Reduced connectivity between auditory and visual regions.
schizophrenia
DYSFUNCTION, CORTEX
A hypothesis-free whole-brain functional network connectivity analysis revealed that the genetic variant was associated with reduced functional connectivity between an auditory (superior temporal) and visual (temporo-occipital) network (Between these two networks, the two strongest reductions of connectivity were observed for the connection between the right anterior superior temporal gyrus and the right temporal occipital fusiform cortex (aSTG r – TOFusC r) as well as between the left posterior superior temporal gyrus and –again- the right occipital fusiform cortex (pSTG l – TOFusC r). Connectivity estimates gradually decreased with growing numbers of C-alleles and turned negative for the homozygous C/C-genotype (Fig. We subsequently tested these two connectivities for the comparison of ketamine versus midazolam in the pharmaco-fMRI dataset and for the comparison of the whole schizophrenia sample versus the healthy control subjects. For the former comparison (ketamine > midazolam), we observed significantly reduced connectivity between the right anterior superior temporal gyrus and the right temporal occipital fusiform cortex (aSTG r – TOFusC r), too, which was explained by the opposing effects of the two drugs, i.e., a ketamine-induced decrease and a midazolam induced increase of functional connectivity. For the latter comparison (schizophrenia > healthy controls) we could reproduce reduced connectivity for both connections (aSTG r – TOFusC r and pSTG l – TOFusC r) in the patients. Accordingly, hypo-connectivity between the superior temporal gyrus and inferior temporo-occipital regions emerged as a consistent finding across the different datasets and contrasts relating it both to schizophrenia and NMDAR dysfunction.