Abstract:
The present work aimed to clarify face tuning in individuals with major depressive disorder, MDD. For this purpose, we used Face-n-Food images, which, unlike other commonly used stimuli, do not automatically trigger face processing. In the behavioral study, MDD individuals demonstrated intact face tuning and remarkably similar recognition dynamics as compared to typically developing, TD individuals. Furthermore, sex/gender differences in face tuning occurred neither for MDD nor TD individuals. However, whereas the face sensitivity was associated with performance on a visual perceptual organization task in MDD, it was linked to social cognitive abilities in TD individuals. This suggests different (compensatory) behavioral strategies and underlying brain networks. In a second step, non-invasive brain imaging (magnetoencephalography, MEG, providing for high spatial and time resolution) was used for the investigation of brain circuits underwriting face tuning. As male depression is currently under-investigated and MEG analysis requires a homogenous group of MDD and TD individuals, the focus was set on male MDD. Cutting-edge analysis of time course and topography of gamma oscillatory brain activity during processing of Face-n-Food images was performed. In line with the initial behavioral (psychophysical) study, the face sensitivity to upright Face-n-Food images was comparable between MDD and TD individuals. Furthermore, in accord with the previous behavioral study, face tuning was intimately tied with the visual perceptual organization in MDD individuals. Time-frequency representation and subsequent source localization of MEG data revealed comparable topography of gamma oscillators at early latencies with peaks over the visual occipital areas. However, at later latencies, gamma oscillatory activity originated from the parietal brain areas in TD, but frontal areas in MDD. Most important, between-group contrast pointed to the left middle temporal cortex, a part of the social brain, primarily involved in feature integration and meaning retrieval. Taken together, these findings implicate intact face sensitivity to face-pareidolia images as well as preserved early information processing in MDD, resulting from compensatory cognitive strategies and alterations in the underlying brain networks. This work sheds light on the face tuning abilities and social functioning in depression with valuable insights for treatment and remediation of this mental disorder.
