Non-invasive Brain Stimulation Using Tdcs of the Third (of Many) Visual Pathways

The studey involves a randomized, parallel group comparison of personalized, MR-guided, cathodal HD-tDCS vs. sham targeting the middle temporal motion-sensitive region (HCP MMP1.0-atlas area MT+ complex) for the reversal of physiological impairments in Sz related to motion processing and social cognitive dysfunction. RDoC constructs to be tested include face emotion recognition (FER) and Understanding Mental State (UMS), which has also been termed Theory of Mind (ToM) or mentalizing. The overall goals of the study are to determine whether tDCS applied over MT+ can ameliorate 1) motion-processing deficits in Sz and 2) deficits in activation of other TVP regions. Key outcome measures include 1) activation of MT+, pSTS and mSTS regions to motion and dynamic FER stimuli and 2) fractional occupancy (FO) of the CAP state corresponding to the TVP structure. Behavioral outcomes will include scores on motion discrimination, FER to dynamic faces, and TASIT sarcasm (UMS). Participants will include 120 individuals with Sz and 30 healthy controls (HC). Sz individuals will be evaluated both cross-sectionally and during blinded, randomized active (cathodal) or sham pHD-tDCS targeted to MTC. HC will be evaluated cross-sectionally only. All participants will first undergo baseline assessment (Visit 1) and baseline physiological assessments (Visit 2). Each Sz participant will then be assigned to blinded intervention with either active or sham tDCS and will participate in one ERP (Visit 3) and one fMRI session (Visit 4) involving up to 40-min stimulation each. The two tDCS sessions will be conducted at least 1 week apart and may occur in either order. For each participant, the same randomized treatment (active vs. sham tDCS) will be used in both the ERP and fMRI sessions (Visits 3 and 4). Behavior is obtained during the ERP session (Visit 3). Comparisons will focus on correlations among the fMRI, ERP and behavioral outcome measures within participants as well as the effects of active vs. sham tDCS across participants.