Movement-related effects in realigned fMRI timeseries can be corrected by regression on linear functions of estimated positional displacements of an individual subject's head during image acquisition. However, this entails biased (under)estimation of the experimental effect whenever subject motion is not independent of the experimental input function. Methods for diagnosing such stimulus-correlated motion (SCM) are illustrated by application to fMRI data acquired from 5 schizophrenics and 5 normal controls during periodic performance of a verbal fluency task. The schizophrenic group data were more severely affected by SCM than the control group data. Analysis of covariance (ANCOVA) was used, with a voxelwise measure of SCM as a covariate, to estimate between-group differences in power of periodic signal change while controlling for variability in SCM across groups. Failure to control for SCM in this way substantially exaggerated the number of voxels, apparently demonstrating a between-group difference in task response.

M ost structural imaging studies in schizophrenia emphasize left-sided temporal lobe abnormalities in addition to more diffuse brain abnormalities (1-3). The association between reduced left temporal lobe volume and hallucinations (4, 5) and theories linking temporal lobe asymmetry with the illness (6) have rekindled interest in abnormal asymmetry of temporal lobe structures in schizophrenia. One such region is the planum temporale, part of the superior temporal gyrus, which is usually larger on the left and which has a critical role in supporting language functions in humans (7). Evidence both for and against reduction of left planum temporale size (and hence reduced asymmetry) in schizophrenia has been presented (8, 9). One possible explanation for this inconsistency is that a left-sided decrease in the volume of temporal lobe language areas is confined to schizophrenic patients who have a strong predisposition to auditory hallucinations. This decrease could account for a number of alterations in functional asymmetry in hallucination-prone schizophrenic indiPreliminary results presented at

Schizophrenic patients displayed attenuated power of response in several frontal regions during word generation but greater power of response in the medial parietal cortex during word repetition.

Schizophrenia has been conceived as a disorder of brain connectivity but it is unclear how this network phenotype is related to the emerging genetics. We used morphometric similarity analysis of magnetic resonance imaging (MRI) data as a marker of inter-areal cortical connectivity in three prior case-control studies of psychosis: in total, N=185 cases and N=227 controls. Psychosis was associated with globally reduced morphometric similarity (MS) in all 3 studies. There was also a replicable pattern of case-control differences in regional MS which was significantly reduced in patients in frontal and temporal cortical areas, but increased in parietal cortex. Using prior brain-wide gene expression data, we found that the cortical map of casecontrol differences in MS was spatially correlated with cortical expression of a weighted combination of genes enriched for neurobiologically relevant ontology terms and pathways. In addition, genes that were normally over-expressed in cortical areas with reduced MS were significantly up-regulated in a prior post mortem study of schizophrenia. We propose that this combination of neuroimaging and transcriptional data provides new insight into how previously implicated genes and proteins, as well as a number of unreported proteins in their vicinity on the protein interaction network, may interact to drive structural brain network changes in schizophrenia. dysconnectivity | network neuroscience | psychosis | partial least squares | Allen Human Brain AtlasCorrespondence: sem91@cam.ac.uk

IMPORTANCEEstimating the current likelihood of transitioning from a clinical high risk for psychosis (CHR-P) to psychosis holds paramount importance for preventive care and applied research. OBJECTIVE To quantitatively examine the consistency and magnitude of transition risk to psychosis in individuals at CHR-P. DATA SOURCES PubMed and Web of Science databases until November 1, 2020. Manual search of references from previous articles. STUDY SELECTION Longitudinal studies reporting transition risks in individuals at CHR-P. DATA EXTRACTION AND SYNTHESIS Meta-analysis compliant with Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) and Meta-analysis of Observational Studies in Epidemiology (MOOSE) reporting guidelines; independent data extraction, manually and through digitalization of Kaplan-Meier curves.MAIN OUTCOME AND MEASURES Primary effect size was cumulative risk of transition to psychosis at 0.5, 1, 1.5, 2, 2.5, 3, 4, and more than 4 years' follow-up, estimated using the numbers of individuals at CHR-P transitioning to psychosis at each time point. These analyses were complemented by meta-analytical Kaplan-Meier curves and speed of transition to psychosis (hazard rate). Random-effects meta-analysis, between-study heterogeneity analysis, study quality assessment, and meta-regressions were conducted. RESULTS A total of 130 studies and 9222 individuals at CHR-P were included. The mean (SD) age was 20.3 (4.4) years, and 5100 individuals (55.3%) were male. The cumulative transition risk was 0.09 (95% CI, 0.