According to a study published in Schizophrenia Research, increased striatal cerebral blood flow is associated with a disruption in functional connectivity between the dorsal striatum and frontal cortex. High cerebral blood flow represents a central pathology in patients with clinical high risk for psychosis.
This study sought to explore the association between striatal cerebral blood flow and executive function by characterizing the functional connectivity between dorsal striatum and the frontal cortex. The study sample included 47 participants recruited from the Early Detection and Intervention Center for Mental Crisis Bern; 29 participants were diagnosed as clinical high risk for psychosis, and 18 were matched non-psychotic controls.
Functional connectivity and mean cerebral blood flow measures were calculated for patients in the resting state from arterial spin labeling 3T MRI data. Patients were further evaluated using ultra-high risk criteria (Structured Interview for Psychosis-Risk Syndromes) and basic symptoms criteria (Schizophrenia Proneness Instrument). The Trail Making Test-B (TMT-B) was the primary measure of executive dysfunction, testing the performance of working memory and cognitive flexibility.
Striatal cerebral blood flow was highest in psychosis-risk patients with executive deficits (abnormal TMT-B performance) compared with psychosis-risk patients with normal executive functioning (normal TMT-B performance) and the control group. However, the clinical high-risk patients revealed significantly lower functional connectivity between the dorsal striatum and the anterior cingulate cortex than the control group. These findings suggest that increased striatal cerebral blood flow in the dorsal striatum is related to executive dysfunction.
A limitation of the study was a small sample size. The nature of the cross-sectional study design further restrained predictions about various patient outcomes, including conversion to full-blown psychosis.
Increased striatal cerebral blood flow was associated with a disruption in functional connectivity between the dorsal striatum and frontal cortex; changes to functional connectivity through early stage of psychosis should be monitored as they relate to an increased risk in developing psychosis.
Hubl D, Schultze-Lutter F, Hauf M, et al. Striatal cerebral blood flow, executive functioning, and fronto-striatal functional connectivity in clinical high risk for psychosis [published online July 10, 2018]. Schizophrenia Res. doi: 10.1016/j.schres.2018.07.018