Schizophrenia has a lifetime prevalence of 1% in the general population. It is positive symptoms including delusions and hallucinations, negative symptoms including anhedonia and avolition, and cognitive symptoms including memory deficits and social impairment. Past studies have found structural and functional changes in the hippocampus. Structural studies have illustrated decreased hippocampal volume in schizophrenia. characterized by Functional MRI studies have revealed resting- state hyperactivity of the hippocampus and have implicated glutamate as a driver of increase CBV. Schizophrenia is also associated with abnormal recruitment of the hippocampus during memory tasks. Some of these structural and functional results have been localized to specific regions of the hippocampus. However, it is unclear when in the natural history of the disease the changes in hippocampal CBV and volume occur. We propose a cross-sectional study that investigates hippocampal CBV and volume in patients with first-episode psychosis and schizophrenia. We hypothesize that hippocampal CBV is increased but hippocampal volume is not affected in first-episode psychosis. We predict that hippocampal CBV will also be increased in schizophrenia, but hippocampal volume will be reduced. In a subset of patients, we will implement a non-invasive inflow-based vascular-space occupancy (iVASO) method. We hypothesize that this method will serve as a more sensitive marker by selectively measuring arterial CBV (instead of arterial and venous CBV). If our hypotheses hold true, CBV measurements may serve as a functional biomarker that precedes hippocampal volume changes seen in schizophrenia and could be used as a target for future pharmacological interventions.
Structural and functional changes in the hippocampus in schizophrenia are well characterized;however, it is unclear when these changes occur. The proposed project will investigate which regions within the hippocampus are affected and when these changes occur.
|Talati, Pratik; Rane, Swati; Kose, Samet et al. (2014) Increased hippocampal CA1 cerebral blood volume in schizophrenia. Neuroimage Clin 5:359-64|