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Oh H, Berrington A, Auer DP, Babourina-Brooks B, Faas H, Jung JY. A preliminary study of dynamic neurochemical changes in the dorsolateral prefrontal cortex during working memory. Eur J Neurosci 2024; 59:2075-2086. [PMID: 38409515 DOI: 10.1111/ejn.16280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 01/28/2024] [Accepted: 01/30/2024] [Indexed: 02/28/2024]
Abstract
Working memory (WM) is one of the fundamental cognitive functions associated with the dorsolateral prefrontal cortex (DLPFC). However, the neurochemical mechanisms of WM, including the dynamic changes in neurometabolites such as glutamate and GABA in the DLPFC, remain unclear. Here, we investigated WM-related glutamate and GABA changes, alongside hemodynamic responses in the DLPFC, using a combination of functional magnetic resonance spectroscopy (fMRS) and functional magnetic resonance imaging (fMRI). During a WM task, we measured Glx (glutamate + glutamine) and GABA levels using GABA editing MEscher-GArwood Point REsolved Spectroscopy (MEGA-PRESS) sequence and blood-oxygen-level-dependent (BOLD) signal changes. In the DLPFC, we observed elevated Glx levels and increased BOLD signal changes during a 2-back task. Specifically, the Glx levels in the DLPFC were significantly higher during the 2-back task compared with fixation, although this difference was not significant when compared with a 0-back task. However, Glx levels during the 0-back task were higher than during fixation. Furthermore, there was a positive correlation between Glx levels in the DLPFC during the 2-back task and the corresponding BOLD signal changes. Notably, higher Glx increases were associated with increased DLPFC activation and lower WM task performance in individuals. No notable changes in DLPFC GABA levels were observed during WM processing. These findings suggest that the modulation of glutamatergic activity in the DLPFC may play a crucial role in both working memory processing and its associated performance outcomes.
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Affiliation(s)
- Hyerin Oh
- Mental Health & Clinical Neurosciences, School of Medicine, University of Nottingham, Nottingham, UK
- Sir Peter Mansfield Imaging Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Adam Berrington
- Sir Peter Mansfield Imaging Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK
| | - Dorothee P Auer
- Mental Health & Clinical Neurosciences, School of Medicine, University of Nottingham, Nottingham, UK
- Sir Peter Mansfield Imaging Centre, School of Medicine, University of Nottingham, Nottingham, UK
- NIHR Nottingham Biomedical Research Centre, Queen's Medical Centre, University of Nottingham, Nottingham, UK
| | - Ben Babourina-Brooks
- Mental Health & Clinical Neurosciences, School of Medicine, University of Nottingham, Nottingham, UK
- Sir Peter Mansfield Imaging Centre, School of Medicine, University of Nottingham, Nottingham, UK
- NIHR Nottingham Biomedical Research Centre, Queen's Medical Centre, University of Nottingham, Nottingham, UK
| | - Henryk Faas
- Mental Health & Clinical Neurosciences, School of Medicine, University of Nottingham, Nottingham, UK
- Sir Peter Mansfield Imaging Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Je Young Jung
- School of Psychology, University of Nottingham, Nottingham, UK
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Belder CRS, Marshall CR, Jiang J, Mazzeo S, Chokesuwattanaskul A, Rohrer JD, Volkmer A, Hardy CJD, Warren JD. Primary progressive aphasia: six questions in search of an answer. J Neurol 2024; 271:1028-1046. [PMID: 37906327 PMCID: PMC10827918 DOI: 10.1007/s00415-023-12030-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Accepted: 09/27/2023] [Indexed: 11/02/2023]
Abstract
Here, we review recent progress in the diagnosis and management of primary progressive aphasia-the language-led dementias. We pose six key unanswered questions that challenge current assumptions and highlight the unresolved difficulties that surround these diseases. How many syndromes of primary progressive aphasia are there-and is syndromic diagnosis even useful? Are these truly 'language-led' dementias? How can we diagnose (and track) primary progressive aphasia better? Can brain pathology be predicted in these diseases? What is their core pathophysiology? In addition, how can primary progressive aphasia best be treated? We propose that pathophysiological mechanisms linking proteinopathies to phenotypes may help resolve the clinical complexity of primary progressive aphasia, and may suggest novel diagnostic tools and markers and guide the deployment of effective therapies.
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Affiliation(s)
- Christopher R S Belder
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, 8 - 11 Queen Square, London, WC1N 3BG, UK
- UK Dementia Research Institute at UCL, UCL Queen Square Institute of Neurology, University College London, London, UK
- Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia
| | - Charles R Marshall
- Preventive Neurology Unit, Wolfson Institute of Population Health, Queen Mary University of London, London, UK
| | - Jessica Jiang
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, 8 - 11 Queen Square, London, WC1N 3BG, UK
| | - Salvatore Mazzeo
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, 8 - 11 Queen Square, London, WC1N 3BG, UK
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Azienda Ospedaliera-Universitaria Careggi, Florence, Italy
| | - Anthipa Chokesuwattanaskul
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, 8 - 11 Queen Square, London, WC1N 3BG, UK
- Division of Neurology, Department of Internal Medicine, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand
- Cognitive Clinical and Computational Neuroscience Research Unit, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Jonathan D Rohrer
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, 8 - 11 Queen Square, London, WC1N 3BG, UK
| | - Anna Volkmer
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, 8 - 11 Queen Square, London, WC1N 3BG, UK
| | - Chris J D Hardy
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, 8 - 11 Queen Square, London, WC1N 3BG, UK
| | - Jason D Warren
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, University College London, 8 - 11 Queen Square, London, WC1N 3BG, UK.
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Kujala J, Ciumas C, Jung J, Bouvard S, Lecaignard F, Lothe A, Bouet R, Ryvlin P, Jerbi K. GABAergic inhibition shapes behavior and neural dynamics in human visual working memory. Cereb Cortex 2024; 34:bhad522. [PMID: 38186005 PMCID: PMC10839845 DOI: 10.1093/cercor/bhad522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 12/08/2023] [Accepted: 12/09/2023] [Indexed: 01/09/2024] Open
Abstract
Neuronal inhibition, primarily mediated by GABAergic neurotransmission, is crucial for brain development and healthy cognition. Gamma-aminobutyric acid concentration levels in sensory areas have been shown to correlate with hemodynamic and oscillatory neuronal responses. How these measures relate to one another during working memory, a higher-order cognitive process, is still poorly understood. We address this gap by collecting magnetoencephalography, functional magnetic resonance imaging, and Flumazenil positron emission tomography data within the same subject cohort using an n-back working-memory paradigm. By probing the relationship between GABAA receptor distribution, neural oscillations, and Blood Oxygen Level Dependent (BOLD) modulations, we found that GABAA receptor density in higher-order cortical areas predicted the reaction times on the working-memory task and correlated positively with the peak frequency of gamma power modulations and negatively with BOLD amplitude. These findings support and extend theories linking gamma oscillations and hemodynamic responses to gamma-aminobutyric acid neurotransmission and to the excitation-inhibition balance and cognitive performance in humans. Considering the small sample size of the study, future studies should test whether these findings also hold for other, larger cohorts as well as to examine in detail how the GABAergic system and neural fluctuations jointly support working-memory task performance.
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Affiliation(s)
- Jan Kujala
- Department of Psychology, University of Jyväskylä, PO Box 35, Jyvaskyla FI-40014, Finland
- Lyon Neuroscience Research Center, INSERM U1028 - CNRS UMR5292, Lyon F-69000, France
| | - Carolina Ciumas
- Lyon Neuroscience Research Center, INSERM U1028 - CNRS UMR5292, Lyon F-69000, France
- Institute for Child and Adolescent with Epilepsy (IDEE), Lyon F-69000, France
| | - Julien Jung
- Lyon Neuroscience Research Center, INSERM U1028 - CNRS UMR5292, Lyon F-69000, France
- Department of Epileptology and Functional Neurology, Lyon Neurological Hospital, Lyon F-69000, France
| | - Sandrine Bouvard
- Institute for Child and Adolescent with Epilepsy (IDEE), Lyon F-69000, France
- CERMEP Imaging Center, Bron F-69003, France
| | - Françoise Lecaignard
- Lyon Neuroscience Research Center, INSERM U1028 - CNRS UMR5292, Lyon F-69000, France
- CERMEP Imaging Center, Bron F-69003, France
| | - Amélie Lothe
- Lyon Neuroscience Research Center, INSERM U1028 - CNRS UMR5292, Lyon F-69000, France
| | - Romain Bouet
- Lyon Neuroscience Research Center, INSERM U1028 - CNRS UMR5292, Lyon F-69000, France
| | - Philippe Ryvlin
- Lyon Neuroscience Research Center, INSERM U1028 - CNRS UMR5292, Lyon F-69000, France
- Institute for Child and Adolescent with Epilepsy (IDEE), Lyon F-69000, France
- Department of Clinical Neurosciences, CHUV, Lausanne 1011, Switzerland
| | - Karim Jerbi
- Lyon Neuroscience Research Center, INSERM U1028 - CNRS UMR5292, Lyon F-69000, France
- Department of Psychology, University of Montreal, Montreal, Québec H3C 3J7, Canada
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Dávila G, Torres-Prioris MJ, López-Barroso D, Berthier ML. Turning the Spotlight to Cholinergic Pharmacotherapy of the Human Language System. CNS Drugs 2023; 37:599-637. [PMID: 37341896 PMCID: PMC10374790 DOI: 10.1007/s40263-023-01017-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/24/2023] [Indexed: 06/22/2023]
Abstract
Even though language is essential in human communication, research on pharmacological therapies for language deficits in highly prevalent neurodegenerative and vascular brain diseases has received little attention. Emerging scientific evidence suggests that disruption of the cholinergic system may play an essential role in language deficits associated with Alzheimer's disease and vascular cognitive impairment, including post-stroke aphasia. Therefore, current models of cognitive processing are beginning to appraise the implications of the brain modulator acetylcholine in human language functions. Future work should be directed further to analyze the interplay between the cholinergic system and language, focusing on identifying brain regions receiving cholinergic innervation susceptible to modulation with pharmacotherapy to improve affected language domains. The evaluation of language deficits in pharmacological cholinergic trials for Alzheimer's disease and vascular cognitive impairment has thus far been limited to coarse-grained methods. More precise, fine-grained language testing is needed to refine patient selection for pharmacotherapy to detect subtle deficits in the initial phases of cognitive decline. Additionally, noninvasive biomarkers can help identify cholinergic depletion. However, despite the investigation of cholinergic treatment for language deficits in Alzheimer's disease and vascular cognitive impairment, data on its effectiveness are insufficient and controversial. In the case of post-stroke aphasia, cholinergic agents are showing promise, particularly when combined with speech-language therapy to promote trained-dependent neural plasticity. Future research should explore the potential benefits of cholinergic pharmacotherapy in language deficits and investigate optimal strategies for combining these agents with other therapeutic approaches.
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Affiliation(s)
- Guadalupe Dávila
- Cognitive Neurology and Aphasia Unit, Centro de Investigaciones Médico-Sanitarias, University of Malaga, Marqués de Beccaria 3, 29010, Malaga, Spain
- Instituto de Investigación Biomédica de Malaga-IBIMA, Malaga, Spain
- Department of Psychobiology and Methodology of Behavioral Sciences, Faculty of Psychology and Speech Therapy, University of Malaga, Malaga, Spain
- Language Neuroscience Research Laboratory, Faculty of Psychology and Speech Therapy, University of Malaga, Malaga, Spain
| | - María José Torres-Prioris
- Cognitive Neurology and Aphasia Unit, Centro de Investigaciones Médico-Sanitarias, University of Malaga, Marqués de Beccaria 3, 29010, Malaga, Spain
- Instituto de Investigación Biomédica de Malaga-IBIMA, Malaga, Spain
- Department of Psychobiology and Methodology of Behavioral Sciences, Faculty of Psychology and Speech Therapy, University of Malaga, Malaga, Spain
- Language Neuroscience Research Laboratory, Faculty of Psychology and Speech Therapy, University of Malaga, Malaga, Spain
| | - Diana López-Barroso
- Cognitive Neurology and Aphasia Unit, Centro de Investigaciones Médico-Sanitarias, University of Malaga, Marqués de Beccaria 3, 29010, Malaga, Spain
- Instituto de Investigación Biomédica de Malaga-IBIMA, Malaga, Spain
- Department of Psychobiology and Methodology of Behavioral Sciences, Faculty of Psychology and Speech Therapy, University of Malaga, Malaga, Spain
- Language Neuroscience Research Laboratory, Faculty of Psychology and Speech Therapy, University of Malaga, Malaga, Spain
| | - Marcelo L Berthier
- Cognitive Neurology and Aphasia Unit, Centro de Investigaciones Médico-Sanitarias, University of Malaga, Marqués de Beccaria 3, 29010, Malaga, Spain.
- Instituto de Investigación Biomédica de Malaga-IBIMA, Malaga, Spain.
- Language Neuroscience Research Laboratory, Faculty of Psychology and Speech Therapy, University of Malaga, Malaga, Spain.
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Paparella I, Vanderwalle G, Stagg CJ, Maquet P. An integrated measure of GABA to characterize post-stroke plasticity. Neuroimage Clin 2023; 39:103463. [PMID: 37406594 PMCID: PMC10339061 DOI: 10.1016/j.nicl.2023.103463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 06/19/2023] [Accepted: 06/24/2023] [Indexed: 07/07/2023]
Abstract
Stroke is a major cause of death and chronic neurological disability. Despite the improvements in stroke care, the number of patients affected by stroke keeps increasing and many stroke survivors are left permanently disabled. Current therapies are limited in efficacy. Understanding the neurobiological mechanisms underlying post-stroke recovery is therefore crucial to find new therapeutic options to address this medical burden. Long-lasting and widespread alterations of γ-aminobutyric acid (GABA) neurotransmission seem to play a key role in stroke recovery. In this review we first discuss a possible model of GABAergic modulation of post-stroke plasticity. We then overview the techniques currently available to non-invasively assess GABA in patients and the conclusions drawn from this limited body of work. Finally, we address the remaining open questions to clarify GABAergic changes underlying post-stroke recovery, we briefly review possible ways to modulate GABA post stroke and propose a novel approach to thoroughly quantify GABA in stroke patients, by integrating its concentration, the activity of its receptors and its link with microstructural changes.
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Affiliation(s)
- Ilenia Paparella
- GIGA-Research, Cyclotron Research Center-In Vivo Imaging Unit, 8 allée du Six Août, Batiment B30, University of Liège, 4000 Liège, Belgium.
| | - Gilles Vanderwalle
- GIGA-Research, Cyclotron Research Center-In Vivo Imaging Unit, 8 allée du Six Août, Batiment B30, University of Liège, 4000 Liège, Belgium
| | - Charlotte J Stagg
- Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Medical Research Council Brain Network Dynamics Unit, Oxford, UK
| | - Pierre Maquet
- GIGA-Research, Cyclotron Research Center-In Vivo Imaging Unit, 8 allée du Six Août, Batiment B30, University of Liège, 4000 Liège, Belgium; Department of Neurology, Domaine Universitaire du Sart Tilman, Bâtiment B35, CHU de Liège, 4000 Liège, Belgium
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6
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Zhuo B, Deng S, Li B, Zhu W, Zhang M, Qin C, Meng Z. Possible Effects of Acupuncture in Poststroke Aphasia. Behav Neurol 2023; 2023:9445381. [PMID: 37091130 PMCID: PMC10115536 DOI: 10.1155/2023/9445381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 12/30/2022] [Accepted: 04/02/2023] [Indexed: 04/25/2023] Open
Abstract
Neural plasticity promotes the reorganization of language networks and is an essential recovery mechanism for poststroke aphasia (PSA). Neuroplasticity may be a pivotal bridge to elucidate the potential recovery mechanisms of acupuncture for aphasia. Therefore, understanding the neuroplasticity mechanism of acupuncture in PSA is crucial. However, the underlying therapeutic mechanism of neuroplasticity in PSA after acupuncture needs to be explored. Excitotoxicity after brain injury affects the activity of neurotransmitters and disrupts the transmission of normal neuron information. Thus, a helpful strategy of acupuncture might be to improve PSA by affecting the availability of these neurotransmitters and glutamate receptors at synapses. In addition, the regulation of neuroplasticity by acupuncture may also be related to the regulation of astrocytes. Considering the guiding significance of acupuncture for clinical treatment, it is necessary to carry out further study about the influence of acupuncture on the recovery of aphasia after stroke. This study summarizes the current research on the neural mechanism of acupuncture in treating PSA. It seeks to elucidate the potential effect of acupuncture on the recovery of PSA from the perspective of synaptic plasticity and integrity of gray and white matter.
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Affiliation(s)
- Bifang Zhuo
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China
| | - Shizhe Deng
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China
| | - Boxuan Li
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China
| | - Weiming Zhu
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China
| | - Menglong Zhang
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China
| | - Chenyang Qin
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China
| | - Zhihong Meng
- First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin, China
- National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion, Tianjin, China
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7
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Ding B, Dragonu I, Rua C, Carlin JD, Halai AD, Liebig P, Heidemann R, Correia MM, Rodgers CT. Parallel transmit (pTx) with online pulse design for task-based fMRI at 7 T. Magn Reson Imaging 2022; 93:163-174. [PMID: 35863691 DOI: 10.1016/j.mri.2022.07.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 06/17/2022] [Accepted: 07/11/2022] [Indexed: 10/31/2022]
Abstract
PURPOSE Parallel transmission (pTx) is an approach to improve image uniformity for ultra-high field imaging. In this study, we modified an echo planar imaging (EPI) sequence to design subject-specific pTx pulses online. We compared its performance against EPI with conventional circularly polarised (CP) pulses. METHODS We compared the pTx-EPI and CP-EPI sequences in a short EPI acquisition protocol and for two different functional paradigms in six healthy volunteers (2 female, aged 23-36 years, mean age 29.2 years). We chose two paradigms that are typically affected by signal dropout at 7 T: a visual objects localiser to determine face/scene selective brain regions and a semantic-processing task. RESULTS Across all subjects, pTx-EPI improved whole-brain mean temporal signal-to-noise ratio (tSNR) by 11.0% compared to CP-EPI. We also compared the ability of pTx-EPI and CP-EPI to detect functional activation for three contrasts over the two paradigms: face > object and scene > object for the visual objects localiser and semantic association > pattern matching for the semantic-processing paradigm. Across all three contrasts, pTx-EPI showed higher median z-scores and detected more active voxels in relevant areas, as determined from previous 3 T studies. CONCLUSION We have demonstrated a workflow for EPI acquisitions with online per-subject pulse calculations. We saw improved performance in both tSNR and functional acquisitions from pTx-EPI. Thus, we believe that online calculation pTx-EPI is robust enough for future fMRI studies, especially where activation is expected in brain areas liable to significant signal dropout.
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Affiliation(s)
- Belinda Ding
- Wolfson Brain Imaging Centre, University of Cambridge, UK.
| | | | - Catarina Rua
- Wolfson Brain Imaging Centre, University of Cambridge, UK; Department of Clinical Neurosciences, University of Cambridge, UK; Invicro, Invicro London, UK
| | | | - Ajay D Halai
- MRC Cognition and Brain Science Unit, Cambridge, UK
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Neurochemical profiles of the anterior temporal lobe predict response of repetitive transcranial magnetic stimulation on semantic processing. Neuroimage 2022; 258:119386. [PMID: 35709948 DOI: 10.1016/j.neuroimage.2022.119386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 05/23/2022] [Accepted: 06/12/2022] [Indexed: 10/18/2022] Open
Abstract
Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive technique used to modulate cortical excitability in the human brain. However, one major challenge with rTMS is that the responses to stimulation are highly variable across individuals. The underlying reasons why responses to rTMS are highly variable between individuals still remain unclear. Here, we investigated whether the response to continuous theta-burst stimulation (cTBS) - an effective rTMS protocol for decreasing cortical excitability - is related to individual differences in glutamate and GABA neurotransmission. We acquired resting-state magnetic resonance spectroscopy (MRS) and functional magnetic resonance imaging (fMRI) during semantic processing. Then, we applied cTBS over the anterior temporal lobe (ATL), a hub for semantic representation, to explore the relationship between the baseline neurochemical profiles in this region and the response to cTBS. We found that the baseline excitation-inhibition balance (glutamate + glutamine/GABA ratio) in the ATL was associated with individual cTBS responsiveness during semantic processing. Specifically, individuals with lower excitation-inhibition balance showed stronger inhibitory effect - poorer semantic performance. Our results revealed that non-responders (subjects who did not show an inhibitory effect of cTBS on subsequent semantic performance) had higher excitatory-inhibitory balance in the ATL, which led to up-regulated task-induced regional activity as well as increased ATL-connectivity with other semantic regions compared to responders. These results disclose that the baseline neurochemical state of a cortical region can be a significant factor in predicting responses to cTBS.
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Koush Y, Rothman DL, Behar KL, de Graaf RA, Hyder F. Human brain functional MRS reveals interplay of metabolites implicated in neurotransmission and neuroenergetics. J Cereb Blood Flow Metab 2022; 42:911-934. [PMID: 35078383 PMCID: PMC9125492 DOI: 10.1177/0271678x221076570] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 12/26/2021] [Accepted: 01/05/2022] [Indexed: 01/28/2023]
Abstract
While functional MRI (fMRI) localizes brain activation and deactivation, functional MRS (fMRS) provides insights into the underlying metabolic conditions. There is much interest in measuring task-induced and resting levels of metabolites implicated in neuroenergetics (e.g., lactate, glucose, or β-hydroxybutyrate (BHB)) and neurotransmission (e.g., γ-aminobutyric acid (GABA) or pooled glutamate and glutamine (Glx)). Ultra-high magnetic field (e.g., 7T) has boosted the fMRS quantification precision, reliability, and stability of spectroscopic observations using short echo-time (TE) 1H-MRS techniques. While short TE 1H-MRS lacks sensitivity and specificity for fMRS at lower magnetic fields (e.g., 3T or 4T), most of these metabolites can also be detected by J-difference editing (JDE) 1H-MRS with longer TE to filter overlapping resonances. The 1H-MRS studies show that JDE can detect GABA, Glx, lactate, and BHB at 3T, 4T and 7T. Most recently, it has also been demonstrated that JDE 1H-MRS is capable of reliable detection of metabolic changes in different brain areas at various magnetic fields. Combining fMRS measurements with fMRI is important for understanding normal brain function, but also clinically relevant for mechanisms and/or biomarkers of neurological and neuropsychiatric disorders. We provide an up-to-date overview of fMRS research in the last three decades, both in terms of applications and technological advances. Overall the emerging fMRS techniques can be expected to contribute substantially to our understanding of metabolism for brain function and dysfunction.
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Affiliation(s)
- Yury Koush
- Magnetic Resonance Research Center, Department of Radiology & Biomedical Imaging, Yale University, New Haven, CT, USA
| | - Douglas L Rothman
- Magnetic Resonance Research Center, Department of Radiology & Biomedical Imaging, Yale University, New Haven, CT, USA
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Kevin L Behar
- Magnetic Resonance Research Center, Department of Radiology & Biomedical Imaging, Yale University, New Haven, CT, USA
- Department of Psychiatry, Yale University, New Haven, CT, USA
| | - Robin A de Graaf
- Magnetic Resonance Research Center, Department of Radiology & Biomedical Imaging, Yale University, New Haven, CT, USA
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Fahmeed Hyder
- Magnetic Resonance Research Center, Department of Radiology & Biomedical Imaging, Yale University, New Haven, CT, USA
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
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10
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Rybář M, Daly I. Neural decoding of semantic concepts: A systematic literature review. J Neural Eng 2022; 19. [PMID: 35344941 DOI: 10.1088/1741-2552/ac619a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 03/27/2022] [Indexed: 11/12/2022]
Abstract
Objective Semantic concepts are coherent entities within our minds. They underpin our thought processes and are a part of the basis for our understanding of the world. Modern neuroscience research is increasingly exploring how individual semantic concepts are encoded within our brains and a number of studies are beginning to reveal key patterns of neural activity that underpin specific concepts. Building upon this basic understanding of the process of semantic neural encoding, neural engineers are beginning to explore tools and methods for semantic decoding: identifying which semantic concepts an individual is focused on at a given moment in time from recordings of their neural activity. In this paper we review the current literature on semantic neural decoding. Approach We conducted this review according to the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) guidelines. Specifically, we assess the eligibility of published peer-reviewed reports via a search of PubMed and Google Scholar. We identify a total of 74 studies in which semantic neural decoding is used to attempt to identify individual semantic concepts from neural activity. Results Our review reveals how modern neuroscientific tools have been developed to allow decoding of individual concepts from a range of neuroimaging modalities. We discuss specific neuroimaging methods, experimental designs, and machine learning pipelines that are employed to aid the decoding of semantic concepts. We quantify the efficacy of semantic decoders by measuring information transfer rates. We also discuss current challenges presented by this research area and present some possible solutions. Finally, we discuss some possible emerging and speculative future directions for this research area. Significance Semantic decoding is a rapidly growing area of research. However, despite its increasingly widespread popularity and use in neuroscientific research this is the first literature review focusing on this topic across neuroimaging modalities and with a focus on quantifying the efficacy of semantic decoders.
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Affiliation(s)
- Milan Rybář
- School of Computer Science and Electronic Engineering, University of Essex, Wivenhoe Park, Colchester, Essex, CO4 3SQ, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Ian Daly
- University of Essex, School of Computer Science and Electronic Engineering, Wivenhoe Park, Colchester, Colchester, Essex, CO4 3SQ, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
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11
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Li H, Heise KF, Chalavi S, Puts NAJ, Edden RAE, Swinnen SP. The role of MRS-assessed GABA in human behavioral performance. Prog Neurobiol 2022; 212:102247. [PMID: 35149113 DOI: 10.1016/j.pneurobio.2022.102247] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 01/25/2022] [Accepted: 02/04/2022] [Indexed: 01/16/2023]
Abstract
Understanding the neurophysiological mechanisms that drive human behavior has been a long-standing focus of cognitive neuroscience. One well-known neuro-metabolite involved in the creation of optimal behavioral repertoires is GABA, the main inhibitory neurochemical in the human brain. Converging evidence from both animal and human studies indicates that individual variations in GABAergic function are associated with behavioral performance. In humans, one increasingly used in vivo approach to measuring GABA levels is through Magnetic Resonance Spectroscopy (MRS). However, the implications of MRS measures of GABA for behavior remain poorly understood. In this respect, it is yet to be determined how GABA levels within distinct task-related brain regions of interest account for differences in behavioral performance. This review summarizes findings from cross-sectional studies that determined baseline MRS-assessed GABA levels and examined their associations with performance on various behaviors representing the perceptual, motor and cognitive domains, with a particular focus on healthy participants across the lifespan. Overall, the results indicate that MRS-assessed GABA levels play a pivotal role in various domains of behavior. Even though some converging patterns emerge, it is challenging to draw comprehensive conclusions due to differences in behavioral task paradigms, targeted brain regions of interest, implemented MRS techniques and reference compounds used. Across all studies, the effects of GABA levels on behavioral performance point to generic and partially independent functions that refer to distinctiveness, interference suppression and cognitive flexibility. On one hand, higher baseline GABA levels may support the distinctiveness of neural representations during task performance and better coping with interference and suppression of preferred response tendencies. On the other hand, lower baseline GABA levels may support a reduction of inhibition, leading to higher cognitive flexibility. These effects are task-dependent and appear to be mediated by age. Nonetheless, additional studies using emerging advanced methods are required to further clarify the role of MRS-assessed GABA in behavioral performance.
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Affiliation(s)
- Hong Li
- Movement Control & Neuroplasticity Research Group, Group Biomedical Sciences, KU Leuven, Belgium; KU Leuven Brain Institute (LBI), KU Leuven, Belgium.
| | - Kirstin-Friederike Heise
- Movement Control & Neuroplasticity Research Group, Group Biomedical Sciences, KU Leuven, Belgium; KU Leuven Brain Institute (LBI), KU Leuven, Belgium; Department of Health Sciences and Research, Medical University of South Carolina, Charleston, SC, USA.
| | - Sima Chalavi
- Movement Control & Neuroplasticity Research Group, Group Biomedical Sciences, KU Leuven, Belgium; KU Leuven Brain Institute (LBI), KU Leuven, Belgium.
| | - Nicolaas A J Puts
- MRC Centre for Neurodevelopmental Disorders, King's College London, London, UK; Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, UK; Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA.
| | - Richard A E Edden
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Stephan P Swinnen
- Movement Control & Neuroplasticity Research Group, Group Biomedical Sciences, KU Leuven, Belgium; KU Leuven Brain Institute (LBI), KU Leuven, Belgium.
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12
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Borghesani V, DeLeon J, Gorno-Tempini ML. Frontotemporal dementia: A unique window on the functional role of the temporal lobes. HANDBOOK OF CLINICAL NEUROLOGY 2022; 187:429-448. [PMID: 35964986 PMCID: PMC9793689 DOI: 10.1016/b978-0-12-823493-8.00011-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Frontotemporal dementia (FTD) is an umbrella term covering a plethora of progressive changes in executive functions, motor abilities, behavior, and/or language. Different clinical syndromes have been described in relation to localized atrophy, informing on the functional networks that underlie these specific cognitive, emotional, and behavioral processes. These functional declines are linked with the underlying neurodegeneration of frontal and/or temporal lobes due to diverse molecular pathologies. Initially, the accumulation of misfolded proteins targets specifically susceptible cell assemblies, leading to relatively focal neurodegeneration that later spreads throughout large-scale cortical networks. Here, we discuss the most recent clinical, neuropathological, imaging, and genetics findings in FTD-spectrum syndromes affecting the temporal lobe. We focus on the semantic variant of primary progressive aphasia and its mirror image, the right temporal variant of FTD. Incipient focal atrophy of the left anterior temporal lobe (ATL) manifests with predominant naming, word comprehension, reading, and object semantic deficits, while cases of predominantly right ATL atrophy present with impairments of socioemotional, nonverbal semantic, and person-specific knowledge. Overall, the observations in FTD allow for crucial clinical-anatomic inferences, shedding light on the role of the temporal lobes in both cognition and complex behaviors. The concerted activity of both ATLs is critical to ensure that percepts are translated into concepts, yet important hemispheric differences should be acknowledged. On one hand, the left ATL attributes meaning to linguistic, external stimuli, thus supporting goal-oriented, action-related behaviors (e.g., integrating sounds and letters into words). On the other hand, the right ATL assigns meaning to emotional, visceral stimuli, thus guiding socially relevant behaviors (e.g., integrating body sensations into feelings of familiarity).
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Affiliation(s)
- Valentina Borghesani
- Centre de recherche de l'Institut universitaire de gériatrie de Montréal, Montréal, QC, Canada; Department of Psychology, Université de Montréal, Montréal, QC, Canada.
| | - Jessica DeLeon
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, CA, United States; Department of Neurology, Dyslexia Center, University of California, San Francisco, CA, United States
| | - Maria Luisa Gorno-Tempini
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, CA, United States; Department of Neurology, Dyslexia Center, University of California, San Francisco, CA, United States
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13
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Krishnamurthy LC, Paredes Spir I, Rocha NO, Soher BJ, Auerbach EJ, Crosson BA, Krishnamurthy V. The association between language-based task-functional magnetic resonance imaging hemodynamics and baseline GABA+ and glutamate-glutamine measured in pre-supplementary motor area: A pilot study in an aging model. Front Psychiatry 2022; 13:904845. [PMID: 36046162 PMCID: PMC9421126 DOI: 10.3389/fpsyt.2022.904845] [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: 03/26/2022] [Accepted: 07/28/2022] [Indexed: 11/13/2022] Open
Abstract
Aging is a natural phenomenon that elicits slow and progressive cerebrovascular and neurophysiological changes that eventually lead to cognitive decline. The objective of this pilot study is to examine the association of GABA+ and glutamate-glutamine (Glx) complex with language-based blood oxygen level dependent (BOLD) hemodynamics in an aging model. More specifically, using standard BOLD we will first attempt to validate whether previously reported findings for BOLD amplitude and resting neurochemical relationships hold in an aging model. Secondly, we will investigate how our recently established neurosensitized task-BOLD energetics relate to resting GABA+ and Glx, especially accounting for titration of task difficulty. To support the above endeavors, we optimize the baseline fitting for edited magnetic resonance spectroscopy (MRS) difference spectra to sensitize GABA+ and Glx concentrations to aging-related differences. We identify a spline-knot spacing of 0.6ppm to yield the optimal aging-related differences in GABA+ and Glx. The optimized MRS values were then graduated to relate to task-BOLD hemodynamics. Our results did not replicate previous findings that relate task-BOLD amplitude and resting GABA+ and Glx. However, we did identify neurochemistry relationships with the vascularly-driven dispersion component of the hemodynamic response function, specifically in older participants. In terms of neuro-sensitized BOLD energetics and the underlying role of GABA+ and Glx, our data suggests that the task demands are supported by both neurometabolites depending on the difficulty of the task stimuli. Another novelty is that we developed task-based functional parcellation of pre-SMA using both groups. In sum, we are the first to demonstrate that multimodal task-fMRI and MRS studies are beneficial to improve our understanding of the aging brain physiology, and to set the platform to better inform approaches for clinical care in aging-related neurovascular diseases. We also urge future studies to replicate our findings in a larger population incorporating a lifespan framework.
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Affiliation(s)
- Lisa C Krishnamurthy
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Healthcare System, Decatur, GA, United States.,Department of Physics & Astronomy, Georgia State University, Atlanta, GA, United States.,Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, United States
| | - Isabella Paredes Spir
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Healthcare System, Decatur, GA, United States
| | - Natalie O Rocha
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Healthcare System, Decatur, GA, United States.,Department of Biology, Georgia State University, Atlanta, GA, United States
| | - Brian J Soher
- Center for Advanced MR Development, Department of Radiology, Duke University, Durham, NC, United States.,Brain Imaging and Analysis Center, Duke University, Durham, NC, United States
| | - Edward J Auerbach
- Department of Radiology, University of Minnesota, Minneapolis, MN, United States.,Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States
| | - Bruce A Crosson
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Healthcare System, Decatur, GA, United States.,Department of Psychology, Georgia State University, Atlanta, GA, United States.,Department of Neurology, Emory University, Atlanta, GA, United States
| | - Venkatagiri Krishnamurthy
- Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Healthcare System, Decatur, GA, United States.,Department of Neurology, Emory University, Atlanta, GA, United States.,Division of Geriatrics and Gerontology, Department of Medicine, Emory University, Atlanta, GA, United States
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14
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Almeida VN, Radanovic M. Semantic priming and neurobiology in schizophrenia: A theoretical review. Neuropsychologia 2021; 163:108058. [PMID: 34655651 DOI: 10.1016/j.neuropsychologia.2021.108058] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 10/06/2021] [Accepted: 10/07/2021] [Indexed: 12/11/2022]
Abstract
In this theoretical review we bridge the cognitive and neurobiological sciences to shed light on the neurocognitive foundations of the semantic priming effect in schizophrenia. We review and theoretically evaluate the neurotransmitter systems (dopaminergic, GABAergic and glutamatergic) and neurobiological underpinnings of behavioural and electrophysiological (N400) semantic priming in the pathology, and the main hypotheses on their geneses: a disinhibition of the semantic spread of activation, a disorganised semantic storage or noisy lexical-semantic associations, a psychomotor artefact, an artefact of relatedness proportions, or an inability to mobilise contextual information. We further assess the literature on the endophenotype of Formal Thought Disorder from multiple standpoints, ranging from neurophysiology to cognition: considerations are weaved on neuronal (PV basket cell, SST, VIP) and receptor deficits (DRD1, NMDA), neurotransmitter imbalances (dopamine), cortical and dopaminergic lateralisation, inter alia. In conclusion, we put forth novel postulates on the underlying causes of controlled hypopriming, automatic hyperpriming, N400 reversals (larger amplitudes for close associations), indirect versus direct hyperpriming, and the endophenotype of lexical-semantic disturbances in schizophrenia.
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Affiliation(s)
- Victor N Almeida
- Faculdade de Letras, Universidade Federal de Minas Gerais (UFMG), Av. Pres. Antônio Carlos, 6627 - Pampulha, Belo Horizonte, MG, 31270-901, Brazil.
| | - Marcia Radanovic
- Laboratório de Neurociências (LIM-27), Faculdade de Medicina, Departamento e Instituto de Psiquiatria, Hospital das Clínicas HCFMUSP, Universidade de São Paulo, Brazil
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15
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Friehs MA, Greene C, Pastötter B. Transcranial direct current stimulation over the left anterior temporal lobe during memory retrieval differentially affects true and false recognition in the DRM task. Eur J Neurosci 2021; 54:4609-4620. [PMID: 34076917 DOI: 10.1111/ejn.15337] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 05/06/2021] [Accepted: 05/24/2021] [Indexed: 01/13/2023]
Abstract
Transcranial direct current stimulation (tDCS) is a form of non-invasive brain stimulation that has been used to modulate human brain activity and cognition. One area which has not yet been extensively explored using tDCS is the generation of false memories. In this study, we combined the Deese-Roediger-McDermott (DRM) task with stimulation of the left anterior temporal lobe (ATL) during retrieval. This area has been shown to be involved in semantic processing in general and retrieval of false memories in the DRM paradigm in particular. During stimulation, 0.7 mA were applied via a 9 cm² electrode over the left ATL, with the 35 cm² return electrode placed over the left deltoid. We contrasted the effects of cathodal, anodal, and sham stimulation, which were applied in the recognition phase of the experiment on a sample of 78 volunteers. Results showed impaired recognition of true memories after both anodal and cathodal stimulation in comparison to sham stimulation, suggesting a reduced signal-to-noise ratio. In addition, the results revealed enhanced false recognition of concept lure items during cathodal stimulation compared to anodal stimulation, indicating a polarity-dependent impact of tDCS on false memories in the DRM task. The pathway by which tDCS modulated false recognition remains unclear: stimulation may have changed the activation of irrelevant lures or affected the weighting and monitoring of lure activations. Nevertheless, these results are a first step towards using brain stimulation to decrease false memories. Practical implications of the findings for real-life settings, for example, in the courtroom, need to be addressed in future work.
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Affiliation(s)
| | - Ciara Greene
- School of Psychology, University College Dublin, Dublin, Ireland
| | - Bernhard Pastötter
- Department of Cognitive Psychology and Methodology, Trier University, Trier, Germany
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16
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Koush Y, de Graaf RA, Kupers R, Dricot L, Ptito M, Behar KL, Rothman DL, Hyder F. Metabolic underpinnings of activated and deactivated cortical areas in human brain. J Cereb Blood Flow Metab 2021; 41:986-1000. [PMID: 33472521 PMCID: PMC8054719 DOI: 10.1177/0271678x21989186] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 11/04/2020] [Accepted: 12/11/2020] [Indexed: 11/16/2022]
Abstract
Neuroimaging with functional MRI (fMRI) identifies activated and deactivated brain regions in task-based paradigms. These patterns of (de)activation are altered in diseases, motivating research to understand their underlying biochemical/biophysical mechanisms. Essentially, it remains unknown how aerobic metabolism of glucose to lactate (aerobic glycolysis) and excitatory-inhibitory balance of glutamatergic and GABAergic neuronal activities vary in these areas. In healthy volunteers, we investigated metabolic distinctions of activating visual cortex (VC, a task-positive area) using a visual task and deactivating posterior cingulate cortex (PCC, a task-negative area) using a cognitive task. We used fMRI-guided J-edited functional MRS (fMRS) to measure lactate, glutamate plus glutamine (Glx) and γ-aminobutyric acid (GABA), as indicators of aerobic glycolysis and excitatory-inhibitory balance, respectively. Both lactate and Glx increased upon activating VC, but did not change upon deactivating PCC. Basal GABA was negatively correlated with BOLD responses in both brain areas, but during functional tasks GABA decreased in VC upon activation and GABA increased in PCC upon deactivation, suggesting BOLD responses in relation to baseline are impacted oppositely by task-induced inhibition. In summary, opposite relations between BOLD response and GABAergic inhibition, and increases in aerobic glycolysis and glutamatergic activity distinguish the BOLD response in (de)activated areas.
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Affiliation(s)
- Yury Koush
- Magnetic Resonance Research Center, Department of Radiology & Biomedical Imaging, Yale University, New Haven, CT, USA
| | - Robin A de Graaf
- Magnetic Resonance Research Center, Department of Radiology & Biomedical Imaging, Yale University, New Haven, CT, USA
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Ron Kupers
- BRAINlab, Department of Neuroscience, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Laurence Dricot
- Institute of NeuroScience (IoNS), Université catholique de Louvain (UCLouvain), Belgium
| | - Maurice Ptito
- School of Optometry, Université de Montreal, Montreal, Canada
| | - Kevin L Behar
- Magnetic Resonance Research Center, Department of Radiology & Biomedical Imaging, Yale University, New Haven, CT, USA
- Department of Psychiatry, Yale University, New Haven, CT, USA
| | - Douglas L Rothman
- Magnetic Resonance Research Center, Department of Radiology & Biomedical Imaging, Yale University, New Haven, CT, USA
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Fahmeed Hyder
- Magnetic Resonance Research Center, Department of Radiology & Biomedical Imaging, Yale University, New Haven, CT, USA
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
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17
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Jung J, Lambon Ralph MA. Enhancing vs. inhibiting semantic performance with transcranial magnetic stimulation over the anterior temporal lobe: Frequency- and task-specific effects. Neuroimage 2021; 234:117959. [PMID: 33744456 PMCID: PMC8204263 DOI: 10.1016/j.neuroimage.2021.117959] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 03/08/2021] [Accepted: 03/10/2021] [Indexed: 11/24/2022] Open
Abstract
Accumulating, converging evidence indicates that the anterior temporal lobe (ATL) appears to be the transmodal hub for semantic representation. A series of repetitive transcranial magnetic stimulation (rTMS) investigations utilizing the ‘virtual lesion’ approach have established the brain-behavioural relationship between the ATL and semantic processing by demonstrating that inhibitory rTMS over the ATL induced impairments in semantic performance in healthy individuals. However, a growing body of rTMS studies suggest that rTMS might also be a tool for cognitive enhancement and rehabilitation, though there has been no previous exploration in semantic cognition. Here, we explored a potential role of rTMS in enhancing and inhibiting semantic performance with contrastive rTMS protocols (1 Hz vs. 20 Hz) by controlling practice effects. Twenty-one healthy participants were recruited and performed an object category judgement task and a pattern matching task serving as a control task before and after the stimulation over the ATL (1 Hz, 20 Hz, and sham). A task familiarization procedure was performed prior to the experiment in order to establish a ‘stable baseline’ prior to stimulation and thus minimize practice effect. Our results demonstrated that it is possible to modulate semantic performance positively or negatively depending on the ATL stimulation frequency: 20 Hz rTMS was optimal for facilitating cortical processing (faster RT in a semantic task) contrasting with diminished semantic performance after 1 Hz rTMS. In addition to cementing the importance of the ATL to semantic representation, our findings suggest that 20 Hz rTMS leads to semantic enhancement in healthy individuals and potentially could be used for patients with semantic impairments as a therapeutic tool.
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Affiliation(s)
- JeYoung Jung
- School of Psychology, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
| | - Matthew A Lambon Ralph
- MRC Cognition and Brain Science Unit (CBU), University of Cambridge, Cambridge CB2 7EF, UK.
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18
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Kiemes A, Davies C, Kempton MJ, Lukow PB, Bennallick C, Stone JM, Modinos G. GABA, Glutamate and Neural Activity: A Systematic Review With Meta-Analysis of Multimodal 1H-MRS-fMRI Studies. Front Psychiatry 2021; 12:644315. [PMID: 33762983 PMCID: PMC7982484 DOI: 10.3389/fpsyt.2021.644315] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 02/15/2021] [Indexed: 12/11/2022] Open
Abstract
Multimodal neuroimaging studies combining proton magnetic resonance spectroscopy (1H-MRS) to quantify GABA and/or glutamate concentrations and functional magnetic resonance imaging (fMRI) to measure brain activity non-invasively have advanced understanding of how neurochemistry and neurophysiology may be related at a macroscopic level. The present study aimed to perform a systematic review and meta-analysis of available studies examining the relationship between 1H-MRS glutamate and/or GABA levels and task-related fMRI signal in the healthy brain. Ovid (Medline, Embase, and PsycINFO) and Pubmed databases were systematically searched to identify articles published until December 2019. The primary outcome of interest was the association between resting levels of glutamate or GABA and task-related fMRI. Fifty-five papers were identified for inclusion in the systematic review. A further 22 studies were entered into four separate meta-analyses. These meta-analyses found evidence of significant negative associations between local GABA levels and (a) fMRI activation to visual tasks in the occipital lobe, and (b) activation to emotion processing in the medial prefrontal cortex (mPFC)/anterior cingulate cortex (ACC). However, there was no significant association between mPFC/ACC glutamate levels and fMRI activation to cognitive control tasks or to emotional processing, with the relationship to emotion processing related neural activity narrowly missing significance. Moreover, our systematic review also found converging evidence of negative associations between GABA levels and local brain activity, and positive associations between glutamate levels and distal brain activity, outside of the 1H-MRS sampling region. Albeit less consistently, additional relationships between GABA levels and distal brain activity and between glutamate levels and local brain activity were found. It remains unclear if the absence of effects for other brain regions and other cognitive-emotional domains reflects study heterogeneity or potential confounding effects of age, sex, or other unknown factors. Advances in 1H-MRS methodology as well as in the integration of 1H-MRS readouts with other imaging modalities for indexing neural activity hold great potential to reveal key aspects of the pathophysiology of mental health disorders involving aberrant interactions between neurochemistry and neurophysiology such as schizophrenia.
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Affiliation(s)
- Amanda Kiemes
- Psychosis Studies Department, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Cathy Davies
- Psychosis Studies Department, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Matthew J Kempton
- Psychosis Studies Department, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom.,Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Paulina B Lukow
- Psychosis Studies Department, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Carly Bennallick
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - James M Stone
- Brighton and Sussex Medical School, University of Sussex & University of Brighton, Brighton, United Kingdom
| | - Gemma Modinos
- Psychosis Studies Department, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom.,Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom.,Medical Research Centre Centre for Neurodevelopmental Disorders, King's College London, London, United Kingdom
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19
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Li W, Kutas M, Gray JA, Hagerman RH, Olichney JM. The Role of Glutamate in Language and Language Disorders - Evidence from ERP and Pharmacologic Studies. Neurosci Biobehav Rev 2020; 119:217-241. [PMID: 33039453 DOI: 10.1016/j.neubiorev.2020.09.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 08/10/2020] [Accepted: 09/21/2020] [Indexed: 12/31/2022]
Abstract
Current models of language processing do not address mechanisms at the neurotransmitter level, nor how pharmacologic agents may improve language function(s) in seemingly disparate disorders. L-Glutamate, the primary excitatory neurotransmitter in the human brain, is extensively involved in various higher cortical functions. We postulate that the physiologic role of L-Glutamate neurotransmission extends to the regulation of language access, comprehension, and production, and that disorders in glutamatergic transmission and circuitry contribute to the pathogenesis of neurodegenerative diseases and sporadic-onset language disorders such as the aphasic stroke syndromes. We start with a review of basic science data pertaining to various glutamate receptors in the CNS and ways that they may influence the physiological processes of language access and comprehension. We then focus on the dysregulation of glutamate neurotransmission in three conditions in which language dysfunction is prominent: Alzheimer's Disease, Fragile X-associated Tremor/Ataxia Syndrome, and Aphasic Stroke Syndromes. Finally, we review the pharmacologic and electrophysiologic (event related brain potential or ERP) data pertaining to the role glutamate neurotransmission plays in language processing and disorders.
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Affiliation(s)
- Wentao Li
- Department of Neurology, University of California, Davis, 4860 Y Street, Suite 3700, Sacramento, CA, 95817, USA.
| | - Marta Kutas
- Department of Cognitive Science, University of California, San Diego, 9500 Gilman Drive #0515, La Jolla, CA, 92093, USA; Department of Neurosciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA.
| | - John A Gray
- Department of Neurology, University of California, Davis, 4860 Y Street, Suite 3700, Sacramento, CA, 95817, USA; Center for Neuroscience, University of California, Davis, 1544 Newton Court, Davis, CA, 95618, USA.
| | - Randi H Hagerman
- MIND Institute, University of California, Davis, 2825 50th Street, Sacramento, CA, 95817, USA.
| | - John M Olichney
- Department of Neurology, University of California, Davis, 4860 Y Street, Suite 3700, Sacramento, CA, 95817, USA; Center for Mind and Brain, University of California, Davis, 267 Cousteau Place, Davis, CA, 95618, USA.
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20
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Benhamou E, Marshall CR, Russell LL, Hardy CJD, Bond RL, Sivasathiaseelan H, Greaves CV, Friston KJ, Rohrer JD, Warren JD, Razi A. The neurophysiological architecture of semantic dementia: spectral dynamic causal modelling of a neurodegenerative proteinopathy. Sci Rep 2020; 10:16321. [PMID: 33004840 PMCID: PMC7530731 DOI: 10.1038/s41598-020-72847-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 09/08/2020] [Indexed: 01/11/2023] Open
Abstract
The selective destruction of large-scale brain networks by pathogenic protein spread is a ubiquitous theme in neurodegenerative disease. Characterising the circuit architecture of these diseases could illuminate both their pathophysiology and the computational architecture of the cognitive processes they target. However, this is challenging using standard neuroimaging techniques. Here we addressed this issue using a novel technique-spectral dynamic causal modelling-that estimates the effective connectivity between brain regions from resting-state fMRI data. We studied patients with semantic dementia-the paradigmatic disorder of the brain system mediating world knowledge-relative to healthy older individuals. We assessed how the effective connectivity of the semantic appraisal network targeted by this disease was modulated by pathogenic protein deposition and by two key phenotypic factors, semantic impairment and behavioural disinhibition. The presence of pathogenic protein in SD weakened the normal inhibitory self-coupling of network hubs in both antero-mesial temporal lobes, with development of an abnormal excitatory fronto-temporal projection in the left cerebral hemisphere. Semantic impairment and social disinhibition were linked to a similar but more extensive profile of abnormally attenuated inhibitory self-coupling within temporal lobe regions and excitatory projections between temporal and inferior frontal regions. Our findings demonstrate that population-level dynamic causal modelling can disclose a core pathophysiological feature of proteinopathic network architecture-attenuation of inhibitory connectivity-and the key elements of distributed neuronal processing that underwrite semantic memory.
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Affiliation(s)
- Elia Benhamou
- Dementia Research Centre, UCL Queen Square Institute of Neurology, University College London, 8-11 Queen Square, London, WC1N 3AR, UK.
| | - Charles R Marshall
- Dementia Research Centre, UCL Queen Square Institute of Neurology, University College London, 8-11 Queen Square, London, WC1N 3AR, UK
- Preventive Neurology Unit, Wolfson Institute of Preventive Medicine, Queen Mary University of London, London, UK
| | - Lucy L Russell
- Dementia Research Centre, UCL Queen Square Institute of Neurology, University College London, 8-11 Queen Square, London, WC1N 3AR, UK
| | - Chris J D Hardy
- Dementia Research Centre, UCL Queen Square Institute of Neurology, University College London, 8-11 Queen Square, London, WC1N 3AR, UK
| | - Rebecca L Bond
- Dementia Research Centre, UCL Queen Square Institute of Neurology, University College London, 8-11 Queen Square, London, WC1N 3AR, UK
| | - Harri Sivasathiaseelan
- Dementia Research Centre, UCL Queen Square Institute of Neurology, University College London, 8-11 Queen Square, London, WC1N 3AR, UK
| | - Caroline V Greaves
- Dementia Research Centre, UCL Queen Square Institute of Neurology, University College London, 8-11 Queen Square, London, WC1N 3AR, UK
| | - Karl J Friston
- Wellcome Centre for Human Neuroimaging, UCL Institute of Neurology, University College London, London, UK
| | - Jonathan D Rohrer
- Dementia Research Centre, UCL Queen Square Institute of Neurology, University College London, 8-11 Queen Square, London, WC1N 3AR, UK
| | - Jason D Warren
- Dementia Research Centre, UCL Queen Square Institute of Neurology, University College London, 8-11 Queen Square, London, WC1N 3AR, UK
| | - Adeel Razi
- Wellcome Centre for Human Neuroimaging, UCL Institute of Neurology, University College London, London, UK
- Turner Institute for Brain and Mental Health, School of Psychological Sciences and Monash Biomedical Imaging, Monash University, Melbourne, Australia
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Muller AM, Meyerhoff DJ. Does an Over-Connected Visual Cortex Undermine Efforts to Stay Sober After Treatment for Alcohol Use Disorder? Front Psychiatry 2020; 11:536706. [PMID: 33362591 PMCID: PMC7758478 DOI: 10.3389/fpsyt.2020.536706] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 11/11/2020] [Indexed: 11/13/2022] Open
Abstract
A fine-tuned interplay of highly synchronized activity within and between the brain's communities is a crucial feature of the brain's functional organization. We wanted to investigate in individuals with alcohol use disorder (AUD) the degree to which the interplay of the brain's community-architecture and the extended brain reward system (eBRS) is affected by drinking status (relapse or abstinence). We used Graph Theory Analysis of resting-state fMRI data from treatment seekers at 1 month of abstinence to model the brain's intrinsic community configuration and their follow-up data as abstainers or relapsers 3 months later to quantify the degree of global across-community interaction between the eBRS and the intrinsic communities at both timepoints. After 1 month of abstinence, the ventromedial PFC in particular showed a significantly higher global across-community interaction in the 22 future relapsers when compared to 30 light/non-drinking controls. These differences were no longer present 3 months later when the relapsers had resumed drinking. We found no significant differences between abstainers and controls at either timepoint. Post hoc tests revealed that one eBRS region, the ventromedial PFC, showed a significant global across-community interaction with a community comprising the visual cortex in relapsers at baseline. In contrast, abstainers showed a significant negative association of the ventromedial PFC with the visual cortex. The increased across-community interaction of the ventromedial PFC and the visual cortex in relapsers at timepoint 1 may be an early indicator for treatment failure in a subgroup of AUD patients.
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Affiliation(s)
- Angela M Muller
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States
| | - Dieter J Meyerhoff
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States
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