Parietal gamma oscillations decreased in cognitive biotype of depression

Cognitive biotype in depression has long been associated with abnormalities in neural oscillations. Among them, gamma oscillations are widely observed correlates of cognitive dysfunction. However, whether gamma oscillations implement causal mechanisms of specific brain function in cognitive biotype of depression remains unclear. Depressed patients in remission were included in this study. Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) Consensus Cognitive Battery (MCCB) was used to identify cognitive biotype. Here, we enrolled 141 individuals with stable depression, 56 were divided into cognitive impairment (CI) biotype according to MCCB scores. And gamma neural oscillations in resting-state were recorded through electroencephalography (EEG). In the eyes-closed condition, CI biotype showed decreased low-gamma power in P3 channel (t =-3.267, FDR = 0.026) except other channels. And there was no statistical difference in low-gamma and high-gamma power in Fp, F, C, T, P, O between CI and NCI biotype in depression. Moreover, statistically correlations between cognitive function and gamma power were observed. In the eyes-closed condition, low-gamma oscillation was correlated with working memory (r = 0.205, P = 0.015). Also, in the eyes-open condition, low- and high-gamma oscillation was correlated with social cognition (r = -0.175, P = 0.038; r = -0.241, P = 0.004). Our results confirmed that gamma neural oscillations decreased in cognitive biotype of depression. The findings also demonstrate a preliminary correlation between gamma-band oscillations and working memory, suggesting that gamma activity may serve as a neural substrate for efficient information processing during cognitive tasks. This reinforces the theoretical framework implicating gamma synchrony in higher-order brain functions and highlights its potential as a biomarker for cognitive assessment.