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Keppler J. Laying the foundations for a theory of consciousness: the significance of critical brain dynamics for the formation of conscious states. Front Hum Neurosci 2024; 18:1379191. [PMID: 38736531 PMCID: PMC11082359 DOI: 10.3389/fnhum.2024.1379191] [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: 01/30/2024] [Accepted: 04/15/2024] [Indexed: 05/14/2024] Open
Abstract
Empirical evidence indicates that conscious states, distinguished by the presence of phenomenal qualities, are closely linked to synchronized neural activity patterns whose dynamical characteristics can be attributed to self-organized criticality and phase transitions. These findings imply that insight into the mechanism by which the brain controls phase transitions will provide a deeper understanding of the fundamental mechanism by which the brain manages to transcend the threshold of consciousness. This article aims to show that the initiation of phase transitions and the formation of synchronized activity patterns is due to the coupling of the brain to the zero-point field (ZPF), which plays a central role in quantum electrodynamics (QED). The ZPF stands for the presence of ubiquitous vacuum fluctuations of the electromagnetic field, represented by a spectrum of normal modes. With reference to QED-based model calculations, the details of the coupling mechanism are revealed, suggesting that critical brain dynamics is governed by the resonant interaction of the ZPF with the most abundant neurotransmitter glutamate. The pyramidal neurons in the cortical microcolumns turn out to be ideally suited to control this interaction. A direct consequence of resonant glutamate-ZPF coupling is the amplification of specific ZPF modes, which leads us to conclude that the ZPF is the key to the understanding of consciousness and that the distinctive feature of neurophysiological processes associated with conscious experience consists in modulating the ZPF. Postulating that the ZPF is an inherently sentient field and assuming that the spectrum of phenomenal qualities is represented by the normal modes of the ZPF, the significance of resonant glutamate-ZPF interaction for the formation of conscious states becomes apparent in that the amplification of specific ZPF modes is inextricably linked with the excitation of specific phenomenal qualities. This theory of consciousness, according to which phenomenal states arise through resonant amplification of zero-point modes, is given the acronym TRAZE. An experimental setup is specified that can be used to test a corollary of the theory, namely, the prediction that normally occurring conscious perceptions are absent under experimental conditions in which resonant glutamate-ZPF coupling is disrupted.
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Rajagopal L, Huang M, Mahjour S, Ryan C, Elzokaky A, Svensson KA, Meltzer HY. The dopamine D1 receptor positive allosteric modulator, DETQ, improves cognition and social interaction in aged mice and enhances cortical and hippocampal acetylcholine efflux. Behav Brain Res 2024; 459:114766. [PMID: 38048913 DOI: 10.1016/j.bbr.2023.114766] [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: 08/16/2023] [Revised: 11/06/2023] [Accepted: 11/15/2023] [Indexed: 12/06/2023]
Abstract
Dopamine (DA) D1 and D2 receptors (Rs) are critical for cognitive functioning. D1 positive allosteric modulators (D1PAMs) activate D1Rs without desensitization or an inverted U-shaped dose response curve. DETQ, [2-(2,6-dichlorophenyl)-1-((1S,3R)-3-(hydroxymethyl)-5-(2-hydroxypropan-2-yl)-1-methyl-3,4-dihydroisoquinolin-2(1H)-yl)ethan-1-one] is highly selective for the human D1Rs as shown in humanized D1R knock-in (hD1Ki) mice. Here, we have ascertained the efficacy of DETQ in aged [13-23-month-old (mo)] hD1Ki mice and their corresponding age-matched wild-type (WT; C57BL/6NTac) controls. We found that in aged mice, DETQ, given acutely, subchronically, and chronically, rescued both novel object recognition memory and social behaviors, using novel object recognition (NOR) and social interaction (SI) tasks, respectively without any adverse effect on body weight or mortality. We have also shown, using in vivo microdialysis, a significant decrease in basal DA and norepinephrine, increase in glutamate (Glu) and gamma-amino butyric acid (GABA) efflux with no significant changes in acetylcholine (ACh) levels in aged vs young mice. In young and aged hD1Ki mice, DETQ, acutely and subchronically increased ACh in the medial prefrontal cortex and hippocampal regions in aged hD1Ki mice without affecting Glu. These results suggest that the D1PAM mechanism is of interest as potential treatment for cognitive and social behavioral deficits in neuropsychiatric disorders including but not restricted to neurodegenerative disorders, such as Parkinson's disease.
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Affiliation(s)
- Lakshmi Rajagopal
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Mei Huang
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Sanaz Mahjour
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Chelsea Ryan
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Ahmad Elzokaky
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Kjell A Svensson
- Neuroscience Discovery, Eli Lilly & Company, Indianapolis, IN, USA
| | - H Y Meltzer
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Chicago, IL 60611, USA.
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3
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Habibollahi F, Kagan BJ, Burkitt AN, French C. Critical dynamics arise during structured information presentation within embodied in vitro neuronal networks. Nat Commun 2023; 14:5287. [PMID: 37648737 PMCID: PMC10469171 DOI: 10.1038/s41467-023-41020-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 08/17/2023] [Indexed: 09/01/2023] Open
Abstract
Understanding how brains process information is an incredibly difficult task. Amongst the metrics characterising information processing in the brain, observations of dynamic near-critical states have generated significant interest. However, theoretical and experimental limitations associated with human and animal models have precluded a definite answer about when and why neural criticality arises with links from attention, to cognition, and even to consciousness. To explore this topic, we used an in vitro neural network of cortical neurons that was trained to play a simplified game of 'Pong' to demonstrate Synthetic Biological Intelligence (SBI). We demonstrate that critical dynamics emerge when neural networks receive task-related structured sensory input, reorganizing the system to a near-critical state. Additionally, better task performance correlated with proximity to critical dynamics. However, criticality alone is insufficient for a neuronal network to demonstrate learning in the absence of additional information regarding the consequences of previous actions. These findings offer compelling support that neural criticality arises as a base feature of incoming structured information processing without the need for higher order cognition.
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Affiliation(s)
- Forough Habibollahi
- Cortical Labs Pty Ltd, Melbourne, 3056, VIC, Australia
- Biomedical Engineering Department, University of Melbourne, Parkville, 3010, VIC, Australia
- Neural Dynamics Laboratory, Department of Medicine, University of Melbourne, Parkville, 3010, VIC, Australia
| | - Brett J Kagan
- Cortical Labs Pty Ltd, Melbourne, 3056, VIC, Australia.
| | - Anthony N Burkitt
- Biomedical Engineering Department, University of Melbourne, Parkville, 3010, VIC, Australia
| | - Chris French
- Neural Dynamics Laboratory, Department of Medicine, University of Melbourne, Parkville, 3010, VIC, Australia
- Neurology Department, Royal Melbourne Hospital, Melbourne, Australia
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Oprisan SA, Clementsmith X, Tompa T, Lavin A. Empirical mode decomposition of local field potential data from optogenetic experiments. Front Comput Neurosci 2023; 17:1223879. [PMID: 37476356 PMCID: PMC10354259 DOI: 10.3389/fncom.2023.1223879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 06/19/2023] [Indexed: 07/22/2023] Open
Abstract
Introduction This study investigated the effects of cocaine administration and parvalbumin-type interneuron stimulation on local field potentials (LFPs) recorded in vivo from the medial prefrontal cortex (mPFC) of six mice using optogenetic tools. Methods The local network was subject to a brief 10 ms laser pulse, and the response was recorded for 2 s over 100 trials for each of the six subjects who showed stable coupling between the mPFC and the optrode. Due to the strong non-stationary and nonlinearity of the LFP, we used the adaptive, data-driven, Empirical Mode Decomposition (EMD) method to decompose the signal into orthogonal Intrinsic Mode Functions (IMFs). Results Through trial and error, we found that seven is the optimum number of orthogonal IMFs that overlaps with known frequency bands of brain activity. We found that the Index of Orthogonality (IO) of IMF amplitudes was close to zero. The Index of Energy Conservation (IEC) for each decomposition was close to unity, as expected for orthogonal decompositions. We found that the power density distribution vs. frequency follows a power law with an average scaling exponent of ~1.4 over the entire range of IMF frequencies 2-2,000 Hz. Discussion The scaling exponent is slightly smaller for cocaine than the control, suggesting that neural activity avalanches under cocaine have longer life spans and sizes.
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Affiliation(s)
- Sorinel A. Oprisan
- Department of Physics and Astronomy, College of Charleston, Charleston, SC, United States
| | - Xandre Clementsmith
- Department of Computer Science, College of Charleston, Charleston, SC, United States
| | - Tamas Tompa
- Faculty of Healthcare, Department of Preventive Medicine, University of Miskolc, Miskolc, Hungary
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States
| | - Antonieta Lavin
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, United States
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5
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Grosu GF, Hopp AV, Moca VV, Bârzan H, Ciuparu A, Ercsey-Ravasz M, Winkel M, Linde H, Mureșan RC. The fractal brain: scale-invariance in structure and dynamics. Cereb Cortex 2023; 33:4574-4605. [PMID: 36156074 PMCID: PMC10110456 DOI: 10.1093/cercor/bhac363] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 08/09/2022] [Accepted: 08/10/2022] [Indexed: 11/12/2022] Open
Abstract
The past 40 years have witnessed extensive research on fractal structure and scale-free dynamics in the brain. Although considerable progress has been made, a comprehensive picture has yet to emerge, and needs further linking to a mechanistic account of brain function. Here, we review these concepts, connecting observations across different levels of organization, from both a structural and functional perspective. We argue that, paradoxically, the level of cortical circuits is the least understood from a structural point of view and perhaps the best studied from a dynamical one. We further link observations about scale-freeness and fractality with evidence that the environment provides constraints that may explain the usefulness of fractal structure and scale-free dynamics in the brain. Moreover, we discuss evidence that behavior exhibits scale-free properties, likely emerging from similarly organized brain dynamics, enabling an organism to thrive in an environment that shares the same organizational principles. Finally, we review the sparse evidence for and try to speculate on the functional consequences of fractality and scale-freeness for brain computation. These properties may endow the brain with computational capabilities that transcend current models of neural computation and could hold the key to unraveling how the brain constructs percepts and generates behavior.
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Affiliation(s)
- George F Grosu
- Department of Experimental and Theoretical Neuroscience, Transylvanian Institute of Neuroscience, Str. Ploiesti 33, 400157 Cluj-Napoca, Romania
- Faculty of Electronics, Telecommunications and Information Technology, Technical University of Cluj-Napoca, Str. Memorandumului 28, 400114 Cluj-Napoca, Romania
| | | | - Vasile V Moca
- Department of Experimental and Theoretical Neuroscience, Transylvanian Institute of Neuroscience, Str. Ploiesti 33, 400157 Cluj-Napoca, Romania
| | - Harald Bârzan
- Department of Experimental and Theoretical Neuroscience, Transylvanian Institute of Neuroscience, Str. Ploiesti 33, 400157 Cluj-Napoca, Romania
- Faculty of Electronics, Telecommunications and Information Technology, Technical University of Cluj-Napoca, Str. Memorandumului 28, 400114 Cluj-Napoca, Romania
| | - Andrei Ciuparu
- Department of Experimental and Theoretical Neuroscience, Transylvanian Institute of Neuroscience, Str. Ploiesti 33, 400157 Cluj-Napoca, Romania
- Faculty of Electronics, Telecommunications and Information Technology, Technical University of Cluj-Napoca, Str. Memorandumului 28, 400114 Cluj-Napoca, Romania
| | - Maria Ercsey-Ravasz
- Department of Experimental and Theoretical Neuroscience, Transylvanian Institute of Neuroscience, Str. Ploiesti 33, 400157 Cluj-Napoca, Romania
- Faculty of Physics, Babes-Bolyai University, Str. Mihail Kogalniceanu 1, 400084 Cluj-Napoca, Romania
| | - Mathias Winkel
- Merck KGaA, Frankfurter Straße 250, 64293 Darmstadt, Germany
| | - Helmut Linde
- Department of Experimental and Theoretical Neuroscience, Transylvanian Institute of Neuroscience, Str. Ploiesti 33, 400157 Cluj-Napoca, Romania
- Merck KGaA, Frankfurter Straße 250, 64293 Darmstadt, Germany
| | - Raul C Mureșan
- Department of Experimental and Theoretical Neuroscience, Transylvanian Institute of Neuroscience, Str. Ploiesti 33, 400157 Cluj-Napoca, Romania
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Tian Y, Tan Z, Hou H, Li G, Cheng A, Qiu Y, Weng K, Chen C, Sun P. Theoretical foundations of studying criticality in the brain. Netw Neurosci 2022; 6:1148-1185. [PMID: 38800464 PMCID: PMC11117095 DOI: 10.1162/netn_a_00269] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 07/12/2022] [Indexed: 05/29/2024] Open
Abstract
Criticality is hypothesized as a physical mechanism underlying efficient transitions between cortical states and remarkable information-processing capacities in the brain. While considerable evidence generally supports this hypothesis, nonnegligible controversies persist regarding the ubiquity of criticality in neural dynamics and its role in information processing. Validity issues frequently arise during identifying potential brain criticality from empirical data. Moreover, the functional benefits implied by brain criticality are frequently misconceived or unduly generalized. These problems stem from the nontriviality and immaturity of the physical theories that analytically derive brain criticality and the statistic techniques that estimate brain criticality from empirical data. To help solve these problems, we present a systematic review and reformulate the foundations of studying brain criticality, that is, ordinary criticality (OC), quasi-criticality (qC), self-organized criticality (SOC), and self-organized quasi-criticality (SOqC), using the terminology of neuroscience. We offer accessible explanations of the physical theories and statistical techniques of brain criticality, providing step-by-step derivations to characterize neural dynamics as a physical system with avalanches. We summarize error-prone details and existing limitations in brain criticality analysis and suggest possible solutions. Moreover, we present a forward-looking perspective on how optimizing the foundations of studying brain criticality can deepen our understanding of various neuroscience questions.
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Affiliation(s)
- Yang Tian
- Department of Psychology & Tsinghua Laboratory of Brain and Intelligence, Tsinghua University, Beijing, China
- Laboratory of Advanced Computing and Storage, Central Research Institute, 2012 Laboratories, Huawei Technologies Co. Ltd., Beijing, China
| | - Zeren Tan
- Institute for Interdisciplinary Information Science, Tsinghua University, Beijing, China
| | - Hedong Hou
- UFR de Mathématiques, Université de Paris, Paris, France
| | - Guoqi Li
- Institute of Automation, Chinese Academy of Science, Beijing, China
- University of Chinese Academy of Science, Beijing, China
| | - Aohua Cheng
- Tsien Excellence in Engineering Program, School of Aerospace Engineering, Tsinghua University, Beijing, China
| | - Yike Qiu
- Tsien Excellence in Engineering Program, School of Aerospace Engineering, Tsinghua University, Beijing, China
| | - Kangyu Weng
- Tsien Excellence in Engineering Program, School of Aerospace Engineering, Tsinghua University, Beijing, China
| | - Chun Chen
- Department of Psychology & Tsinghua Laboratory of Brain and Intelligence, Tsinghua University, Beijing, China
| | - Pei Sun
- Department of Psychology & Tsinghua Laboratory of Brain and Intelligence, Tsinghua University, Beijing, China
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7
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Martinez-Saito M. Discrete scaling and criticality in a chain of adaptive excitable integrators. CHAOS, SOLITONS & FRACTALS 2022; 163:112574. [DOI: 10.1016/j.chaos.2022.112574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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8
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Kelty-Stephen DG, Mangalam M. Turing's cascade instability supports the coordination of the mind, brain, and behavior. Neurosci Biobehav Rev 2022; 141:104810. [PMID: 35932950 DOI: 10.1016/j.neubiorev.2022.104810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 06/09/2022] [Accepted: 08/01/2022] [Indexed: 10/16/2022]
Abstract
Turing inspired a computer metaphor of the mind and brain that has been handy and has spawned decades of empirical investigation, but he did much more and offered behavioral and cognitive sciences another metaphor-that of the cascade. The time has come to confront Turing's cascading instability, which suggests a geometrical framework driven by power laws and can be studied using multifractal formalism and multiscale probability density function analysis. Here, we review a rapidly growing body of scientific investigations revealing signatures of cascade instability and their consequences for a perceiving, acting, and thinking organism. We review work related to executive functioning (planning to act), postural control (bodily poise for turning plans into action), and effortful perception (action to gather information in a single modality and action to blend multimodal information). We also review findings on neuronal avalanches in the brain, specifically about neural participation in body-wide cascades. Turing's cascade instability blends the mind, brain, and behavior across space and time scales and provides an alternative to the dominant computer metaphor.
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Affiliation(s)
- Damian G Kelty-Stephen
- Department of Psychology, State University of New York at New Paltz, New Paltz, NY, USA.
| | - Madhur Mangalam
- Department of Physical Therapy, Movement and Rehabilitation Sciences, Northeastern University, Boston, MA, USA.
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9
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Ortega J, Plaska CR, Gomes BA, Ellmore TM. Spontaneous Eye Blink Rate During the Working Memory Delay Period Predicts Task Accuracy. Front Psychol 2022; 13:788231. [PMID: 35242077 PMCID: PMC8886217 DOI: 10.3389/fpsyg.2022.788231] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 01/11/2022] [Indexed: 11/17/2022] Open
Abstract
Spontaneous eye blink rate (sEBR) has been linked to attention and memory, specifically working memory (WM). sEBR is also related to striatal dopamine (DA) activity with schizophrenia and Parkinson’s disease showing increases and decreases, respectively, in sEBR. A weakness of past studies of sEBR and WM is that correlations have been reported using blink rates taken at baseline either before or after performance of the tasks used to assess WM. The goal of the present study was to understand how fluctuations in sEBR during different phases of a visual WM task predict task accuracy. In two experiments, with recordings of sEBR collected inside and outside of a magnetic resonance imaging bore, we observed sEBR to be positively correlated with WM task accuracy during the WM delay period. We also found task-related modulation of sEBR, including higher sEBR during the delay period compared to rest, and lower sEBR during task phases (e.g., stimulus encoding) that place demands on visual attention. These results provide further evidence that sEBR could be an important predictor of WM task performance with the changes during the delay period suggesting a role in WM maintenance. The relationship of sEBR to DA activity and WM maintenance is discussed.
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Affiliation(s)
- Jefferson Ortega
- Department of Psychology, The City College of the City University of New York, New York, NY, United States
| | - Chelsea Reichert Plaska
- Department of Psychology, The City College of the City University of New York, New York, NY, United States.,Behavioral and Cognitive Neuroscience Program, The Graduate Center of the City University of New York, New York, NY, United States
| | - Bernard A Gomes
- Department of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Timothy M Ellmore
- Department of Psychology, The City College of the City University of New York, New York, NY, United States.,Behavioral and Cognitive Neuroscience Program, The Graduate Center of the City University of New York, New York, NY, United States
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10
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Keppler J. Building Blocks for the Development of a Self-Consistent Electromagnetic Field Theory of Consciousness. Front Hum Neurosci 2021; 15:723415. [PMID: 34650416 PMCID: PMC8505726 DOI: 10.3389/fnhum.2021.723415] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 09/08/2021] [Indexed: 11/16/2022] Open
Abstract
The goal of this work is to compile the basic components for the construction of an electromagnetic field theory of consciousness that meets the standards of a fundamental theory. An essential cornerstone of the conceptual framework is the vacuum state of quantum electrodynamics which, contrary to the classical notion of the vacuum, can be viewed as a vibrant ocean of energy, termed zero-point field (ZPF). Being the fundamental substrate mediating the electromagnetic force, the ubiquitous ZPF constitutes the ultimate bedrock of all electromagnetic phenomena. In particular, resonant interaction with the ZPF is critical for understanding rapidly forming, long-range coherent activity patterns that are characteristic of brain dynamics. Assuming that the entire phenomenal color palette is rooted in the vibrational spectrum of the ZPF and that each normal mode of the ZPF is associated with an elementary shade of consciousness, it stands to reason that conscious states are caused by the coupling of the brain to a particular set of normal modes selectively filtered from the full frequency spectrum of the ZPF. From this perspective, the brain is postulated to function as a resonant oscillator that couples to a specific range of ZPF modes, using these modes as a keyboard for the composition of an enormous variety of phenomenal states. Theoretical considerations suggest that the brain-ZPF interface is controlled by altering the concentrations of neurotransmitters, placing the detailed study of the neurotransmitter-ZPF interaction at the center of future research activities.
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11
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Bonetti L, Bruzzone SEP, Sedghi NA, Haumann NT, Paunio T, Kantojärvi K, Kliuchko M, Vuust P, Brattico E. Brain predictive coding processes are associated to COMT gene Val158Met polymorphism. Neuroimage 2021; 233:117954. [PMID: 33716157 DOI: 10.1016/j.neuroimage.2021.117954] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 03/02/2021] [Accepted: 03/06/2021] [Indexed: 10/21/2022] Open
Abstract
Predicting events in the ever-changing environment is a fundamental survival function intrinsic to the physiology of sensory systems, whose efficiency varies among the population. Even though it is established that a major source of such variations is genetic heritage, there are no studies tracking down auditory predicting processes to genetic mutations. Thus, we examined the neurophysiological responses to deviant stimuli recorded with magnetoencephalography (MEG) in 108 healthy participants carrying different variants of Val158Met single-nucleotide polymorphism (SNP) within the catechol-O-methyltransferase (COMT) gene, responsible for the majority of catecholamines degradation in the prefrontal cortex. Our results showed significant amplitude enhancement of prediction error responses originating from the inferior frontal gyrus, superior and middle temporal cortices in heterozygous genotype carriers (Val/Met) vs homozygous (Val/Val and Met/Met) carriers. Integrating neurophysiology and genetics, this study shows how the neural mechanisms underlying optimal deviant detection vary according to the gene-determined cathecolamine levels in the brain.
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Affiliation(s)
- L Bonetti
- Center for Music in the Brain, Department of Clinical Medicine, Aarhus University & The Royal Academy of Music Aarhus/Aalborg, Denmark
| | - S E P Bruzzone
- Center for Music in the Brain, Department of Clinical Medicine, Aarhus University & The Royal Academy of Music Aarhus/Aalborg, Denmark
| | - N A Sedghi
- Center for Music in the Brain, Department of Clinical Medicine, Aarhus University & The Royal Academy of Music Aarhus/Aalborg, Denmark
| | - N T Haumann
- Center for Music in the Brain, Department of Clinical Medicine, Aarhus University & The Royal Academy of Music Aarhus/Aalborg, Denmark
| | - T Paunio
- Department of Psychiatry, University of Helsinki, Finland
| | - K Kantojärvi
- Department of Psychiatry, University of Helsinki, Finland
| | - M Kliuchko
- Center for Music in the Brain, Department of Clinical Medicine, Aarhus University & The Royal Academy of Music Aarhus/Aalborg, Denmark
| | - P Vuust
- Center for Music in the Brain, Department of Clinical Medicine, Aarhus University & The Royal Academy of Music Aarhus/Aalborg, Denmark
| | - E Brattico
- Center for Music in the Brain, Department of Clinical Medicine, Aarhus University & The Royal Academy of Music Aarhus/Aalborg, Denmark; Department of Education, Psychology, Communication, University of Bari Aldo Moro, Italy
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12
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Heiney K, Huse Ramstad O, Fiskum V, Christiansen N, Sandvig A, Nichele S, Sandvig I. Criticality, Connectivity, and Neural Disorder: A Multifaceted Approach to Neural Computation. Front Comput Neurosci 2021; 15:611183. [PMID: 33643017 PMCID: PMC7902700 DOI: 10.3389/fncom.2021.611183] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 01/18/2021] [Indexed: 01/03/2023] Open
Abstract
It has been hypothesized that the brain optimizes its capacity for computation by self-organizing to a critical point. The dynamical state of criticality is achieved by striking a balance such that activity can effectively spread through the network without overwhelming it and is commonly identified in neuronal networks by observing the behavior of cascades of network activity termed "neuronal avalanches." The dynamic activity that occurs in neuronal networks is closely intertwined with how the elements of the network are connected and how they influence each other's functional activity. In this review, we highlight how studying criticality with a broad perspective that integrates concepts from physics, experimental and theoretical neuroscience, and computer science can provide a greater understanding of the mechanisms that drive networks to criticality and how their disruption may manifest in different disorders. First, integrating graph theory into experimental studies on criticality, as is becoming more common in theoretical and modeling studies, would provide insight into the kinds of network structures that support criticality in networks of biological neurons. Furthermore, plasticity mechanisms play a crucial role in shaping these neural structures, both in terms of homeostatic maintenance and learning. Both network structures and plasticity have been studied fairly extensively in theoretical models, but much work remains to bridge the gap between theoretical and experimental findings. Finally, information theoretical approaches can tie in more concrete evidence of a network's computational capabilities. Approaching neural dynamics with all these facets in mind has the potential to provide a greater understanding of what goes wrong in neural disorders. Criticality analysis therefore holds potential to identify disruptions to healthy dynamics, granted that robust methods and approaches are considered.
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Affiliation(s)
- Kristine Heiney
- Department of Computer Science, Oslo Metropolitan University, Oslo, Norway
- Department of Computer Science, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Ola Huse Ramstad
- Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Vegard Fiskum
- Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Nicholas Christiansen
- Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Axel Sandvig
- Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
- Department of Clinical Neuroscience, Umeå University Hospital, Umeå, Sweden
- Department of Neurology, St. Olav's Hospital, Trondheim, Norway
| | - Stefano Nichele
- Department of Computer Science, Oslo Metropolitan University, Oslo, Norway
- Department of Holistic Systems, Simula Metropolitan, Oslo, Norway
| | - Ioanna Sandvig
- Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
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13
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Bellay T, Shew WL, Yu S, Falco-Walter JJ, Plenz D. Selective Participation of Single Cortical Neurons in Neuronal Avalanches. Front Neural Circuits 2021; 14:620052. [PMID: 33551757 PMCID: PMC7862716 DOI: 10.3389/fncir.2020.620052] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 12/21/2020] [Indexed: 12/17/2022] Open
Abstract
Neuronal avalanches are scale-invariant neuronal population activity patterns in the cortex that emerge in vivo in the awake state and in vitro during balanced excitation and inhibition. Theory and experiments suggest that avalanches indicate a state of cortex that improves numerous aspects of information processing by allowing for the transient and selective formation of local as well as system-wide spanning neuronal groups. If avalanches are indeed involved with information processing, one might expect that single neurons would participate in avalanche patterns selectively. Alternatively, all neurons could participate proportionally to their own activity in each avalanche as would be expected for a population rate code. Distinguishing these hypotheses, however, has been difficult as robust avalanche analysis requires technically challenging measures of their intricate organization in space and time at the population level, while also recording sub- or suprathreshold activity from individual neurons with high temporal resolution. Here, we identify repeated avalanches in the ongoing local field potential (LFP) measured with high-density microelectrode arrays in the cortex of awake nonhuman primates and in acute cortex slices from young and adult rats. We studied extracellular unit firing in vivo and intracellular responses of pyramidal neurons in vitro. We found that single neurons participate selectively in specific LFP-based avalanche patterns. Furthermore, we show in vitro that manipulating the balance of excitation and inhibition abolishes this selectivity. Our results support the view that avalanches represent the selective, scale-invariant formation of neuronal groups in line with the idea of Hebbian cell assemblies underlying cortical information processing.
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Affiliation(s)
- Timothy Bellay
- Section on Critical Brain Dynamics, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, United States
- Department of Neuroscience, Brown University, Providence, RI, United States
| | - Woodrow L. Shew
- Section on Critical Brain Dynamics, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, United States
| | - Shan Yu
- Section on Critical Brain Dynamics, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, United States
| | - Jessica J. Falco-Walter
- Section on Critical Brain Dynamics, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, United States
| | - Dietmar Plenz
- Section on Critical Brain Dynamics, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, United States
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14
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Varley TF, Sporns O, Puce A, Beggs J. Differential effects of propofol and ketamine on critical brain dynamics. PLoS Comput Biol 2020; 16:e1008418. [PMID: 33347455 PMCID: PMC7785236 DOI: 10.1371/journal.pcbi.1008418] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 01/05/2021] [Accepted: 10/05/2020] [Indexed: 11/18/2022] Open
Abstract
Whether the brain operates at a critical "tipping" point is a long standing scientific question, with evidence from both cellular and systems-scale studies suggesting that the brain does sit in, or near, a critical regime. Neuroimaging studies of humans in altered states of consciousness have prompted the suggestion that maintenance of critical dynamics is necessary for the emergence of consciousness and complex cognition, and that reduced or disorganized consciousness may be associated with deviations from criticality. Unfortunately, many of the cellular-level studies reporting signs of criticality were performed in non-conscious systems (in vitro neuronal cultures) or unconscious animals (e.g. anaesthetized rats). Here we attempted to address this knowledge gap by exploring critical brain dynamics in invasive ECoG recordings from multiple sessions with a single macaque as the animal transitioned from consciousness to unconsciousness under different anaesthetics (ketamine and propofol). We use a previously-validated test of criticality: avalanche dynamics to assess the differences in brain dynamics between normal consciousness and both drug-states. Propofol and ketamine were selected due to their differential effects on consciousness (ketamine, but not propofol, is known to induce an unusual state known as "dissociative anaesthesia"). Our analyses indicate that propofol dramatically restricted the size and duration of avalanches, while ketamine allowed for more awake-like dynamics to persist. In addition, propofol, but not ketamine, triggered a large reduction in the complexity of brain dynamics. All states, however, showed some signs of persistent criticality when testing for exponent relations and universal shape-collapse. Further, maintenance of critical brain dynamics may be important for regulation and control of conscious awareness.
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Affiliation(s)
- Thomas F. Varley
- Psychological & Brain Sciences, Indiana University, Bloomington, Indiana, USA
- School of Informatics, Indiana University, Bloomington, Indiana, USA
| | - Olaf Sporns
- Psychological & Brain Sciences, Indiana University, Bloomington, Indiana, USA
| | - Aina Puce
- Psychological & Brain Sciences, Indiana University, Bloomington, Indiana, USA
| | - John Beggs
- Department of Physics, Indiana University, Bloomington, Indiana, USA
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15
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Abstract
The review states that antidepressants (ADs) increase brain-derived neurotrophic factor (BDNF) transmission concomitantly in the brain and the blood: ADs increasing BDNF synthesis in specific areas of the central nervous system (CNS) could presumably affect megakaryocyte's production of platelets. ADs increase BDNF levels in the CNS and improve mood. In the blood, ADs increase BDNF release from platelets. The hypothesis presented here is that the release of BDNF from platelets contributes to the ADs effects on neurogenesis and on tumor growth in the cancer disease. Oncological studies indicate that chemicals ADs exert an aggravating effect on the cancer disease, possibly by promoting proplatelets formation and enhancing BDNF release from platelets in the tumor.
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Affiliation(s)
- Francis Lavergne
- Physiopathologie des maladies Psychiatriques, Institut de Psychiatrie et Neurosciences de Paris, UMR_S 1266 INSERM, Paris, France
| | - Therese M Jay
- Physiopathologie des maladies Psychiatriques, Institut de Psychiatrie et Neurosciences de Paris, UMR_S 1266 INSERM, Paris, France.,Faculté de Médecine Paris Descartes, Université Paris Descartes, Paris, France
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16
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Balleine BW. The Meaning of Behavior: Discriminating Reflex and Volition in the Brain. Neuron 2020; 104:47-62. [PMID: 31600515 DOI: 10.1016/j.neuron.2019.09.024] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 08/20/2019] [Accepted: 09/16/2019] [Indexed: 12/11/2022]
Abstract
The ability to establish behaviorally what psychological capacity an animal is deploying-to discern accurately what an animal is doing-is key to functional analyses of the brain. Our current understanding of these capacities suggests, however, that this task is complex; there is evidence that multiple capacities are engaged simultaneously and contribute independently to the control of behavior. As such, establishing the contribution of a cell, circuit, or neural system to any one function requires careful dissection of that role from its influence on other functions and, therefore, the careful selection and design of behavioral tasks fit for that purpose. Here I describe recent research that has sought to utilize behavioral tools to investigate the neural bases of instrumental conditioning, particularly the circuits and systems supporting the capacity for goal-directed action, as opposed to conditioned reflexes and habits, and how these sources of action control interact to generate adaptive behavior.
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17
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Hu G, Huang X, Jiang T, Yu S. Multi-Scale Expressions of One Optimal State Regulated by Dopamine in the Prefrontal Cortex. Front Physiol 2019; 10:113. [PMID: 30873039 PMCID: PMC6404637 DOI: 10.3389/fphys.2019.00113] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 01/30/2019] [Indexed: 11/13/2022] Open
Abstract
The prefrontal cortex (PFC), which plays key roles in many higher cognitive processes, is a hierarchical system consisting of multi-scale organizations. Optimizing the working state at each scale is essential for PFC's information processing. Typical optimal working states at different scales have been separately reported, including the dopamine-mediated inverted-U profile of the working memory (WM) at the system level, critical dynamics at the network level, and detailed balance of excitatory and inhibitory currents (E/I balance) at the cellular level. However, it remains unclear whether these states are scale-specific expressions of the same optimal state and, if so, what is the underlying mechanism for its regulation traversing across scales. Here, by studying a neural network model, we show that the optimal performance of WM co-occurs with the critical dynamics at the network level and the E/I balance at the level of individual neurons, suggesting the existence of a unified, multi-scale optimal state for the PFC. Importantly, such a state could be modulated by dopamine at the synaptic level through a series of U or inverted-U profiles. These results suggest that seemingly different optimal states for specific scales are multi-scale expressions of one condition regulated by dopamine. Our work suggests a cross-scale perspective to understand the PFC function and its modulation.
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Affiliation(s)
- Guyue Hu
- Brainnetome Center, Institute of Automation, Chinese Academy of Sciences, Beijing, China.,National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Xuhui Huang
- Brainnetome Center, Institute of Automation, Chinese Academy of Sciences, Beijing, China.,National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China.,Research Center for Brain-inspired Intelligence, Institute of Automation, Chinese Academy of Sciences, Beijing, China.,CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Beijing, China
| | - Tianzi Jiang
- Brainnetome Center, Institute of Automation, Chinese Academy of Sciences, Beijing, China.,National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China.,CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Shan Yu
- Brainnetome Center, Institute of Automation, Chinese Academy of Sciences, Beijing, China.,National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China.,CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
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18
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Hwa LS, Neira S, Pina MM, Pati D, Calloway R, Kash TL. Predator odor increases avoidance and glutamatergic synaptic transmission in the prelimbic cortex via corticotropin-releasing factor receptor 1 signaling. Neuropsychopharmacology 2019; 44:766-775. [PMID: 30470839 PMCID: PMC6372588 DOI: 10.1038/s41386-018-0279-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 10/31/2018] [Accepted: 11/01/2018] [Indexed: 12/21/2022]
Abstract
Acute exposure to a salient stressor, such as in post-traumatic stress disorder, can have lasting impacts upon an individual and society. To study stress in rodents, some naturalistic methods have included acute exposure to a predator odor, such as the synthetic fox odor 2,4,5, trimethyl-3-thiazoline (TMT). These experiments explore the stress-related behaviors and cortical activity induced by TMT exposure in adult male C57BL/6J mice and the influence of the stress neuropeptide corticotropin-releasing factor (CRF) on these responses. Compared to H2O and a novel odorant, vanilla, mice exposed to TMT in the home cage showed increased avoidance and defensive burying indicative of evident stress responses. Consistent with stress-induced activation of the medial prefrontal cortex (mPFC), we found that the prelimbic (PL) and infralimbic (IL) subregions of the mPFC had elevated c-Fos immunolabeling after TMT and vanilla compared to H2O. Slice physiology recordings were performed in layers 2/3 and 5 of the PL and IL, following TMT, vanilla, or H2O exposure. In TMT mice, but not vanilla or H2O mice, PL layers 2/3 showed heightened spontaneous excitatory post-synaptic currents and synaptic drive, suggesting TMT enhanced excitatory transmission. Synaptic drive in PL was increased in both TMT and H2O mice following bath application of 300 nM CRF, but only H2O mice increased excitatory currents with 100 nM CRF, suggesting dose-effect curve shifts in TMT mice. Further, systemic pretreatment with the CRF-R1 antagonist CP154526 and bath application with the CRF-R1 antagonist NBI27914 reduced excitatory transmission in TMT mice, but not H2O mice. CP154526 also reduced stress-reactive behaviors induced by TMT. Taken together, these findings suggest that exposure to TMT leads to CRF-R1 driven changes in behavior and changes in synaptic function in layer 2/3 neurons in the PL, which are consistent with previous findings that CRF-R1 in the mPFC plays an important role in predator odor-related behaviors.
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Affiliation(s)
- Lara S Hwa
- Departments of Pharmacology, Neuroscience, and the Bowles Alcohol Research Center, University of North Carolina School of Medicine, 104 Manning Drive, Chapel Hill, NC, 27599, USA
| | - Sofia Neira
- Departments of Pharmacology, Neuroscience, and the Bowles Alcohol Research Center, University of North Carolina School of Medicine, 104 Manning Drive, Chapel Hill, NC, 27599, USA
| | - Melanie M Pina
- Departments of Pharmacology, Neuroscience, and the Bowles Alcohol Research Center, University of North Carolina School of Medicine, 104 Manning Drive, Chapel Hill, NC, 27599, USA
| | - Dipanwita Pati
- Departments of Pharmacology, Neuroscience, and the Bowles Alcohol Research Center, University of North Carolina School of Medicine, 104 Manning Drive, Chapel Hill, NC, 27599, USA
| | - Rachel Calloway
- Departments of Pharmacology, Neuroscience, and the Bowles Alcohol Research Center, University of North Carolina School of Medicine, 104 Manning Drive, Chapel Hill, NC, 27599, USA
| | - Thomas L Kash
- Departments of Pharmacology, Neuroscience, and the Bowles Alcohol Research Center, University of North Carolina School of Medicine, 104 Manning Drive, Chapel Hill, NC, 27599, USA.
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19
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Krueger J, Disney AA. Structure and function of dual-source cholinergic modulation in early vision. J Comp Neurol 2018; 527:738-750. [PMID: 30520037 DOI: 10.1002/cne.24590] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 10/29/2018] [Accepted: 11/01/2018] [Indexed: 12/21/2022]
Abstract
Behavioral states such as arousal and attention have profound effects on sensory processing, determining how-even whether-a stimulus is perceived. This state-dependence is believed to arise, at least in part, in response to inputs from subcortical structures that release neuromodulators such as acetylcholine, often nonsynaptically. The mechanisms that underlie the interaction between these nonsynaptic signals and the more point-to-point synaptic cortical circuitry are not well understood. This review highlights the state of the field, with a focus on cholinergic action in early visual processing. Key anatomical and physiological features of both the cholinergic and the visual systems are discussed. Furthermore, presenting evidence of cholinergic modulation in visual thalamus and primary visual cortex, we explore potential functional roles of acetylcholine and its effects on the processing of visual input over the sleep-wake cycle, sensory gain control during wakefulness, and consider evidence for cholinergic support of visual attention.
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Affiliation(s)
- Juliane Krueger
- Department of Neurobiology, Duke University School of Medicine, Durham, North Carolina
| | - Anita A Disney
- Department of Neurobiology, Duke University School of Medicine, Durham, North Carolina
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20
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Fagerholm ED, Dinov M, Knöpfel T, Leech R. The characteristic patterns of neuronal avalanches in mice under anesthesia and at rest: An investigation using constrained artificial neural networks. PLoS One 2018; 13:e0197893. [PMID: 29795654 PMCID: PMC5967741 DOI: 10.1371/journal.pone.0197893] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 05/10/2018] [Indexed: 11/19/2022] Open
Abstract
Local perturbations within complex dynamical systems can trigger cascade-like events that spread across significant portions of the system. Cascades of this type have been observed across a broad range of scales in the brain. Studies of these cascades, known as neuronal avalanches, usually report the statistics of large numbers of avalanches, without probing the characteristic patterns produced by the avalanches themselves. This is partly due to limitations in the extent or spatiotemporal resolution of commonly used neuroimaging techniques. In this study, we overcome these limitations by using optical voltage (genetically encoded voltage indicators) imaging. This allows us to record cortical activity in vivo across an entire cortical hemisphere, at both high spatial (~30um) and temporal (~20ms) resolution in mice that are either in an anesthetized or awake state. We then use artificial neural networks to identify the characteristic patterns created by neuronal avalanches in our data. The avalanches in the anesthetized cortex are most accurately classified by an artificial neural network architecture that simultaneously connects spatial and temporal information. This is in contrast with the awake cortex, in which avalanches are most accurately classified by an architecture that treats spatial and temporal information separately, due to the increased levels of spatiotemporal complexity. This is in keeping with reports of higher levels of spatiotemporal complexity in the awake brain coinciding with features of a dynamical system operating close to criticality.
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Affiliation(s)
- Erik D. Fagerholm
- Centre for Neuroimaging Sciences, King’s College London, London, United Kingdom
| | - Martin Dinov
- The Computational, Cognitive and Clinical Neuroimaging Laboratory, The Centre for Neuroscience, The Division of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, London, United Kingdom
| | - Thomas Knöpfel
- Centre for Neurotechnology, Institute of Biomedical Engineering, Imperial College London, South Kensington Campus, London, United Kingdom
| | - Robert Leech
- Centre for Neuroimaging Sciences, King’s College London, London, United Kingdom
- * E-mail:
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21
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Seshadri S, Klaus A, Winkowski DE, Kanold PO, Plenz D. Altered avalanche dynamics in a developmental NMDAR hypofunction model of cognitive impairment. Transl Psychiatry 2018; 8:3. [PMID: 29317600 PMCID: PMC5802445 DOI: 10.1038/s41398-017-0060-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 08/29/2017] [Accepted: 09/13/2017] [Indexed: 12/25/2022] Open
Abstract
Disturbed activity patterns in cortical networks contribute to the pathophysiology of schizophrenia (SZ). Several lines of evidence implicate NMDA receptor hypofunction in SZ, and blocking NMDA receptor signaling during early neurodevelopment produces cognitive deficits in rodent models that resemble those seen in schizophrenic patients. However, the altered network dynamics underlying these cognitive impairments largely remain to be characterized, especially at the cellular level. Here, we use in vivo two-photon calcium imaging to describe pathological dynamics, occurring in parallel with cognitive dysfunction, in a developmental NMDA receptor hypofunction model. We observed increased synchrony and specific alterations in spatiotemporal activity propagation, which could be causally linked to a previously unidentified persistent bursting phenotype. This phenotype was rescued by acute treatment with the NMDA receptor co-agonist D-serine or the GABAB receptor agonist baclofen, which similarly rescued working memory performance. It was not reproduced by optogenetic inhibition of fast-spiking interneurons. These results provide novel insight into network-level abnormalities mediating the cognitive impairment induced by NMDA receptor hypofunction.
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Affiliation(s)
- Saurav Seshadri
- 0000 0004 0464 0574grid.416868.5Section on Critical Brain Dynamics, National Institute of Mental Health, Bethesda, MD USA
| | - Andreas Klaus
- 0000 0004 0464 0574grid.416868.5Section on Critical Brain Dynamics, National Institute of Mental Health, Bethesda, MD USA
| | - Daniel E. Winkowski
- 0000 0001 0941 7177grid.164295.dDepartment of Biology, Univ. of Maryland, College Park, MD USA
| | - Patrick O. Kanold
- 0000 0001 0941 7177grid.164295.dDepartment of Biology, Univ. of Maryland, College Park, MD USA
| | - Dietmar Plenz
- Section on Critical Brain Dynamics, National Institute of Mental Health, Bethesda, MD, USA.
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22
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Atasoy S, Roseman L, Kaelen M, Kringelbach ML, Deco G, Carhart-Harris RL. Connectome-harmonic decomposition of human brain activity reveals dynamical repertoire re-organization under LSD. Sci Rep 2017; 7:17661. [PMID: 29247209 PMCID: PMC5732294 DOI: 10.1038/s41598-017-17546-0] [Citation(s) in RCA: 94] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 11/24/2017] [Indexed: 12/31/2022] Open
Abstract
Recent studies have started to elucidate the effects of lysergic acid diethylamide (LSD) on the human brain but the underlying dynamics are not yet fully understood. Here we used 'connectome-harmonic decomposition', a novel method to investigate the dynamical changes in brain states. We found that LSD alters the energy and the power of individual harmonic brain states in a frequency-selective manner. Remarkably, this leads to an expansion of the repertoire of active brain states, suggestive of a general re-organization of brain dynamics given the non-random increase in co-activation across frequencies. Interestingly, the frequency distribution of the active repertoire of brain states under LSD closely follows power-laws indicating a re-organization of the dynamics at the edge of criticality. Beyond the present findings, these methods open up for a better understanding of the complex brain dynamics in health and disease.
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Affiliation(s)
- Selen Atasoy
- Center of Brain and Cognition, Computational Neuroscience Group, Universitat Pompeu Fabra, Barcelona, Spain.
| | - Leor Roseman
- Psychedelic Research Group, Psychopharmacology Unit, Centre for Psychiatry, Department of Medicine, Imperial College London, London, UK
| | - Mendel Kaelen
- Psychedelic Research Group, Psychopharmacology Unit, Centre for Psychiatry, Department of Medicine, Imperial College London, London, UK
| | - Morten L Kringelbach
- Department of Psychiatry, University of Oxford, Oxford, UK
- Center for Music in the Brain, Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Gustavo Deco
- Center of Brain and Cognition, Computational Neuroscience Group, 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, Melbourne, Australia
| | - Robin L Carhart-Harris
- Psychedelic Research Group, Psychopharmacology Unit, Centre for Psychiatry, Department of Medicine, Imperial College London, London, UK
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23
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Yu S, Ribeiro TL, Meisel C, Chou S, Mitz A, Saunders R, Plenz D. Maintained avalanche dynamics during task-induced changes of neuronal activity in nonhuman primates. eLife 2017; 6. [PMID: 29115213 PMCID: PMC5677367 DOI: 10.7554/elife.27119] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 10/28/2017] [Indexed: 11/24/2022] Open
Abstract
Sensory events, cognitive processing and motor actions correlate with transient changes in neuronal activity. In cortex, these transients form widespread spatiotemporal patterns with largely unknown statistical regularities. Here, we show that activity associated with behavioral events carry the signature of scale-invariant spatiotemporal clusters, neuronal avalanches. Using high-density microelectrode arrays in nonhuman primates, we recorded extracellular unit activity and the local field potential (LFP) in premotor and prefrontal cortex during motor and cognitive tasks. Unit activity and negative LFP deflections (nLFP) consistently changed in rate at single electrodes during tasks. Accordingly, nLFP clusters on the array deviated from scale-invariance compared to ongoing activity. Scale-invariance was recovered using ‘adaptive binning’, that is identifying clusters at temporal resolution given by task-induced changes in nLFP rate. Measures of LFP synchronization confirmed and computer simulations detailed our findings. We suggest optimization principles identified for avalanches during ongoing activity to apply to cortical information processing during behavior.
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Affiliation(s)
- Shan Yu
- Section on Critical Brain Dynamics, National Institute of Mental Health, Bethesda, United States
| | - Tiago L Ribeiro
- Section on Critical Brain Dynamics, National Institute of Mental Health, Bethesda, United States
| | - Christian Meisel
- Section on Critical Brain Dynamics, National Institute of Mental Health, Bethesda, United States
| | - Samantha Chou
- Section on Critical Brain Dynamics, National Institute of Mental Health, Bethesda, United States
| | - Andrew Mitz
- Laboratory of Neuropsychology, National Institute of Mental Health, Bethesda, United States
| | - Richard Saunders
- Laboratory of Neuropsychology, National Institute of Mental Health, Bethesda, United States
| | - Dietmar Plenz
- Section on Critical Brain Dynamics, National Institute of Mental Health, Bethesda, United States
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24
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Cocchi L, Gollo LL, Zalesky A, Breakspear M. Criticality in the brain: A synthesis of neurobiology, models and cognition. Prog Neurobiol 2017; 158:132-152. [PMID: 28734836 DOI: 10.1016/j.pneurobio.2017.07.002] [Citation(s) in RCA: 223] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 06/15/2017] [Accepted: 07/13/2017] [Indexed: 11/26/2022]
Abstract
Cognitive function requires the coordination of neural activity across many scales, from neurons and circuits to large-scale networks. As such, it is unlikely that an explanatory framework focused upon any single scale will yield a comprehensive theory of brain activity and cognitive function. Modelling and analysis methods for neuroscience should aim to accommodate multiscale phenomena. Emerging research now suggests that multi-scale processes in the brain arise from so-called critical phenomena that occur very broadly in the natural world. Criticality arises in complex systems perched between order and disorder, and is marked by fluctuations that do not have any privileged spatial or temporal scale. We review the core nature of criticality, the evidence supporting its role in neural systems and its explanatory potential in brain health and disease.
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Affiliation(s)
- Luca Cocchi
- QIMR Berghofer Medical Research Institute, Brisbane, Australia.
| | | | - Andrew Zalesky
- Melbourne Neuropsychiatry Centre, The University of Melbourne, Melbourne, Australia
| | - Michael Breakspear
- QIMR Berghofer Medical Research Institute, Brisbane, Australia; Metro North Mental Health Service, Brisbane, Australia
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25
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Mastwal S, Cao V, Wang KH. Genetic Feedback Regulation of Frontal Cortical Neuronal Ensembles Through Activity-Dependent Arc Expression and Dopaminergic Input. Front Neural Circuits 2016; 10:100. [PMID: 27999532 PMCID: PMC5138219 DOI: 10.3389/fncir.2016.00100] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 11/23/2016] [Indexed: 12/15/2022] Open
Abstract
Mental functions involve coordinated activities of specific neuronal ensembles that are embedded in complex brain circuits. Aberrant neuronal ensemble dynamics is thought to form the neurobiological basis of mental disorders. A major challenge in mental health research is to identify these cellular ensembles and determine what molecular mechanisms constrain their emergence and consolidation during development and learning. Here, we provide a perspective based on recent studies that use activity-dependent gene Arc/Arg3.1 as a cellular marker to identify neuronal ensembles and a molecular probe to modulate circuit functions. These studies have demonstrated that the transcription of Arc is activated in selective groups of frontal cortical neurons in response to specific behavioral tasks. Arc expression regulates the persistent firing of individual neurons and predicts the consolidation of neuronal ensembles during repeated learning. Therefore, the Arc pathway represents a prototypical example of activity-dependent genetic feedback regulation of neuronal ensembles. The activation of this pathway in the frontal cortex starts during early postnatal development and requires dopaminergic (DA) input. Conversely, genetic disruption of Arc leads to a hypoactive mesofrontal dopamine circuit and its related cognitive deficit. This mutual interaction suggests an auto-regulatory mechanism to amplify the impact of neuromodulators and activity-regulated genes during postnatal development. Such a mechanism may contribute to the association of mutations in dopamine and Arc pathways with neurodevelopmental psychiatric disorders. As the mesofrontal dopamine circuit shows extensive activity-dependent developmental plasticity, activity-guided modulation of DA projections or Arc ensembles during development may help to repair circuit deficits related to neuropsychiatric disorders.
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Affiliation(s)
- Surjeet Mastwal
- Unit on Neural Circuits and Adaptive Behaviors, Clinical and Translational Neuroscience Branch, National Institute of Mental Health Bethesda, MD, USA
| | - Vania Cao
- Unit on Neural Circuits and Adaptive Behaviors, Clinical and Translational Neuroscience Branch, National Institute of Mental Health Bethesda, MD, USA
| | - Kuan Hong Wang
- Unit on Neural Circuits and Adaptive Behaviors, Clinical and Translational Neuroscience Branch, National Institute of Mental Health Bethesda, MD, USA
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26
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Klaus A, Plenz D. A Low-Correlation Resting State of the Striatum during Cortical Avalanches and Its Role in Movement Suppression. PLoS Biol 2016; 14:e1002582. [PMID: 27923040 PMCID: PMC5147796 DOI: 10.1371/journal.pbio.1002582] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 11/08/2016] [Indexed: 12/13/2022] Open
Abstract
During quiet resting behavior, involuntary movements are suppressed. Such movement control is attributed to cortico-basal ganglia loops, yet population dynamics within these loops during resting and their relation to involuntary movements are not well characterized. Here, we show by recording cortical and striatal ongoing population activity in awake rats during quiet resting that intrastriatal inhibition maintains a low-correlation striatal resting state in the presence of cortical neuronal avalanches. Involuntary movements arise from disturbed striatal resting activity through two different population dynamics. Nonselectively reducing intrastriatal γ-aminobutyric acid (GABA) receptor-A inhibition synchronizes striatal dynamics, leading to involuntary movements at low rate. In contrast, reducing striatal interneuron (IN)-mediated inhibition maintains decorrelation and induces intermittent involuntary movements at high rate. This latter scenario was highly effective in modulating cortical dynamics at a subsecond timescale. To distinguish intrastriatal processing from loop dynamics, cortex-striatum-midbrain cultures, which lack feedback to cortex, were used. Cortical avalanches in vitro were accompanied by low-correlated resting activity in the striatum and nonselective reduction in striatal inhibition synchronized striatal neurons similar to in vivo. Importantly, reduction of inhibition from striatal INs maintained low correlations in the striatum while reorganizing functional connectivities among striatal neurons. Our results demonstrate the importance of two major striatal microcircuits in distinctly regulating striatal and cortical resting state dynamics. These findings suggest that specific functional connectivities of the striatum that are maintained by local inhibition are important in movement control. Why don’t neuronal “avalanches” in resting-state cortex cause involuntary movements? This study shows that a low-correlation striatal resting state suppresses such movements and explores mechanisms that disrupt this inhibition. Even in the absence of apparent motor output, the brain produces a rich repertoire of neuronal activity patterns known as “resting state” activity. In the outer layer of the cortex, resting state patterns emerge as neuronal avalanches, precisely scale-invariant spatiotemporal bursts that often engage large populations of neurons. Little is known about how the brain suppresses involuntary movements during such activity. Here, we show that the striatum, which is part of the cortex-basal ganglia loop, maintains a low-correlation state during resting activity. By using a combination of in vivo and in vitro approaches with pharmacological manipulations, we demonstrate that the precise configuration of this low-correlation state effectively contributes to involuntary movements. Nonselective blockade of intra-striatal inhibition abolished the low-correlation striatal resting state, barely affected cortical avalanches, and led to involuntary movements at low rate. In contrast, selectively reducing striatal interneuron inhibition strongly affected cortical avalanches and triggered involuntary movements at high rate while maintaining a relatively decorrelated striatal resting state. Our results demonstrate the importance of different inhibitory striatal circuits in the suppression of involuntary movements and suggest that the precise spatiotemporal configuration of striatal activity plays an active role in the regulation of cortical resting state activity and motor control.
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Affiliation(s)
- Andreas Klaus
- Section on Critical Brain Dynamics, National Institute of Mental Health, Bethesda, Maryland, United States of America
- * E-mail:
| | - Dietmar Plenz
- Section on Critical Brain Dynamics, National Institute of Mental Health, Bethesda, Maryland, United States of America
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Ribeiro TL, Ribeiro S, Copelli M. Repertoires of Spike Avalanches Are Modulated by Behavior and Novelty. Front Neural Circuits 2016; 10:16. [PMID: 27047341 PMCID: PMC4802163 DOI: 10.3389/fncir.2016.00016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 03/07/2016] [Indexed: 11/13/2022] Open
Abstract
Neuronal avalanches measured as consecutive bouts of thresholded field potentials represent a statistical signature that the brain operates near a critical point. In theory, criticality optimizes stimulus sensitivity, information transmission, computational capability and mnemonic repertoires size. Field potential avalanches recorded via multielectrode arrays from cortical slice cultures are repeatable spatiotemporal activity patterns. It remains unclear whether avalanches of action potentials observed in forebrain regions of freely-behaving rats also form recursive repertoires, and whether these have any behavioral relevance. Here, we show that spike avalanches, recorded from hippocampus (HP) and sensory neocortex of freely-behaving rats, constitute distinct families of recursive spatiotemporal patterns. A significant number of those patterns were specific to a behavioral state. Although avalanches produced during sleep were mostly similar to others that occurred during waking, the repertoire of patterns recruited during sleep differed significantly from that of waking. More importantly, exposure to novel objects increased the rate at which new patterns arose, also leading to changes in post-exposure repertoires, which were significantly different from those before the exposure. A significant number of families occurred exclusively during periods of whisker contact with objects, but few were associated with specific objects. Altogether, the results provide original evidence linking behavior and criticality at the spike level: spike avalanches form repertoires that emerge in waking, recur during sleep, are diversified by novelty and contribute to object representation.
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Affiliation(s)
- Tiago L Ribeiro
- Section on Critical Brain Dynamics, National Institute of Mental Health (NIMH), National Institutes of Health (NIH)Bethesda, MD, USA; Physics Department, Federal University of Pernambuco (UFPE)Recife, PE, Brazil
| | - Sidarta Ribeiro
- Brain Institute, Federal University of Rio Grande do Norte (UFRN) Natal, RN, Brazil
| | - Mauro Copelli
- Physics Department, Federal University of Pernambuco (UFPE) Recife, PE, Brazil
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Wang SJ, Ouyang G, Guang J, Zhang M, Wong KYM, Zhou C. Stochastic Oscillation in Self-Organized Critical States of Small Systems: Sensitive Resting State in Neural Systems. PHYSICAL REVIEW LETTERS 2016; 116:018101. [PMID: 26799044 DOI: 10.1103/physrevlett.116.018101] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Indexed: 06/05/2023]
Abstract
Self-organized critical states (SOCs) and stochastic oscillations (SOs) are simultaneously observed in neural systems, which appears to be theoretically contradictory since SOCs are characterized by scale-free avalanche sizes but oscillations indicate typical scales. Here, we show that SOs can emerge in SOCs of small size systems due to temporal correlation between large avalanches at the finite-size cutoff, resulting from the accumulation-release process in SOCs. In contrast, the critical branching process without accumulation-release dynamics cannot exhibit oscillations. The reconciliation of SOCs and SOs is demonstrated both in the sandpile model and robustly in biologically plausible neuronal networks. The oscillations can be suppressed if external inputs eliminate the prominent slow accumulation process, providing a potential explanation of the widely studied Berger effect or event-related desynchronization in neural response. The features of neural oscillations and suppression are confirmed during task processing in monkey eye-movement experiments. Our results suggest that finite-size, columnar neural circuits may play an important role in generating neural oscillations around the critical states, potentially enabling functional advantages of both SOCs and oscillations for sensitive response to transient stimuli.
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Affiliation(s)
- Sheng-Jun Wang
- Department of Physics, Shaanxi Normal University, Xi'An 710119, China
- Department of Physics, Centre for Nonlinear Studies and Beijing-Hong Kong-Singapore Joint Centre for Nonlinear and Complex Systems (Hong Kong), Institute of Computational and Theoretical Studies, Hong Kong Baptist University, Kowloon Tong, Hong Kong
| | - Guang Ouyang
- Department of Physics, Centre for Nonlinear Studies and Beijing-Hong Kong-Singapore Joint Centre for Nonlinear and Complex Systems (Hong Kong), Institute of Computational and Theoretical Studies, Hong Kong Baptist University, Kowloon Tong, Hong Kong
| | - Jing Guang
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing 100875, China
| | - Mingsha Zhang
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing 100875, China
| | - K Y Michael Wong
- Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Changsong Zhou
- Department of Physics, Centre for Nonlinear Studies and Beijing-Hong Kong-Singapore Joint Centre for Nonlinear and Complex Systems (Hong Kong), Institute of Computational and Theoretical Studies, Hong Kong Baptist University, Kowloon Tong, Hong Kong
- Beijing Computational Science Research Center, Beijing 100084, China
- Research Centre, HKBU Institute of Research and Continuing Education, Virtual University Park Building, South Area Hi-tech Industrial Park, Shenzhen 518057, China
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Hellyer PJ, Jachs B, Clopath C, Leech R. Local inhibitory plasticity tunes macroscopic brain dynamics and allows the emergence of functional brain networks. Neuroimage 2015; 124:85-95. [PMID: 26348562 DOI: 10.1016/j.neuroimage.2015.08.069] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 08/28/2015] [Accepted: 08/31/2015] [Indexed: 11/28/2022] Open
Abstract
Rich, spontaneous brain activity has been observed across a range of different temporal and spatial scales. These dynamics are thought to be important for efficient neural functioning. A range of experimental evidence suggests that these neural dynamics are maintained across a variety of different cognitive states, in response to alterations of the environment and to changes in brain configuration (e.g., across individuals, development and in many neurological disorders). This suggests that the brain has evolved mechanisms to maintain rich dynamics across a broad range of situations. Several mechanisms based around homeostatic plasticity have been proposed to explain how these dynamics emerge from networks of neurons at the microscopic scale. Here we explore how a homeostatic mechanism may operate at the macroscopic scale: in particular, focusing on how it interacts with the underlying structural network topology and how it gives rise to well-described functional connectivity networks. We use a simple mean-field model of the brain, constrained by empirical white matter structural connectivity where each region of the brain is simulated using a pool of excitatory and inhibitory neurons. We show, as with the microscopic work, that homeostatic plasticity regulates network activity and allows for the emergence of rich, spontaneous dynamics across a range of brain configurations, which otherwise show a very limited range of dynamic regimes. In addition, the simulated functional connectivity of the homeostatic model better resembles empirical functional connectivity network. To accomplish this, we show how the inhibitory weights adapt over time to capture important graph theoretic properties of the underlying structural network. Therefore, this work presents suggests how inhibitory homeostatic mechanisms facilitate stable macroscopic dynamics to emerge in the brain, aiding the formation of functional connectivity networks.
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Affiliation(s)
- Peter J Hellyer
- Computational, Cognitive, and Clinical Neuroimaging Laboratory, Division of Brain Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK; Centre for Neuroimaging Science, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, De Crespigny Park, London SE5 8AF, UK
| | - Barbara Jachs
- Computational, Cognitive, and Clinical Neuroimaging Laboratory, Division of Brain Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Claudia Clopath
- Department of Bioengineering, Imperial College London, Room B435, Bessemer Building, South Kensington Campus, SW7 2AZ, UK.
| | - Robert Leech
- Computational, Cognitive, and Clinical Neuroimaging Laboratory, Division of Brain Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK.
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Bellay T, Klaus A, Seshadri S, Plenz D. Irregular spiking of pyramidal neurons organizes as scale-invariant neuronal avalanches in the awake state. eLife 2015; 4:e07224. [PMID: 26151674 PMCID: PMC4492006 DOI: 10.7554/elife.07224] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 06/10/2015] [Indexed: 12/22/2022] Open
Abstract
Spontaneous fluctuations in neuronal activity emerge at many spatial and temporal scales in cortex. Population measures found these fluctuations to organize as scale-invariant neuronal avalanches, suggesting cortical dynamics to be critical. Macroscopic dynamics, though, depend on physiological states and are ambiguous as to their cellular composition, spatiotemporal origin, and contributions from synaptic input or action potential (AP) output. Here, we study spontaneous firing in pyramidal neurons (PNs) from rat superficial cortical layers in vivo and in vitro using 2-photon imaging. As the animal transitions from the anesthetized to awake state, spontaneous single neuron firing increases in irregularity and assembles into scale-invariant avalanches at the group level. In vitro spike avalanches emerged naturally yet required balanced excitation and inhibition. This demonstrates that neuronal avalanches are linked to the global physiological state of wakefulness and that cortical resting activity organizes as avalanches from firing of local PN groups to global population activity. DOI:http://dx.doi.org/10.7554/eLife.07224.001 Even when we are not engaged in any specific task, the brain shows coordinated patterns of spontaneous activity that can be monitored using electrodes placed on the scalp. This resting activity shapes the way that the brain responds to subsequent stimuli. Changes in resting activity patterns are seen in various neurological and psychiatric disorders, as well as in healthy individuals following sleep deprivation. The brain's outer layer is known as the cortex. On a large scale, when monitoring many thousands of neurons, resting activity in the cortex demonstrates propagation in the brain in an organized manner. Specifically, resting activity was found to organize as so-called neuronal avalanches, in which large bursts of neuronal activity are grouped with medium-sized and smaller bursts in a very characteristic order. In fact, the sizes of these bursts—that is, the number of neurons that fire—are found to be scale-invariant, that is, the ratio of large bursts to medium-sized bursts is the same as that of medium-sized to small bursts. Such scale-invariance suggests that neuronal bursts are not independent of one another. However, it is largely unclear how neuronal avalanches arise from individual neurons, which fire simply in a noisy, irregular manner. Bellay, Klaus et al. have now provided insights into this process by examining patterns of firing of a particular type of neuron—known as a pyramidal cell—in the cortex of rats as they recover from anesthesia. As the animals awaken, the firing of individual pyramidal cells in the cortex becomes even more irregular than under anesthesia. However, by considering the activity of a group of these neurons, Bellay, Klaus et al. realized that it is this more irregular firing that gives rise to neuronal avalanches, and that this occurs only when the animals are awake. Further experiments on individual pyramidal cells grown in the laboratory confirmed that neuronal avalanches emerge spontaneously from the irregular firing of individual neurons. These avalanches depend on there being a balance between two types of activity among the cells: ‘excitatory’ activity that causes other neurons to fire, and ‘inhibitory’ activity that prevents neuronal firing. Given that resting activity influences the brain's responses to the outside world, the origins of neuronal avalanches are likely to provide clues about the way the brain processes information. Future experiments should also examine the possibility that the emergence of neuronal avalanches marks the transition from unconsciousness to wakefulness within the brain. DOI:http://dx.doi.org/10.7554/eLife.07224.002
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Affiliation(s)
- Timothy Bellay
- Section on Critical Brain Dynamics, National Institute of Mental Health, Bethesda, United States
| | - Andreas Klaus
- Section on Critical Brain Dynamics, National Institute of Mental Health, Bethesda, United States
| | - Saurav Seshadri
- Section on Critical Brain Dynamics, National Institute of Mental Health, Bethesda, United States
| | - Dietmar Plenz
- Section on Critical Brain Dynamics, National Institute of Mental Health, Bethesda, United States
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Peinado A, Abrams CK. Patterns of Spontaneous Local Network Activity in Developing Cerebral Cortex: Relationship to Adult Cognitive Function. PLoS One 2015; 10:e0131259. [PMID: 26098958 PMCID: PMC4476761 DOI: 10.1371/journal.pone.0131259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 05/29/2015] [Indexed: 11/18/2022] Open
Abstract
Detecting neurodevelopμental disorders of cognition at the earliest possible stages could assist in understanding them mechanistically and ultimately in treating them. Finding early physiological predictors that could be visualized with functional neuroimaging would represent an important advance in this regard. We hypothesized that one potential source of physiological predictors is the spontaneous local network activity prominent during specific periods in development. To test this we used calcium imaging in brain slices and analyzed variations in the frequency and intensity of this early activity in one area, the entorhinal cortex (EC), in order to correlate early activity with level of cognitive function later in life. We focused on EC because of its known role in different types of cognitive processes and because it is an area where spontaneous activity is prominent during early postnatal development in rodent models of cortical development. Using rat strains (Long-Evans, Wistar, Sprague-Dawley and Brattleboro) known to differ in cognitive performance in adulthood we asked whether neonatal animals exhibit corresponding strain-related differences in EC spontaneous activity. Our results show significant differences in this activity between strains: compared to a high cognitive-performing strain, we consistently found an increase in frequency and decrease in intensity in neonates from three lower performing strains. Activity was most different in one strain considered a model of schizophrenia-like psychopathology. While we cannot necessarily infer a causal relationship between early activity and adult cognition our findings suggest that the pattern of spontaneous activity in development could be an early predictor of a developmental trajectory advancing toward sub-optimal cognitive performance in adulthood. Our results further suggest that the strength of dopaminergic signaling, by setting the balance between excitation and inhibition, is a potential underlying mechanism that could explain the observed differences in early spontaneous activity patterns.
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MESH Headings
- Age Factors
- Animals
- Animals, Newborn/anatomy & histology
- Animals, Newborn/growth & development
- Cerebral Cortex/growth & development
- Cognition/physiology
- Entorhinal Cortex/anatomy & histology
- Entorhinal Cortex/growth & development
- Nerve Net/anatomy & histology
- Nerve Net/growth & development
- Nerve Net/physiology
- Rats
- Rats, Brattleboro/growth & development
- Rats, Brattleboro/physiology
- Rats, Long-Evans/growth & development
- Rats, Long-Evans/physiology
- Rats, Sprague-Dawley/growth & development
- Rats, Sprague-Dawley/physiology
- Rats, Wistar/growth & development
- Rats, Wistar/physiology
- Receptors, Dopamine D1/physiology
- Receptors, Dopamine D5/physiology
- Receptors, GABA-A/physiology
- Species Specificity
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Affiliation(s)
- Alejandro Peinado
- Department of Neurology and Department of Physiology and Pharmacology, State University of New York, Downstate Medical Center, Brooklyn, New York, United States of America
- * E-mail:
| | - Charles K. Abrams
- Department of Neurology and Department of Physiology and Pharmacology, State University of New York, Downstate Medical Center, Brooklyn, New York, United States of America
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Synaptic plasticity enables adaptive self-tuning critical networks. PLoS Comput Biol 2015; 11:e1004043. [PMID: 25590427 PMCID: PMC4295840 DOI: 10.1371/journal.pcbi.1004043] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 11/17/2014] [Indexed: 11/19/2022] Open
Abstract
During rest, the mammalian cortex displays spontaneous neural activity. Spiking of single neurons during rest has been described as irregular and asynchronous. In contrast, recent in vivo and in vitro population measures of spontaneous activity, using the LFP, EEG, MEG or fMRI suggest that the default state of the cortex is critical, manifested by spontaneous, scale-invariant, cascades of activity known as neuronal avalanches. Criticality keeps a network poised for optimal information processing, but this view seems to be difficult to reconcile with apparently irregular single neuron spiking. Here, we simulate a 10,000 neuron, deterministic, plastic network of spiking neurons. We show that a combination of short- and long-term synaptic plasticity enables these networks to exhibit criticality in the face of intrinsic, i.e. self-sustained, asynchronous spiking. Brief external perturbations lead to adaptive, long-term modification of intrinsic network connectivity through long-term excitatory plasticity, whereas long-term inhibitory plasticity enables rapid self-tuning of the network back to a critical state. The critical state is characterized by a branching parameter oscillating around unity, a critical exponent close to -3/2 and a long tail distribution of a self-similarity parameter between 0.5 and 1.
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Hesse J, Gross T. Self-organized criticality as a fundamental property of neural systems. Front Syst Neurosci 2014; 8:166. [PMID: 25294989 PMCID: PMC4171833 DOI: 10.3389/fnsys.2014.00166] [Citation(s) in RCA: 191] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 08/25/2014] [Indexed: 11/19/2022] Open
Abstract
The neural criticality hypothesis states that the brain may be poised in a critical state at a boundary between different types of dynamics. Theoretical and experimental studies show that critical systems often exhibit optimal computational properties, suggesting the possibility that criticality has been evolutionarily selected as a useful trait for our nervous system. Evidence for criticality has been found in cell cultures, brain slices, and anesthetized animals. Yet, inconsistent results were reported for recordings in awake animals and humans, and current results point to open questions about the exact nature and mechanism of criticality, as well as its functional role. Therefore, the criticality hypothesis has remained a controversial proposition. Here, we provide an account of the mathematical and physical foundations of criticality. In the light of this conceptual framework, we then review and discuss recent experimental studies with the aim of identifying important next steps to be taken and connections to other fields that should be explored.
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Affiliation(s)
- Janina Hesse
- Computational Neurophysiology Group, Institute for Theoretical Biology, Humboldt Universität zu Berlin Berlin, Germany ; Bernstein Center for Computational Neuroscience Berlin Berlin, Germany ; École Normale Supérieure Paris, France
| | - Thilo Gross
- Department of Engineering Mathematics, Merchant Venturers School of Engineering, University of Bristol Bristol, UK
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Sleimen-Malkoun R, Temprado JJ, Hong SL. Aging induced loss of complexity and dedifferentiation: consequences for coordination dynamics within and between brain, muscular and behavioral levels. Front Aging Neurosci 2014; 6:140. [PMID: 25018731 PMCID: PMC4073624 DOI: 10.3389/fnagi.2014.00140] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 06/11/2014] [Indexed: 11/13/2022] Open
Abstract
Growing evidence demonstrates that aging not only leads to structural and functional alterations of individual components of the neuro-musculo-skeletal system (NMSS) but also results in a systemic re-organization of interactions within and between the different levels and functional domains. Understanding the principles that drive the dynamics of these re-organizations is an important challenge for aging research. The present Hypothesis and Theory paper is a contribution in this direction. We propose that age-related declines in brain and behavior that have been characterized in the literature as dedifferentiation and the loss of complexity (LOC) are: (i) synonymous; and (ii) integrated. We argue that a causal link between the aforementioned phenomena exists, evident in the dynamic changes occurring in the aging NMSS. Through models and methods provided by a dynamical systems approach to coordination processes in complex living systems, we: (i) formalize operational hypotheses about the general principles of changes in cross-level and cross-domain interactions during aging; and (ii) develop a theory of the aging NMSS based on the combination of the frameworks of coordination dynamics (CD), dedifferentiation, and LOC. Finally, we provide operational predictions in the study of aging at neural, muscular, and behavioral levels, which lead to testable hypotheses and an experimental agenda to explore the link between CD, LOC and dedifferentiation within and between these different levels.
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Affiliation(s)
- Rita Sleimen-Malkoun
- CNRS, Institut des Sciences du Mouvement UMR 7287, Aix-Marseille Université Marseille, France ; Inserm, Institut de Neurosciences des Systèmes UMR_S 1106, Faculté de Médecine Timone, Aix-Marseille Université Marseille, France
| | - Jean-Jacques Temprado
- CNRS, Institut des Sciences du Mouvement UMR 7287, Aix-Marseille Université Marseille, France
| | - S Lee Hong
- Ohio Musculoskeletal and Neurological Institute, Ohio University Athens, OH, USA
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Abstract
The brain encodes information about past experience in specific populations of neurons that communicate with one another by firing action potentials. Studies of experience-dependent neural plasticity have largely focused on individual synaptic changes in response to neuronal input. Indicative of the neuronal output transmitted to downstream neurons, persistent firing patterns are affected by prior experience in selective neuronal populations. However, little is known about the molecular and cellular mechanisms by which experience-related persistent firing patterns are regulated in specific neuronal populations. Using frontal cortical slices prepared from transgenic mice carrying a fluorescent reporter of Arc gene expression, this study investigates how behavioral experience and the activity-regulated Arc gene affect patterns of neuronal firing. We found that motor training increases Arc expression in subsets of excitatory neurons. Those neurons exhibit persistent firing in contrast to Arc-negative neurons from the same mice or neurons from the untrained mice. Furthermore, in mice carrying genetic deletion of Arc, the frontal cortical circuitry is still in place to initiate experience-dependent gene expression, but the level of persistent firing thereafter is diminished. Finally, our results showed that the emergence of persistent activity is associated with Arc-dependent changes in the function of NMDA-type glutamate receptors, rather than changes in AMPA-type receptors or membrane excitability. Our findings therefore reveal an Arc-dependent molecular pathway by which gene-experience interaction regulates the emergence of persistent firing patterns in specific neuronal populations.
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Carron R, Filipchuk A, Nardou R, Singh A, Michel FJ, Humphries MD, Hammond C. Early hypersynchrony in juvenile PINK1(-)/(-) motor cortex is rescued by antidromic stimulation. Front Syst Neurosci 2014; 8:95. [PMID: 24904316 PMCID: PMC4033197 DOI: 10.3389/fnsys.2014.00095] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2014] [Accepted: 05/05/2014] [Indexed: 11/14/2022] Open
Abstract
In Parkinson’s disease (PD), cortical networks show enhanced synchronized activity but whether this precedes motor signs is unknown. We investigated this question in PINK1−/− mice, a genetic rodent model of the PARK6 variant of familial PD which shows impaired spontaneous locomotion at 16 months. We used two-photon calcium imaging and whole-cell patch clamp in slices from juvenile (P14–P21) wild-type or PINK1−/− mice. We designed a horizontal tilted cortico-subthalamic slice where the only connection between cortex and subthalamic nucleus (STN) is the hyperdirect cortico-subthalamic pathway. We report excessive correlation and synchronization in PINK1−/− M1 cortical networks 15 months before motor impairment. The percentage of correlated pairs of neurons and their strength of correlation were higher in the PINK1−/− M1 than in the wild type network and the synchronized network events involved a higher percentage of neurons. Both features were independent of thalamo-cortical pathways, insensitive to chronic levodopa treatment of pups, but totally reversed by antidromic invasion of M1 pyramidal neurons by axonal spikes evoked by high frequency stimulation (HFS) of the STN. Our study describes an early excess of synchronization in the PINK1−/− cortex and suggests a potential role of antidromic activation of cortical interneurons in network desynchronization. Such backward effect on interneurons activity may be of importance for HFS-induced network desynchronization.
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Affiliation(s)
- Romain Carron
- Aix Marseille Université Marseille, France ; Institut National de la Recherche Médicale et de la Santé, INMED, UMR 901 Marseille, France ; APHM, Hopital de la Timone, Service de Neurochirurgie Fonctionnelle et Stereotaxique Marseille, France
| | - Anton Filipchuk
- Aix Marseille Université Marseille, France ; Institut National de la Recherche Médicale et de la Santé, INMED, UMR 901 Marseille, France ; Instituto de Neurociencias, CSIC and Universidad Miguel Hernández, San Juan de Alicante Alicante, Spain
| | | | - Abhinav Singh
- Faculty of Life Sciences, University of Manchester Manchester, UK
| | | | - Mark D Humphries
- Faculty of Life Sciences, University of Manchester Manchester, UK
| | - Constance Hammond
- Aix Marseille Université Marseille, France ; Institut National de la Recherche Médicale et de la Santé, INMED, UMR 901 Marseille, France
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37
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Scarpetta S, de Candia A. Alternation of up and down states at a dynamical phase-transition of a neural network with spatiotemporal attractors. Front Syst Neurosci 2014; 8:88. [PMID: 24904311 PMCID: PMC4032888 DOI: 10.3389/fnsys.2014.00088] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 04/28/2014] [Indexed: 11/13/2022] Open
Abstract
Complex collective activity emerges spontaneously in cortical circuits in vivo and in vitro, such as alternation of up and down states, precise spatiotemporal patterns replay, and power law scaling of neural avalanches. We focus on such critical features observed in cortical slices. We study spontaneous dynamics emerging in noisy recurrent networks of spiking neurons with sparse structured connectivity. The emerging spontaneous dynamics is studied, in presence of noise, with fixed connections. Note that no short-term synaptic depression is used. Two different regimes of spontaneous activity emerge changing the connection strength or noise intensity: a low activity regime, characterized by a nearly exponential distribution of firing rates with a maximum at rate zero, and a high activity regime, characterized by a nearly Gaussian distribution peaked at a high rate for high activity, with long-lasting replay of stored patterns. Between this two regimes, a transition region is observed, where firing rates show a bimodal distribution, with alternation of up and down states. In this region, one observes neuronal avalanches exhibiting power laws in size and duration, and a waiting time distribution between successive avalanches which shows a non-monotonic behavior. During periods of high activity (up states) consecutive avalanches are correlated, since they are part of a short transient replay initiated by noise focusing, and waiting times show a power law distribution. One can think at this critical dynamics as a reservoire of dynamical patterns for memory functions.
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Affiliation(s)
- Silvia Scarpetta
- Dipartimento di Fisica "E. R. Caianiello", Università di Salerno Fisciano (SA), Italy ; INFN Gr. Coll. di Salerno Fisciano (SA), Italy
| | - Antonio de Candia
- Dipartimento di Fisica, Università di Napoli Federico II Napoli, Italy ; CNR-SPIN, Sezione di Napoli Italy ; INFN, Sezione di Napoli, Complesso Universitario di Monte S. Angelo Naples, Italy
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38
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Prenatal iron deficiency and monoamine oxidase A (MAOA) polymorphisms: combined risk for later cognitive performance in rhesus monkeys. GENES AND NUTRITION 2014; 9:381. [PMID: 24402517 DOI: 10.1007/s12263-013-0381-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 12/20/2013] [Indexed: 10/25/2022]
Abstract
Monoamine oxidase A (MAOA) gene polymorphisms resulting in high and low transcription rates are associated with individual differences in reward efficacy and response inhibition. Iron deficiency (ID) is the most frequent single-nutrient deficiency worldwide, and prenatal ID has recently been shown to carry a risk for lower mental development scores in infants. In this study, a potential interaction of MAOA genotype and prenatal ID was studied in young male rhesus monkeys. Cognitive tasks, including problem solving, responsiveness to reward and attention, were used to characterize the potential interaction of these two fetal risks. ID was induced by feeding rhesus monkey dams an iron-deficient (10 ppm, ID) or an iron-sufficient (100 ppm, IS) diet during gestation (n = 10/group). Subgroups of the ID and IS diet offspring had low-MAOA or high-MAOA transcription rate polymorphisms. ID combined with low-MAOA genotype showed distinctive effects on reward preference and problem solving while ID in hi-MAOA juveniles modified response inhibition. Given the incidence of ID and MAOA polymorphisms in humans, this interaction could be a significant determinant of cognitive performance.
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39
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Wu JJS, Chang WP, Shih HC, Yen CT, Shyu BC. Cingulate seizure-like activity reveals neuronal avalanche regulated by network excitability and thalamic inputs. BMC Neurosci 2014; 15:3. [PMID: 24387299 PMCID: PMC3893465 DOI: 10.1186/1471-2202-15-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 12/30/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cortical neurons display network-level dynamics with unique spatiotemporal patterns that construct the backbone of processing information signals and contribute to higher functions. Recent years have seen a wealth of research on the characteristics of neuronal networks that are sufficient conditions to activate or cease network functions. Local field potentials (LFPs) exhibit a scale-free and unique event size distribution (i.e., a neuronal avalanche) that has been proven in the cortex across species, including mice, rats, and humans, and may be used as an index of cortical excitability. In the present study, we induced seizure activity in the anterior cingulate cortex (ACC) with medial thalamic inputs and evaluated the impact of cortical excitability and thalamic inputs on network-level dynamics. We measured LFPs from multi-electrode recordings in mouse cortical slices and isoflurane-anesthetized rats. RESULTS The ACC activity exhibited a neuronal avalanche with regard to avalanche size distribution, and the slope of the power-law distribution of the neuronal avalanche reflected network excitability in vitro and in vivo. We found that the slope of the neuronal avalanche in seizure-like activity significantly correlated with cortical excitability induced by γ-aminobutyric acid system manipulation. The thalamic inputs desynchronized cingulate seizures and affected the level of cortical excitability, the modulation of which could be determined by the slope of the avalanche size. CONCLUSIONS We propose that the neuronal avalanche may be a tool for analyzing cortical activity through LFPs to determine alterations in network dynamics.
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Affiliation(s)
| | | | | | | | - Bai Chuang Shyu
- Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan.
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40
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Yu S, Yang H, Shriki O, Plenz D. Universal organization of resting brain activity at the thermodynamic critical point. Front Syst Neurosci 2013; 7:42. [PMID: 23986660 PMCID: PMC3749752 DOI: 10.3389/fnsys.2013.00042] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 07/31/2013] [Indexed: 11/19/2022] Open
Abstract
Thermodynamic criticality describes emergent phenomena in a wide variety of complex systems. In the mammalian cortex, one type of complex dynamics that spontaneously emerges from neuronal interactions has been characterized as neuronal avalanches. Several aspects of neuronal avalanches such as their size and life time distributions are described by power laws with unique exponents, indicating an underlying critical branching process that governs avalanche formation. Here, we show that neuronal avalanches also reflect an organization of brain dynamics close to a thermodynamic critical point. We recorded spontaneous cortical activity in monkeys and humans at rest using high-density intracranial microelectrode arrays and magnetoencephalography, respectively. By numerically changing a control parameter equivalent to thermodynamic temperature, we observed typical critical behavior in cortical activities near the actual physiological condition, including the phase transition of an order parameter, as well as the divergence of susceptibility and specific heat. Finite-size scaling of these quantities allowed us to derive robust critical exponents highly consistent across monkey and humans that uncover a distinct, yet universal organization of brain dynamics. Our results demonstrate that normal brain dynamics at rest resides near or at criticality, which maximizes several aspects of information processing such as input sensitivity and dynamic range.
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Affiliation(s)
- Shan Yu
- Section on Critical Brain Dynamics, National Institute of Mental Health, NIH Bethesda, MD, USA
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41
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Scarpetta S, de Candia A. Neural avalanches at the critical point between replay and non-replay of spatiotemporal patterns. PLoS One 2013; 8:e64162. [PMID: 23840301 PMCID: PMC3688722 DOI: 10.1371/journal.pone.0064162] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Accepted: 04/08/2013] [Indexed: 12/02/2022] Open
Abstract
We model spontaneous cortical activity with a network of coupled spiking units, in which multiple spatio-temporal patterns are stored as dynamical attractors. We introduce an order parameter, which measures the overlap (similarity) between the activity of the network and the stored patterns. We find that, depending on the excitability of the network, different working regimes are possible. For high excitability, the dynamical attractors are stable, and a collective activity that replays one of the stored patterns emerges spontaneously, while for low excitability, no replay is induced. Between these two regimes, there is a critical region in which the dynamical attractors are unstable, and intermittent short replays are induced by noise. At the critical spiking threshold, the order parameter goes from zero to one, and its fluctuations are maximized, as expected for a phase transition (and as observed in recent experimental results in the brain). Notably, in this critical region, the avalanche size and duration distributions follow power laws. Critical exponents are consistent with a scaling relationship observed recently in neural avalanches measurements. In conclusion, our simple model suggests that avalanche power laws in cortical spontaneous activity may be the effect of a network at the critical point between the replay and non-replay of spatio-temporal patterns.
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Affiliation(s)
- Silvia Scarpetta
- Dipartimento di Fisica E. R. Caianiello, Università di Salerno, Fisciano (SA), Italy.
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42
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Shriki O, Alstott J, Carver F, Holroyd T, Henson RNA, Smith ML, Coppola R, Bullmore E, Plenz D. Neuronal avalanches in the resting MEG of the human brain. J Neurosci 2013; 33:7079-90. [PMID: 23595765 PMCID: PMC3665287 DOI: 10.1523/jneurosci.4286-12.2013] [Citation(s) in RCA: 179] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Revised: 03/13/2013] [Accepted: 03/18/2013] [Indexed: 11/21/2022] Open
Abstract
What constitutes normal cortical dynamics in healthy human subjects is a major question in systems neuroscience. Numerous in vitro and in vivo animal studies have shown that ongoing or resting cortical dynamics are characterized by cascades of activity across many spatial scales, termed neuronal avalanches. In experiment and theory, avalanche dynamics are identified by two measures: (1) a power law in the size distribution of activity cascades with an exponent of -3/2 and (2) a branching parameter of the critical value of 1, reflecting balanced propagation of activity at the border of premature termination and potential blowup. Here we analyzed resting-state brain activity recorded using noninvasive magnetoencephalography (MEG) from 124 healthy human subjects and two different MEG facilities using different sensor technologies. We identified large deflections at single MEG sensors and combined them into spatiotemporal cascades on the sensor array using multiple timescales. Cascade size distributions obeyed power laws. For the timescale at which the branching parameter was close to 1, the power law exponent was -3/2. This relationship was robust to scaling and coarse graining of the sensor array. It was absent in phase-shuffled controls with the same power spectrum or empty scanner data. Our results demonstrate that normal cortical activity in healthy human subjects at rest organizes as neuronal avalanches and is well described by a critical branching process. Theory and experiment have shown that such critical, scale-free dynamics optimize information processing. Therefore, our findings imply that the human brain attains an optimal dynamical regime for information processing.
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Affiliation(s)
- Oren Shriki
- Section on Critical Brain Dynamics, National Institute of Mental Health, Bethesda, Maryland 20892, USA.
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43
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Neuronal long-range temporal correlations and avalanche dynamics are correlated with behavioral scaling laws. Proc Natl Acad Sci U S A 2013; 110:3585-90. [PMID: 23401536 DOI: 10.1073/pnas.1216855110] [Citation(s) in RCA: 268] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Scale-free fluctuations are ubiquitous in behavioral performance and neuronal activity. In time scales from seconds to hundreds of seconds, psychophysical dynamics and the amplitude fluctuations of neuronal oscillations are governed by power-law-form long-range temporal correlations (LRTCs). In millisecond time scales, neuronal activity comprises cascade-like neuronal avalanches that exhibit power-law size and lifetime distributions. However, it remains unknown whether these neuronal scaling laws are correlated with those characterizing behavioral performance or whether neuronal LRTCs and avalanches are related. Here, we show that the neuronal scaling laws are strongly correlated both with each other and with behavioral scaling laws. We used source reconstructed magneto- and electroencephalographic recordings to characterize the dynamics of ongoing cortical activity. We found robust power-law scaling in neuronal LRTCs and avalanches in resting-state data and during the performance of audiovisual threshold stimulus detection tasks. The LRTC scaling exponents of the behavioral performance fluctuations were correlated with those of concurrent neuronal avalanches and LRTCs in anatomically identified brain systems. The behavioral exponents also were correlated with neuronal scaling laws derived from a resting-state condition and with a similar anatomical topography. Finally, despite the difference in time scales, the scaling exponents of neuronal LRTCs and avalanches were strongly correlated during both rest and task performance. Thus, long and short time-scale neuronal dynamics are related and functionally significant at the behavioral level. These data suggest that the temporal structures of human cognitive fluctuations and behavioral variability stem from the scaling laws of individual and intrinsic brain dynamics.
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44
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Hong SL, Rebec GV. Biological sources of inflexibility in brain and behavior with aging and neurodegenerative diseases. Front Syst Neurosci 2012; 6:77. [PMID: 23226117 PMCID: PMC3510451 DOI: 10.3389/fnsys.2012.00077] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 11/14/2012] [Indexed: 11/24/2022] Open
Abstract
Almost unequivocally, aging and neurodegeneration lead to deficits in neural information processing. These declines are marked by increased neural noise that is associated with increased variability or inconsistency in behavioral patterns. While it is often viewed that these problems arise from dysregulation of dopamine (DA), a monoamine modulator, glutamate (GLU), an excitatory amino acid that interacts with DA, also plays a role in determining the level of neural noise. We review literature demonstrating that neural noise is highest at both high and low levels of DA and GLU, allowing their interaction to form a many-to-one solution map for neural noise modulation. With aging and neurodegeneration, the range over which DA and GLU can be modulated is decreased leading to inflexibility in brain activity and behavior. As the capacity to modulate neural noise is restricted, the ability to shift noise from one brain region to another is reduced, leading to greater uniformity in signal-to-noise ratios across the entire brain. A negative consequence at the level of behavior is inflexibility that reduces the ability to: (1) switch from one behavior to another; and (2) stabilize a behavioral pattern against external perturbations. In this paper, we develop a theoretical framework where inflexibility across brain and behavior, rather than inconsistency and variability is the more important problem in aging and neurodegeneration. This theoretical framework of inflexibility in aging and neurodegeneration leads to the hypotheses that: (1) dysfunction in either or both of the DA and GLU systems restricts the ability to modulate neural noise; and (2) levels of neural noise and variability in brain activation will be dedifferentiated and more evenly distributed across the brain; and (3) changes in neural noise and behavioral variability in response to different task demands and changes in the environment will be reduced.
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Affiliation(s)
- S. Lee Hong
- Department of Biomedical Sciences, Ohio UniversityAthens, OH, USA
| | - George V. Rebec
- Department of Psychological and Brain Sciences, Indiana UniversityBloomington, IN, USA
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45
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Critical-state dynamics of avalanches and oscillations jointly emerge from balanced excitation/inhibition in neuronal networks. J Neurosci 2012; 32:9817-23. [PMID: 22815496 DOI: 10.1523/jneurosci.5990-11.2012] [Citation(s) in RCA: 217] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Criticality has gained widespread interest in neuroscience as an attractive framework for understanding the character and functional implications of variability in brain activity. The metastability of critical systems maximizes their dynamic range, storage capacity, and computational power. Power-law scaling-a hallmark of criticality-has been observed on different levels, e.g., in the distribution of neuronal avalanches in vitro and in vivo, but also in the decay of temporal correlations in behavioral performance and ongoing oscillations in humans. An unresolved issue is whether power-law scaling on different organizational levels in the brain-and possibly in other hierarchically organized systems-can be related. Here, we show that critical-state dynamics of avalanches and oscillations jointly emerge in a neuronal network model when excitation and inhibition is balanced. The oscillatory activity of the model was qualitatively similar to what is typically observed in recordings of human resting-state MEG. We propose that homeostatic plasticity mechanisms tune this balance in healthy brain networks, and that it is essential for critical behavior on multiple levels of neuronal organization with ensuing functional benefits. Based on our network model, we introduce a concept of multi-level criticality in which power-law scaling can emerge on multiple time scales in oscillating networks.
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46
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Horiguchi M, Hannaway KE, Adelekun AE, Huang M, Jayathilake K, Meltzer HY. D(1) receptor agonists reverse the subchronic phencyclidine (PCP)-induced novel object recognition (NOR) deficit in female rats. Behav Brain Res 2012; 238:36-43. [PMID: 23018127 DOI: 10.1016/j.bbr.2012.09.030] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Revised: 09/14/2012] [Accepted: 09/18/2012] [Indexed: 12/26/2022]
Abstract
Development of dopamine (DA) D(1) receptor agonists is a priority to improve cognitive impairment in schizophrenia (CIS). This study examined the dose-response relationship of the selective D(1) agonist, SKF38393 (0.5-40 mg/kg), to reverse the deficit in novel object recognition (NOR), an analog of declarative memory in man, produced by subchronic phencyclidine (PCP), an N-methyl-D-aspartate (NMDA) receptor non-competitive antagonist, and the ability of the D(1) antagonists, SCH23390 (0.05 mg/kg) and SKF83566 (0.15 mg/kg), to impair NOR in normal Long-Evans female rats. We also examined the ability of tandospirone, a serotonin (5-HT)(1A) receptor partial agonist, and LY341495, a mGluR2/3 receptor antagonist, to potentiate or block the effects of SKF38393 on NOR, respectively. SKF38393 reversed the persistent NOR deficit produced by subchronic PCP; the dose-response curve for SKF38393 was an inverted U-shape, with the peak effect at 6 mg/kg. SKF83566 and SCH23390 impaired NOR in normal rats. Co-administration of sub-effective doses of SKF38393 (0.25 mg/kg) and tandospirone (0.2 mg/kg) improved the PCP-induced NOR deficit, while LY341495 (1 mg/kg) blocked the ameliorating effect of SKF38393 (6 mg/kg), respectively. These data provide the first evidence that the reversal of the PCP-induced NOR deficit by D(1) agonism has an inverted U-shaped dose-response curve and that 5-HT(1A) and mGluR2/3 receptor signalling facilitates the efficacy of D(1) agonism to improve these deficits. These data suggest that although D(1) agonists may be useful to improve CIS, these agents, particularly higher doses, may also worsen cognitive function in some patients, because of an inverted U-shaped dose response curve.
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Affiliation(s)
- Masakuni Horiguchi
- Division of Psychopharmacology, Vanderbilt University Medical Center, Nashville, TN 37212, USA
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47
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Beggs JM, Timme N. Being critical of criticality in the brain. Front Physiol 2012; 3:163. [PMID: 22701101 PMCID: PMC3369250 DOI: 10.3389/fphys.2012.00163] [Citation(s) in RCA: 238] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 05/07/2012] [Indexed: 11/23/2022] Open
Abstract
Relatively recent work has reported that networks of neurons can produce avalanches of activity whose sizes follow a power law distribution. This suggests that these networks may be operating near a critical point, poised between a phase where activity rapidly dies out and a phase where activity is amplified over time. The hypothesis that the electrical activity of neural networks in the brain is critical is potentially important, as many simulations suggest that information processing functions would be optimized at the critical point. This hypothesis, however, is still controversial. Here we will explain the concept of criticality and review the substantial objections to the criticality hypothesis raised by skeptics. Points and counter points are presented in dialog form.
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Affiliation(s)
- John M Beggs
- Department of Physics, Indiana University Bloomington, IN, USA
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48
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Synaptic activity unmasks dopamine D2 receptor modulation of a specific class of layer V pyramidal neurons in prefrontal cortex. J Neurosci 2012; 32:4959-71. [PMID: 22492051 DOI: 10.1523/jneurosci.5835-11.2012] [Citation(s) in RCA: 161] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Dopamine D2 receptors (D2Rs) play a major role in the function of the prefrontal cortex (PFC), and may contribute to prefrontal dysfunction in conditions such as schizophrenia. Here we report that in mouse PFC, D2Rs are selectively expressed by a subtype of layer V pyramidal neurons that have thick apical tufts, prominent h-current, and subcortical projections. Within this subpopulation, the D2R agonist quinpirole elicits a novel afterdepolarization that generates voltage fluctuations and spiking for hundreds of milliseconds. Surprisingly, this afterdepolarization is masked in quiescent brain slices, but is readily unmasked by physiologic levels of synaptic input which activate NMDA receptors, possibly explaining why this phenomenon has not been reported previously. Notably, we could still elicit this afterdepolarization for some time after the cessation of synaptic stimulation. In addition to NMDA receptors, the quinpirole-induced afterdepolarization also depended on L-type Ca(2+) channels and was blocked by the selective L-type antagonist nimodipine. To confirm that D2Rs can elicit this afterdepolarization by enhancing Ca(2+) (and Ca(2+)-dependent) currents, we measured whole-cell Ca(2+) potentials that occur after blocking Na(+) and K(+) channels, and found quinpirole enhanced these potentials, while the selective D2R antagonist sulpiride had the opposite effect. Thus, D2Rs can elicit a Ca(2+)-channel-dependent afterdepolarization that powerfully modulates activity in specific prefrontal neurons. Through this mechanism, D2Rs might enhance outputs to subcortical structures, contribute to reward-related persistent firing, or increase the level of noise in prefrontal circuits.
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49
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Abstract
Rapidly growing empirical evidence supports the hypothesis that the cortex operates near criticality. Although the confirmation of this hypothesis would mark a significant advance in fundamental understanding of cortical physiology, a natural question arises: What functional benefits are endowed to cortical circuits that operate at criticality? In this review, we first describe an introductory-level thought experiment to provide the reader with an intuitive understanding of criticality. Second, we discuss some practical approaches for investigating criticality. Finally, we review quantitative evidence that three functional properties of the cortex are optimized at criticality: 1) dynamic range, 2) information transmission, and 3) information capacity. We focus on recently reported experimental evidence and briefly discuss the theory and history of these ideas.
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Affiliation(s)
- Woodrow L. Shew
- University of Arkansas, Department of Physics, Fayetteville, AR, USA
| | - Dietmar Plenz
- National Institutes of Health, NIMH, Bethesda, MD, USA
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50
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Meck WH, Cheng RK, MacDonald CJ, Gainetdinov RR, Caron MG, Çevik MÖ. Gene-dose dependent effects of methamphetamine on interval timing in dopamine-transporter knockout mice. Neuropharmacology 2012; 62:1221-9. [DOI: 10.1016/j.neuropharm.2011.01.042] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 01/19/2011] [Accepted: 01/24/2011] [Indexed: 10/18/2022]
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