Electrophysiological correlates of cortico-subcortical interaction: a cross-frequency spectral EEG analysis

Several studies have provided evidence for the notion that the coupling between slow and fast frequency in the EEG spectrum indicates cortico-subcortical cross-talk (CSC-ct). In addition, findings for increased limbic activation due to reduced cortical inhibition have recently been acquired. To get further insights into these mechanisms, the current study investigated whether CSC-ct would decrease as a function of increased slow (SW) or fast wave (FW) activity.

Resting state EEG recordings were obtained from 46 healthy, right-handed participants. CSC-ct was quantified by computing cross-frequency correlations between the power in the slow and fast frequency range. CSC-ct was compared between groups with relatively low and high SW activity and groups with relatively low and high FW activity.

Relatively reduced SW, but not FW activity was associated with a significant coupling between slow and fast frequency EEG. Furthermore, relatively enhanced resting state SW activity was paralleled by slow and fast frequency EEG decoupling.

These findings are in line with the notion that increased subcortical drive can go accompanied by reduced CSC-ct.

Cross-frequency EEG analyses might provide a unique approach to obtain novel insights into cortico-subcortical interactions in relation to affective and cognitive behavior.