1
|
Mograbi DC, Rodrigues R, Bienemann B, Huntley J. Brain Networks, Neurotransmitters and Psychedelics: Towards a Neurochemistry of Self-Awareness. Curr Neurol Neurosci Rep 2024; 24:323-340. [PMID: 38980658 PMCID: PMC11258181 DOI: 10.1007/s11910-024-01353-y] [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] [Accepted: 06/17/2024] [Indexed: 07/10/2024]
Abstract
PURPOSE OF REVIEW Self-awareness can be defined as the capacity of becoming the object of one's own awareness and, increasingly, it has been the target of scientific inquiry. Self-awareness has important clinical implications, and a better understanding of the neurochemical basis of self-awareness may help clarifying causes and developing interventions for different psychopathological conditions. The current article explores the relationship between neurochemistry and self-awareness, with special attention to the effects of psychedelics. RECENT FINDINGS The functioning of self-related networks, such as the default-mode network and the salience network, and how these are influenced by different neurotransmitters is discussed. The impact of psychedelics on self-awareness is reviewed in relation to specific processes, such as interoception, body ownership, agency, metacognition, emotional regulation and autobiographical memory, within a framework based on predictive coding. Improved outcomes in emotional regulation and autobiographical memory have been observed in association with the use of psychedelics, suggesting higher-order self-awareness changes, which can be modulated by relaxation of priors and improved coping mechanisms linked to cognitive flexibility. Alterations in bodily self-awareness are less consistent, being potentially impacted by doses employed, differences in acute/long-term effects and the presence of clinical conditions. Future studies investigating the effects of different molecules in rebalancing connectivity between resting-state networks may lead to novel therapeutic approaches and the refinement of existing treatments.
Collapse
Affiliation(s)
- Daniel C Mograbi
- Department of Psychology, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro, Brazil.
- Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.
| | - Rafael Rodrigues
- Department of Psychology, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Bheatrix Bienemann
- Department of Psychology, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Jonathan Huntley
- Division of Psychiatry, University College London, London, UK
- Wellcome Centre for Human Neuroimaging, University College London, London, UK
| |
Collapse
|
2
|
Gruzman R, Hempel M, Domke AK, Hartling C, Stippl A, Carstens L, Bajbouj M, Gärtner M, Grimm S. Investigating the impact of rumination and adverse childhood experiences on resting-state neural activity and connectivity in depression. J Affect Disord 2024; 358:283-291. [PMID: 38387672 DOI: 10.1016/j.jad.2024.02.068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 02/15/2024] [Accepted: 02/17/2024] [Indexed: 02/24/2024]
Abstract
BACKGROUND Both ruminative thought processes and adverse childhood experiences (ACEs) are well-established risk factors for the emergence and maintenance of depression. However, the neurobiological mechanisms underlying these associations remain poorly understood. METHODS We examined resting-state functional magnetic resonance imaging data (3 T Tim Trio MR scanner; Siemens, Erlangen) of 44 individuals diagnosed with an acute depressive episode. Specifically, we focused on investigating functional brain activity and connectivity within and between three large-scale neural networks associated with processes affected in depression: the default mode network (DMN), the salience network (SN), and the central executive network (CEN). Correlational and regression-based analyses were performed. RESULTS Our regions of interest analyses revealed that region-specific spontaneous neural activity in the anterior DMN was associated with self-reported trait rumination, specifically, the pregenual anterior cingulate cortex (pgACC). Furthermore, using a liberal statistical threshold, we found that spontaneous neural activity of the ventromedial prefrontal cortex and the pgACC were associated with depression symptom severity. Neither spontaneous neural activity in the SN and CEN nor functional connectivity within and across the investigated networks was associated with depression severity or rumination. Furthermore, there was no association between ACEs and brain activity and connectivity. LIMITATIONS Lack of a formal control group or low-risk group for comparison. CONCLUSIONS Overall, our results indicate network-specific changes in spontaneous brain activity, that are linked to both depression severity and rumination. Findings underscore the crucial role of the pgACC in depression and contribute to a dimensional and symptom-based understanding of depression-related network imbalances.
Collapse
Affiliation(s)
- Rebecca Gruzman
- Department of Psychology, MSB Medical School Berlin, Rüdesheimer Straße 50, 14197 Berlin, Germany.
| | - Moritz Hempel
- Department of Psychology, MSB Medical School Berlin, Rüdesheimer Straße 50, 14197 Berlin, Germany
| | - Ann-Kathrin Domke
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt - Universität zu Berlin, Berlin Institute of Health, Campus Benjamin Franklin, Hindenburgdamm 30, 12203 Berlin, Germany
| | - Corinna Hartling
- Department of Psychology, MSB Medical School Berlin, Rüdesheimer Straße 50, 14197 Berlin, Germany; Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt - Universität zu Berlin, Berlin Institute of Health, Campus Benjamin Franklin, Hindenburgdamm 30, 12203 Berlin, Germany
| | - Anna Stippl
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt - Universität zu Berlin, Berlin Institute of Health, Campus Benjamin Franklin, Hindenburgdamm 30, 12203 Berlin, Germany
| | - Luisa Carstens
- Department of Psychology, MSB Medical School Berlin, Rüdesheimer Straße 50, 14197 Berlin, Germany
| | - Malek Bajbouj
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt - Universität zu Berlin, Berlin Institute of Health, Campus Benjamin Franklin, Hindenburgdamm 30, 12203 Berlin, Germany
| | - Matti Gärtner
- Department of Psychology, MSB Medical School Berlin, Rüdesheimer Straße 50, 14197 Berlin, Germany; Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt - Universität zu Berlin, Berlin Institute of Health, Campus Benjamin Franklin, Hindenburgdamm 30, 12203 Berlin, Germany
| | - Simone Grimm
- Department of Psychology, MSB Medical School Berlin, Rüdesheimer Straße 50, 14197 Berlin, Germany; Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt - Universität zu Berlin, Berlin Institute of Health, Campus Benjamin Franklin, Hindenburgdamm 30, 12203 Berlin, Germany; Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Lenggstrasse 31, 8032 Zurich, Switzerland
| |
Collapse
|
3
|
Ait Bentaleb K, Boisvert M, Tourjman V, Potvin S. A Meta-Analysis of Functional Neuroimaging Studies of Ketamine Administration in Healthy Volunteers. J Psychoactive Drugs 2024; 56:211-224. [PMID: 36921026 DOI: 10.1080/02791072.2023.2190758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 02/22/2023] [Indexed: 03/17/2023]
Abstract
Ketamine administration leads to a psychotomimetic state when taken in large bolus doses, making it a valid model of psychosis. Therefore, understanding ketamine's effects on brain functioning is particularly relevant. This meta-analysis focused on neuroimaging studies that examined ketamine-induced brain activation at rest and during a task. Included are 10 resting-state studies and 23 task-based studies, 9 of which were measuring executive functions. Using a stringent statistical threshold (TFCE <0.05), the results showed increased activity at rest in the dorsal anterior cingulate cortex (ACC), and increased activation of the right Heschl's gyrus during executive tasks, following ketamine administration. Uncorrected results showed increased activation at rest in the right (anterior) insula and the right-fusiform gyrus, as well as increased activation during executive tasks in the rostral ACC. Rest-state studies highlighted alterations in core hubs of the salience network, while task-based studies suggested an impact on task-irrelevant brain regions. Increased activation in the rostral ACC may indicate a failure to deactivate the default mode network during executive tasks following ketamine administration. The results are coherent with alterations found in schizophrenia, which confer external validity to the ketamine model of psychosis. Studies investigating the neural mechanisms of ketamine's antidepressant action are warranted.
Collapse
Affiliation(s)
- Karim Ait Bentaleb
- Centre de recherche de l'Institut Universitaire en Santé Mentale de Montréal, Montréal, Canada
- Department of psychiatry and addiction, Université de Montréal, Montréal, Canada
| | - Mélanie Boisvert
- Centre de recherche de l'Institut Universitaire en Santé Mentale de Montréal, Montréal, Canada
- Department of psychiatry and addiction, Université de Montréal, Montréal, Canada
| | - Valérie Tourjman
- Centre de recherche de l'Institut Universitaire en Santé Mentale de Montréal, Montréal, Canada
- Department of psychiatry and addiction, Université de Montréal, Montréal, Canada
| | - Stéphane Potvin
- Centre de recherche de l'Institut Universitaire en Santé Mentale de Montréal, Montréal, Canada
- Department of psychiatry and addiction, Université de Montréal, Montréal, Canada
| |
Collapse
|
4
|
Boucherie DE, Reneman L, Ruhé HG, Schrantee A. Neurometabolite changes in response to antidepressant medication: A systematic review of 1H-MRS findings. Neuroimage Clin 2023; 40:103517. [PMID: 37812859 PMCID: PMC10563053 DOI: 10.1016/j.nicl.2023.103517] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 09/22/2023] [Accepted: 09/23/2023] [Indexed: 10/11/2023]
Abstract
Selective serotonin reuptake inhibitors (SSRIs), serotonin and noradrenaline reuptake inhibitors (SNRIs), and (es)ketamine are used to treat major depressive disorder (MDD). These different types of medication may involve common neural pathways related to glutamatergic and GABAergic neurotransmitter systems, both of which have been implicated in MDD pathology. We conducted a systematic review of pharmacological proton Magnetic Resonance Spectroscopy (1H-MRS) studies in healthy volunteers and individuals with MDD to explore the potential impact of these medications on glutamatergic and GABAergic systems. We searched PubMed, Web of Science and Embase and included randomized controlled trials or cohort studies, which assessed the effects of SSRIs, SNRIs, or (es)ketamine on glutamate, glutamine, Glx or GABA using single-voxel 1H-MRS or Magnetic Resonance Spectroscopic Imaging (MRSI). Additionally, studies were included when they used a field strength > 1.5 T, and when a comparison of metabolite levels between antidepressant treatment and placebo or baseline with post-medication metabolite levels was done. We excluded animal studies, duplicate publications, or articles with 1H-MRS data already described in another included article. Twenty-nine studies were included in this review. Fifteen studies investigated the effect of administration or treatment with SSRIs or SNRIs, and fourteen studies investigated the effect of (es)ketamine on glutamatergic and GABAergic metabolite levels. Studies on SSRIs and SNRIs were highly variable, generally underpowered, and yielded no consistent findings across brain regions or specific populations. Although studies on (es)ketamine were also highly variable, some demonstrated an increase in glutamate levels in the anterior cingulate cortex in a time-dependent manner after administration. Our findings highlight the need for standardized study and acquisition protocols. Additionally, measuring metabolites dynamically over time or combining 1H-MRS with whole brain functional imaging techniques could provide valuable insights into the effects of these medications on glutamate and GABAergic neurometabolism.
Collapse
Affiliation(s)
- Daphne E Boucherie
- Amsterdam UMC, Location AMC, Department of Radiology and Nuclear Medicine, Meibergdreef 9, 1109 AZ Amsterdam, the Netherlands.
| | - Liesbeth Reneman
- Department of Psychiatry, Radboudumc, Radboud University, Reinier Postlaan 4, 6525 GC Nijmegen, the Netherlands
| | - Henricus G Ruhé
- Amsterdam UMC, Location AMC, Department of Radiology and Nuclear Medicine, Meibergdreef 9, 1109 AZ Amsterdam, the Netherlands; Department of Psychiatry, Radboudumc, Radboud University, Reinier Postlaan 4, 6525 GC Nijmegen, the Netherlands; Donders Institute for Brain Cognition and Behaviour, Radboud University, Kapittelweg 29, 6525 EN Nijmegen, the Netherlands
| | - Anouk Schrantee
- Amsterdam UMC, Location AMC, Department of Radiology and Nuclear Medicine, Meibergdreef 9, 1109 AZ Amsterdam, the Netherlands
| |
Collapse
|
5
|
Association of the delayed changes in glutamate levels and functional connectivity with the immediate network effects of S-ketamine. Transl Psychiatry 2023; 13:60. [PMID: 36797238 PMCID: PMC9935558 DOI: 10.1038/s41398-023-02346-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 01/20/2023] [Accepted: 01/30/2023] [Indexed: 02/18/2023] Open
Abstract
Ketamine shows rapid antidepressant effects peaking 24 h after administration. The antidepressant effects may occur through changes in glutamatergic metabolite levels and resting-state functional connectivity (rsFC) within the default mode network (DMN). A multistage drug effect of ketamine has been suggested, inducing acute effects on dysfunctional network configuration and delayed effects on homeostatic synaptic plasticity. Whether the DMN-centered delayed antidepressant-related changes are associated with the immediate changes remains unknown. Thirty-five healthy male participants (25.1 ± 4.2 years) underwent 7 T magnetic resonance spectroscopy (MRS) and resting-state functional magnetic resonance imaging (rsfMRI) before, during, and 24 h after a single S-ketamine or placebo infusion. Changes in glutamatergic measures and rsFC in the DMN node pregenual anterior cingulate cortex (pgACC) were examined. A delayed rsFC decrease of the pgACC to inferior parietal lobe (family-wise error corrected p (pFWEc) = 0.018) and dorsolateral prefrontal cortex (PFC; pFWEc = 0.002) was detected that was preceded by an immediate rsFC increase of the pgACC to medial PFC (pFWEc < 0.001) and dorsomedial PFC (pFWEc = 0.005). Additionally, the immediate rsFC reconfigurations correlated with the delayed pgACC glutamate (Glu) level increase (p = 0.024) after 24 h at trend level (p = 0.067). Baseline measures of rsFC and MRS were furthermore associated with the magnitude of the respective delayed changes (p's < 0.05). In contrast, the delayed changes were not associated with acute psychotomimetic side effects or plasma concentrations of ketamine and its metabolites. This multimodal study suggests an association between immediate S-ketamine-induced network effects and delayed brain changes at a time point relevant in its clinical context.
Collapse
|
6
|
Abstract
Anorexia nervosa is a disorder associated with serious adverse health outcomes, for which there is currently considerable treatment ineffectiveness. Characterised by restrictive eating behaviours, distorted body image perceptions and excessive physical activity, there is growing recognition anorexia nervosa is associated with underlying dysfunction in excitatory and inhibitory neurometabolite metabolism and signalling. This narrative review critically explores the role of N-methyl-D-aspartate receptor-mediated excitatory and inhibitory neurometabolite dysfunction in anorexia nervosa and its associated biomarkers. The existing magnetic resonance spectroscopy literature in anorexia nervosa is reviewed and we outline the brain region-specific neurometabolite changes that have been reported and their connection to anorexia nervosa psychopathology. Considering the proposed role of dysfunctional neurotransmission in anorexia nervosa, the potential utility of zinc supplementation and sub-anaesthetic doses of ketamine in normalising this is discussed with reference to previous research in anorexia nervosa and other neuropsychiatric conditions. The rationale for future research to investigate the combined use of low-dose ketamine and zinc supplementation to potentially extend the therapeutic benefits in anorexia nervosa is subsequently explored and promising biological markers for assessing and potentially predicting treatment response are outlined.
Collapse
|