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Sarasso P, Billeci M, Ronga I, Raffone F, Martiadis V, Di Petta G. Disembodiment and Affective Resonances in Esketamine Treatment of Depersonalized Depression Subtype: Two Case Studies. Psychopathology 2024:1-12. [PMID: 39173608 DOI: 10.1159/000539714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Accepted: 06/02/2024] [Indexed: 08/24/2024]
Abstract
INTRODUCTION Dissociative experiences are considered undesirable ketamine's adverse events. However, they might be crucial for ketamine's antidepressant effects, at least in some depression subtypes. Current understandings of ketamine's therapeutic potentials converge on the so-called "relaxed prior hypothesis," suggesting that glutamatergic blockage up-weights bottom-up surprising somatosensory/affective states. As a result, ketamine improves short-term plasticity in depression by enhancing sensitivity to interoceptive signals. METHODS We selected 2 case studies for their paradigmatic description of "depersonalized depression" (Entfremdungsdepression) symptoms. Patients were included in a 6-month-long esketamine program for treatment resistant depression, during which we collected their spontaneous experience with esketamine. According to a neurophenomenological approach, we combined subjective reports from unstructured clinical interviews and the review of previous objective neuroimaging results and neurocomputational models to unveil the relation between esketamine antidepressant effects and interoceptive sensitivity. RESULTS According to our clinical observations, esketamine-induced dissociation might be particularly effective in the depersonalized depression subtype, in which interoceptive awareness and interaffectivity are particularly compromised. Ketamine and esketamine's dissociative effects and particularly disembodiment might suspend previously acquired patterns of feeling, sensing, and behaving. CONCLUSIONS Coherently with previous research, we suggest that esketamine-induced disembodiment allows for a transient window of psychological plasticity and enhanced sensitivity, where the body recovers its permeability to affective affordances.
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Affiliation(s)
- Pietro Sarasso
- Brain Plasticity and Behaviour Changes Research Group, Department of Psychology, University of Turin, Turin, Italy
| | - Martina Billeci
- SPDC, Mental Health Department, Santa Maria delle Grazie Hospital, ASL 2, Naples, Italy
| | - Irene Ronga
- Brain Plasticity and Behaviour Changes Research Group, Department of Psychology, University of Turin, Turin, Italy
| | | | | | - Gilberto Di Petta
- SPDC, Mental Health Department, Santa Maria delle Grazie Hospital, ASL 2, Naples, Italy
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2
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Zhao Z, Feng Y, Wang M, Wei J, Tan T, Li R, Hu H, Wang M, Chen P, Gao X, Wei Y, Wang C, Gao Z, Jiang W, Zhou X, Li M, Wang C, Pang T, Yu Y. Investigating cortical complexity and connectivity in rats with schizophrenia. Front Neuroinform 2024; 18:1392271. [PMID: 39211912 PMCID: PMC11358091 DOI: 10.3389/fninf.2024.1392271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 07/29/2024] [Indexed: 09/04/2024] Open
Abstract
Background The above studies indicate that the SCZ animal model has abnormal gamma oscillations and abnormal functional coupling ability of brain regions at the cortical level. However, few researchers have focused on the correlation between brain complexity and connectivity at the cortical level. In order to provide a more accurate representation of brain activity, we studied the complexity of electrocorticogram (ECoG) signals and the information interaction between brain regions in schizophrenic rats, and explored the correlation between brain complexity and connectivity. Methods We collected ECoG signal from SCZ rats. The frequency domain and time domain functional connectivity of SCZ rats were evaluated by magnitude square coherence and mutual information (MI). Permutation entropy (PE) and permutation Lempel-Ziv complexity (PLZC) were used to analyze the complexity of ECoG, and the relationship between them was evaluated. In addition, in order to further understand the causal structure of directional information flow among brain regions, we used phase transfer entropy (PTE) to analyze the effective connectivity of the brain. Results Firstly, in the high gamma band, the complexity of brain regions in SCZ rats is higher than that in normal rats, and the neuronal activity is irregularity. Secondly, the information integration ability of SCZ rats decreased and the communication of brain network information was hindered at the cortical level. Finally, compared with normal rats, the causal relationship between brain regions of SCZ rats was closer, but the information interaction center was not clear. Conclusion The above findings suggest that at the cortical level, complexity and connectivity are valid biomarkers for identifying SCZ. This bridges the gap between peak potentials and EEG. This may help to understand the pathophysiological mechanisms at the cortical level in schizophrenics.
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Affiliation(s)
- Zongya Zhao
- School of Medical Engineering, Xinxiang Medical University, Xinxiang, China
- Engineering Technology Research Center of Neurosense and Control of Henan Province, Xinxiang, China
- Henan International Joint Laboratory of Neural Information Analysis and Drug Intelligent Design, Xinxiang, China
| | - Yifan Feng
- School of Medical Engineering, Xinxiang Medical University, Xinxiang, China
- Henan International Joint Laboratory of Neural Information Analysis and Drug Intelligent Design, Xinxiang, China
| | - Menghan Wang
- School of Medical Engineering, Xinxiang Medical University, Xinxiang, China
- Henan International Joint Laboratory of Neural Information Analysis and Drug Intelligent Design, Xinxiang, China
| | - Jiarong Wei
- School of Medical Engineering, Xinxiang Medical University, Xinxiang, China
- Henan International Joint Laboratory of Neural Information Analysis and Drug Intelligent Design, Xinxiang, China
| | - Tao Tan
- School of Medical Engineering, Xinxiang Medical University, Xinxiang, China
- Henan International Joint Laboratory of Neural Information Analysis and Drug Intelligent Design, Xinxiang, China
| | - Ruijiao Li
- School of Medical Engineering, Xinxiang Medical University, Xinxiang, China
- Henan International Joint Laboratory of Neural Information Analysis and Drug Intelligent Design, Xinxiang, China
| | - Heshun Hu
- School of Medical Engineering, Xinxiang Medical University, Xinxiang, China
- Henan International Joint Laboratory of Neural Information Analysis and Drug Intelligent Design, Xinxiang, China
| | - Mengke Wang
- School of Medical Engineering, Xinxiang Medical University, Xinxiang, China
- Henan International Joint Laboratory of Neural Information Analysis and Drug Intelligent Design, Xinxiang, China
| | - Peiqi Chen
- School of Medical Engineering, Xinxiang Medical University, Xinxiang, China
- Henan International Joint Laboratory of Neural Information Analysis and Drug Intelligent Design, Xinxiang, China
| | - Xudong Gao
- School of Medical Engineering, Xinxiang Medical University, Xinxiang, China
- Henan International Joint Laboratory of Neural Information Analysis and Drug Intelligent Design, Xinxiang, China
| | - Yinping Wei
- School of Medical Engineering, Xinxiang Medical University, Xinxiang, China
- Henan International Joint Laboratory of Neural Information Analysis and Drug Intelligent Design, Xinxiang, China
| | - Chang Wang
- School of Medical Engineering, Xinxiang Medical University, Xinxiang, China
- Engineering Technology Research Center of Neurosense and Control of Henan Province, Xinxiang, China
- Henan International Joint Laboratory of Neural Information Analysis and Drug Intelligent Design, Xinxiang, China
| | - Zhixian Gao
- School of Medical Engineering, Xinxiang Medical University, Xinxiang, China
- Engineering Technology Research Center of Neurosense and Control of Henan Province, Xinxiang, China
- Henan International Joint Laboratory of Neural Information Analysis and Drug Intelligent Design, Xinxiang, China
| | - Wenshuai Jiang
- School of Medical Engineering, Xinxiang Medical University, Xinxiang, China
- Engineering Technology Research Center of Neurosense and Control of Henan Province, Xinxiang, China
- Henan International Joint Laboratory of Neural Information Analysis and Drug Intelligent Design, Xinxiang, China
| | - Xuezhi Zhou
- School of Medical Engineering, Xinxiang Medical University, Xinxiang, China
- Engineering Technology Research Center of Neurosense and Control of Henan Province, Xinxiang, China
- Henan International Joint Laboratory of Neural Information Analysis and Drug Intelligent Design, Xinxiang, China
| | - Mingcai Li
- School of Medical Engineering, Xinxiang Medical University, Xinxiang, China
- Engineering Technology Research Center of Neurosense and Control of Henan Province, Xinxiang, China
- Henan International Joint Laboratory of Neural Information Analysis and Drug Intelligent Design, Xinxiang, China
| | - Chong Wang
- School of Medical Engineering, Xinxiang Medical University, Xinxiang, China
- Engineering Technology Research Center of Neurosense and Control of Henan Province, Xinxiang, China
- Henan International Joint Laboratory of Neural Information Analysis and Drug Intelligent Design, Xinxiang, China
| | - Ting Pang
- Engineering Technology Research Center of Neurosense and Control of Henan Province, Xinxiang, China
- Henan International Joint Laboratory of Neural Information Analysis and Drug Intelligent Design, Xinxiang, China
- Center of Image and Signal Processing, Faculty of Computer Science and Information Technology, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Yi Yu
- School of Medical Engineering, Xinxiang Medical University, Xinxiang, China
- Engineering Technology Research Center of Neurosense and Control of Henan Province, Xinxiang, China
- Henan International Joint Laboratory of Neural Information Analysis and Drug Intelligent Design, Xinxiang, China
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Lewis-Healey E, Tagliazucchi E, Canales-Johnson A, Bekinschtein TA. Breathwork-induced psychedelic experiences modulate neural dynamics. Cereb Cortex 2024; 34:bhae347. [PMID: 39191666 DOI: 10.1093/cercor/bhae347] [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: 04/02/2024] [Revised: 08/01/2024] [Accepted: 08/12/2024] [Indexed: 08/29/2024] Open
Abstract
Breathwork is an understudied school of practices involving intentional respiratory modulation to induce an altered state of consciousness (ASC). We simultaneously investigate the phenomenological and neural dynamics of breathwork by combining Temporal Experience Tracing, a quantitative methodology that preserves the temporal dynamics of subjective experience, with low-density portable EEG devices. Fourteen novice participants completed a course of up to 28 breathwork sessions-of 20, 40, or 60 min-in 28 days, yielding a neurophenomenological dataset of 301 breathwork sessions. Using hypothesis-driven and data-driven approaches, we found that "psychedelic-like" subjective experiences were associated with increased neural Lempel-Ziv complexity during breathwork. Exploratory analyses showed that the aperiodic exponent of the power spectral density-but not oscillatory alpha power-yielded similar neurophenomenological associations. Non-linear neural features, like complexity and the aperiodic exponent, neurally map both a multidimensional data-driven composite of positive experiences, and hypothesis-driven aspects of psychedelic-like experience states such as high bliss.
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Affiliation(s)
- Evan Lewis-Healey
- Cambridge Consciousness and Cognition Lab, Department of Psychology, Downing Place, University of Cambridge, Cambridge, CB2 3EB, United Kingdom
| | - Enzo Tagliazucchi
- Consciousness, Culture and Complexity Lab, Department of Physics, Pabellón I, University of Buenos Aires, 1428, Buenos Aires, Argentina
- Latin American Brain Health Institute (BrainLat), Universidad Adolfo Ibanez, Santiago, 7910000, Chile
- Cognitive Neuroscience Center, Universidad de San Andrés, Vito Dumas 284, B1644BID Victoria, Provincia de Buenos Aires, Argentina
| | - Andres Canales-Johnson
- Cambridge Consciousness and Cognition Lab, Department of Psychology, Downing Place, University of Cambridge, Cambridge, CB2 3EB, United Kingdom
- The Neuropsychology and Cognitive Neurosciences Research Center, Faculty of Health Sciences, Universidad Católica del Maule, 3460000, Talca, Chile
| | - Tristan A Bekinschtein
- Cambridge Consciousness and Cognition Lab, Department of Psychology, Downing Place, University of Cambridge, Cambridge, CB2 3EB, United Kingdom
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Haddon JE, Titherage D, Heckenast JR, Carter J, Owen MJ, Hall J, Wilkinson LS, Jones MW. Linking haploinsufficiency of the autism- and schizophrenia-associated gene Cyfip1 with striatal-limbic-cortical network dysfunction and cognitive inflexibility. Transl Psychiatry 2024; 14:256. [PMID: 38876996 PMCID: PMC11178837 DOI: 10.1038/s41398-024-02969-x] [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: 06/27/2023] [Revised: 05/01/2024] [Accepted: 05/29/2024] [Indexed: 06/16/2024] Open
Abstract
Impaired behavioural flexibility is a core feature of neuropsychiatric disorders and is associated with underlying dysfunction of fronto-striatal circuitry. Reduced dosage of Cyfip1 is a risk factor for neuropsychiatric disorder, as evidenced by its involvement in the 15q11.2 (BP1-BP2) copy number variant: deletion carriers are haploinsufficient for CYFIP1 and exhibit a two- to four-fold increased risk of schizophrenia, autism and/or intellectual disability. Here, we model the contributions of Cyfip1 to behavioural flexibility and related fronto-striatal neural network function using a recently developed haploinsufficient, heterozygous knockout rat line. Using multi-site local field potential (LFP) recordings during resting state, we show that Cyfip1 heterozygous rats (Cyfip1+/-) harbor disrupted network activity spanning medial prefrontal cortex, hippocampal CA1 and ventral striatum. In particular, Cyfip1+/- rats showed reduced influence of nucleus accumbens and increased dominance of prefrontal and hippocampal inputs, compared to wildtype controls. Adult Cyfip1+/- rats were able to learn a single cue-response association, yet unable to learn a conditional discrimination task that engages fronto-striatal interactions during flexible pairing of different levers and cue combinations. Together, these results implicate Cyfip1 in development or maintenance of cortico-limbic-striatal network integrity, further supporting the hypothesis that alterations in this circuitry contribute to behavioural inflexibility observed in neuropsychiatric diseases including schizophrenia and autism.
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Affiliation(s)
- Josephine E Haddon
- Neuroscience and Mental Health Innovation Institute, Cardiff University, Cardiff, UK.
- Division of Psychological Medicine and Clinical Neurosciences (DPMCN), School of Medicine, Cardiff University, Cardiff, UK.
| | - Daniel Titherage
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, UK
- Centre for Academic Mental Health, Population Health sciences, University of Bristol, Bristol, UK
| | - Julia R Heckenast
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, UK
| | - Jennifer Carter
- Division of Psychological Medicine and Clinical Neurosciences (DPMCN), School of Medicine, Cardiff University, Cardiff, UK
| | - Michael J Owen
- Neuroscience and Mental Health Innovation Institute, Cardiff University, Cardiff, UK
- Division of Psychological Medicine and Clinical Neurosciences (DPMCN), School of Medicine, Cardiff University, Cardiff, UK
- MRC Centre for Neuropsychiatric Genetics and Genomics, Cardiff University, Cardiff, UK
| | - Jeremy Hall
- Neuroscience and Mental Health Innovation Institute, Cardiff University, Cardiff, UK
- Division of Psychological Medicine and Clinical Neurosciences (DPMCN), School of Medicine, Cardiff University, Cardiff, UK
- MRC Centre for Neuropsychiatric Genetics and Genomics, Cardiff University, Cardiff, UK
| | - Lawrence S Wilkinson
- Neuroscience and Mental Health Innovation Institute, Cardiff University, Cardiff, UK
- Division of Psychological Medicine and Clinical Neurosciences (DPMCN), School of Medicine, Cardiff University, Cardiff, UK
- MRC Centre for Neuropsychiatric Genetics and Genomics, Cardiff University, Cardiff, UK
- School of Psychology, Cardiff University, Cardiff, UK
| | - Matthew W Jones
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, UK
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Glynos NG, Huels ER, Nelson A, Kim Y, Kennedy RT, Mashour GA, Pal D. Neurochemical and Neurophysiological Effects of Intravenous Administration of N,N-dimethyltryptamine in Rats. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.19.589047. [PMID: 38712161 PMCID: PMC11071436 DOI: 10.1101/2024.04.19.589047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
N,N-dimethyltryptamine (DMT) is a serotonergic psychedelic that is being investigated clinically for the treatment of psychiatric disorders. Although the neurophysiological effects of DMT in humans are well-characterized, similar studies in animal models as well as data on the neurochemical effects of DMT are generally lacking, which are critical for mechanistic understanding. In the current study, we combined behavioral analysis, high-density (32-channel) electroencephalography, and ultra-high-performance liquid chromatography-tandem mass spectrometry to simultaneously quantify changes in behavior, cortical neural dynamics, and levels of 17 neurochemicals in medial prefrontal and somatosensory cortices before, during, and after intravenous administration of three different doses of DMT (0.75 mg/kg, 3.75 mg/kg, 7.5 mg/kg) in male and female adult rats. All three doses of DMT produced head twitch response with most twitches observed after the low dose. DMT caused dose-dependent increases in serotonin and dopamine levels in both cortical sites along with a reduction in EEG spectral power in theta (4-10 Hz) and low gamma (25-55 Hz), and increase in power in delta (1-4 Hz), medium gamma (65-115), and high gamma (125-155 Hz) bands. Functional connectivity decreased in the delta band and increased across the gamma bands. In addition, we provide the first measurements of endogenous DMT in these cortical sites at levels comparable to serotonin and dopamine, which together with a previous study in occipital cortex, suggests a physiological role for endogenous DMT. This study represents one of the most comprehensive characterizations of psychedelic drug action in rats and the first to be conducted with DMT.
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Affiliation(s)
- Nicolas G. Glynos
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Anesthesiology, University of Michigan, Ann Abor, MI 48109, USA
- Michigan Psychedelic Center, University of Michigan, Ann Arbor, MI 48109, USA
- Center for Consciousness Science, University of Michigan, Ann Arbor, MI 48109, USA
| | - Emma R. Huels
- Department of Anesthesiology, University of Michigan, Ann Abor, MI 48109, USA
- Michigan Psychedelic Center, University of Michigan, Ann Arbor, MI 48109, USA
- Center for Consciousness Science, University of Michigan, Ann Arbor, MI 48109, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Amanda Nelson
- Department of Anesthesiology, University of Michigan, Ann Abor, MI 48109, USA
| | - Youngsoo Kim
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Robert T. Kennedy
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - George A. Mashour
- Department of Anesthesiology, University of Michigan, Ann Abor, MI 48109, USA
- Michigan Psychedelic Center, University of Michigan, Ann Arbor, MI 48109, USA
- Center for Consciousness Science, University of Michigan, Ann Arbor, MI 48109, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Dinesh Pal
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Anesthesiology, University of Michigan, Ann Abor, MI 48109, USA
- Michigan Psychedelic Center, University of Michigan, Ann Arbor, MI 48109, USA
- Center for Consciousness Science, University of Michigan, Ann Arbor, MI 48109, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
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Luppi AI, Girn M, Rosas FE, Timmermann C, Roseman L, Erritzoe D, Nutt DJ, Stamatakis EA, Spreng RN, Xing L, Huttner WB, Carhart-Harris RL. A role for the serotonin 2A receptor in the expansion and functioning of human transmodal cortex. Brain 2024; 147:56-80. [PMID: 37703310 DOI: 10.1093/brain/awad311] [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: 04/13/2023] [Revised: 08/14/2023] [Accepted: 08/18/2023] [Indexed: 09/15/2023] Open
Abstract
Integrating independent but converging lines of research on brain function and neurodevelopment across scales, this article proposes that serotonin 2A receptor (5-HT2AR) signalling is an evolutionary and developmental driver and potent modulator of the macroscale functional organization of the human cerebral cortex. A wealth of evidence indicates that the anatomical and functional organization of the cortex follows a unimodal-to-transmodal gradient. Situated at the apex of this processing hierarchy-where it plays a central role in the integrative processes underpinning complex, human-defining cognition-the transmodal cortex has disproportionately expanded across human development and evolution. Notably, the adult human transmodal cortex is especially rich in 5-HT2AR expression and recent evidence suggests that, during early brain development, 5-HT2AR signalling on neural progenitor cells stimulates their proliferation-a critical process for evolutionarily-relevant cortical expansion. Drawing on multimodal neuroimaging and cross-species investigations, we argue that, by contributing to the expansion of the human cortex and being prevalent at the apex of its hierarchy in the adult brain, 5-HT2AR signalling plays a major role in both human cortical expansion and functioning. Owing to its unique excitatory and downstream cellular effects, neuronal 5-HT2AR agonism promotes neuroplasticity, learning and cognitive and psychological flexibility in a context-(hyper)sensitive manner with therapeutic potential. Overall, we delineate a dual role of 5-HT2ARs in enabling both the expansion and modulation of the human transmodal cortex.
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Affiliation(s)
- Andrea I Luppi
- Department of Clinical Neurosciences and Division of Anaesthesia, University of Cambridge, Cambridge, CB2 0QQ, UK
- Leverhulme Centre for the Future of Intelligence, University of Cambridge, Cambridge, CB2 1SB, UK
- The Alan Turing Institute, London, NW1 2DB, UK
| | - Manesh Girn
- Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Montreal, H3A 2B4, Canada
- Psychedelics Division-Neuroscape, Department of Neurology, University of California SanFrancisco, San Francisco, CA 94158, USA
| | - Fernando E Rosas
- Centre for Psychedelic Research, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, SW7 2AZ, UK
- Data Science Institute, Imperial College London, London, SW7 2AZ, UK
- Centre for Complexity Science, Imperial College London, London, SW7 2AZ, UK
| | - Christopher Timmermann
- Centre for Psychedelic Research, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, SW7 2AZ, UK
| | - Leor Roseman
- Centre for Psychedelic Research, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, SW7 2AZ, UK
| | - David Erritzoe
- Centre for Psychedelic Research, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, SW7 2AZ, UK
| | - David J Nutt
- Centre for Psychedelic Research, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, SW7 2AZ, UK
| | - Emmanuel A Stamatakis
- Department of Clinical Neurosciences and Division of Anaesthesia, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - R Nathan Spreng
- Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Montreal, H3A 2B4, Canada
| | - Lei Xing
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, 01307, Germany
| | - Wieland B Huttner
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, 01307, Germany
| | - Robin L Carhart-Harris
- Psychedelics Division-Neuroscape, Department of Neurology, University of California SanFrancisco, San Francisco, CA 94158, USA
- Centre for Psychedelic Research, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, SW7 2AZ, UK
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7
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Ivan VE, Tomàs-Cuesta DP, Esteves IM, Curic D, Mohajerani M, McNaughton BL, Davidsen J, Gruber AJ. The Nonclassic Psychedelic Ibogaine Disrupts Cognitive Maps. BIOLOGICAL PSYCHIATRY GLOBAL OPEN SCIENCE 2024; 4:275-283. [PMID: 38298796 PMCID: PMC10829624 DOI: 10.1016/j.bpsgos.2023.07.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 07/20/2023] [Accepted: 07/23/2023] [Indexed: 02/02/2024] Open
Abstract
Background The ability of psychedelic compounds to profoundly alter mental function has been long known, but the underlying changes in cellular-level information encoding remain poorly understood. Methods We used two-photon microscopy to record from the retrosplenial cortex in head-fixed mice running on a treadmill before and after injection of the nonclassic psychedelic ibogaine (40 mg/kg intraperitoneally). Results We found that the cognitive map, formed by the representation of position encoded by ensembles of individual neurons in the retrosplenial cortex, was destabilized by ibogaine when mice had to infer position between tactile landmarks. This corresponded with increased neural activity rates, loss of correlation structure, and increased responses to cues. Ibogaine had surprisingly little effect on the size-frequency distribution of network activity events, suggesting that signal propagation within the retrosplenial cortex was largely unaffected. Conclusions Taken together, these data support proposals that compounds with psychedelic properties disrupt representations that are important for constraining neocortical activity, thereby increasing the entropy of neural signaling. Furthermore, the loss of expected position encoding between landmarks recapitulated effects of hippocampal impairment, suggesting that disruption of cognitive maps or other hippocampal processing may be a contributing mechanism of discoordinated neocortical activity in psychedelic states.
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Affiliation(s)
- Victorita E. Ivan
- Canadian Center for Behavioural Neuroscience, Department of Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada
| | - David P. Tomàs-Cuesta
- Canadian Center for Behavioural Neuroscience, Department of Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Ingrid M. Esteves
- Canadian Center for Behavioural Neuroscience, Department of Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Davor Curic
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - Majid Mohajerani
- Canadian Center for Behavioural Neuroscience, Department of Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Bruce L. McNaughton
- Canadian Center for Behavioural Neuroscience, Department of Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada
- Center for the Neurobiology of Learning and Memory, University of California Irvine, Irvine, California
| | - Joern Davidsen
- Department of Physics and Astronomy, University of Calgary, Calgary, Alberta, Canada
| | - Aaron J. Gruber
- Canadian Center for Behavioural Neuroscience, Department of Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada
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8
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Reinwald JR, Schmitz CN, Skorodumov I, Kuchar M, Weber-Fahr W, Spanagel R, Meinhardt MW. Psilocybin-induced default mode network hypoconnectivity is blunted in alcohol-dependent rats. Transl Psychiatry 2023; 13:392. [PMID: 38097569 PMCID: PMC10721862 DOI: 10.1038/s41398-023-02690-1] [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: 08/04/2023] [Revised: 11/15/2023] [Accepted: 11/27/2023] [Indexed: 12/17/2023] Open
Abstract
Alcohol Use Disorder (AUD) adversely affects the lives of millions of people, but still lacks effective treatment options. Recent advancements in psychedelic research suggest psilocybin to be potentially efficacious for AUD. However, major knowledge gaps remain regarding (1) psilocybin's general mode of action and (2) AUD-specific alterations of responsivity to psilocybin treatment in the brain that are crucial for treatment development. Here, we conducted a randomized, placebo-controlled crossover pharmaco-fMRI study on psilocybin effects using a translational approach with healthy rats and a rat model of alcohol relapse. Psilocybin effects were quantified with resting-state functional connectivity using data-driven whole-brain global brain connectivity, network-based statistics, graph theory, hypothesis-driven Default Mode Network (DMN)-specific connectivity, and entropy analyses. Results demonstrate that psilocybin induced an acute wide-spread decrease in different functional connectivity domains together with a distinct increase of connectivity between serotonergic core regions and cortical areas. We could further provide translational evidence for psilocybin-induced DMN hypoconnectivity reported in humans. Psilocybin showed an AUD-specific blunting of DMN hypoconnectivity, which strongly correlated to the alcohol relapse intensity and was mainly driven by medial prefrontal regions. In conclusion, our results provide translational validity for acute psilocybin-induced neural effects in the rodent brain. Furthermore, alcohol relapse severity was negatively correlated with neural responsivity to psilocybin treatment. Our data suggest that a clinical standard dose of psilocybin may not be sufficient to treat severe AUD cases; a finding that should be considered for future clinical trials.
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Affiliation(s)
- Jonathan R Reinwald
- Research Group Translational Imaging, Department of Neuroimaging, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
- Research Group Systems Neuroscience and Mental Health, Department of Psychiatry and Psychotherapy, University Medical Center Mainz, Johannes Gutenberg University, Mainz, Germany
| | - Christian N Schmitz
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
- Department of Molecular Neuroimaging, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Ivan Skorodumov
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Martin Kuchar
- Forensic Laboratory of Biologically Active Substances, Department of Chemistry of Natural Compounds, University of Chemistry and Technology Prague, Prague, Czech Republic
- Psychedelics Research Centre, National Institute of Mental Health, Klecany, Czech Republic
| | - Wolfgang Weber-Fahr
- Research Group Translational Imaging, Department of Neuroimaging, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Rainer Spanagel
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany.
| | - Marcus W Meinhardt
- Department of Molecular Neuroimaging, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany.
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany.
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9
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Wsół A. Cardiovascular safety of psychedelic medicine: current status and future directions. Pharmacol Rep 2023; 75:1362-1380. [PMID: 37874530 PMCID: PMC10661823 DOI: 10.1007/s43440-023-00539-4] [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: 08/29/2023] [Revised: 10/02/2023] [Accepted: 10/02/2023] [Indexed: 10/25/2023]
Abstract
Psychedelics are powerful psychoactive substances that alter perception and mood processes. Their effectiveness in the treatment of psychiatric diseases was known before their prohibition. An increasing number of recent studies, due to the indisputable resurgence of serotonergic hallucinogens, have shown their efficacy in alleviating depression, anxiety, substance abuse therapies, and existential distress treatment in patients facing life-threatening illness. Psychedelics are generally considered to be physiologically safe with low toxicity and low addictive potential. However, their agonism at serotonergic receptors should be considered in the context of possible serotonin-related cardiotoxicity (5-HT2A/2B and 5-HT4 receptors), influence on platelet aggregation (5-HT2A receptor), and their proarrhythmic potential. The use of psychedelics has also been associated with significant sympathomimetic effects in both experimental and clinical studies. Therefore, the present review aims to provide a critical discussion of the cardiovascular safety of psilocybin, d-lysergic acid diethylamide (LSD), N,N-dimethyltryptamine, ayahuasca, and mescaline, based on the results of experimental research and clinical trials in humans. Experimental studies provide inconsistent information on the potential cardiovascular effects and toxicity of psychedelics. Data from clinical trials point to the relative cardiovascular safety of psychedelic-assisted therapies in the population of "healthy" volunteers. However, there is insufficient evidence from therapies carried out with microdoses of psychedelics, and there is still a lack of data on the safety of psychedelics in the population of patients with cardiovascular disease. Therefore, the exact determination of the cardiovascular safety of psychedelic therapies (especially long-term therapies) requires further research.
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Affiliation(s)
- Agnieszka Wsół
- Chair and Department of Experimental and Clinical Physiology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Banacha 1B, 02-097, Warsaw, Poland.
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10
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Bottemanne H, Berkovitch L, Gauld C, Balcerac A, Schmidt L, Mouchabac S, Fossati P. Storm on predictive brain: A neurocomputational account of ketamine antidepressant effect. Neurosci Biobehav Rev 2023; 154:105410. [PMID: 37793581 DOI: 10.1016/j.neubiorev.2023.105410] [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: 04/22/2023] [Revised: 08/24/2023] [Accepted: 09/26/2023] [Indexed: 10/06/2023]
Abstract
For the past decade, ketamine, an N-methyl-D-aspartate receptor (NMDAr) antagonist, has been considered a promising treatment for major depressive disorder (MDD). Unlike the delayed effect of monoaminergic treatment, ketamine may produce fast-acting antidepressant effects hours after a single administration at subanesthetic dose. Along with these antidepressant effects, it may also induce transient dissociative (disturbing of the sense of self and reality) symptoms during acute administration which resolve within hours. To understand ketamine's rapid-acting antidepressant effect, several biological hypotheses have been explored, but despite these promising avenues, there is a lack of model to understand the timeframe of antidepressant and dissociative effects of ketamine. In this article, we propose a neurocomputational account of ketamine's antidepressant and dissociative effects based on the Predictive Processing (PP) theory, a framework for cognitive and sensory processing. PP theory suggests that the brain produces top-down predictions to process incoming sensory signals, and generates bottom-up prediction errors (PEs) which are then used to update predictions. This iterative dynamic neural process would relies on N-methyl-D-aspartate (NMDAr) and α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic receptors (AMPAr), two major component of the glutamatergic signaling. Furthermore, it has been suggested that MDD is characterized by over-rigid predictions which cannot be updated by the PEs, leading to miscalibration of hierarchical inference and self-reinforcing negative feedback loops. Based on former empirical studies using behavioral paradigms, neurophysiological recordings, and computational modeling, we suggest that ketamine impairs top-down predictions by blocking NMDA receptors, and enhances presynaptic glutamate release and PEs, producing transient dissociative symptoms and fast-acting antidepressant effect in hours following acute administration. Moreover, we present data showing that ketamine may enhance a delayed neural plasticity pathways through AMPAr potentiation, triggering a prolonged antidepressant effect up to seven days for unique administration. Taken together, the two sides of antidepressant effects with distinct timeframe could constitute the keystone of antidepressant properties of ketamine. These PP disturbances may also participate to a ketamine-induced time window of mental flexibility, which can be used to improve the psychotherapeutic process. Finally, these proposals could be used as a theoretical framework for future research into fast-acting antidepressants, and combination with existing antidepressant and psychotherapy.
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Affiliation(s)
- Hugo Bottemanne
- Paris Brain Institute - Institut du Cerveau (ICM), UMR 7225 / UMRS 1127, Sorbonne University / CNRS / INSERM, Paris, France; Sorbonne University, Department of Philosophy, Science Norm Democracy Research Unit, UMR, 8011, Paris, France; Sorbonne University, Department of Psychiatry, Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France.
| | - Lucie Berkovitch
- Saclay CEA Centre, Neurospin, Gif-Sur-Yvette Cedex, France; Department of Psychiatry, GHU Paris Psychiatrie et Neurosciences, Service Hospitalo-Universitaire, Paris, France
| | - Christophe Gauld
- Department of Child Psychiatry, CHU de Lyon, F-69000 Lyon, France; Institut des Sciences Cognitives Marc Jeannerod, UMR 5229 CNRS & Université Claude Bernard Lyon 1, F-69000 Lyon, France
| | - Alexander Balcerac
- Paris Brain Institute - Institut du Cerveau (ICM), UMR 7225 / UMRS 1127, Sorbonne University / CNRS / INSERM, Paris, France; Sorbonne University, Department of Neurology, Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
| | - Liane Schmidt
- Paris Brain Institute - Institut du Cerveau (ICM), UMR 7225 / UMRS 1127, Sorbonne University / CNRS / INSERM, Paris, France
| | - Stephane Mouchabac
- Paris Brain Institute - Institut du Cerveau (ICM), UMR 7225 / UMRS 1127, Sorbonne University / CNRS / INSERM, Paris, France; Sorbonne University, Department of Psychiatry, Saint-Antoine Hospital, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
| | - Philippe Fossati
- Paris Brain Institute - Institut du Cerveau (ICM), UMR 7225 / UMRS 1127, Sorbonne University / CNRS / INSERM, Paris, France; Sorbonne University, Department of Philosophy, Science Norm Democracy Research Unit, UMR, 8011, Paris, France
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11
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Inserra A, Piot A, De Gregorio D, Gobbi G. Lysergic Acid Diethylamide (LSD) for the Treatment of Anxiety Disorders: Preclinical and Clinical Evidence. CNS Drugs 2023; 37:733-754. [PMID: 37603260 DOI: 10.1007/s40263-023-01008-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/19/2023] [Indexed: 08/22/2023]
Abstract
Anxiety disorders (ADs) represent the sixth leading cause of disability worldwide, resulting in a significant global economic burden. Over 50% of individuals with ADs do not respond to standard therapies, making the identification of more effective anxiolytic drugs an ongoing research priority. In this work, we review the preclinical literature concerning the effects of lysergic acid diethylamide (LSD) on anxiety-like behaviors in preclinical models, and the clinical literature on anxiolytic effects of LSD in healthy volunteers and patients with ADs. Preclinical and clinical findings show that even if LSD may exacerbate anxiety acutely (both in "microdoses" and "full doses"), it induces long-lasting anxiolytic effects. Only two randomized controlled trials combining LSD and psychotherapy have been performed in patients with ADs with and without life-threatening conditions, showing a good safety profile and persisting decreases in anxiety outcomes. The effect of LSD on anxiety may be mediated by serotonin receptors (5-HT1A/1B, 5-HT2A/2C, and 5-HT7) and/or transporter in brain networks and circuits (default mode network, cortico-striato-thalamo-cortical circuit, and prefrontal cortex-amygdala circuit), involved in the modulation of anxiety. It remains unclear whether LSD can be an efficacious treatment alone or only when combined with psychotherapy, and if "microdosing" may elicit the same sustained anxiolytic effects as the "full doses". Further randomized controlled trials with larger sample size cohorts of patients with ADs are required to clearly define the effective regimens, safety profile, efficacy, and feasibility of LSD for the treatment of ADs.
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Affiliation(s)
- Antonio Inserra
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, Avenue des Pins Ouest, Montreal, QC, H3A 1A1, Canada
| | - Alexandre Piot
- UCL Queen Square Institute of Neurology, University College London, London, UK
| | - Danilo De Gregorio
- Division of Neuroscience, Vita-Salute San Raffaele University, Milan, Italy
| | - Gabriella Gobbi
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, Avenue des Pins Ouest, Montreal, QC, H3A 1A1, Canada.
- McGill University Health Center, Montreal, QC, Canada.
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12
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Frohlich J, Crone JS, Mediano PAM, Toker D, Bor D. Editorial: Dissociations between neural activity and conscious state: a key to understanding consciousness. Front Hum Neurosci 2023; 17:1256168. [PMID: 37600551 PMCID: PMC10433896 DOI: 10.3389/fnhum.2023.1256168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 07/20/2023] [Indexed: 08/22/2023] Open
Affiliation(s)
- Joel Frohlich
- Institute for Neuromodulation and Neurotechnology, University Hospital and University of Tuebingen, Tuebingen, Germany
- Institute for Advanced Consciousness Studies, Santa Monica, CA, United States
| | - Julia S. Crone
- Vienna Cognitive Science Hub, University of Vienna, Vienna, Austria
| | - Pedro A. M. Mediano
- Department of Computing, Imperial College London, London, United Kingdom
- Department of Psychology, University of Cambridge, Cambridge, United Kingdom
| | - Daniel Toker
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Daniel Bor
- Department of Psychology, University of Cambridge, Cambridge, United Kingdom
- Department of Psychology, Queen Mary University of London, London, United Kingdom
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13
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Hipólito I, Mago J, Rosas FE, Carhart-Harris R. Pattern breaking: a complex systems approach to psychedelic medicine. Neurosci Conscious 2023; 2023:niad017. [PMID: 37424966 PMCID: PMC10325487 DOI: 10.1093/nc/niad017] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 05/19/2023] [Accepted: 06/08/2023] [Indexed: 07/11/2023] Open
Abstract
Recent research has demonstrated the potential of psychedelic therapy for mental health care. However, the psychological experience underlying its therapeutic effects remains poorly understood. This paper proposes a framework that suggests psychedelics act as destabilizers, both psychologically and neurophysiologically. Drawing on the 'entropic brain' hypothesis and the 'RElaxed Beliefs Under pSychedelics' model, this paper focuses on the richness of psychological experience. Through a complex systems theory perspective, we suggest that psychedelics destabilize fixed points or attractors, breaking reinforced patterns of thinking and behaving. Our approach explains how psychedelic-induced increases in brain entropy destabilize neurophysiological set points and lead to new conceptualizations of psychedelic psychotherapy. These insights have important implications for risk mitigation and treatment optimization in psychedelic medicine, both during the peak psychedelic experience and during the subacute period of potential recovery.
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Affiliation(s)
- Inês Hipólito
- Berlin School of Mind and Brain, Humboldt-Universität zu Berlin, Berlin 10117, Germany
- Department of Philosophy, Macquarie University, New South Wales 2109, Australia
| | - Jonas Mago
- Wellcome Centre for Human Neuroimaging, University College London, London WC1N 3AR, United Kingdom
- Integrative Program in Neuroscience, McGill University, Montreal, Quebec QC H3A, Canada
| | - Fernando E Rosas
- Department of Brain Sciences, Centre for Psychedelic Research, Imperial College London, London SW7 2BX, United Kingdom
- Centre for Complexity Science, Imperial College London, London SW7 2BX, United Kingdom
- Data Science Institute, Imperial College London, London SW7 2BX, United Kingdom
- Department of Informatics, University of Sussex, Brighton BN1 9RH, United Kingdom
- Centre for Eudaimonia and Human Flourishing, University of Oxford, Oxford OX3 9BX, United Kingdom
| | - Robin Carhart-Harris
- Department of Brain Sciences, Centre for Psychedelic Research, Imperial College London, London SW7 2BX, United Kingdom
- Psychedelics Division, University of California San Francisco, San Francisco, CA 92521, United States
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14
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Frohlich J, Mediano PAM, Bavato F, Gharabaghi A. Paradoxical pharmacological dissociations result from drugs that enhance delta oscillations but preserve consciousness. Commun Biol 2023; 6:654. [PMID: 37340024 DOI: 10.1038/s42003-023-04988-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 05/26/2023] [Indexed: 06/22/2023] Open
Abstract
Low-frequency (<4 Hz) neural activity, particularly in the delta band, is generally indicative of loss of consciousness and cortical down states, particularly when it is diffuse and high amplitude. Remarkably, however, drug challenge studies of several diverse classes of pharmacological agents-including drugs which treat epilepsy, activate GABAB receptors, block acetylcholine receptors, or produce psychedelic effects-demonstrate neural activity resembling cortical down states even as the participants remain conscious. Of those substances that are safe to use in healthy volunteers, some may be highly valuable research tools for investigating which neural activity patterns are sufficient for consciousness or its absence.
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Affiliation(s)
- Joel Frohlich
- Institute for Neuromodulation and Neurotechnology, University Hospital and University of Tuebingen, Tuebingen, Germany.
| | - Pedro A M Mediano
- Department of Computing, Imperial College London, London, UK
- Department of Psychology, University of Cambridge, Cambridge, UK
| | - Francesco Bavato
- Experimental and Clinical Pharmacopsychology, Department of Psychiatry, Psychotherapy, and Psychosomatics, Psychiatric University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Alireza Gharabaghi
- Institute for Neuromodulation and Neurotechnology, University Hospital and University of Tuebingen, Tuebingen, Germany
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15
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Bedford P, Hauke DJ, Wang Z, Roth V, Nagy-Huber M, Holze F, Ley L, Vizeli P, Liechti ME, Borgwardt S, Müller F, Diaconescu AO. The effect of lysergic acid diethylamide (LSD) on whole-brain functional and effective connectivity. Neuropsychopharmacology 2023:10.1038/s41386-023-01574-8. [PMID: 37185950 PMCID: PMC10267115 DOI: 10.1038/s41386-023-01574-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 03/22/2023] [Accepted: 03/23/2023] [Indexed: 05/17/2023]
Abstract
Psychedelics have emerged as promising candidate treatments for various psychiatric conditions, and given their clinical potential, there is a need to identify biomarkers that underlie their effects. Here, we investigate the neural mechanisms of lysergic acid diethylamide (LSD) using regression dynamic causal modelling (rDCM), a novel technique that assesses whole-brain effective connectivity (EC) during resting-state functional magnetic resonance imaging (fMRI). We modelled data from two randomised, placebo-controlled, double-blind, cross-over trials, in which 45 participants were administered 100 μg LSD and placebo in two resting-state fMRI sessions. We compared EC against whole-brain functional connectivity (FC) using classical statistics and machine learning methods. Multivariate analyses of EC parameters revealed predominantly stronger interregional connectivity and reduced self-inhibition under LSD compared to placebo, with the notable exception of weakened interregional connectivity and increased self-inhibition in occipital brain regions as well as subcortical regions. Together, these findings suggests that LSD perturbs the Excitation/Inhibition balance of the brain. Notably, whole-brain EC did not only provide additional mechanistic insight into the effects of LSD on the Excitation/Inhibition balance of the brain, but EC also correlated with global subjective effects of LSD and discriminated experimental conditions in a machine learning-based analysis with high accuracy (91.11%), highlighting the potential of using whole-brain EC to decode or predict subjective effects of LSD in the future.
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Affiliation(s)
- Peter Bedford
- Krembil Centre for Neuroinformatics, Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada
| | - Daniel J Hauke
- Centre for Medical Image Computing, Department of Computer Science, University College London, London, UK.
| | - Zheng Wang
- Krembil Centre for Neuroinformatics, Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada
| | - Volker Roth
- Department of Mathematics and Computer Science, University of Basel, Basel, Switzerland
| | - Monika Nagy-Huber
- Department of Mathematics and Computer Science, University of Basel, Basel, Switzerland
| | - Friederike Holze
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine and Department of Clinical Research, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Laura Ley
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine and Department of Clinical Research, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Patrick Vizeli
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine and Department of Clinical Research, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Matthias E Liechti
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine and Department of Clinical Research, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Stefan Borgwardt
- Department of Psychiatry and Psychotherapy, Translational Psychiatry, Lübeck, Germany
| | - Felix Müller
- Department of Psychiatry (UPK), University of Basel, Basel, Switzerland
| | - Andreea O Diaconescu
- Krembil Centre for Neuroinformatics, Centre for Addiction and Mental Health (CAMH), Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
- Department of Psychology, University of Toronto, Toronto, ON, Canada
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16
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Varley TF, Pope M, Faskowitz J, Sporns O. Multivariate information theory uncovers synergistic subsystems of the human cerebral cortex. Commun Biol 2023; 6:451. [PMID: 37095282 PMCID: PMC10125999 DOI: 10.1038/s42003-023-04843-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 04/14/2023] [Indexed: 04/26/2023] Open
Abstract
One of the most well-established tools for modeling the brain is the functional connectivity network, which is constructed from pairs of interacting brain regions. While powerful, the network model is limited by the restriction that only pairwise dependencies are considered and potentially higher-order structures are missed. Here, we explore how multivariate information theory reveals higher-order dependencies in the human brain. We begin with a mathematical analysis of the O-information, showing analytically and numerically how it is related to previously established information theoretic measures of complexity. We then apply the O-information to brain data, showing that synergistic subsystems are widespread in the human brain. Highly synergistic subsystems typically sit between canonical functional networks, and may serve an integrative role. We then use simulated annealing to find maximally synergistic subsystems, finding that such systems typically comprise ≈10 brain regions, recruited from multiple canonical brain systems. Though ubiquitous, highly synergistic subsystems are invisible when considering pairwise functional connectivity, suggesting that higher-order dependencies form a kind of shadow structure that has been unrecognized by established network-based analyses. We assert that higher-order interactions in the brain represent an under-explored space that, accessible with tools of multivariate information theory, may offer novel scientific insights.
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Affiliation(s)
- Thomas F Varley
- School of Informatics, Computing & Engineering, Indiana University, Bloomington, IN, 47405, USA.
- Department of Psychological & Brain Sciences, Indiana University, Bloomington, IN, 47405, USA.
| | - Maria Pope
- School of Informatics, Computing & Engineering, Indiana University, Bloomington, IN, 47405, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA
| | - Joshua Faskowitz
- Department of Psychological & Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA
| | - Olaf Sporns
- School of Informatics, Computing & Engineering, Indiana University, Bloomington, IN, 47405, USA
- Department of Psychological & Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA
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17
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Herzog R, Mediano PAM, Rosas FE, Lodder P, Carhart-Harris R, Perl YS, Tagliazucchi E, Cofre R. A whole-brain model of the neural entropy increase elicited by psychedelic drugs. Sci Rep 2023; 13:6244. [PMID: 37069186 PMCID: PMC10110594 DOI: 10.1038/s41598-023-32649-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 03/30/2023] [Indexed: 04/19/2023] Open
Abstract
Psychedelic drugs, including lysergic acid diethylamide (LSD) and other agonists of the serotonin 2A receptor (5HT2A-R), induce drastic changes in subjective experience, and provide a unique opportunity to study the neurobiological basis of consciousness. One of the most notable neurophysiological signatures of psychedelics, increased entropy in spontaneous neural activity, is thought to be of relevance to the psychedelic experience, mediating both acute alterations in consciousness and long-term effects. However, no clear mechanistic explanation for this entropy increase has been put forward so far. We sought to do this here by building upon a recent whole-brain model of serotonergic neuromodulation, to study the entropic effects of 5HT2A-R activation. Our results reproduce the overall entropy increase observed in previous experiments in vivo, providing the first model-based explanation for this phenomenon. We also found that entropy changes were not uniform across the brain: entropy increased in all regions, but the larger effect were localised in visuo-occipital regions. Interestingly, at the whole-brain level, this reconfiguration was not well explained by 5HT2A-R density, but related closely to the topological properties of the brain's anatomical connectivity. These results help us understand the mechanisms underlying the psychedelic state and, more generally, the pharmacological modulation of whole-brain activity.
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Affiliation(s)
- Rubén Herzog
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Pje Harrington 287, 2360103, Valparaíso, Chile.
| | - Pedro A M Mediano
- Department of Computing, Imperial College London, London, SW7 2DD, UK
- Department of Psychology, University of Cambridge, Cambridge, CB2 3EB, UK
| | - Fernando E Rosas
- Department of Informatics, University of Sussex, Brighton, BN1 9RH, UK
- Centre for Psychedelic Research, Department of Brain Science, Imperial College London, London, SW7 2DD, UK
- Centre for Complexity Science, Imperial College London, London, SW7 2AZ, UK
- Centre for Eudaimonia and Human Flourishing, University of Oxford, Oxford, OX3 9BX, UK
| | - Paul Lodder
- Informatics Institute, University of Amsterdam, P.O. Box 94323, 1090 GH, Amsterdam, The Netherlands
| | - Robin Carhart-Harris
- Centre for Psychedelic Research, Department of Brain Science, Imperial College London, London, SW7 2DD, UK
- Psychedelics Division, Neuroscape, University of California San Francisco, San Francisco, CA, USA
| | - Yonatan Sanz Perl
- Computational Neuroscience Group, Center for Brain and Cognition, Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona, Catalonia, Spain
- Universidad de San Andres, Buenos Aires, Argentina
- Institut du Cerveau et de la Moelle épinière, ICM, Paris, France
| | - Enzo Tagliazucchi
- Buenos Aires Physics Institute and Physics Department, University of Buenos Aires, Buenos Aires, Argentina
- Latin American Brain Health Institute (BrainLat), Universidad Adolfo Ibáñez, Santiago, Chile
| | - Rodrigo Cofre
- CIMFAV-Ingemat, Facultad de Ingeniería, Universidad de Valparaíso, Valparaíso, Chile
- Institute of Neuroscience (NeuroPSI), Paris-Saclay University, Centre National de la Recherche Scientifique (CNRS), Gif-sur-Yvette, France
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18
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Kringelbach ML, Perl YS, Tagliazucchi E, Deco G. Toward naturalistic neuroscience: Mechanisms underlying the flattening of brain hierarchy in movie-watching compared to rest and task. SCIENCE ADVANCES 2023; 9:eade6049. [PMID: 36638163 PMCID: PMC9839335 DOI: 10.1126/sciadv.ade6049] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 12/13/2022] [Indexed: 06/04/2023]
Abstract
Identifying the functional specialization of the brain has moved from using cognitive tasks and resting state to using ecological relevant, naturalistic movies. We leveraged a large-scale neuroimaging dataset to directly investigate the hierarchical reorganization of functional brain activity when watching naturalistic films compared to performing seven cognitive tasks and resting. A thermodynamics-inspired whole-brain model paradigm revealed the generative underlying mechanisms for changing the balance in causal interactions between brain regions in different conditions. Paradoxically, the hierarchy is flatter for movie-watching, and the level of nonreversibility is significantly smaller in comparison to both rest and tasks, where the latter in turn have the highest levels of hierarchy and nonreversibility. The underlying mechanisms were revealed by the model-based generative effective connectivity (GEC). Naturalistic films could therefore provide a fast and convenient way to measure important changes in GEC (integrating functional and anatomical connectivity) found in, for example, neuropsychiatric disorders. Overall, this study demonstrates the benefits of moving toward a more naturalistic neuroscience.
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Affiliation(s)
- Morten L. Kringelbach
- Centre for Eudaimonia and Human Flourishing, Linacre College, University of Oxford, Oxford, UK
- Department of Psychiatry, University of Oxford, Oxford, UK
- Center for Music in the Brain, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Yonatan Sanz Perl
- Center for Brain and Cognition, Computational Neuroscience Group, Department of Information and Communication Technologies, Universitat Pompeu Fabra, Roc Boronat 138, Barcelona 08018, Spain
- Department of Physics, University of Buenos Aires, Buenos Aires, Argentina
| | - Enzo Tagliazucchi
- Department of Physics, University of Buenos Aires, Buenos Aires, Argentina
- Latin American Brain Health Institute (BrainLat), Universidad Adolfo Ibanez, Santiago, Chile
| | - Gustavo Deco
- Center for Brain and Cognition, Computational Neuroscience Group, Department of Information and Communication Technologies, Universitat Pompeu Fabra, Roc Boronat 138, Barcelona 08018, Spain
- Institució Catalana de la Recerca i Estudis Avançats (ICREA), Passeig Lluís Companys 23, Barcelona 08010, Spain
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19
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Marguilho M, Figueiredo I, Castro-Rodrigues P. A unified model of ketamine's dissociative and psychedelic properties. J Psychopharmacol 2023; 37:14-32. [PMID: 36527355 PMCID: PMC9834329 DOI: 10.1177/02698811221140011] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Ketamine is an N-methyl-d-aspartate antagonist which is increasingly being researched and used as a treatment for depression. In low doses, it can cause a transitory modification in consciousness which was classically labelled as 'dissociation'. However, ketamine is also commonly classified as an atypical psychedelic and it has been recently reported that ego dissolution experiences during ketamine administration are associated with greater antidepressant response. Neuroimaging studies have highlighted several similarities between the effects of ketamine and those of serotonergic psychedelics in the brain; however, no unified account has been proposed for ketamine's multi-level effects - from molecular to network and psychological levels. Here, we propose that the fast, albeit transient, antidepressant effects observed after ketamine infusions are mainly driven by its acute modulation of reward circuits and sub-acute increase in neuroplasticity, while its dissociative and psychedelic properties are driven by dose- and context-dependent disruption of large-scale functional networks. Computationally, as nodes of the salience network (SN) represent high-level priors about the body ('minimal' self) and nodes of the default-mode network (DMN) represent the highest-level priors about narrative self-experience ('biographical' self), we propose that transitory SN desegregation and disintegration accounts for ketamine's 'dissociative' state, while transitory DMN desegregation and disintegration accounts for ketamine's 'psychedelic' state. In psychedelic-assisted psychotherapy, a relaxation of the highest-level beliefs with psychotherapeutic support may allow a revision of pathological self-representation models, for which neuroplasticity plays a permissive role. Our account provides a multi-level rationale for using the psychedelic properties of ketamine to increase its long-term benefits.
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Affiliation(s)
| | | | - Pedro Castro-Rodrigues
- Centro Hospitalar Psiquiátrico de Lisboa, Lisbon, Portugal,NOVA Medical School, NMS, Universidade Nova de Lisboa, Lisbon, Portugal,Pedro Castro-Rodrigues, Centro Hospitalar Psiquiátrico de Lisboa, Avenida do Brasil, 53, Lisbon, 1749-002, Portugal.
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20
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Schizophrenia and psychedelic state: Dysconnection versus hyper-connection. A perspective on two different models of psychosis stemming from dysfunctional integration processes. Mol Psychiatry 2023; 28:59-67. [PMID: 35931756 DOI: 10.1038/s41380-022-01721-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 07/15/2022] [Accepted: 07/22/2022] [Indexed: 01/07/2023]
Abstract
Psychotic symptoms are a cross-sectional dimension affecting multiple diagnostic categories, despite schizophrenia represents the prototype of psychoses. Initially, dopamine was considered the most involved molecule in the neurobiology of schizophrenia. Over the next years, several biological factors were added to the discussion helping to constitute the concept of schizophrenia as a disease marked by a deficit of functional integration, contributing to the formulation of the Dysconnection Hypothesis in 1995. Nowadays the notion of dysconnection persists in the conceptualization of schizophrenia enriched by neuroimaging findings which corroborate the hypothesis. At the same time, in recent years, psychedelics received a lot of attention by the scientific community and astonishing findings emerged about the rearrangement of brain networks under the effect of these compounds. Specifically, a global decrease in functional connectivity was found, highlighting the disintegration of preserved and functional circuits and an increase of overall connectivity in the brain. The aim of this paper is to compare the biological bases of dysconnection in schizophrenia with the alterations of neuronal cyto-architecture induced by psychedelics and the consequent state of cerebral hyper-connection. These two models of psychosis, despite diametrically opposed, imply a substantial deficit of integration of neural signaling reached through two opposite paths.
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21
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Kotler S, Mannino M, Kelso S, Huskey R. First few seconds for flow: A comprehensive proposal of the neurobiology and neurodynamics of state onset. Neurosci Biobehav Rev 2022; 143:104956. [PMID: 36368525 DOI: 10.1016/j.neubiorev.2022.104956] [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: 07/03/2022] [Revised: 10/22/2022] [Accepted: 11/06/2022] [Indexed: 11/09/2022]
Abstract
Flow is a cognitive state that manifests when there is complete attentional absorption while performing a task. Flow occurs when certain internal as well as external conditions are present, including intense concentration, a sense of control, feedback, and a balance between the challenge of the task and the relevant skillset. Phenomenologically, flow is accompanied by a loss of self-consciousness, seamless integration of action and awareness, and acute changes in time perception. Research has begun to uncover some of the neurophysiological correlates of flow, as well as some of the state's neuromodulatory processes. We comprehensively review this work and consider the neurodynamics of the onset of the state, considering large-scale brain networks, as well as dopaminergic, noradrenergic, and endocannabinoid systems. To accomplish this, we outline an evidence-based hypothetical situation, and consider the flow state in a broader context including other profound alterations in consciousness, such as the psychedelic state and the state of traumatic stress that can induce PTSD. We present a broad theoretical framework which may motivate future testable hypotheses.
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Affiliation(s)
| | | | - Scott Kelso
- Human Brain & Behavior Laboratory, Center for Complex Systems and Brain Sciences, Florida Atlantic University, United States; Intelligent Systems Research Centre, Ulster University, Derry∼Londonderry, North Ireland
| | - Richard Huskey
- Cognitive Communication Science Lab, Department of Communication, University of California Davis, United States; Cognitive Science Program, University of California Davis, United States; Center for Mind and Brain, University of California Davis, United States.
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22
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Rajpal H, Mediano PAM, Rosas FE, Timmermann CB, Brugger S, Muthukumaraswamy S, Seth AK, Bor D, Carhart-Harris RL, Jensen HJ. Psychedelics and schizophrenia: Distinct alterations to Bayesian inference. Neuroimage 2022; 263:119624. [PMID: 36108798 DOI: 10.1016/j.neuroimage.2022.119624] [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: 05/10/2022] [Revised: 08/11/2022] [Accepted: 09/10/2022] [Indexed: 11/28/2022] Open
Abstract
Schizophrenia and states induced by certain psychotomimetic drugs may share some physiological and phenomenological properties, but they differ in fundamental ways: one is a crippling chronic mental disease, while the others are temporary, pharmacologically-induced states presently being explored as treatments for mental illnesses. Building towards a deeper understanding of these different alterations of normal consciousness, here we compare the changes in neural dynamics induced by LSD and ketamine (in healthy volunteers) against those associated with schizophrenia, as observed in resting-state M/EEG recordings. While both conditions exhibit increased neural signal diversity, our findings reveal that this is accompanied by an increased transfer entropy from the front to the back of the brain in schizophrenia, versus an overall reduction under the two drugs. Furthermore, we show that these effects can be reproduced via different alterations of standard Bayesian inference applied on a computational model based on the predictive processing framework. In particular, the effects observed under the drugs are modelled as a reduction of the precision of the priors, while the effects of schizophrenia correspond to an increased precision of sensory information. These findings shed new light on the similarities and differences between schizophrenia and two psychotomimetic drug states, and have potential implications for the study of consciousness and future mental health treatments.
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Affiliation(s)
- Hardik Rajpal
- Centre for Complexity Science, Imperial College London, South Kensington, London, United Kingdom; Department of Mathematics, Imperial College London, South Kensington, London, United Kingdom; Public Policy Program, The Alan Turing Institute, London, United Kingdom.
| | - Pedro A M Mediano
- Department of Computing, Imperial College London, South Kensington, London, United Kingdom; Department of Psychology, University of Cambridge, Cambridge, United Kingdom; Department of Psychology, Queen Mary University of London, London, United Kingdom.
| | - Fernando E Rosas
- Centre for Complexity Science, Imperial College London, South Kensington, London, United Kingdom; Centre for Psychedelic Research, Department of Brain Sciences, Imperial College London, London, United Kingdom; Data Science Institute, Imperial College London, London, United Kingdom; Department of Informatics, University of Sussex, Brighton, United Kingdom
| | - Christopher B Timmermann
- Centre for Psychedelic Research, Department of Brain Sciences, Imperial College London, London, United Kingdom
| | - Stefan Brugger
- Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff University, United Kingdom; Centre for Academic Mental Health, Bristol Medical School, University of Bristol, United Kingdom
| | | | - Anil K Seth
- School of Engineering and Informatics, University of Sussex, United Kingdom; CIFAR Program on Brain, Mind, and Consciousness, Toronto, Canada
| | - Daniel Bor
- Department of Psychology, University of Cambridge, Cambridge, United Kingdom; Department of Psychology, Queen Mary University of London, London, United Kingdom
| | - Robin L Carhart-Harris
- Centre for Psychedelic Research, Department of Brain Sciences, Imperial College London, London, United Kingdom; Psychedelics Division, Neuroscape, Department of Neurology, University of California San Francisco, US
| | - Henrik J Jensen
- Centre for Complexity Science, Imperial College London, South Kensington, London, United Kingdom; Department of Mathematics, Imperial College London, South Kensington, London, United Kingdom; Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
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23
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Mediano PAM, Rosas FE, Bor D, Seth AK, Barrett AB. The strength of weak integrated information theory. Trends Cogn Sci 2022; 26:646-655. [PMID: 35659757 DOI: 10.1016/j.tics.2022.04.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 04/21/2022] [Accepted: 04/21/2022] [Indexed: 12/27/2022]
Abstract
The integrated information theory of consciousness (IIT) is divisive: while some believe it provides an unprecedentedly powerful approach to address the 'hard problem', others dismiss it on grounds that it is untestable. We argue that the appeal and applicability of IIT can be greatly widened if we distinguish two flavours of the theory: strong IIT, which identifies consciousness with specific properties associated with maxima of integrated information; and weak IIT, which tests pragmatic hypotheses relating aspects of consciousness to broader measures of information dynamics. We review challenges for strong IIT, explain how existing empirical findings are well explained by weak IIT without needing to commit to the entirety of strong IIT, and discuss the outlook for both flavours of IIT.
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Affiliation(s)
- Pedro A M Mediano
- Department of Psychology, University of Cambridge, Cambridge, UK; Department of Psychology, Queen Mary University of London, London, UK.
| | - Fernando E Rosas
- Centre for Psychedelic Research, Imperial College London, London, UK; Data Science Institute, Imperial College London, London, UK; Centre for Complexity Science, Imperial College London, London, UK
| | - Daniel Bor
- Department of Psychology, University of Cambridge, Cambridge, UK; Department of Psychology, Queen Mary University of London, London, UK
| | - Anil K Seth
- Sackler Centre for Consciousness Science, Department of Informatics, University of Sussex, Brighton, UK; CIFAR Program on Brain, Mind, and Consciousness, Toronto, Canada
| | - Adam B Barrett
- Sackler Centre for Consciousness Science, Department of Informatics, University of Sussex, Brighton, UK; The Data Intensive Science Centre, Department of Informatics, University of Sussex, Brighton, UK.
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24
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Lehmann M, Neumann C, Wasserthal S, Delis A, Schultz J, Hurlemann R, Ettinger U. Ketamine increases fronto-posterior functional connectivity during meta-perceptual confidence ratings. Behav Brain Res 2022; 430:113925. [DOI: 10.1016/j.bbr.2022.113925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 04/12/2022] [Accepted: 05/09/2022] [Indexed: 11/17/2022]
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25
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Girn M, Roseman L, Bernhardt B, Smallwood J, Carhart-Harris R, Nathan Spreng R. Serotonergic psychedelic drugs LSD and psilocybin reduce the hierarchical differentiation of unimodal and transmodal cortex. Neuroimage 2022; 256:119220. [PMID: 35483649 DOI: 10.1016/j.neuroimage.2022.119220] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 04/03/2022] [Accepted: 04/15/2022] [Indexed: 12/20/2022] Open
Abstract
Lysergic acid diethylamide (LSD) and psilocybin are serotonergic psychedelic compounds with potential in the treatment of mental health disorders. Past neuroimaging investigations have revealed that both compounds can elicit significant changes to whole-brain functional organization and dynamics. A recent proposal linked past findings into a unified model and hypothesized reduced whole-brain hierarchical organization as a key mechanism underlying the psychedelic state, but this has yet to be directly tested. We applied a non-linear dimensionality reduction technique previously used to map hierarchical connectivity gradients to assess cortical organization in the LSD and psilocybin state from two previously published pharmacological resting-state fMRI datasets (N = 15 and 9, respectively). Results supported our primary hypothesis: The principal gradient of cortical connectivity, describing a hierarchy from unimodal to transmodal cortex, was significantly flattened under both drugs relative to their respective placebo conditions. Between-condition contrasts revealed that this was driven by a reduction of functional differentiation at both hierarchical extremes - default and frontoparietal networks at the upper end, and somatomotor at the lower. Gradient-based connectivity mapping indicated that this was underpinned by a disruption of modular unimodal connectivity and increased unimodal-transmodal crosstalk. Results involving the second and third gradient, which, respectively represent axes of sensory and executive differentiation, also showed significant alterations across both drugs. These findings provide support for a recent mechanistic model of the psychedelic state relevant to therapeutic applications of psychedelics. More fundamentally, we provide the first evidence that macroscale connectivity gradients are sensitive to an acute pharmacological manipulation, supporting a role for psychedelics as scientific tools to perturb cortical functional organization.
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Affiliation(s)
- Manesh Girn
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 Rue Université, Montreal, QC H3A 2B4, Canada.
| | - Leor Roseman
- Centre for Psychedelic Research, Department of Brain Sciences, Imperial College London, London, United Kingdom
| | - Boris Bernhardt
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 Rue Université, Montreal, QC H3A 2B4, Canada
| | | | - Robin Carhart-Harris
- Neuroscape Psychedelics Division, Department of Neurology, University of California San Francisco, San Francisco, CA, United States
| | - R Nathan Spreng
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 Rue Université, Montreal, QC H3A 2B4, Canada; Departments of Psychiatry and Psychology, McGill University, Montreal, QC, Canada; Douglas Mental Health University Institute, Verdun, QC, Canada; McConnell Brain Imaging Centre, McGill University, Montreal, QC, Canada
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26
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Zamani A, Carhart-Harris R, Christoff K. Prefrontal contributions to the stability and variability of thought and conscious experience. Neuropsychopharmacology 2022; 47:329-348. [PMID: 34545195 PMCID: PMC8616944 DOI: 10.1038/s41386-021-01147-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 08/02/2021] [Accepted: 08/03/2021] [Indexed: 02/08/2023]
Abstract
The human prefrontal cortex is a structurally and functionally heterogenous brain region, including multiple subregions that have been linked to different large-scale brain networks. It contributes to a broad range of mental phenomena, from goal-directed thought and executive functions to mind-wandering and psychedelic experience. Here we review what is known about the functions of different prefrontal subregions and their affiliations with large-scale brain networks to examine how they may differentially contribute to the diversity of mental phenomena associated with prefrontal function. An important dimension that distinguishes across different kinds of conscious experience is the stability or variability of mental states across time. This dimension is a central feature of two recently introduced theoretical frameworks-the dynamic framework of thought (DFT) and the relaxed beliefs under psychedelics (REBUS) model-that treat neurocognitive dynamics as central to understanding and distinguishing between different mental phenomena. Here, we bring these two frameworks together to provide a synthesis of how prefrontal subregions may differentially contribute to the stability and variability of thought and conscious experience. We close by considering future directions for this work.
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Affiliation(s)
- Andre Zamani
- Department of Psychology, University of British Columbia, 2136 West Mall, Vancouver, BC, Canada.
| | - Robin Carhart-Harris
- Centre for Psychedelic Research, Department of Brain Sciences, Imperial College London, London, UK
| | - Kalina Christoff
- Department of Psychology, University of British Columbia, 2136 West Mall, Vancouver, BC, Canada
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27
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Beating Pain with Psychedelics: Matter over Mind? Neurosci Biobehav Rev 2021; 134:104482. [PMID: 34922987 DOI: 10.1016/j.neubiorev.2021.12.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 11/19/2021] [Accepted: 12/04/2021] [Indexed: 02/08/2023]
Abstract
Basic pain research has shed light on key cellular and molecular mechanisms underlying nociceptive and phenomenological aspects of pain. Despite these advances, [[we still yearn for] the discovery of novel therapeutic strategies to address the unmet needs of about 70% of chronic neuropathic pain patients whose pain fails to respond to opioids as well as to other conventional analgesic agents. Importantly, a substantial body of clinical observations over the past decade cumulatively suggests that the psychedelic class of drugs may possess heuristic value for understanding and treating chronic pain conditions. The present review presents a theoretical framework for hitherto insufficiently understood neuroscience-based mechanisms of psychedelics' potential analgesic effects. To that end, searches of PubMed-indexed journals were performed using the following Medical Subject Headings' terms: pain, analgesia, inflammatory, brain connectivity, ketamine, psilocybin, functional imaging, and dendrites. Recursive sets of scientific and clinical evidence extracted from this literature review were summarized within the following key areas: (1) studies employing psychedelics for alleviation of physical and emotional pain; (2) potential neuro-restorative effects of psychedelics to remediate the impaired connectivity underlying the dissociation between pain-related conscious states/cognitions and the subcortical activity/function leading to the eventual chronicity through immediate and long-term effects on dentritic plasticity; (3) anti-neuroinflammatory and pro-immunomodulatory actions of psychedelics as the may pertain to the role of these factors in the pathogenesis of neuropathic pain; (4) safety, legal, and ethical consideration inherent in psychedelics' pharmacotherapy. In addition to direct beneficial effects in terms of reduction of pain and suffering, psychedelics' inclusion in the analgesic armamentarium will contribute to deeper and more sophisticated insights not only into pain syndromes but also into frequently comorbid psychiatric condition associated with emotional pain, e.g., depressive and anxiety disorders. Further inquiry is clearly warranted into the above areas that have potential to evolve into further elucidate the mechanisms of chronic pain and affective disorders, and lead to the development of innovative, safe, and more efficacious neurobiologically-based therapeutic approaches.
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28
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Bachmann T. Representational 'touch' and modulatory 'retouch'-two necessary neurobiological processes in thalamocortical interaction for conscious experience. Neurosci Conscious 2021; 2021:niab045. [PMID: 34925911 PMCID: PMC8672242 DOI: 10.1093/nc/niab045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 11/16/2021] [Accepted: 11/30/2021] [Indexed: 12/01/2022] Open
Abstract
Theories of consciousness using neurobiological data or being influenced by these data have been focused either on states of consciousness or contents of consciousness. These theories have occasionally used evidence from psychophysical phenomena where conscious experience is a dependent experimental variable. However, systematic catalog of many such relevant phenomena has not been offered in terms of these theories. In the perceptual retouch theory of thalamocortical interaction, recently developed to become a blend with the dendritic integration theory, consciousness states and contents of consciousness are explained by the same mechanism. This general-purpose mechanism has modulation of the cortical layer-5 pyramidal neurons that represent contents of consciousness as its core. As a surplus, many experimental psychophysical phenomena of conscious perception can be explained by the workings of this mechanism. Historical origins and current views inherent in this theory are presented and reviewed.
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Affiliation(s)
- Talis Bachmann
- Department of Penal Law, Laboratory of Cognitive Neuroscience, School of Law, University of Tartu (Tallinn Branch), Kaarli puiestee 3, Tallinn 10119, Estonia
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29
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Vilca-Melendez S, Uthaug MV, Griffin JL. 1H Nuclear Magnetic Resonance: A Future Approach to the Metabolic Profiling of Psychedelics in Human Biofluids? Front Psychiatry 2021; 12:742856. [PMID: 34966300 PMCID: PMC8710695 DOI: 10.3389/fpsyt.2021.742856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 11/18/2021] [Indexed: 11/25/2022] Open
Abstract
While psychedelics may have therapeutic potential for treating mental health disorders such as depression, further research is needed to better understand their biological effects and mechanisms of action when considering the development of future novel therapy approaches. Psychedelic research could potentially benefit from the integration of metabonomics by proton nuclear magnetic resonance (1H NMR) spectroscopy which is an analytical chemistry-based approach that can measure the breakdown of drugs into their metabolites and their metabolic consequences from various biofluids. We have performed a systematic review with the primary aim of exploring published literature where 1H NMR analysed psychedelic substances including psilocin, lysergic acid diethylamide (LSD), LSD derivatives, N,N-dimethyltryptamine (DMT), 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) and bufotenin. The second aim was to assess the benefits and limitations of 1H NMR spectroscopy-based metabolomics as a tool in psychedelic research and the final aim was to explore potential future directions. We found that the most current use of 1H NMR in psychedelic research has been for the structural elucidation and analytical characterisation of psychedelic molecules and that no papers used 1H NMR in the metabolic profiling of biofluids, thus exposing a current research gap and the underuse of 1H NMR. The efficacy of 1H NMR spectroscopy was also compared to mass spectrometry, where both metabonomics techniques have previously shown to be appropriate for biofluid analysis in other applications. Additionally, potential future directions for psychedelic research were identified as real-time NMR, in vivo 1H nuclear magnetic resonance spectroscopy (MRS) and 1H NMR studies of the gut microbiome. Further psychedelic studies need to be conducted that incorporate the use of 1H NMR spectroscopy in the analysis of metabolites both in the peripheral biofluids and in vivo to determine whether it will be an effective future approach for clinical and naturalistic research.
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Affiliation(s)
- Sylvana Vilca-Melendez
- Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Malin V. Uthaug
- The Centre for Psychedelic Research, Department of Brain Sciences, Faculty of Medicine, Imperial College London, London, United Kingdom
- Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands
| | - Julian L. Griffin
- Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London, United Kingdom
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30
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Sarasso S, Casali AG, Casarotto S, Rosanova M, Sinigaglia C, Massimini M. Consciousness and complexity: a consilience of evidence. Neurosci Conscious 2021; 2021:niab023. [PMID: 38496724 PMCID: PMC10941977 DOI: 10.1093/nc/niab023] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 06/19/2021] [Accepted: 07/29/2021] [Indexed: 03/19/2024] Open
Abstract
Over the last years, a surge of empirical studies converged on complexity-related measures as reliable markers of consciousness across many different conditions, such as sleep, anesthesia, hallucinatory states, coma, and related disorders. Most of these measures were independently proposed by researchers endorsing disparate frameworks and employing different methods and techniques. Since this body of evidence has not been systematically reviewed and coherently organized so far, this positive trend has remained somewhat below the radar. The aim of this paper is to make this consilience of evidence in the science of consciousness explicit. We start with a systematic assessment of the growing literature on complexity-related measures and identify their common denominator, tracing it back to core theoretical principles and predictions put forward more than 20 years ago. In doing this, we highlight a consistent trajectory spanning two decades of consciousness research and provide a provisional taxonomy of the present literature. Finally, we consider all of the above as a positive ground to approach new questions and devise future experiments that may help consolidate and further develop a promising field where empirical research on consciousness appears to have, so far, naturally converged.
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Affiliation(s)
- Simone Sarasso
- Department of Biomedical and Clinical Sciences ‘L. Sacco’, University of Milan, Milan 20157, Italy
| | - Adenauer Girardi Casali
- Instituto de Ciência e Tecnologia, Universidade Federal de São Paulo, Sao Jose dos Campos, 12247-014, Brazil
| | - Silvia Casarotto
- Department of Biomedical and Clinical Sciences ‘L. Sacco’, University of Milan, Milan 20157, Italy
- IRCCS Fondazione Don Carlo Gnocchi ONLUS, Milan 20148, Italy
| | - Mario Rosanova
- Department of Biomedical and Clinical Sciences ‘L. Sacco’, University of Milan, Milan 20157, Italy
| | | | - Marcello Massimini
- Department of Biomedical and Clinical Sciences ‘L. Sacco’, University of Milan, Milan 20157, Italy
- IRCCS Fondazione Don Carlo Gnocchi ONLUS, Milan 20148, Italy
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31
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Greco A, Gallitto G, D’Alessandro M, Rastelli C. Increased Entropic Brain Dynamics during DeepDream-Induced Altered Perceptual Phenomenology. ENTROPY (BASEL, SWITZERLAND) 2021; 23:839. [PMID: 34208923 PMCID: PMC8306862 DOI: 10.3390/e23070839] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 06/20/2021] [Accepted: 06/23/2021] [Indexed: 01/02/2023]
Abstract
In recent years, the use of psychedelic drugs to study brain dynamics has flourished due to the unique opportunity they offer to investigate the neural mechanisms of conscious perception. Unfortunately, there are many difficulties to conduct experiments on pharmacologically-induced hallucinations, especially regarding ethical and legal issues. In addition, it is difficult to isolate the neural effects of psychedelic states from other physiological effects elicited by the drug ingestion. Here, we used the DeepDream algorithm to create visual stimuli that mimic the perception of hallucinatory states. Participants were first exposed to a regular video, followed by its modified version, while recording electroencephalography (EEG). Results showed that the frontal region's activity was characterized by a higher entropy and lower complexity during the modified video, with respect to the regular one, at different time scales. Moreover, we found an increased undirected connectivity and a greater level of entropy in functional connectivity networks elicited by the modified video. These findings suggest that DeepDream and psychedelic drugs induced similar altered brain patterns and demonstrate the potential of adopting this method to study altered perceptual phenomenology in neuroimaging research.
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Affiliation(s)
- Antonino Greco
- Department of Psychology and Cognitive Science, University of Trento, 38068 Rovereto, Italy;
- Centre for Integrative Neuroscience, University of Tübingen, 72076 Tübingen, Germany
- MEG Center, University of Tübingen, 72076 Tübingen, Germany
| | - Giuseppe Gallitto
- Department of Neurology, University Hospital Essen, 45147 Essen, Germany;
| | - Marco D’Alessandro
- Institute of Cognitive Sciences and Technologies, National Research Council, 00185 Rome, Italy;
| | - Clara Rastelli
- Department of Psychology and Cognitive Science, University of Trento, 38068 Rovereto, Italy;
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32
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de Wit H, Bershad AK, Hutchison W, Bremmer M. Can MDMA Change Sociopolitical Values? Insights From a Research Participant. Biol Psychiatry 2021; 89:e61-e62. [PMID: 33814127 DOI: 10.1016/j.biopsych.2021.01.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 01/25/2021] [Accepted: 01/27/2021] [Indexed: 12/22/2022]
Affiliation(s)
- Harriet de Wit
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, Chicago, Illinois.
| | - Anya K Bershad
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, California
| | - William Hutchison
- Department of English Language and Literature, University of Chicago, Chicago, Illinois
| | - Michael Bremmer
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, Chicago, Illinois
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33
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Deco G, Vidaurre D, Kringelbach ML. Revisiting the global workspace orchestrating the hierarchical organization of the human brain. Nat Hum Behav 2021; 5:497-511. [PMID: 33398141 PMCID: PMC8060164 DOI: 10.1038/s41562-020-01003-6] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 10/12/2020] [Indexed: 12/31/2022]
Abstract
A central challenge in neuroscience is how the brain organizes the information necessary to orchestrate behaviour. Arguably, this whole-brain orchestration is carried out by a core subset of integrative brain regions, a 'global workspace', but its constitutive regions remain unclear. We quantified the global workspace as the common regions across seven tasks as well as rest, in a common 'functional rich club'. To identify this functional rich club, we determined the information flow between brain regions by means of a normalized directed transfer entropy framework applied to multimodal neuroimaging data from 1,003 healthy participants and validated in participants with retest data. This revealed a set of regions orchestrating information from perceptual, long-term memory, evaluative and attentional systems. We confirmed the causal significance and robustness of our results by systematically lesioning a generative whole-brain model. Overall, this framework describes a complex choreography of the functional hierarchical organization of the human brain.
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Affiliation(s)
- Gustavo Deco
- Center for Brain and Cognition, Computational Neuroscience Group, Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona, Spain.
- Institució Catalana de la Recerca i Estudis Avançats (ICREA), Barcelona, Spain.
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
- School of Psychological Sciences, Monash University, Clayton, Victoria, Australia.
| | - Diego Vidaurre
- Department of Psychiatry, University of Oxford, Oxford, UK
- Center for Functionally Integrative Neuroscience, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Morten L Kringelbach
- Department of Psychiatry, University of Oxford, Oxford, UK.
- Centre for Eudaimonia and Human Flourishing, University of Oxford, Oxford, UK.
- Center for Music in the Brain, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
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34
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Frohlich J, Toker D, Monti MM. Consciousness among delta waves: a paradox? Brain 2021; 144:2257-2277. [PMID: 33693596 DOI: 10.1093/brain/awab095] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 02/12/2021] [Accepted: 02/25/2021] [Indexed: 01/29/2023] Open
Abstract
A common observation in EEG research is that consciousness vanishes with the appearance of delta (1 - 4 Hz) waves, particularly when those waves are high amplitude. High amplitude delta oscillations are very frequently observed in states of diminished consciousness, including slow wave sleep, anaesthesia, generalised epileptic seizures, and disorders of consciousness such as coma and vegetative state. This strong correlation between loss of consciousness and high amplitude delta oscillations is thought to stem from the widespread cortical deactivation that occurs during the "down states" or troughs of these slow oscillations. Recently, however, many studies have reported the presence of prominent delta activity during conscious states, which casts doubt on the hypothesis that high amplitude delta oscillations are an indicator of unconsciousness. These studies include work in Angelman syndrome, epilepsy, behavioural responsiveness during propofol anaesthesia, postoperative delirium, and states of dissociation from the environment such as dreaming and powerful psychedelic states. The foregoing studies complement an older, yet largely unacknowledged, body of literature that has documented awake, conscious patients with high amplitude delta oscillations in clinical reports from Rett syndrome, Lennox-Gastaut syndrome, schizophrenia, mitochondrial diseases, hepatic encephalopathy, and nonconvulsive status epilepticus. At the same time, a largely parallel body of recent work has reported convincing evidence that the complexity or entropy of EEG and magnetoencephalogram or MEG signals strongly relates to an individual's level of consciousness. Having reviewed this literature, we discuss plausible mechanisms that would resolve the seeming contradiction between high amplitude delta oscillations and consciousness. We also consider implications concerning theories of consciousness, such as integrated information theory and the entropic brain hypothesis. Finally, we conclude that false inferences of unconscious states can be best avoided by examining measures of electrophysiological complexity in addition to spectral power.
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Affiliation(s)
- Joel Frohlich
- Department of Psychology, University of California Los Angeles, 3423 Franz Hall, Los Angeles, California 90095, USA
| | - Daniel Toker
- Department of Psychology, University of California Los Angeles, 3423 Franz Hall, Los Angeles, California 90095, USA
| | - Martin M Monti
- Department of Psychology, University of California Los Angeles, 3423 Franz Hall, Los Angeles, California 90095, USA.,Department of Neurosurgery, UCLA Brain Injury Research Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California 90095, USA
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35
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Stochastic synchronization of dynamics on the human connectome. Neuroimage 2021; 229:117738. [PMID: 33454400 DOI: 10.1016/j.neuroimage.2021.117738] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 11/30/2020] [Accepted: 01/09/2021] [Indexed: 11/20/2022] Open
Abstract
Synchronization is a collective mechanism by which oscillatory networks achieve their functions. Factors driving synchronization include the network's topological and dynamical properties. However, how these factors drive the emergence of synchronization in the presence of potentially disruptive external inputs like stochastic perturbations is not well understood, particularly for real-world systems such as the human brain. Here, we aim to systematically address this problem using a large-scale model of the human brain network (i.e., the human connectome). The results show that the model can produce complex synchronization patterns transitioning between incoherent and coherent states. When nodes in the network are coupled at some critical strength, a counterintuitive phenomenon emerges where the addition of noise increases the synchronization of global and local dynamics, with structural hub nodes benefiting the most. This stochastic synchronization effect is found to be driven by the intrinsic hierarchy of neural timescales of the brain and the heterogeneous complex topology of the connectome. Moreover, the effect coincides with clustering of node phases and node frequencies and strengthening of the functional connectivity of some of the connectome's subnetworks. Overall, the work provides broad theoretical insights into the emergence and mechanisms of stochastic synchronization, highlighting its putative contribution in achieving network integration underpinning brain function.
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36
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Inserra A, De Gregorio D, Gobbi G. Psychedelics in Psychiatry: Neuroplastic, Immunomodulatory, and Neurotransmitter Mechanisms. Pharmacol Rev 2020; 73:202-277. [PMID: 33328244 DOI: 10.1124/pharmrev.120.000056] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Mounting evidence suggests safety and efficacy of psychedelic compounds as potential novel therapeutics in psychiatry. Ketamine has been approved by the Food and Drug Administration in a new class of antidepressants, and 3,4-methylenedioxymethamphetamine (MDMA) is undergoing phase III clinical trials for post-traumatic stress disorder. Psilocybin and lysergic acid diethylamide (LSD) are being investigated in several phase II and phase I clinical trials. Hence, the concept of psychedelics as therapeutics may be incorporated into modern society. Here, we discuss the main known neurobiological therapeutic mechanisms of psychedelics, which are thought to be mediated by the effects of these compounds on the serotonergic (via 5-HT2A and 5-HT1A receptors) and glutamatergic [via N-methyl-d-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors] systems. We focus on 1) neuroplasticity mediated by the modulation of mammalian target of rapamycin-, brain-derived neurotrophic factor-, and early growth response-related pathways; 2) immunomodulation via effects on the hypothalamic-pituitary-adrenal axis, nuclear factor ĸB, and cytokines such as tumor necrosis factor-α and interleukin 1, 6, and 10 production and release; and 3) modulation of serotonergic, dopaminergic, glutamatergic, GABAergic, and norepinephrinergic receptors, transporters, and turnover systems. We discuss arising concerns and ways to assess potential neurobiological changes, dependence, and immunosuppression. Although larger cohorts are required to corroborate preliminary findings, the results obtained so far are promising and represent a critical opportunity for improvement of pharmacotherapies in psychiatry, an area that has seen limited therapeutic advancement in the last 20 years. Studies are underway that are trying to decouple the psychedelic effects from the therapeutic effects of these compounds. SIGNIFICANCE STATEMENT: Psychedelic compounds are emerging as potential novel therapeutics in psychiatry. However, understanding of molecular mechanisms mediating improvement remains limited. This paper reviews the available evidence concerning the effects of psychedelic compounds on pathways that modulate neuroplasticity, immunity, and neurotransmitter systems. This work aims to be a reference for psychiatrists who may soon be faced with the possibility of prescribing psychedelic compounds as medications, helping them assess which compound(s) and regimen could be most useful for decreasing specific psychiatric symptoms.
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Affiliation(s)
- Antonio Inserra
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, Montreal, Quebec, Canada
| | - Danilo De Gregorio
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, Montreal, Quebec, Canada
| | - Gabriella Gobbi
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, Montreal, Quebec, Canada
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37
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Leptourgos P, Fortier-Davy M, Carhart-Harris R, Corlett PR, Dupuis D, Halberstadt AL, Kometer M, Kozakova E, LarØi F, Noorani TN, Preller KH, Waters F, Zaytseva Y, Jardri R. Hallucinations Under Psychedelics and in the Schizophrenia Spectrum: An Interdisciplinary and Multiscale Comparison. Schizophr Bull 2020; 46:1396-1408. [PMID: 32944778 PMCID: PMC7707069 DOI: 10.1093/schbul/sbaa117] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The recent renaissance of psychedelic science has reignited interest in the similarity of drug-induced experiences to those more commonly observed in psychiatric contexts such as the schizophrenia-spectrum. This report from a multidisciplinary working group of the International Consortium on Hallucinations Research (ICHR) addresses this issue, putting special emphasis on hallucinatory experiences. We review evidence collected at different scales of understanding, from pharmacology to brain-imaging, phenomenology and anthropology, highlighting similarities and differences between hallucinations under psychedelics and in the schizophrenia-spectrum disorders. Finally, we attempt to integrate these findings using computational approaches and conclude with recommendations for future research.
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Affiliation(s)
- Pantelis Leptourgos
- Department of Psychiatry, Connecticut Mental Health Center, Yale University, New Haven, CT
| | - Martin Fortier-Davy
- Institut Jean Nicod, École des Hautes Études en Sciences Sociales, École Normale Supérieure, PSL Research University, Paris France
| | | | - Philip R Corlett
- Department of Psychiatry, Connecticut Mental Health Center, Yale University, New Haven, CT
| | - David Dupuis
- Department of Anthropology, University of Durham, Durham, UK
| | - Adam L Halberstadt
- Department of Psychiatry, University of California San Diego, La Jolla, CA
- Research Service, VA San Diego Healthcare System, San Diego, CA
| | - Michael Kometer
- Pharmaco-Neuroimaging and Cognitive-Emotional Processing, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Eva Kozakova
- Department of Applied Neurosciences and Brain Imaging, National Institute of Mental Health, Klecany, Czechia
- Department of Psychology, Faculty of Arts, Charles University, Prague, Czechia
| | - Frank LarØi
- Department of Biological and Medical Psychology, Faculty of Psychology, University of Bergen, Bergen, Norway
- Psychology and Neuroscience of Cognition Research Unit, University of Liège, Liège, Belgium
- Norwegian Center of Excellence for Mental Disorders Research, University of Oslo, Oslo, Norway
| | | | - Katrin H Preller
- Pharmaco-Neuroimaging and Cognitive-Emotional Processing, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Flavie Waters
- School of Psychological Sciences, The University of Western Australia, Perth, Western Australia
| | - Yuliya Zaytseva
- Department of Applied Neurosciences and Brain Imaging, National Institute of Mental Health, Klecany, Czechia
- Department of Psychiatry and Medical Psychology, 3rd Faculty of Medicine, Charles University in Prague, Prague, Czechia
| | - Renaud Jardri
- Univ. Lille, INSERM U1172, CHU Lille, Lille Neuroscience & Cognition Centre (LiNC), Plasticity & SubjectivitY team, Lille, France
- Laboratoire de Neurosciences Cognitives et Computationnelles, ENS, INSERM U960, PSL Research University, Paris, France
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38
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Herzog R, Mediano PAM, Rosas FE, Carhart-Harris R, Perl YS, Tagliazucchi E, Cofre R. A mechanistic model of the neural entropy increase elicited by psychedelic drugs. Sci Rep 2020; 10:17725. [PMID: 33082424 PMCID: PMC7575594 DOI: 10.1038/s41598-020-74060-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 09/24/2020] [Indexed: 12/27/2022] Open
Abstract
Psychedelic drugs, including lysergic acid diethylamide and other agonists of the serotonin 2A receptor (5HT2A-R), induce drastic changes in subjective experience, and provide a unique opportunity to study the neurobiological basis of consciousness. One of the most notable neurophysiological signatures of psychedelics, increased entropy in spontaneous neural activity, is thought to be of relevance to the psychedelic experience, mediating both acute alterations in consciousness and long-term effects. However, no clear mechanistic explanation for this entropy increase has been put forward so far. We sought to do this here by building upon a recent whole-brain model of serotonergic neuromodulation, to study the entropic effects of 5HT2A-R activation. Our results reproduce the overall entropy increase observed in previous experiments in vivo, providing the first model-based explanation for this phenomenon. We also found that entropy changes were not uniform across the brain: entropy increased in some regions and decreased in others, suggesting a topographical reconfiguration mediated by 5HT2A-R activation. Interestingly, at the whole-brain level, this reconfiguration was not well explained by 5HT2A-R density, but related closely to the topological properties of the brain's anatomical connectivity. These results help us understand the mechanisms underlying the psychedelic state and, more generally, the pharmacological modulation of whole-brain activity.
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Affiliation(s)
- Rubén Herzog
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Pje Harrington 287, 2360103, Valparaiso, Chile.
| | - Pedro A M Mediano
- Department of Psychology, University of Cambridge, Cambridge, CB2 3EB, UK
| | - Fernando E Rosas
- Department of Brain Science, Centre for Psychedelic Research, Imperial College London, London, SW7 2DD, UK.,Data Science Institute, Imperial College London, London, SW7 2AZ, UK.,Centre for Complexity Science, Imperial College London, London, SW7 2AZ, UK
| | - Robin Carhart-Harris
- Department of Brain Science, Centre for Psychedelic Research, Imperial College London, London, SW7 2DD, UK
| | - Yonatan Sanz Perl
- Buenos Aires Physics Institute and Physics Department, University of Buenos Aires, Buenos Aires, Argentina.,National Scientific and Technical Research Council, Buenos Aires, Argentina.,Universidad de San Andres, Buenos Aires, Argentina
| | - Enzo Tagliazucchi
- Buenos Aires Physics Institute and Physics Department, University of Buenos Aires, Buenos Aires, Argentina.,National Scientific and Technical Research Council, Buenos Aires, Argentina
| | - Rodrigo Cofre
- CIMFAV-Ingemat, Facultad de Ingeniería, Universidad de Valparaíso, Valparaiso, Chile
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