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Limongi R, Jeon P, Mackinley M, Das T, Dempster K, Théberge J, Bartha R, Wong D, Palaniyappan L. Glutamate and Dysconnection in the Salience Network: Neurochemical, Effective Connectivity, and Computational Evidence in Schizophrenia. Biol Psychiatry 2020; 88:273-281. [PMID: 32312577 DOI: 10.1016/j.biopsych.2020.01.021] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 01/06/2020] [Accepted: 01/27/2020] [Indexed: 11/17/2022]
Abstract
BACKGROUND Functional dysconnection in schizophrenia is underwritten by a pathophysiology of the glutamate neurotransmission that affects the excitation-inhibition balance in key nodes of the salience network. Physiologically, this manifests as aberrant effective connectivity in intrinsic connections involving inhibitory interneurons. In computational terms, this produces a pathology of evidence accumulation and ensuing inference in the brain. Finally, the pathophysiology and aberrant inference would partially account for the psychopathology of schizophrenia as measured in terms of symptoms and signs. We refer to this formulation as the 3-level hypothesis. METHODS We tested the hypothesis in core nodes of the salience network (the dorsal anterior cingulate cortex [dACC] and the anterior insula) of 20 patients with first-episode psychosis and 20 healthy control subjects. We established 3-way correlations between the magnetic resonance spectroscopy measures of glutamate, effective connectivity of resting-state functional magnetic resonance imaging, and correlations between measures of this connectivity and estimates of precision (inherent in evidence accumulation in the Stroop task) and psychopathology. RESULTS Glutamate concentration in the dACC was associated with higher and lower inhibitory connectivity in the dACC and in the anterior insula, respectively. Crucially, glutamate concentration correlated negatively with the inhibitory influence on the excitatory neuronal population in the dACC of subjects with first-episode psychosis. Furthermore, aberrant computational parameters of the Stroop task performance were associated with aberrant inhibitory connections. Finally, the strength of connections from the dACC to the anterior insula correlated negatively with severity of social withdrawal. CONCLUSIONS These findings support a link between glutamate-mediated cortical disinhibition, effective-connectivity deficits, and computational performance in psychosis.
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Affiliation(s)
- Roberto Limongi
- Department of Psychiatry, Western University, London, Ontario, Canada; Robarts Research Institute, Western University, London, Ontario, Canada.
| | - Peter Jeon
- Department of Medical Biophysics, Western University, London, Ontario, Canada
| | - Michael Mackinley
- Department of Psychiatry, Western University, London, Ontario, Canada; Robarts Research Institute, Western University, London, Ontario, Canada
| | - Tushar Das
- Department of Strategic Enterprise Solutions, Fanshawe College, London, Ontario, Canada
| | - Kara Dempster
- Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Jean Théberge
- Department of Psychiatry, Western University, London, Ontario, Canada; Department of Medical Biophysics, Western University, London, Ontario, Canada; Department of Medical Imaging, Western University, London, Ontario, Canada; Neuropsychiatry Imaging Lab, Lawson Health Research Institute, London, Ontario, Canada; Department of Diagnostic Imaging, St. Joseph's Health Care London, London, Ontario, Canada
| | - Robert Bartha
- Department of Medical Biophysics, Western University, London, Ontario, Canada
| | - Dickson Wong
- Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Lena Palaniyappan
- Department of Psychiatry, Western University, London, Ontario, Canada; Robarts Research Institute, Western University, London, Ontario, Canada; Lawson Health Research Institute, London, Ontario, Canada.
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Morriss J, Gell M, van Reekum CM. The uncertain brain: A co-ordinate based meta-analysis of the neural signatures supporting uncertainty during different contexts. Neurosci Biobehav Rev 2018; 96:241-249. [PMID: 30550858 DOI: 10.1016/j.neubiorev.2018.12.013] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 12/09/2018] [Accepted: 12/10/2018] [Indexed: 12/23/2022]
Abstract
Uncertainty is often inevitable in everyday life and can be both stressful and exciting. Given its relevance to psychopathology and wellbeing, recent research has begun to address the brain basis of uncertainty. In the current review we examined whether there are discrete and shared neural signatures for different uncertain contexts. From the literature we identified three broad categories of uncertainty currently empirically studied using functional MRI (fMRI): basic threat and reward uncertainty, decision-making under uncertainty, and associative learning under uncertainty. We examined the neural basis of each category by using a coordinate based meta-analysis, where brain activation foci from previously published fMRI experiments were drawn together (1998-2017; 87 studies). The analyses revealed shared and discrete patterns of neural activation for uncertainty, such as the insula and amygdala, depending on the category. Such findings will have relevance for researchers attempting to conceptualise uncertainty, as well as clinical researchers examining the neural basis of uncertainty in relation to psychopathology.
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Affiliation(s)
- Jayne Morriss
- Centre for Integrative Neuroscience and Neurodynamics, School of Psychology and Clinical Language Sciences, University of Reading, Reading, UK.
| | - Martin Gell
- Centre for Integrative Neuroscience and Neurodynamics, School of Psychology and Clinical Language Sciences, University of Reading, Reading, UK
| | - Carien M van Reekum
- Centre for Integrative Neuroscience and Neurodynamics, School of Psychology and Clinical Language Sciences, University of Reading, Reading, UK
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Limongi R, Bohaterewicz B, Nowicka M, Plewka A, Friston KJ. Knowing when to stop: Aberrant precision and evidence accumulation in schizophrenia. Schizophr Res 2018; 197:386-391. [PMID: 29331218 PMCID: PMC6020132 DOI: 10.1016/j.schres.2017.12.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 12/29/2017] [Accepted: 12/29/2017] [Indexed: 11/24/2022]
Abstract
Predictive coding and active inference formulations of the dysconnection hypothesis suggest that subjects with schizophrenia (SZ) hold unduly precise prior beliefs to compensate for a failure of sensory attenuation. This implies that SZ subjects should both initiate responses prematurely during evidence-accumulation tasks and fail to inhibit their responses at long stop-signal delays. SZ and healthy control subjects were asked to report the timing of billiards-ball collisions and were occasionally required to withhold their responses. SZ subjects showed larger temporal estimation errors, which were associated with premature responses and decreased response inhibition. To account for these effects, we used hierarchical (Bayesian) drift-diffusion models (HDDM) and model selection procedures to adjudicate among four hypotheses. HDDM revealed that the precision of prior beliefs (i.e., starting point) rather than increased sensory precision (i.e., drift rate) drove premature responses and impaired response inhibition in patients with SZ. From the perspective of active inference, we suggest that premature predictions in SZ are responses that, heuristically, are traded off against accuracy to ensure action execution. On the basis of previous work, we suggest that the right insular cortex might mediate this trade-off.
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Affiliation(s)
- Roberto Limongi
- Universidad Tecnológica de Chile INACAP, Chile; Pontificia Universidad Católica de Valparaíso, Chile.
| | - Bartosz Bohaterewicz
- University of Social Sciences and Humanities, Department of Psychology of Individual Differences, Warsaw, Poland; Department of Cognitive Neuroscience and Neuroergonomics, Institute of Applied Psychology, Jagiellonian University, Krakow, Poland
| | - Magdalena Nowicka
- University of Social Sciences and Humanities, Department of Psychology of Individual Differences, Warsaw, Poland
| | | | - Karl J Friston
- Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, UK
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Limongi R, Silva AM. Temporal Prediction Errors Affect Short-Term Memory Scanning Response Time. Exp Psychol 2016; 63:333-342. [DOI: 10.1027/1618-3169/a000339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Abstract. The Sternberg short-term memory scanning task has been used to unveil cognitive operations involved in time perception. Participants produce time intervals during the task, and the researcher explores how task performance affects interval production – where time estimation error is the dependent variable of interest. The perspective of predictive behavior regards time estimation error as a temporal prediction error (PE), an independent variable that controls cognition, behavior, and learning. Based on this perspective, we investigated whether temporal PEs affect short-term memory scanning. Participants performed temporal predictions while they maintained information in memory. Model inference revealed that PEs affected memory scanning response time independently of the memory-set size effect. We discuss the results within the context of formal and mechanistic models of short-term memory scanning and predictive coding, a Bayes-based theory of brain function. We state the hypothesis that our finding could be associated with weak frontostriatal connections and weak striatal activity.
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Affiliation(s)
- Roberto Limongi
- Facultad de Medicina, Universidad de Valparaíso, Valparaíso, Chile
- Instituto Venezolano de Investigaciones Lingüísticas y Literarias Andres Bello, Laboratorio de Lenguaje y Cognición, Caracas, Venezuela
| | - Angélica M. Silva
- Escuela de Pedagogía, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
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