalographic regional field power in healthy subjects

While the brainstem is in charge of the automatic control of ventilation, the cortex is involved in the voluntary control of breathing but also receives inputs from the brainstem, which influence the perception of breathing and the arousal state and sleep architecture in conditions of hypoxia/hypercapnia. We evaluated in eleven healthy subjects the effects of breath hold (BH: 30 seconds of apneas and 30 seconds of normal breathing) and BH-related CO2/O2 changes on electroencephalogram (EEG) global field power (GFP) and regional field power (RFP) in 9 different areas (3 rostrocaudal sections -anterior, central, posterior- and 3 sagittal sections -left, middle, right) in the δ and α bands, by cross correlation analysis. No significant differences were observed in GFP and RFP when comparing free breathing (FB) with the BH task. Within the BH task, the shift from apnea to normal ventilation was accompanied by an increase in the δ power and a decrease in the α power. The end-tidal pressure of CO2 (PETCO2) was positively correlated with the δ-band and negatively with the α- band with a positive time shift, while an opposite behaviour was found for the end-tidal pressure of O2 (PETO2). Notably, the time shift between PETCO2/PETO2 signals and cortical activity at RFP was heterogenous and seems to follow a hierarchical activation with the δ-band responding earlier than the α band. Overall, these findings suggest that the effect of BH on the cortex may follow specific ascending pathways from the brainstem and be related to chemoreflex stimulation