Altered functional connectivity between primary and secondary somatosensory areas in panic disorder.

Disturbance in the interpretation of bodily sensation has been widely reported in patients with panic disorder (PD). However, it remains substantially unknown whether patients with PD exhibit any defect in cortical somatosensory processing of non-threatening stimuli. Thus, the present study aimed to examine the functional integrity of the cortical somatosensory system in patients with PD using neurophysiological recordings. A total of 20 patients with PD and 20 healthy controls (HC) were recruited to investigate the cortical responses to median nerve stimulation through whole-head magnetoencephalographic (MEG) imaging. To comprehensively investigate all somatosensory functioning, we studied the regional activation of the primary somatosensory cortex (SI), contralateral (SIIc), and ipsilateral (SIIi) secondary somatosensory cortices, as well as functional connectivity among the SI, SIIc, and SIIi in alpha, beta, and gamma frequency bands. We found that patients with PD demonstrated a reduction in SI activity compared with those in the HC group. Furthermore, a significantly weaker gamma-band functional connectivity between SI and SIIc was found in the PD group relative to the HC group. Our data suggest that patients with PD exhibit abnormal responses to non-threatening (i.e., pain-free) stimuli in the cortical somatosensory system.