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Schifani C, Hafizi S, Da Silva T, Watts JJ, Khan MS, Mizrahi R. Using molecular imaging to understand early schizophrenia-related psychosis neurochemistry: a review of human studies. Int Rev Psychiatry 2017; 29:555-566. [PMID: 29219634 PMCID: PMC8011813 DOI: 10.1080/09540261.2017.1396205] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Schizophrenia is a chronic psychiatric disorder generally preceded by a so-called prodromal phase, which is characterized by attenuated psychotic symptoms. Advances in clinical research have enabled prospective identification of those individuals who are at clinical high risk (CHR) for psychosis, with the power to predict psychosis onset within the near future. Changes in several brain neurochemical systems and molecular mechanisms are implicated in the pathophysiology of schizophrenia and the psychosis spectrum, including the dopaminergic, γ-aminobutyric acid (GABA)-ergic, glutamatergic, endocannabinoid, and immunologic (i.e. glial activation) system and other promising future directions such as synaptic density, which are possible to quantify in vivo using positron emission tomography (PET). This paper aims to review in vivo PET studies in the mentioned systems in the early course of psychosis (i.e. CHR and first-episode psychosis (FEP)). The results of reviewed studies are promising; however, the current understanding of the underlying pathology of psychosis is still limited. Importantly, promising efforts involve the development of novel PET radiotracers targeting systems with growing interest in schizophrenia, like the nociceptive system and synaptic density.
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Affiliation(s)
- Christin Schifani
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Sina Hafizi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Tania Da Silva
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Jeremy Joseph Watts
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - M. Saad Khan
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Romina Mizrahi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
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Kambeitz J, Abi-Dargham A, Kapur S, Howes OD. Alterations in cortical and extrastriatal subcortical dopamine function in schizophrenia: systematic review and meta-analysis of imaging studies. Br J Psychiatry 2014; 204:420-9. [PMID: 25029687 DOI: 10.1192/bjp.bp.113.132308] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND The hypothesis that cortical dopaminergic alterations underlie aspects of schizophrenia has been highly influential. AIMS To bring together and evaluate the imaging evidence for dopaminergic alterations in cortical and other extrastriatal regions in schizophrenia. METHOD Electronic databases were searched for in vivo molecular studies of extrastriatal dopaminergic function in schizophrenia. Twenty-three studies (278 patients and 265 controls) were identified. Clinicodemographic and imaging variables were extracted and effect sizes determined for the dopaminergic measures. There were sufficient data to permit meta-analyses for the temporal cortex, thalamus and substantia nigra but not for other regions. RESULTS The meta-analysis of dopamine D2/D3 receptor availability found summary effect sizes of d = -0.32 (95% CI -0.68 to 0.03) for the thalamus, d = -0.23 (95% CI -0.54 to 0.07) for the temporal cortex and d = 0.04 (95% CI -0.92 to 0.99) for the substantia nigra. Confidence intervals were wide and all included no difference between groups. Evidence for other measures/regions is limited because of the small number of studies and in some instances inconsistent findings, although significant differences were reported for D2/D3 receptors in the cingulate and uncus, for D1 receptors in the prefrontal cortex and for dopamine transporter availability in the thalamus. CONCLUSIONS There is a relative paucity of direct evidence for cortical dopaminergic alterations in schizophrenia, and findings are inconclusive. This is surprising given the wide influence of the hypothesis. Large, well-controlled studies in drug-naive patients are warranted to definitively test this hypothesis.
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Affiliation(s)
- Joseph Kambeitz
- Joseph Kambeitz, MD, Department of Psychosis Studies, Institute of Psychiatry, King's College London, UK; Anissa Abi-Dargham, MD, Department of Psychiatry, Columbia University, New York State Psychiatric Institute, New York, USA;Shitij Kapur, MD, PhD, Department of Psychosis Studies, Institute of Psychiatry, King's College London, UK; Oliver D. Howes, BM, BCh, MA, MRCPsych, PhD, DM, Department of Psychosis Studies, Institute of Psychiatry, King's College London, and Psychiatric Imaging Group, Medical Research Council Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, UK
| | - Anissa Abi-Dargham
- Joseph Kambeitz, MD, Department of Psychosis Studies, Institute of Psychiatry, King's College London, UK; Anissa Abi-Dargham, MD, Department of Psychiatry, Columbia University, New York State Psychiatric Institute, New York, USA;Shitij Kapur, MD, PhD, Department of Psychosis Studies, Institute of Psychiatry, King's College London, UK; Oliver D. Howes, BM, BCh, MA, MRCPsych, PhD, DM, Department of Psychosis Studies, Institute of Psychiatry, King's College London, and Psychiatric Imaging Group, Medical Research Council Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, UK
| | - Shitij Kapur
- Joseph Kambeitz, MD, Department of Psychosis Studies, Institute of Psychiatry, King's College London, UK; Anissa Abi-Dargham, MD, Department of Psychiatry, Columbia University, New York State Psychiatric Institute, New York, USA;Shitij Kapur, MD, PhD, Department of Psychosis Studies, Institute of Psychiatry, King's College London, UK; Oliver D. Howes, BM, BCh, MA, MRCPsych, PhD, DM, Department of Psychosis Studies, Institute of Psychiatry, King's College London, and Psychiatric Imaging Group, Medical Research Council Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, UK
| | - Oliver D Howes
- Joseph Kambeitz, MD, Department of Psychosis Studies, Institute of Psychiatry, King's College London, UK; Anissa Abi-Dargham, MD, Department of Psychiatry, Columbia University, New York State Psychiatric Institute, New York, USA;Shitij Kapur, MD, PhD, Department of Psychosis Studies, Institute of Psychiatry, King's College London, UK; Oliver D. Howes, BM, BCh, MA, MRCPsych, PhD, DM, Department of Psychosis Studies, Institute of Psychiatry, King's College London, and Psychiatric Imaging Group, Medical Research Council Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, UK
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Relationship of frontal D(2/3) binding potentials to cognition: a study of antipsychotic-naive schizophrenia patients. Int J Neuropsychopharmacol 2013; 16:23-36. [PMID: 22338593 DOI: 10.1017/s146114571200003x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Studies of in vivo dopamine receptors in schizophrenia have mostly focused on D(2) receptors in striatal areas or on D(1) receptors in cortex. No previous study has examined the correlation between cortical dopamine D(2/3) receptor binding potentials and cognition in schizophrenia patients. The objective was to examine this relation in the frontal cortex in first-episode, drug-naive schizophrenia patients. Based on preclinical and pharmacological evidence, we specifically expected to find a relation between D(2/3) receptor binding potentials and set shifting. This was a cross-sectional, case-control study using single-photon emission computerized tomography with the D(2/3)-receptor ligand [(123)I]epidepride, co-registered with structural magnetic resonance imaging and correlated to cognitive measures. Participants were 24 antipsychotic-naive, first-episode schizophrenia patients and 20 healthy controls matched for gender and age. For patients, a significant linear correlation between D(2/3) BP(ND) and set shifting was found, while significant quadratic associations were observed for verbal fluency, planning and attention. For controls, the only significant association with D(2/3) BP(ND) was a quadratic partial correlation for set shifting. The main findings indicated a relation between D(2/3) receptor binding in the frontal cortex and set shifting, planning and attention, but also support a differential involvement of cortical dopamine D(2/3) receptor binding in at least some cognitive functions, perhaps particularly attention, in schizophrenia patients compared to healthy people. The results suggest that cortical D(2/3) receptor function may be more involved in some cognitive functions (i.e. attention, fluency and planning) in patients with schizophrenia than in healthy people, suggesting that information processing in schizophrenia may be characterized by lower signal:noise ratios.
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Abstract
After decades of research aimed at elucidating the pathophysiology and etiology of schizophrenia, it has become increasingly apparent that it is an illness knowing few boundaries. Psychopathological manifestations extend across several domains, impacting multiple facets of real-world functioning for the affected individual. Even within one such domain, arguably the most enduring, difficult to treat, and devastating to long-term functioning-executive impairment-there are not only a host of disrupted component processes, but also a complex underlying dysfunctional neural architecture. Further, just as implicated brain structures (eg, dorsolateral prefrontal cortex) through postmortem and neuroimaging techniques continue to show alterations in multiple, interacting signaling pathways, so too does evolving understanding of genetic risk factors suggest multiple molecular entry points to illness liability. With this expansive network of interactions in mind, the present chapter takes a systems-level approach to executive dysfunction in schizophrenia, by identifying key regions both within and outside of the frontal lobes that show changes in schizophrenia and are important in cognitive control neural circuitry, summarizing current knowledge of their relevant functional interactions, and reviewing emerging links between schizophrenia risk genetics and characteristic executive circuit aberrancies observed with neuroimaging methods.
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Prentice KJ, Gold JM, Buchanan RW. The Wisconsin Card Sorting impairment in schizophrenia is evident in the first four trials. Schizophr Res 2008; 106:81-7. [PMID: 17933496 PMCID: PMC3747838 DOI: 10.1016/j.schres.2007.07.015] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2006] [Revised: 06/15/2007] [Accepted: 07/09/2007] [Indexed: 11/28/2022]
Abstract
BACKGROUND Schizophrenia (SZ) patients' low scores on the Wisconsin Card Sorting Test (WCST) are often attributed to frequent perseverative errors, a pattern typically interpreted as a failure to shift from previously rewarded behavior in response to negative feedback. In this study we tested the hypothesis that SZ patients, due to dysregulated error-processing mechanisms, are more fundamentally impaired in their on-line, trial-to-trial use of feedback to guide behavior. METHODS Analysis of archival WCST data from 145 adults with schizophrenia and 80 healthy comparison subjects. RESULTS Schizophrenia patients' impaired use of negative feedback was evident on the first four WCST cards, where they were significantly less accurate than comparison subjects. Performance on these early cards significantly predicted overall task success as indexed by categories completed and proportion of perseverative errors. CONCLUSIONS Patients' poor performance on pre-shift WCST trials likely reflects a fundamental impairment in the ability to use feedback to guide behavior. Recent data from both humans and primates suggest that reward-based learning processes like those employed in the WCST are driven by phasic changes in midbrain dopamine activity. It might, therefore, be possible to interpret higher order executive dysfunction in schizophrenia as a manifestation of altered DA signaling.
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Affiliation(s)
- Kristen J. Prentice
- VA Capitol Healthcare Network MIRECC, 10 North Greene Street, Baltimore, MD, 21201 USA,University of Maryland School of Medicine, Department of Psychiatry and Maryland Psychiatric Research Center, P.O. Box 21247, Baltimore, MD, 21228 USA
| | - James M. Gold
- University of Maryland School of Medicine, Department of Psychiatry and Maryland Psychiatric Research Center, P.O. Box 21247, Baltimore, MD, 21228 USA
| | - Robert W. Buchanan
- University of Maryland School of Medicine, Department of Psychiatry and Maryland Psychiatric Research Center, P.O. Box 21247, Baltimore, MD, 21228 USA
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Buchsbaum MS, Buchsbaum BR, Chokron S, Tang C, Wei TC, Byne W. Thalamocortical circuits: fMRI assessment of the pulvinar and medial dorsal nucleus in normal volunteers. Neurosci Lett 2006; 404:282-7. [PMID: 16860474 DOI: 10.1016/j.neulet.2006.05.063] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2005] [Revised: 03/10/2006] [Accepted: 05/15/2006] [Indexed: 11/16/2022]
Abstract
This fMRI study investigates the activation of the thalamic nuclei in a spatial focusing-of-attention task previously shown to activate the pulvinar with FDG-PET and assesses the connectivity of the thalamic nuclei with cortical areas. Normal right-handed subjects (eight men, eight women, average age=32 years) viewed four types of stimuli positioned to the right or left of the central fixation point (left hemifield-large letter, left hemifield-small letter display with flanking letters; right hemifield-large letter, right hemifield-small letter display with flankers). BOLD responses to small letters surrounded by flankers were compared with responses to large isolated letters. To examine maximum functional regional connectivity, we modeled "subject" as a random effect and attained fixed effect parameter estimates and t-statistics for functional connectivity between each of the thalamic nuclei (pulvinar, medial dorsal, and anterior) as the seed region and each non-seed voxel. Greater BOLD activation for letters surrounded by flankers than for large letters was observed in the pulvinar as anticipated and was also marked in the medial dorsal nucleus (MDN), anterior and superior cingulate (BA24 and BA24'), dorsolateral prefrontal cortex, and frontal operculum and insula. For the MDN, maximal functional connectivity was with the dorsolateral prefrontal cortex; correlations with left superior temporal, parietal, posterior frontal, and occipital regions were also observed. For the pulvinar, maximal functional connectivity was with parietal BA39; for anterior thalamus, with anterior cingulate.
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Affiliation(s)
- Monte S Buchsbaum
- Department of Psychiatry, Mount Sinai School of Medicine, Box 1505, New York, NY 10029-6574, USA.
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