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Standardized Data Acquisition for Neuromelanin-Sensitive Magnetic Resonance Imaging of the Substantia Nigra
Published on: September 8, 2021
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Frontostriatothalamic effective connectivity and dopaminergic function in the psychosis continuum
Kristina Sabaroedin1, Adeel Razi1,2,3, Sidhant Chopra1
1Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Clayton, Victoria 3800, Australia.
Brain : a Journal of Neurology
|January 30, 2022
Summary
Subcortical circuit dysfunction characterizes early psychosis, while cortical issues appear later. Nigrostriatal and striatothalamic pathways link to dopamine synthesis capacity in psychosis.
Area of Science:
- Neuroscience
- Psychiatry
- Medical Imaging
Background:
- Fronto-striato-thalamic (FST) circuit dysfunction is implicated in psychosis.
- The role of subcortical versus cortical dysfunction in psychosis onset is debated.
Purpose of the Study:
- To investigate the effective connectivity of FST circuits in first-episode psychosis (FEP) and established schizophrenia.
- To explore the relationship between FST connectivity and striatal dopamine synthesis.
Main Methods:
- Spectral dynamic causal modeling of resting-state fMRI data.
- Analysis of two independent patient cohorts (antipsychotic-naïve FEP and established schizophrenia) and healthy controls.
- Concurrent fMRI and PET imaging to assess striatal 18F-DOPA uptake in healthy individuals.
Main Results:
- Midbrain and thalamic connectivity were dysfunctional in both FEP and schizophrenia patients.
- FEP patients showed subcortical dysconnectivity, linked to positive symptom severity.
- Cortical-subcortical dysconnectivity was observed only in established schizophrenia.
- In healthy individuals, striatal dopamine synthesis capacity correlated with nigrostriatal and striatothalamic pathway connectivity.
Conclusions:
- Subcortical dysconnectivity is an early feature of psychosis.
- Cortical involvement in FST circuits may develop later in the illness progression.
- Nigrostriatal and striatothalamic signaling are associated with dopamine synthesis capacity, a marker for psychosis.
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