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Mograbi DC, Rodrigues R, Bienemann B, Huntley J. Brain Networks, Neurotransmitters and Psychedelics: Towards a Neurochemistry of Self-Awareness. Curr Neurol Neurosci Rep 2024; 24:323-340. [PMID: 38980658 PMCID: PMC11258181 DOI: 10.1007/s11910-024-01353-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/17/2024] [Indexed: 07/10/2024]
Abstract
PURPOSE OF REVIEW Self-awareness can be defined as the capacity of becoming the object of one's own awareness and, increasingly, it has been the target of scientific inquiry. Self-awareness has important clinical implications, and a better understanding of the neurochemical basis of self-awareness may help clarifying causes and developing interventions for different psychopathological conditions. The current article explores the relationship between neurochemistry and self-awareness, with special attention to the effects of psychedelics. RECENT FINDINGS The functioning of self-related networks, such as the default-mode network and the salience network, and how these are influenced by different neurotransmitters is discussed. The impact of psychedelics on self-awareness is reviewed in relation to specific processes, such as interoception, body ownership, agency, metacognition, emotional regulation and autobiographical memory, within a framework based on predictive coding. Improved outcomes in emotional regulation and autobiographical memory have been observed in association with the use of psychedelics, suggesting higher-order self-awareness changes, which can be modulated by relaxation of priors and improved coping mechanisms linked to cognitive flexibility. Alterations in bodily self-awareness are less consistent, being potentially impacted by doses employed, differences in acute/long-term effects and the presence of clinical conditions. Future studies investigating the effects of different molecules in rebalancing connectivity between resting-state networks may lead to novel therapeutic approaches and the refinement of existing treatments.
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Affiliation(s)
- Daniel C Mograbi
- Department of Psychology, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro, Brazil.
- Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.
| | - Rafael Rodrigues
- Department of Psychology, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Bheatrix Bienemann
- Department of Psychology, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Jonathan Huntley
- Division of Psychiatry, University College London, London, UK
- Wellcome Centre for Human Neuroimaging, University College London, London, UK
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2
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Do Nicotinic Receptors Modulate High-Order Cognitive Processing? Trends Neurosci 2020; 43:550-564. [DOI: 10.1016/j.tins.2020.06.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 05/19/2020] [Accepted: 06/01/2020] [Indexed: 12/19/2022]
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Lou HC, Rømer Thomsen K, Changeux JP. The Molecular Organization of Self-awareness: Paralimbic Dopamine-GABA Interaction. Front Syst Neurosci 2020; 14:3. [PMID: 32047425 PMCID: PMC6997345 DOI: 10.3389/fnsys.2020.00003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 01/10/2020] [Indexed: 11/13/2022] Open
Abstract
The electrophysiology of the paralimbic network ("default mode") for self-awareness has drawn much attention in the past couple of decades. In contrast, knowledge of the molecular organization of conscious experience has only lately come into focus. We here review newer data on dopaminergic control of awareness in humans, particularly in self-awareness. These results implicate mainly dopaminergic neurotransmission and the control of GABAergic function directly in the paralimbic network. The findings are important for understanding addiction, developmental disorders, and dysfunctional consciousness.
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Affiliation(s)
- Hans C Lou
- Center of Functionally Integrative Neuroscience, Institute for Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Kristine Rømer Thomsen
- Department of Psychology and Behavioral Sciences, Center for Alcohol and Drug Research, School of Business and Social Sciences, Aarhus, Denmark
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Møller A, Rømer Thomsen K, Brooks DJ, Mouridsen K, Blicher JU, Hansen KV, Lou HC. Attenuation of dopamine-induced GABA release in problem gamblers. Brain Behav 2019; 9:e01239. [PMID: 30788911 PMCID: PMC6422713 DOI: 10.1002/brb3.1239] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 01/17/2019] [Accepted: 01/18/2019] [Indexed: 12/17/2022] Open
Abstract
INTRODUCTION We have previously shown that an interaction between medial prefrontal and parietal cortices is instrumental in promoting self-awareness via synchronizing oscillations in the gamma range. The synchronization of these oscillations is modulated by dopamine release. Given that such oscillations result from intermittent GABA stimulation of pyramidal cells, it is of interest to determine whether the dopaminergic system regulates GABA release directly in cortical paralimbic regions. Here, we test the hypothesis that the regulation of the GABA-ergic system by the dopaminergic system becomes attenuated in problem gamblers resulting in addictive behaviors and impaired self-awareness. METHODS [11 C]Ro15-4513 PET, a marker of benzodiazepine α1/α5 receptor availability in the GABA receptor complex, was used to detect changes in synaptic GABA levels after oral doses of 100mg L-dopa in a double-blind controlled study of male problem gamblers (N = 10) and age-matched healthy male controls (N = 10). RESULTS The mean reduction of cortical gray matter GABA/BDZ receptor availability induced by L-dopa was significantly attenuated in the problem gambling group compared to the healthy control group (p = 0.0377). CONCLUSIONS Our findings demonstrate that: (a) Exogenous dopamine can induce synaptic GABA release in healthy controls. (b) This release is attenuated in frontal cortical areas of males suffering from problem gambling, possibly contributing to their loss of inhibitory control. This suggests that dysfunctional dopamine regulation of GABA release may contribute to problem gambling and gambling disorder.
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Affiliation(s)
- Arne Møller
- Nuclear Medicine and PET-Center, Aarhus University Hospital, Aarhus, Denmark.,Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
| | | | - David J Brooks
- Nuclear Medicine and PET-Center, Aarhus University Hospital, Aarhus, Denmark.,Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark.,Division of Neuroscience, University of Newcastle, Tyne, UK
| | - Kim Mouridsen
- Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
| | - Jakob U Blicher
- Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
| | - Kim V Hansen
- Nuclear Medicine and PET-Center, Aarhus University Hospital, Aarhus, Denmark
| | - Hans C Lou
- Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
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The relationship between semantic access and introspective awareness. Brain Cogn 2018. [PMID: 29518670 DOI: 10.1016/j.bandc.2018.02.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
There have long been speculations about the relationship between consciousness and language. This study aimed to determine whether an individual's level of introspective awareness, based on self-report, relates to accessibility of their semantic system as evaluated by the N400. Thirty-five university students completed the study. All were right-handed, with normal or corrected-to-normal vision, without known neurological or psychological health issues. They first performed on a lexical decision task while their brain electrophysiological responses were recorded. Then, they provided assessment ratings about their levels of introspective awareness. Analysis revealed moderate to strong correlations (Pearson's rs = 0.49-0.62) between awareness self-ratings and ease of semantic access as indexed by the N400. Correlation between the self-report measure and the objective neurophysiological measure suggests that subjective assessment of awareness may deserve more credibility, which in addition to reflecting subjective perception and evaluation about one's own higher order mental functioning, may also interact with the neurophysiological processes contributive and subject to such awareness. Implications for future research on the role of semantic network in the mechanism of introspective awareness are discussed.
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Farisco M, Evers K, Changeux JP. Drug Addiction: From Neuroscience to Ethics. Front Psychiatry 2018; 9:595. [PMID: 30524319 PMCID: PMC6262362 DOI: 10.3389/fpsyt.2018.00595] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 10/26/2018] [Indexed: 12/22/2022] Open
Abstract
In the present paper, we suggest a potential new ethical analysis of addiction focusing on the relationship between aware and unaware processing in the brain. We take the case of the opioids epidemics to argue that a consideration of both aware and unaware processing provides a more comprehensive ethical framework to discuss the ethical issues raised by addiction. Finally, our hypothesis is that in addition to identified Central Nervous System's neuronal/neurochemical factors contributing to addictive dynamics, the socio-economic status plays a causal role through epigenetic processes, originating the need for additional reward in the brain. This provides a strong base for a socio-political form of responsibility for preventing and managing addiction crisis.
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Affiliation(s)
- Michele Farisco
- Centre for Research Ethics and Bioethics, Uppsala University, Uppsala, Sweden.,Science and Society Unit, Biogem, Biology and Molecular Genetics Institute, Ariano Irpino, Italy
| | - Kathinka Evers
- Centre for Research Ethics and Bioethics, Uppsala University, Uppsala, Sweden
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Towards a cognitive neuroscience of self-awareness. Neurosci Biobehav Rev 2017; 83:765-773. [DOI: 10.1016/j.neubiorev.2016.04.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Revised: 03/19/2016] [Accepted: 04/07/2016] [Indexed: 11/17/2022]
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Climbing Brain Levels of Organisation from Genes to Consciousness. Trends Cogn Sci 2017; 21:168-181. [PMID: 28161289 DOI: 10.1016/j.tics.2017.01.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 12/24/2016] [Accepted: 01/04/2017] [Indexed: 12/24/2022]
Abstract
Given the tremendous complexity of brain organisation, here I propose a strategy that dynamically links stages of brain organisation from genes to consciousness, at four privileged structural levels: genes; transcription factors (TFs)-gene networks; synaptic epigenesis; and long-range connectivity. These structures are viewed as nested and reciprocally inter-regulated, with a hierarchical organisation that proceeds on different timescales during the course of evolution and development. Interlevel bridging mechanisms include intrinsic variation-selection mechanisms, which offer a community of bottom-up and top-down models linking genes to consciousness in a stepwise manner.
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Rømer Thomsen K, Whybrow PC, Kringelbach ML. Reconceptualizing anhedonia: novel perspectives on balancing the pleasure networks in the human brain. Front Behav Neurosci 2015; 9:49. [PMID: 25814941 PMCID: PMC4356228 DOI: 10.3389/fnbeh.2015.00049] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 02/11/2015] [Indexed: 12/18/2022] Open
Abstract
Anhedonia, the lack of pleasure, has been shown to be a critical feature of a range of psychiatric disorders. Yet, it is currently measured primarily through subjective self-reports and as such has been difficult to submit to rigorous scientific analysis. New insights from affective neuroscience hold considerable promise in improving our understanding of anhedonia and for providing useful objective behavioral measures to complement traditional self-report measures, potentially leading to better diagnoses and novel treatments. Here, we review the state-of-the-art of hedonia research and specifically the established mechanisms of wanting, liking, and learning. Based on this framework we propose to conceptualize anhedonia as impairments in some or all of these processes, thereby departing from the longstanding view of anhedonia as solely reduced subjective experience of pleasure. We discuss how deficits in each of the reward components can lead to different expressions, or subtypes, of anhedonia affording novel ways of measurement. Specifically, we review evidence suggesting that patients suffering from depression and schizophrenia show impairments in wanting and learning, while some aspects of conscious liking seem surprisingly intact. Furthermore, the evidence suggests that anhedonia is heterogeneous across psychiatric disorders, depending on which parts of the pleasure networks are most affected. This in turn has implications for diagnosis and treatment of anhedonia.
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Affiliation(s)
- Kristine Rømer Thomsen
- Center of Functionally Integrative Neuroscience (CFIN), University of Aarhus Aarhus, Denmark ; Department of Psychiatry, Warneford Hospital, University of Oxford Oxford, UK ; Centre for Alcohol and Drug Research, School of Business and Social Sciences, University of Aarhus Aarhus, Denmark
| | - Peter C Whybrow
- Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles, LA, USA
| | - Morten L Kringelbach
- Center of Functionally Integrative Neuroscience (CFIN), University of Aarhus Aarhus, Denmark ; Department of Psychiatry, Warneford Hospital, University of Oxford Oxford, UK
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Rømer Thomsen K, Fjorback LO, Møller A, Lou HC. Applying incentive sensitization models to behavioral addiction. Neurosci Biobehav Rev 2014; 45:343-9. [PMID: 25036890 DOI: 10.1016/j.neubiorev.2014.07.009] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 07/01/2014] [Accepted: 07/08/2014] [Indexed: 01/05/2023]
Abstract
The incentive sensitization theory is a promising model for understanding the mechanisms underlying drug addiction, and has received support in animal and human studies. So far the theory has not been applied to the case of behavioral addictions like Gambling Disorder, despite sharing clinical symptoms and underlying neurobiology. We examine the relevance of this theory for Gambling Disorder and point to predictions for future studies. The theory promises a significant contribution to the understanding of behavioral addiction and opens new avenues for treatment.
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Affiliation(s)
- Kristine Rømer Thomsen
- Centre of Functionally Integrative Neuroscience, University of Aarhus, 8000 Aarhus C, Denmark.
| | - Lone O Fjorback
- Research Clinic for Functional Disorders and Psychosomatics, Aarhus University Hospital, Denmark
| | - Arne Møller
- Centre of Functionally Integrative Neuroscience, University of Aarhus, 8000 Aarhus C, Denmark
| | - Hans C Lou
- Centre of Functionally Integrative Neuroscience, University of Aarhus, 8000 Aarhus C, Denmark
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Karczmar AG. Cholinergic behaviors, emotions, and the "self". J Mol Neurosci 2013; 53:291-7. [PMID: 24264529 DOI: 10.1007/s12031-013-0143-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Macromolecular cholinergic pathways are involved in the regulation of addiction, emotions, and motivations, as described at this ISCM. Indeed, in view of the omnipresence in the brain of cholinergic pathways and of their connections with other transmitters' sites and pathways, their involvement in all known human and animal behaviors could be expected and numerous current reports describe such cholinergic correlates. This minireview describes the current status and the future of the cholinergic impact on behavior and emotions, and particularly on one important human phenomenon, the "self" or the "I" (it is only speculative to impute the self to animals).
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12
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Changeux JP. The concept of allosteric interaction and its consequences for the chemistry of the brain. J Biol Chem 2013; 288:26969-26986. [PMID: 23878193 DOI: 10.1074/jbc.x113.503375] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Throughout this Reflections article, I have tried to follow up on the genesis in the 1960s and subsequent evolution of the concept of allosteric interaction and to examine its consequences within the past decades, essentially in the field of the neuroscience. The main conclusion is that allosteric mechanisms built on similar structural principles operate in bacterial regulatory enzymes, gene repressors (and the related nuclear receptors), rhodopsin, G-protein-coupled receptors, neurotransmitter receptors, ion channels, and so on from prokaryotes up to the human brain yet with important features of their own. Thus, future research on these basic cybernetic sensors is expected to develop in two major directions: at the elementary level, toward the atomic structure and molecular dynamics of the conformational changes involved in signal recognition and transduction, but also at a higher level of organization, the contribution of allosteric mechanisms to the modulation of brain functions.
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Affiliation(s)
- Jean-Pierre Changeux
- Collège de France, 75005 Paris and the Institut Pasteur, 75724 Paris Cedex 15, France.
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Abstract
The introduction of magnetoencephalography has made it possible to study electromagnetic signaling in deeper, paralimbic cortical structures such as the medial prefrontal/anterior cingulate (ACC) and medial parietal/posterior cingulate (PCC) cortices. Self-awareness and self-control have been attributed to these regions. To test the hypothesis that they are dysfunctional in pathological gambling with poor self-control, we studied gamblers with and without previous stimulant abuse and age- and sex-matched controls. We found that pathological gamblers were more impulsive than controls in a stop-signal task and attributed this to changes in the activity of the paralimbic network: Pathological gamblers had reduced synchronization at rest in the high gamma range (55-100 Hz) compared with controls and failed to show an increase in gamma synchronization during rest compared with the task, as observed in controls. Subgroup analysis revealed that pathological gamblers without a history of stimulant abuse had lower PCC power during the stop-signal task compared with controls and gamblers with previous stimulant abuse. Furthermore, gamblers with a history of stimulant abuse had up to four times higher power at the ACC site during rest and the task compared with controls. In conclusion, pathological gamblers had higher impulsivity and functional paralimbic abnormalities, which could not be explained by a history of stimulant abuse. In addition, previous stimulant abuse had a marked effect on the amplitude of oscillatory brain activity in the ACC and PCC, suggesting long-term deleterious effects of repeated dopaminergic drug exposure. These consequences should be investigated in more detail in longitudinal studies.
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Lowe SR, Acevedo BP, Griffin KW, Botvin GJ. Longitudinal Relationships Between Self-Management Skills and Substance Use in an Urban Sample of Predominantly Minority Adolescents. JOURNAL OF DRUG ISSUES 2013; 43:103-118. [PMID: 23450848 PMCID: PMC3582216 DOI: 10.1177/0022042612462221] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We explored changes in self-management skills and substance use from 7th to 11th grade in a multiwave study of predominantly minority adolescents (N = 1,756). Using latent growth curve analysis, we found that substance use significantly increased, whereas self-management skills significantly decreased. In a parallel process model, we found that participants who reported higher self-management skills in the 7th grade had smaller increases in substance use. Participants who had larger decreases in self-management skills tended to have greater increases in substance use. We also explored the influence of grades and gender and found that (a) participants with higher grades at baseline had lower initial substance use, higher initial self-management skills, and smaller increases in substance use, and (b) male participants had greater increases in substance use. These results suggest that the provision of self-management skills may be an effective strategy for preventing substance-use initiation and escalation during adolescence.
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Abstract
PURPOSE OF REVIEW Can a general anesthetic binding to its membrane receptors alter global brain activity to cause loss of consciousness? RECENT FINDINGS The identification of the neurobiological mechanisms of conscious processing in awake patients that are altered by general anesthetics and the atomic structure of the general anesthetic's binding site. SUMMARY An important feature of general anesthesia is a preferential inhibition of global feedback connectivity when general anesthetics bind to allosteric sites of gamma-aminobutyric acid receptors present in the cerebral cortex.
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Synaptic Epigenesis and the Evolution of Higher Brain Functions. ACTA ACUST UNITED AC 2012. [DOI: 10.1007/978-3-642-27913-3_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Giessing C, Thiel CM. Pro-cognitive drug effects modulate functional brain network organization. Front Behav Neurosci 2012; 6:53. [PMID: 22973209 PMCID: PMC3428580 DOI: 10.3389/fnbeh.2012.00053] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 07/25/2012] [Indexed: 12/14/2022] Open
Abstract
Previous studies document that cholinergic and noradrenergic drugs improve attention, memory and cognitive control in healthy subjects and patients with neuropsychiatric disorders. In humans neural mechanisms of cholinergic and noradrenergic modulation have mainly been analyzed by investigating drug-induced changes of task-related neural activity measured with functional magnetic resonance imaging (fMRI). Endogenous neural activity has often been neglected. Further, although drugs affect the coupling between neurons, only a few human studies have explicitly addressed how drugs modulate the functional connectome, i.e., the functional neural interactions within the brain. These studies have mainly focused on synchronization or correlation of brain activations. Recently, there are some drug studies using graph theory and other new mathematical approaches to model the brain as a complex network of interconnected processing nodes. Using such measures it is possible to detect not only focal, but also subtle, widely distributed drug effects on functional network topology. Most important, graph theoretical measures also quantify whether drug-induced changes in topology or network organization facilitate or hinder information processing. Several studies could show that functional brain integration is highly correlated with behavioral performance suggesting that cholinergic and noradrenergic drugs which improve measures of cognitive performance should increase functional network integration. The purpose of this paper is to show that graph theory provides a mathematical tool to develop theory-driven biomarkers of pro-cognitive drug effects, and also to discuss how these approaches can contribute to the understanding of the role of cholinergic and noradrenergic modulation in the human brain. Finally we discuss the "global workspace" theory as a theoretical framework of pro-cognitive drug effects and argue that pro-cognitive effects of cholinergic and noradrenergic drugs might be related to higher network integration.
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Affiliation(s)
- Carsten Giessing
- Biological Psychology Lab, Institute of Psychology, University of OldenburgOldenburg, Germany
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dos Santos Coura R, Granon S. Prefrontal neuromodulation by nicotinic receptors for cognitive processes. Psychopharmacology (Berl) 2012; 221:1-18. [PMID: 22249358 DOI: 10.1007/s00213-011-2596-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Accepted: 11/17/2011] [Indexed: 11/30/2022]
Abstract
RATIONALE The prefrontal cortex (PFC) mediates executive functions, a set of control processes that optimize performance on cognitive tasks. It enables appropriate decision-making and mediates adapted behaviors, all processes impaired in psychiatric or degenerative disorders. Key players of normal functioning of the PFC are neurotransmitter (NT) systems arising from subcortical nuclei and targeting PFC subareas and, also, neuronal nicotinic acetylcholine receptors (nAChRs). These ion channels, located on multiple cell compartments in all brain areas, mediate direct cholinergic transmission and modulate the release of NTs that cross onto PFC neurons or interneurons. OBJECTIVE We compiled current knowledge concerning the role of nAChRs in NT release, focusing on the PFC. We point out plausible mechanisms of interaction among PFC circuits implicated in executive functions and emphasized the role of β2-containing nAChRs, the high-affinity receptors for acetylcholine (ACh). These receptors are more directly implicated in behavioral flexibility either when located on PFC neurons or in the monoaminergic or cholinergic systems targeting the PFC. RESULTS We shed light on potentially crucial roles played by nAChRs in complex interactions between local and afferent NTs. We show how they could act on cognition via PFC networks. CONCLUSIONS nAChRs are crucial for decision-making, during integration of emotional and motivational features, both mediated by different NT pathways in the PFC. We review the knowledge recently gained on cognitive functions in mice and our current understanding of PFC NT modulation. The combination of these data is expected to provide new hypotheses concerning the role of AChRs in cognitive processes.
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Lou HC. Paradigm shift in consciousness research: the child's self-awareness and abnormalities in autism, ADHD and schizophrenia. Acta Paediatr 2012; 101:112-9. [PMID: 21883452 DOI: 10.1111/j.1651-2227.2011.02456.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
UNLABELLED Self-awareness is a pivotal component of any conscious experience and conscious self-regulation of behaviour. A paralimbic network is active, specific and causal in self-awareness. Its regions interact by gamma synchrony. Gamma synchrony develops throughout infancy, childhood and adolescence into adulthood and is regulated by dopamine and other neurotransmitters via GABA interneurons. Major derailments of this network and self-awareness occur in developmental disorders of conscious self-regulation like autism, attention deficit hyperactivity disorder (ADHD) and schizophrenia. CONCLUSION Recent research on conscious experience is no longer limited to the study of neural 'correlations' but is increasingly lending itself to the study of causality. This paradigm shift opens new perspectives for understanding the neural mechanisms of the developing self and the causal effects of their disturbance in developmental disorders.
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Affiliation(s)
- Hans C Lou
- Center of Functionally Integrative Neuroscience, Aarhus University, Denmark.
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Lou HC, Joensson M, Kringelbach ML. Yoga lessons for consciousness research: a paralimbic network balancing brain resource allocation. Front Psychol 2011; 2:366. [PMID: 22203808 PMCID: PMC3241341 DOI: 10.3389/fpsyg.2011.00366] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Accepted: 11/21/2011] [Indexed: 11/21/2022] Open
Abstract
Consciousness has been proposed to play a key role in shaping flexible learning and as such is thought to confer an evolutionary advantage. Attention and awareness are the perhaps most important underlying processes, yet their precise relationship is presently unclear. Both of these processes must, however, serve the evolutionary imperatives of survival and procreation. They are thus intimately bound by reward and emotion to help to prioritize efficient brain resource allocation in order to predict and optimize behavior. Here we show how this process is served by a paralimbic network consisting primarily of regions located on the midline of the human brain. Using many different techniques, experiments have demonstrated that this network is effective and specific for self-awareness and contributes to the sense of unity of consciousness by acting as a common neural path for a wide variety of conscious experiences. Interestingly, hemodynamic activity in the network decreases with focusing on external stimuli, which has led to the idea of a default mode network. This network is one of many networks that wax and vane as resources are allocated to accommodate the different cyclical needs of the organism primarily related to the fundamental pleasures afforded by evolution: food, sex, and conspecifics. Here we hypothesize, however, that the paralimbic network serves a crucial role in balancing and regulating brain resource allocation, and discuss how it can be thought of as a link between current theories of so-called “default mode,” “resting state networks,” and “global workspace.” We show how major developmental disorders of self-awareness and self-control can arise from problems in the paralimbic network as demonstrated here by the example of Asperger syndrome. We conclude that attention, awareness, and emotion are integrated by a paralimbic network that helps to efficiently allocate brain resources to optimize behavior and help survival.
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Affiliation(s)
- Hans C Lou
- Centre for Functionally Integrative Neuroscience, Aarhus University Aarhus, Denmark
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