Aberrant cortico-cerebellar connectivity of the default mode network in individuals at ultra-high risk for psychosis: a resting-state fMRI study

Poster B45, Friday, October 21, 11:30 am - 1:00 pm, Le Baron

Minji Bang1,2, Chongwon Pae3,4, Hae-Jeong Park3,4, Suk Kyoon An1,2; 1Section of Affect and Neuroscience, Institute of Behavioral Science in Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea, 2Department of Psychiatry, Yonsei University College of Medicine, Seoul, Severance Hospital, Republic of Korea, 3BK21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea, 4Department of Nuclear Medicine, Yonsei University College of Medicine, Severance Hospital, Republic of Korea

Dysfunction of the cerebellum in schizophrenia is established as the concept of ‘cognitive dysmetria,’ which suggests impairments in sensorimotor and mental coordination resulting in perceptual disturbance, disorganized thoughts and speech, and cognitive dysfunction. It has become evident that cerebellar dysfunction is already present in individuals at ultra-high risk (UHR) for psychosis. We investigated functional connectivity of cortico-cerebellar circuits focusing on the default mode network (DMN) during rest in UHR individuals to figure out neurofunctional correlates of disease-related vulnerability. Thirty-three UHR individuals (including 8 converters during follow-up) and 56 healthy controls underwent fMRI scanning during rest at baseline. Seed-based functional connectivity analysis was performed using two cerebellar seeds in bilateral crus I, previously known to be associated with the DMN. We conducted a statistical comparison of cortico-cerebellar functional connectivity in the DMN between three groups; converters, non-converters, and healthy controls. Converters showed significantly decreased connectivity in the anterior cingulate cortex, supplementary motor area, and inferior parietal cortex as compared with both non-converters and healthy controls. The middle frontal cortex was shown to be more decreased in both converters and non-converters than healthy controls. This result suggests that aberrant cortico-cerebellar connectivity in the DMN is evident prior to the development of psychotic symptoms in UHR individuals who later become overt psychosis. The cerebellum, as an internal-model control system, may play an important role in developing psychosis and give some clues to identify ‘true’ UHR individuals for psychosis.

Topic Area: Neuroimaging

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