Altered Function of Superior Parietal Lobule Associated with Perceptive Awareness in First-Episode Drug-Naïve Panic Disorders: A Preliminary fMRI Study

BACKGROUND: Biased fear-related perception is one main characteristic in patients with panic disorder (PD) and their prominent cardiovascular symptoms associated with enhanced heartbeat perception. PATIENTS AND METHODS: We investigated interoceptive perception in 18 first-onset drug-naïve PD patients and 21 age- and gender-matched healthy controls (HC). Moreover, we compared blood oxygen level-dependent (BOLD) responses between the two groups during a heartbeat perception (interoception) task to assess task-evoked activity and its relationship with heartbeat perception scores (HPSs). RESULTS: We found that patients with PD compared to HCs revealed a trend higher but insignificant HPSs. Higher activity in the bilateral superior parietal lobule (SPL) was observed in PD patients compared to HCs during the perception of both heartbeats and pure tones compared to rest. Furthermore, patients with PD exhibited a significant positive correlation between BOLD activity in the left SPL during heartbeat > resting-state and HPS. CONCLUSION: Using a sample of first-episode drug-naïve patients, our study reports that patients with PD show altered activation in the bilateral SPL during both interoceptive and exteroceptive perception. The increased activation during interoceptive stimuli might render PD patients more engaged in processing information associated with their internal states.