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Schulz J, Zimmermann J, Sorg C, Menegaux A, Brandl F. Magnetic resonance imaging of the dopamine system in schizophrenia - A scoping review. Front Psychiatry 2022; 13:925476. [PMID: 36203848 PMCID: PMC9530597 DOI: 10.3389/fpsyt.2022.925476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 07/08/2022] [Indexed: 11/30/2022] Open
Abstract
For decades, aberrant dopamine transmission has been proposed to play a central role in schizophrenia pathophysiology. These theories are supported by human in vivo molecular imaging studies of dopamine transmission, particularly positron emission tomography. However, there are several downsides to such approaches, for example limited spatial resolution or restriction of the measurement to synaptic processes of dopaminergic neurons. To overcome these limitations and to measure complementary aspects of dopamine transmission, magnetic resonance imaging (MRI)-based approaches investigating the macrostructure, metabolism, and connectivity of dopaminergic nuclei, i.e., substantia nigra pars compacta and ventral tegmental area, can be employed. In this scoping review, we focus on four dopamine MRI methods that have been employed in patients with schizophrenia so far: neuromelanin MRI, which is thought to measure long-term dopamine function in dopaminergic nuclei; morphometric MRI, which is assumed to measure the volume of dopaminergic nuclei; diffusion MRI, which is assumed to measure fiber-based structural connectivity of dopaminergic nuclei; and resting-state blood-oxygenation-level-dependent functional MRI, which is thought to measure functional connectivity of dopaminergic nuclei based on correlated blood oxygenation fluctuations. For each method, we describe the underlying signal, outcome measures, and downsides. We present the current state of research in schizophrenia and compare it to other disorders with either similar (psychotic) symptoms, i.e., bipolar disorder and major depressive disorder, or dopaminergic abnormalities, i.e., substance use disorder and Parkinson's disease. Finally, we discuss overarching issues and outline future research questions.
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Affiliation(s)
- Julia Schulz
- Department of Neuroradiology, School of Medicine, Technical University of Munich, Munich, Germany.,TUM-NIC Neuroimaging Center, School of Medicine, Technical University of Munich, Munich, Germany
| | - Juliana Zimmermann
- Department of Neuroradiology, School of Medicine, Technical University of Munich, Munich, Germany.,TUM-NIC Neuroimaging Center, School of Medicine, Technical University of Munich, Munich, Germany
| | - Christian Sorg
- Department of Neuroradiology, School of Medicine, Technical University of Munich, Munich, Germany.,TUM-NIC Neuroimaging Center, School of Medicine, Technical University of Munich, Munich, Germany.,Department of Psychiatry and Psychotherapy, School of Medicine, Technical University of Munich, Munich, Germany
| | - Aurore Menegaux
- Department of Neuroradiology, School of Medicine, Technical University of Munich, Munich, Germany.,TUM-NIC Neuroimaging Center, School of Medicine, Technical University of Munich, Munich, Germany
| | - Felix Brandl
- Department of Neuroradiology, School of Medicine, Technical University of Munich, Munich, Germany.,TUM-NIC Neuroimaging Center, School of Medicine, Technical University of Munich, Munich, Germany.,Department of Psychiatry and Psychotherapy, School of Medicine, Technical University of Munich, Munich, Germany
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Karlsgodt KH. White Matter Microstructure across the Psychosis Spectrum. Trends Neurosci 2020; 43:406-416. [PMID: 32349908 DOI: 10.1016/j.tins.2020.03.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 03/12/2020] [Accepted: 03/30/2020] [Indexed: 12/11/2022]
Abstract
Diffusion-weighted imaging (DWI) is a neuroimaging technique that has allowed us an unprecedented look at the role that white matter microstructure may play in mental illnesses, such as psychosis. Psychosis-related illnesses, including schizophrenia, are increasingly viewed as existing along a spectrum; spectrums may be defined based on factors such as stage of illness, symptom severity, or genetic liability. This review first focuses on an overview of some of the recent findings from DWI studies. Then, it examines the ways in which DWI analyses have been extended across the broader psychosis spectrum, or spectrums, and what we have learned from such approaches.
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Affiliation(s)
- Katherine H Karlsgodt
- Departments of Psychology and Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, 1285 Franz Hall, Box 951563, Los Angeles, CA 90095, USA.
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Bracht T, Viher PV, Stegmayer K, Strik W, Federspiel A, Wiest R, Walther S. Increased structural connectivity of the medial forebrain bundle in schizophrenia spectrum disorders is associated with delusions of paranoid threat and grandiosity. NEUROIMAGE-CLINICAL 2019; 24:102044. [PMID: 31678911 PMCID: PMC6978276 DOI: 10.1016/j.nicl.2019.102044] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 10/12/2019] [Accepted: 10/17/2019] [Indexed: 12/25/2022]
Abstract
Increased FA of bilateral slMFB can be found in delusional SSD-patients. Findings are supported by a psychopathological model of paranoia and grandiosity. Findings are in line with a model of underlying network physiology (slMFB).
In many cases delusions in schizophrenia spectrum disorders (SSD) are driven by strong emotions such as feelings of paranoia or grandiosity. We refer to these extreme emotional experiences as psychotic affectivity. We hypothesized that increased structural connectivity of the supero-lateral medial forebrain bundle (slMFB), a major tract of the reward system, is associated with delusional psychotic affectivity. Forty-six patients with SSD and 44 healthy controls (HC) underwent diffusion weighted magnetic resonance imaging (DW-MRI)-scans. The slMFB and a comparison tract (corticospinal tract) were reconstructed using diffusion tensor imaging (DTI)-based tractography. Fractional anisotropy (FA) was sampled across the tracts. We used a mixed-model analyses of variance controlling for age and gender to compare FA of bilateral slMFB between SSD-patients and HC. Correlations of FA of bilateral slMFB and the PANSS-positive item delusions were calculated. In addition, FA was compared between three clinically homogeneous SSD-subgroups in terms of psychotic affectivity (severe, mild and no PA, sPA, mPA, nPA) and HC. FA of the slMFB did not differ between all SSD-patients and HC. In SSD-patients there was a positive correlation between delusions and FA in bilateral slMFB. Likewise, SSD-subgroups of psychotic affectivity and HC differed significantly in FA of the slMFB. Results were driven by higher FA in the right slMFB in sPA as compared to nPA and to HC. There was no significant effect for the comparison tract. In conclusion, increased structural connectivity of the slMFB may underlie delusional experiences of paranoia and grandiosity in SSD.
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Affiliation(s)
- Tobias Bracht
- University Hospital of Psychiatry, University of Bern, Bern, Switzerland; Translational Research Centre, University Hospital of Psychiatry, University of Bern, Bern, Switzerland.
| | - Petra V Viher
- University Hospital of Psychiatry, University of Bern, Bern, Switzerland; Translational Research Centre, University Hospital of Psychiatry, University of Bern, Bern, Switzerland
| | - Katharina Stegmayer
- University Hospital of Psychiatry, University of Bern, Bern, Switzerland; Translational Research Centre, University Hospital of Psychiatry, University of Bern, Bern, Switzerland
| | - Werner Strik
- University Hospital of Psychiatry, University of Bern, Bern, Switzerland; Translational Research Centre, University Hospital of Psychiatry, University of Bern, Bern, Switzerland
| | - Andrea Federspiel
- Translational Research Centre, University Hospital of Psychiatry, University of Bern, Bern, Switzerland
| | - Roland Wiest
- Institute of Diagnostic and Interventional Neuroradiology, University of Bern, Bern, Switzerland
| | - Sebastian Walther
- University Hospital of Psychiatry, University of Bern, Bern, Switzerland; Translational Research Centre, University Hospital of Psychiatry, University of Bern, Bern, Switzerland
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GPRIN3 Controls Neuronal Excitability, Morphology, and Striatal-Dependent Behaviors in the Indirect Pathway of the Striatum. J Neurosci 2019; 39:7513-7528. [PMID: 31363062 DOI: 10.1523/jneurosci.2454-18.2019] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Revised: 07/16/2019] [Accepted: 07/19/2019] [Indexed: 12/15/2022] Open
Abstract
The regulation of the striatum by the GPCR signaling through neuromodulators is essential for its physiology and physiopathology, so it is necessary to know all the compounds of these pathways. In this study, we identified a new important partner of the dopaminergic pathway: GPRIN3 (a member of the GPRIN family). GPRIN3 is highly expressed in the striatum but with undefined function. Cell sorting of medium spiny neurons (MSNs) in indirect MSNs and direct MSNs indicated the presence of the GPRIN3 gene in both populations with a preferential expression in indirect MSNs. This led us to generate GPRIN3 KO mice by CRISPR/Cas9 and test male animals to access possible alterations in morphological, electrophysiological, and behavioral parameters following its absence. 3D reconstruction analysis of MSNs revealed increased neuronal arborization in GPRIN3 KO and modified passive and active electrophysiological properties. These cellular alterations were coupled with increased motivation and cocaine-induced hyperlocomotion. Additionally, using a specific indirect MSN knockdown, we showed a preferential role for GPRIN3 in indirect MSNs related to the D2R signaling. Together, these results show that GPRIN3 is a mediator of D2R function in the striatum playing a major role in striatal physiology.SIGNIFICANCE STATEMENT The striatum is the main input of the basal ganglia processing information from different brain regions through the combined actions of direct pathway neurons and indirect pathway neurons. Both neuronal populations are defined by the expression of dopamine D1R or D2R GPCRs, respectively. How these neurons signal to the respective G-protein is still debatable. Here we identified GPRIN3 as a putative selective controller of D2R function in the striatum playing a critical role in striatal-associated behaviors and cellular functions. This study represents the identification of a new target to tackle striatal dysfunction associated with the D2R, such as schizophrenia, Parkinson's disease, and drug addiction.
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