Decreased gamma band power and increased betagamma phaseamplitude coupling are characteristic of brain activity in patients with chronic spinal cord injury

Neurophysiological biomarkers are needed to characterize the condition of patients with spinal cord injury (SCI), for which effective symptomatic biomarkers are lacking. We recorded the resting-state magnetoencephalography data of 22 patients with SCI and 29 healthy controls. Power spectral density and phase-amplitude coupling (PAC) were assessed for six frequency bands using source-reconstructed cortical currents. Compared with controls, SCI patients exhibited significantly reduced gamma band power and increased beta-gamma PAC in the frontal cortex, including the primary motor area (q < 0.05, FDR corrected). No significant differences were observed in alpha or beta power. These results suggest that decreased gamma power and increased beta-gamma coupling reflect altered cortical dynamics after SCI and may serve as potential neurophysiological signatures for chronic cortical adaptation.