Brain reward prediction error abnormalities in antipsychotic naïve early psychosis

Poster B55, Friday, October 21, 11:30 am - 1:00 pm, Le Baron

Graham Murray1,2, Anna Ermakova1, Azucena Justicia1,2, Ed Bullmore1,2, Peter Jones1,2, Trevor Robbins1,2, Paul Fletcher1,2; 1University of Cambridge, 2CAMEO, Cambridgeshire and Peterborough NHS Foundation Trust

There is preliminary, though partially inconsistent, evidence of neural abnormalities in signalling prediction errors in people with psychosis, consistent with theories that suggest mechanistic links between the disruption of these processes and the generation of psychotic symptoms. In particular, no previous studies have demonstrated midbrain reward prediction error abnormalities in psychosis in an entirely antipsychotic naïve sample ,and no previous studies have examined brain reward prediction error signalling in people at clinical risk of psychosis. Our aim was to investigate the involvement of meso-cortico-striatal circuitry during reward prediction error signalling in antipsychotic naïve early psychosis. Patients with first episode of psychosis (FEP, n = 14), people at clinical risk for developing psychosis (ARMS, n= 29), and healthy volunteers (n = 39) performed a reinforcement learning task involving monetary gains and losses that enables measures of neural reward prediction error during fMRI scanning. On region of interest analysis (p<0.05 family wise error corrected), patients with FEP had disrupted prediction error signalling compared to controls in the midbrain ventral tegmental area, striatum (left head of caudate), and right middle frontal gyrus. In the ventral tegmental area, ARMS patients had intermediate activation that was significantly greater than FEP but significantly less than controls. However, there was no evidence of abnormal activation in the right middle frontal gyrus or caudate in the ARMS. Our study confirms that patients with FEP have abnormal mesocorticostriatal signalling of reward prediction errors with dysfunction in the ARMS localised to the dopaminergic midbrain.

Topic Area: Neuroimaging

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