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125. Auditory parabelt gray matter is related to impaired selective attention in first-episode psychosis
Selective attention is impaired at the first episode of psychosis (FEP). Using EEG or MEG, selective attention can be measured with N1 modulation during an auditory oddball task, as N1 amplitude increases with attention. The difference between N1 amplitudes on attend vs ignore trials produces a negative difference (Nd). Our data show FEP have a reduced Nd, suggesting impaired modulation of N1 with selective attention. In this study, we source-resolved the Nd during an auditory oddball task and examined gray matter (GM) deficits in FEP within regions implicated by the source-resolved activity. While EEG and MEG were recorded, individuals either ignored tones while watching a silent movie (Ignore) or selectively attended the tones by pressing a button to every oddball tone (Attend). To estimate Nd source activity, differential source MEG activity between “ignore” vs “attend” conditions was estimated with MNE 100ms post-stimulus in 10 healthy controls (HC). The HCP Glasser parcellation was used to identify the maximum region of Nd source activity, which was the parabelt region. GM thickness within parabelt was estimated from T1w MRI data for 11 HC and 15 FEP. FEP had thinner GM in auditory parabelt (Cohen’s d = 0.7). In FEP, a more impaired Nd was associated with less GM in the parabelt region in AC (ρ=-0.75, p=0.001). No such correlation was found in HC (p>.05).In healthy controls, source activity of N1 modulation was found within auditory parabelt. Further, this study suggests that impaired N1 modulation with selective attention in FEP is related to GM deficits in the auditory parabelt region.