Frontal brain oscillatory coupling among men who vary in salivary testosterone levels

Recent studies suggest that cross-frequency coupling supports the integration of distinct neuronal oscillatory modes. In particular, spectral coupling between slow-wave delta and fast-wave beta oscillations may reflect subcortical-cortical interactions. Prior experiments have shown that delta-beta coupling appears to be sensitive to steroid hormone patterning. We attempted to extend this hypothesis by examining the relation between delta-beta EEG spectral coupling and endogenous testosterone measures in men. We collected resting regional brain electrical (EEG) activity and salivary testosterone from 34 healthy young adult males (M age=24 years). Males with high testosterone showed non-significant delta-beta coupling (delta-beta decoupling), while males with low testosterone exhibited significant delta-beta coupling. These relations were only found for the frontal brain region. There was also a significant group difference in the magnitude of coupling, but no differences in absolute delta and beta power. Findings are discussed in terms of emerging evidence relating steroid hormones to cross-frequency spectral coupling and directions for future work.