Examining spontaneous neural activity patterns in developmental prosopagnosia using resting state EEG

Developmental prosopagnosia (DP) is characterized by a lifelong difficulty in learning and recognizing faces. While task-based studies have identified brain regions associated with face processing deficits in DPs, less is known about the spontaneous, intrinsic brain activity patterns in the absence of explicit tasks. To address this, resting-state electroencephalography (EEG) data were obtained from 32 DPs and 25 controls during five-minute open-eye recordings. The data were preprocessed at 0.5 to 100 Hz, ICA artifact corrected and average referenced to extract absolute spectral power values for delta (1-4 Hz), theta (4-8 Hz), alpha (8-13 Hz), beta (14-30 Hz), and gamma (30-80 Hz) bands for each electrode and then pooled into regional electrode clusters (frontal, central, parietal, temporal and occipital). A 3 way mixed ANOVA for the two groups, hemispheres, and regions revealed significant interactions for alpha and gamma bands, highlighting hemispheric differences. Individuals with DP displayed significantly lower alpha power in the left hemisphere compared to the right. This was driven by central and temporal electrode regions. In contrast, both groups exhibited significantly greater gamma power in the left hemisphere, with controls showing a larger hemispheric asymmetry. This asymmetry was driven by electrodes in the parietal, temporal, and occipital regions in controls, leading to significant DP vs control group differences. Alterations in alpha power have been associated with neuronal excitability and gamma in higher-level feature binding, both critical for face processing. Furthermore, both alpha and gamma have also been implicated in N170 ERP for face specific processing. Our findings provide evidence for the first time that there are cross-hemisphere differences in resting state alpha and gamma band power between DPs and controls.