Multimodal Imaging in Individuals at Clinical High Risk for Psychosis

Presentation First Author: 
Tiziano Colibazzi

The development of psychotic illness is preceded by a long phase characterized by attenuated or brief psychotic symptoms as well as functional decline. We have collected imaging data in multiple modalities in a cohort consisting of 61 subjects deemed at Clinical High Risk (CHR) for psychosis as well as 55 age- and gender matched healthy controls. Analyses of baseline functional data during performance of a task engaging cognitive control (Simon task) revealed in CHR subjects elevated functional activity during trials not associated with conflict. This excessive level of baseline function was present throughout several areas of the cortico-striatal-thalamic-cortical (CSTC) loops. CHR individuals also showed increased functional connectivity between the striatum and the thalamus as well as increased degree of centrality of the thalamus. Furthermore, posterior cortical areas revealed a marked disruption of their pattern of connectivity with the rest of the brain and in particular with the prefrontal cortex and the thalamus. Diffusion imaging revealed in patients a disruption of white matter organization around the thalamus and in tracts connecting the striatum with the prefrontal cortex, confirming that abnormal anatomical connectivity underlies the observed disturbances in functional connectivity. Finally, we found cortical thinning in CHR participants in the same areas where we observed abnormal function. Taken together our results suggest the presence of 1) widespread disturbances in the functional and anatomical architecture of CSTC loops, which appear to be overactive in patients and 2) a disruption of the anatomy and connections of posterior cortices with these circuits.

Conference Name: 
Presentation Date: 
January, 2015
Additional Authors: 
Guillermo Horga - Zhishun Wang - Yuankai Huo - Zhen Yang - Cheryl Corcoran - Dongrong Xu - Jianping Qiao - Hui Wang - Ragy Girgis - Anissa Abi-Dargham - Bradley Peterson
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