Atypical intra- and inter-regional coupling patterns involved in repetitive non-suicidal self-injury

Non-suicidal self-injury (NSSI) is becoming more common among youth with major depressive disorder (MDD). Repetitive NSSI (R-NSSI), a severe type of NSSI, is a growing concern. As a behavioural addiction, R-NSSI may be closely linked to aberrant response inhibition. This study aimed to investigate the neural correlation of response inhibition within R-NSSI.

A total of 85 youths participated in a Go/NoGo task during magnetoencephalography scanning, including 27 MDD youths with R-NSSI, 28 MDD youths without NSSI and 30 healthy controls. Phase amplitude coupling and functional connectivity were calculated to detect the intra- and inter-regional coupling patterns. Further, phase slope indexes were used to ascertain the brain information flow direction.

Locally, the R-NSSI group showed hyper-coupling of gamma amplitude and beta phase within the temporal region. Globally, connectivity within the prefrontal cognitive control circuit, mediated by both beta and gamma oscillations, was diminished. Notably, the R-NSSI group showed a negative frontoparietal information flow contrasted with a positive temporoparietal information flow. Furthermore, the strength of functional connectivity mediated the association between NSSI and childhood trauma.

Our findings suggest disrupted local and regional control processes in youths with R-NSSI. Overall, NSSI manifests an inefficient prefrontal network compensated by enhanced activity in temporal lobe regions. These results offer electrophysiological insights into the neural mechanisms of NSSI.