Attenuated theta-band activity and cross-frequency coupling in schizophrenia during affective response inhibition

Schizophrenia (SZ) is marked by impaired cognitive control; however, the underlying neural mechanisms remain unclear. This study examined theta-band (4-7 Hz) neural oscillatory activity and cross-frequency coupling with gamma (30-50 Hz) in an affective cognitive control paradigm in SZ in comparison with healthy controls (HC) and those with bipolar disorder (BD).

Thirty-two participants with SZ, 67 with BD, and 48 HC completed an affective Go/No-Go Task with emotional face stimuli during electroencephalography recording. Time-frequency decomposition quantified theta-band power and intertrial phase consistency (ITPC) over midline fronto-central areas. Theta-gamma phase-amplitude coupling (PAC; Kullback-Leibler Modulation Index) was indexed within the midline frontal area and cross-regionally between midline frontal theta and bilateral parietal gamma.

Participants with SZ displayed decreased midline frontal theta power, ITPC, and local midline frontal theta-gamma PAC compared to HC, with BD falling in between SZ and HC groups across all these measures. Theta power, ITPC, and theta-gamma PAC were correlated with behavioral performance, particularly in the SZ group.

Findings show abnormalities across the amplitude, phase consistency, and cross-frequency coordination aspects of theta-related activity when individuals with SZ engage in affective cognitive control.

This study supports the assertion that SZ is associated with abnormal theta-related neural activity.