Resting-State Perfusion and Glutamatergic Neurotransmission in Schizotypy: A Multimodal Imaging Study

Poster B54, Friday, October 21, 11:30 am - 1:00 pm, Le Baron

Anna P. McLaughlin1, Meghan O’Sullivan1, Katrina McMullen2, Veena Kumari1, Gareth J. Barker1, Steve C. R. Williams1, Gemma Modinos1; 1Institute of Psychiatry, Psychology and Neuroscience, King’s College London, UK, 2Centre for Brain Health, University of British Columbia, Canada

Hippocampal hypermetabolism and glutamatergic abnormalities in the anterior cingulate cortex (ACC) are both observed in schizophrenia, and have been linked to symptom severity. However, findings vary depending on illness stage and antipsychotic use. Schizotypal individuals exhibit subclinical psychotic symptoms, but are free of illness-related confounds, making the study of schizotypy valuable in understanding the pathophysiology of schizophrenia. In the first study of this kind, we investigated resting-state perfusion and glutamatergic neurotransmission in schizotypy. We recruited 45 participants with high schizotypy (HS) and low schizotypy (LS), as defined by the Oxford and Liverpool Inventory of Feelings and Experiences (O-LIFE). Arterial Spin Labeling (ASL) was used to measure resting-state brain perfusion, with region-of-interest analysis in the hippocampus and ACC. Proton magnetic resonance spectroscopy (1H-MRS) was used to quantify glutamate concentrations in the ACC. Although groups did not differ significantly in perfusion or glutamate concentrations, within the HS group increased severity of psychotic-like symptoms (Total O-LIFE) was associated with hippocampal (p=0.035 FWE) and ACC perfusion (p=0.066 FWE, trend). Furthermore, while the hippocampus and ACC were strongly functionally connected in LS subjects (r=0.743, p<0.001), this was absent in high schizotypes. Finally, multimodal analysis revealed a negative association between hippocampal perfusion and ACC glutamate in HS subjects (p=0.029 FWE). These findings suggest that HS is associated with changes in hippocampal and ACC perfusion that are related to levels of psychotic-like symptoms and ACC glutamate concentrations. The lack of stronger group effects relative to schizophrenia studies might reflect compensatory mechanisms, which require further investigation.

Topic Area: Neuroimaging

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