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Samona EA, Chowdury A, Kopchick J, Thomas P, Rajan U, Khatib D, Zajac-Benitez C, Amirsadri A, Haddad L, Stanley JA, Diwadkar VA. The importance of covert memory consolidation in schizophrenia: Dysfunctional network profiles of the hippocampus and the dorsolateral prefrontal cortex. Psychiatry Res Neuroimaging 2024; 340:111805. [PMID: 38447230 PMCID: PMC11188056 DOI: 10.1016/j.pscychresns.2024.111805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 01/24/2024] [Accepted: 02/20/2024] [Indexed: 03/08/2024]
Abstract
Altered brain network profiles in schizophrenia (SCZ) during memory consolidation are typically observed during task-active periods such as encoding or retrieval. However active processes are also sub served by covert periods of memory consolidation. These periods are active in that they allow memories to be recapitulated even in the absence of overt sensorimotor processing. It is plausible that regions central to memory formation like the dlPFC and the hippocampus, exert network signatures during covert periods. Are these signatures altered in patients? The question is clinically relevant because real world learning and memory is facilitated by covert processing, and may be impaired in schizophrenia. Here, we compared network signatures of the dlPFC and the hippocampus during covert periods of a learning and memory task. Because behavioral proficiency increased non-linearly, functional connectivity of the dlPFC and hippocampus [psychophysiological interaction (PPI)] was estimated for each of the Early (linear increases in performance) and Late (asymptotic performance) covert periods. During Early periods, we observed hypo-modulation by the hippocampus but hyper-modulation by dlPFC. Conversely, during Late periods, we observed hypo-modulation by both the dlPFC and the hippocampus. We stitch these results into a conceptual model of network deficits during covert periods of memory consolidation.
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Affiliation(s)
- Elias A Samona
- Department of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - Asadur Chowdury
- Department of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - John Kopchick
- Department of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - Patricia Thomas
- Department of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - Usha Rajan
- Department of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - Dalal Khatib
- Department of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - Caroline Zajac-Benitez
- Department of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - Alireza Amirsadri
- Department of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - Luay Haddad
- Department of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - Jeffrey A Stanley
- Department of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, United States
| | - Vaibhav A Diwadkar
- Department of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, United States.
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Herkströter F, Zahedi A, Standke I, Dannlowski U, Lencer R, Schubotz RI, Trempler I. Gray matter matters: Cognitive stability and flexibility in schizophrenia spectrum disorder. Psychophysiology 2024:e14596. [PMID: 38691383 DOI: 10.1111/psyp.14596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 03/12/2024] [Accepted: 04/10/2024] [Indexed: 05/03/2024]
Abstract
Cognitive dysfunction constitutes a core characteristic of schizophrenia spectrum disorders (SZ). Specifically, deficits in updating generative models (i.e., cognitive flexibility) and shielding against distractions (i.e., cognitive stability) are considered critical contributors to cognitive impairment in these patients. Here, we examined the structural integrity of frontostriatal networks and their associations with reduced cognitive stability and flexibility in SZ patients. In a sample of 21 patients diagnosed with SZ and 22 healthy controls, we measured gray matter volume (GMV) using structural MRI. Further, cognitive stability and flexibility were assessed using a switch-drift paradigm, quantifying the successful ignoring of distracters and detection of rule switches. Compared to controls, patients showed significantly smaller GMV in the whole brain and three predefined regions of interest: the medial prefrontal cortex (mPFC), inferior frontal gyrus (IFG), and caudate nucleus (CN). Notably, GMV in these areas positively correlated with correct rule-switch detection but not with ignoring rule-compatible drifts. Further, the volumetric differences between SZ patients and controls were statistically explainable by considering the behavioral performance in the switch-drift task. Our results indicate that morphological abnormalities in frontostriatal networks are associated with deficient flexibility in SZ patients and highlight the necessity of minimizing neurodevelopmental and progressive brain atrophy in this population.
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Affiliation(s)
- Florentine Herkströter
- Department of Neurology, Niels-Stensen-Kliniken, Marienhospital Osnabrück-Standort Natruper Holz, Osnabrueck, Germany
| | - Anoushiravan Zahedi
- Institute of Psychology, University of Muenster, Muenster, Germany
- Otto Creutzfeldt-Center for Cognitive and Behavioral Neuroscience, University of Muenster, Muenster, Germany
| | - Isabel Standke
- Institute for Translational Psychiatry, University of Muenster, Muenster, Germany
| | - Udo Dannlowski
- Institute of Psychology, University of Muenster, Muenster, Germany
- Institute for Translational Psychiatry, University of Muenster, Muenster, Germany
| | - Rebekka Lencer
- Institute for Translational Psychiatry, University of Muenster, Muenster, Germany
- Department of Psychiatry and Psychotherapy, University of Luebeck, Luebeck, Germany
| | - Ricarda I Schubotz
- Institute of Psychology, University of Muenster, Muenster, Germany
- Otto Creutzfeldt-Center for Cognitive and Behavioral Neuroscience, University of Muenster, Muenster, Germany
| | - Ima Trempler
- Institute of Psychology, University of Muenster, Muenster, Germany
- Otto Creutzfeldt-Center for Cognitive and Behavioral Neuroscience, University of Muenster, Muenster, Germany
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Hasan SM, Huq MS, Chowdury AZ, Baajour S, Kopchick J, Robison AJ, Thakkar KN, Haddad L, Amirsadri A, Thomas P, Khatib D, Rajan U, Stanley JA, Diwadkar VA. Learning without contingencies: A loss of synergy between memory and reward circuits in schizophrenia. Schizophr Res 2023; 258:21-35. [PMID: 37467677 PMCID: PMC10521382 DOI: 10.1016/j.schres.2023.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 02/09/2023] [Accepted: 06/11/2023] [Indexed: 07/21/2023]
Abstract
Motivational deficits in schizophrenia may interact with foundational cognitive processes including learning and memory to induce impaired cognitive proficiency. If such a loss of synergy exists, it is likely to be underpinned by a loss of synchrony between the brains learning and reward sub-networks. Moreover, this loss should be observed even during tasks devoid of explicit reward contingencies given that such tasks are better models of real world performance than those with artificial contingencies. Here we applied undirected functional connectivity (uFC) analyses to fMRI data acquired while participants engaged in an associative learning task without contingencies or feedback. uFC was estimated and inter-group differences (between schizophrenia patients and controls, n = 54 total, n = 28 patients) were assessed within and between reward (VTA and NAcc) and learning/memory (Basal Ganglia, DPFC, Hippocampus, Parahippocampus, Occipital Lobe) sub-networks. The task paradigm itself alternated between Encoding, Consolidation, and Retrieval conditions, and uFC differences were quantified for each of the conditions. Significantly reduced uFC dominated the connectivity profiles of patients across all conditions. More pertinent to our motivations, these reductions were observed within and across classes of sub-networks (reward-related and learning/memory related). We suggest that disrupted functional connectivity between reward and learning sub-networks may drive many of the performance deficits that characterize schizophrenia. Thus, cognitive deficits in schizophrenia may in fact be underpinned by a loss of synergy between reward-sensitivity and cognitive processes.
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Affiliation(s)
- Sazid M Hasan
- Oakland University William Beaumont School of Medicine, USA
| | - Munajj S Huq
- Michigan State University, College of Osteopathic Medicine, USA
| | - Asadur Z Chowdury
- Dept. of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, USA
| | - Shahira Baajour
- Dept. of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, USA
| | - John Kopchick
- Dept. of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, USA
| | - A J Robison
- Dept. of Physiology, Michigan State University, USA
| | | | - Luay Haddad
- Dept. of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, USA
| | - Alireza Amirsadri
- Dept. of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, USA
| | - Patricia Thomas
- Dept. of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, USA
| | - Dalal Khatib
- Dept. of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, USA
| | - Usha Rajan
- Dept. of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, USA
| | - Jeffrey A Stanley
- Dept. of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, USA
| | - Vaibhav A Diwadkar
- Dept. of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, USA.
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