1
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Wang X, Padawer-Curry JA, Bice AR, Kim B, Rosenthal ZP, Lee JM, Goyal MS, Macauley SL, Bauer AQ. Spatiotemporal relationships between neuronal, metabolic, and hemodynamic signals in the awake and anesthetized mouse brain. Cell Rep 2024; 43:114723. [PMID: 39277861 DOI: 10.1016/j.celrep.2024.114723] [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: 08/01/2023] [Revised: 07/08/2024] [Accepted: 08/21/2024] [Indexed: 09/17/2024] Open
Abstract
Neurovascular coupling (NVC) and neurometabolic coupling (NMC) provide the basis for functional magnetic resonance imaging and positron emission tomography to map brain neurophysiology. While increases in neuronal activity are often accompanied by increases in blood oxygen delivery and oxidative metabolism, these observations are not the rule. This decoupling is important when interpreting brain network organization (e.g., resting-state functional connectivity [RSFC]) because it is unclear whether changes in NMC/NVC affect RSFC measures. We leverage wide-field optical imaging in Thy1-jRGECO1a mice to map cortical calcium activity in pyramidal neurons, flavoprotein autofluorescence (representing oxidative metabolism), and hemodynamic activity during wake and ketamine/xylazine anesthesia. Spontaneous dynamics of all contrasts exhibit patterns consistent with RSFC. NMC/NVC relative to excitatory activity varies over the cortex. Ketamine/xylazine profoundly alters NVC but not NMC. Compared to awake RSFC, ketamine/xylazine affects metabolic-based connectomes moreso than hemodynamic-based measures of RSFC. Anesthesia-related differences in NMC/NVC timing do not appreciably alter RSFC structure.
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Affiliation(s)
- Xiaodan Wang
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Biomedical Engineering, Washington University in Saint Louis, St. Louis, MO 63130, USA
| | - Jonah A Padawer-Curry
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Imaging Sciences Program, Washington University in Saint Louis, St. Louis, MO 63130, USA
| | - Annie R Bice
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Byungchan Kim
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Zachary P Rosenthal
- Department of Psychiatry, University of Pennsylvania Health System Penn Medicine, Philadelphia, PA 19104, USA
| | - Jin-Moo Lee
- Department of Biomedical Engineering, Washington University in Saint Louis, St. Louis, MO 63130, USA; Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Manu S Goyal
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Shannon L Macauley
- Department of Physiology, University of Kentucky, Lexington, KY 40508, USA
| | - Adam Q Bauer
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Biomedical Engineering, Washington University in Saint Louis, St. Louis, MO 63130, USA; Imaging Sciences Program, Washington University in Saint Louis, St. Louis, MO 63130, USA.
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2
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Lewis CM, Wunderle T, Fries P. Top-down modulation of visual cortical stimulus encoding and gamma independent of firing rates. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.11.589006. [PMID: 38645050 PMCID: PMC11030389 DOI: 10.1101/2024.04.11.589006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Neurons in primary visual cortex integrate sensory input with signals reflecting the animal's internal state to support flexible behavior. Internal variables, such as expectation, attention, or current goals, are imposed in a top-down manner via extensive feedback projections from higher-order areas. We optogenetically activated a high-order visual area, area 21a, in the lightly anesthetized cat (OptoTD), while recording from neuronal populations in V1. OptoTD induced strong, up to several fold, changes in gamma-band synchronization together with much smaller changes in firing rate, and the two effects showed no correlation. OptoTD effects showed specificity for the features of the simultaneously presented visual stimuli. OptoTD-induced changes in gamma synchronization, but not firing rates, were predictive of simultaneous changes in the amount of encoded stimulus information. Our findings suggest that one important role of top-down signals is to modulate synchronization and the information encoded by populations of sensory neurons.
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3
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Greene AS, Horien C, Barson D, Scheinost D, Constable RT. Why is everyone talking about brain state? Trends Neurosci 2023; 46:508-524. [PMID: 37164869 PMCID: PMC10330476 DOI: 10.1016/j.tins.2023.04.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 03/17/2023] [Accepted: 04/07/2023] [Indexed: 05/12/2023]
Abstract
The rapid and coordinated propagation of neural activity across the brain provides the foundation for complex behavior and cognition. Technical advances across neuroscience subfields have advanced understanding of these dynamics, but points of convergence are often obscured by semantic differences, creating silos of subfield-specific findings. In this review we describe how a parsimonious conceptualization of brain state as the fundamental building block of whole-brain activity offers a common framework to relate findings across scales and species. We present examples of the diverse techniques commonly used to study brain states associated with physiology and higher-order cognitive processes, and discuss how integration across them will enable a more comprehensive and mechanistic characterization of the neural dynamics that are crucial to survival but are disrupted in disease.
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Affiliation(s)
- Abigail S Greene
- Interdepartmental Neuroscience Program, Yale School of Medicine, New Haven, CT 06520, USA; MD/PhD program, Yale School of Medicine, New Haven, CT 06520, USA.
| | - Corey Horien
- Interdepartmental Neuroscience Program, Yale School of Medicine, New Haven, CT 06520, USA; MD/PhD program, Yale School of Medicine, New Haven, CT 06520, USA.
| | - Daniel Barson
- Interdepartmental Neuroscience Program, Yale School of Medicine, New Haven, CT 06520, USA; MD/PhD program, Yale School of Medicine, New Haven, CT 06520, USA; Department of Neuroscience, Yale School of Medicine, New Haven, CT 06520, USA.
| | - Dustin Scheinost
- Interdepartmental Neuroscience Program, Yale School of Medicine, New Haven, CT 06520, USA; Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT 06520, USA; Department of Biomedical Engineering, Yale School of Engineering and Applied Science, New Haven, CT 06520, USA; Department of Statistics and Data Science, Yale University, New Haven, CT 06511, USA; Child Study Center, Yale School of Medicine, New Haven, CT 06520, USA
| | - R Todd Constable
- Interdepartmental Neuroscience Program, Yale School of Medicine, New Haven, CT 06520, USA; Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT 06520, USA; Department of Biomedical Engineering, Yale School of Engineering and Applied Science, New Haven, CT 06520, USA; Department of Neurosurgery, Yale School of Medicine, New Haven, CT 06520, USA
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4
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Engel TA, Schölvinck ML, Lewis CM. The diversity and specificity of functional connectivity across spatial and temporal scales. Neuroimage 2021; 245:118692. [PMID: 34751153 PMCID: PMC9531047 DOI: 10.1016/j.neuroimage.2021.118692] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 10/27/2021] [Accepted: 10/28/2021] [Indexed: 01/01/2023] Open
Abstract
Macroscopic neuroimaging modalities in humans have revealed the organization of brain-wide activity into distributed functional networks that re-organize according to behavioral demands. However, the inherent coarse-graining of macroscopic measurements conceals the diversity and specificity in responses and connectivity of many individual neurons contained in each local region. New invasive approaches in animals enable recording and manipulating neural activity at meso- and microscale resolution, with cell-type specificity and temporal precision down to milliseconds. Determining how brain-wide activity patterns emerge from interactions across spatial and temporal scales will allow us to identify the key circuit mechanisms contributing to global brain states and how the dynamic activity of these states enables adaptive behavior.
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Affiliation(s)
- Tatiana A Engel
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, United States.
| | - Marieke L Schölvinck
- Ernst Strüngmann Institute for Neuroscience in Cooperation with Max Planck Society, Frankfurt am Main, Germany.
| | - Christopher M Lewis
- Laboratory of Neural Circuit Dynamics, Brain Research Institute, University of Zürich, Zürich 8057, Switzerland.
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5
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Alpha suppression indexes a spotlight of visual-spatial attention that can shine on both perceptual and memory representations. Psychon Bull Rev 2021; 29:681-698. [PMID: 34877635 PMCID: PMC10067153 DOI: 10.3758/s13423-021-02034-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/18/2021] [Indexed: 11/08/2022]
Abstract
Although researchers have been recording the human electroencephalogram (EEG) for almost a century, we still do not completely understand what cognitive processes are measured by the activity of different frequency bands. The 8- to 12-Hz activity in the alpha band has long been a focus of this research, but our understanding of its links to cognitive mechanisms has been rapidly evolving recently. Here, we review and discuss the existing evidence for two competing perspectives about alpha activity. One view proposes that the suppression of alpha-band power following the onset of a stimulus array measures attentional selection. The competing view is that this same activity measures the buffering of the task-relevant representations in working memory. We conclude that alpha-band activity following the presentation of stimuli appears to be due to the operation of an attentional selection mechanism, with characteristics that mirror the classic views of attention as selecting both perceptual inputs and representations already stored in memory.
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6
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Kienitz R, Schmid MC, Dugué L. Rhythmic sampling revisited: Experimental paradigms and neural mechanisms. Eur J Neurosci 2021; 55:3010-3024. [PMID: 34643973 DOI: 10.1111/ejn.15489] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 07/31/2021] [Accepted: 09/21/2021] [Indexed: 11/28/2022]
Abstract
Sampling of information is thought to be an important aspect of explorative behaviour. Evidence for it has been gained in behavioural assessments of a variety of overt and covert cognitive domains, including sensation, attention, memory, eye movements and dexterity. A common aspect across many findings is that sampling tends to exhibit a rhythmicity at low frequencies (theta, 4-8 Hz; alpha, 9-12 Hz). Neurophysiological investigations in a wide range of species, including rodents, non-human primates and humans have demonstrated the presence of sampling related neural oscillations in a number of brain areas ranging from early sensory cortex, hippocampus to high-level cognitive areas. However, to assess whether rhythmic sampling represents a general aspect of exploratory behaviour one must critically evaluate the task parameters, and their potential link with neural oscillations. Here we focus on sampling during attentive vision to present an overview on the experimental conditions that are used to investigate rhythmic sampling and associated oscillatory brain activity in this domain. This review aims to (1) provide guidelines to efficiently quantify behavioural rhythms, (2) compare results from human and non-human primate studies and (3) argue that the underlying neural mechanisms of sampling can co-occur in both sensory and high-level areas.
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Affiliation(s)
- Ricardo Kienitz
- Epilepsy Center Frankfurt Rhine-Main, Center of Neurology and Neurosurgery, Goethe University, Frankfurt am Main, Germany.,Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, Frankfurt, Germany.,Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle, UK
| | - Michael C Schmid
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle, UK.,Department of Movement and Neuroscience, Faculty of Natural Sciences and Medicine, University of Fribourg, Fribourg, Switzerland
| | - Laura Dugué
- Université de Paris, INCC UMR 8002, CNRS, Paris, France.,Institut Universitaire de France (IUF), Paris, France
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7
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Kragel JE, Ezzyat Y, Lega BC, Sperling MR, Worrell GA, Gross RE, Jobst BC, Sheth SA, Zaghloul KA, Stein JM, Kahana MJ. Distinct cortical systems reinstate the content and context of episodic memories. Nat Commun 2021; 12:4444. [PMID: 34290240 PMCID: PMC8295370 DOI: 10.1038/s41467-021-24393-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 04/07/2021] [Indexed: 02/06/2023] Open
Abstract
Episodic recall depends upon the reinstatement of cortical activity present during the formation of a memory. Evidence from functional neuroimaging and invasive recordings in humans suggest that reinstatement organizes our memories by time or content, yet the neural systems involved in reinstating these unique types of information remain unclear. Here, combining computational modeling and intracranial recordings from 69 epilepsy patients, we show that two cortical systems uniquely reinstate the semantic content and temporal context of previously studied items during free recall. Examining either the posterior medial or anterior temporal networks, we find that forward encoding models trained on the brain's response to the temporal and semantic attributes of items can predict the serial position and semantic category of unseen items. During memory recall, these models uniquely link reinstatement of temporal context and semantic content to these posterior and anterior networks, respectively. These findings demonstrate how specialized cortical systems enable the human brain to target specific memories.
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Affiliation(s)
- James E. Kragel
- grid.25879.310000 0004 1936 8972Department of Psychology, University of Pennsylvania, Philadelphia, PA USA
| | - Youssef Ezzyat
- grid.25879.310000 0004 1936 8972Department of Psychology, University of Pennsylvania, Philadelphia, PA USA
| | - Bradley C. Lega
- grid.267313.20000 0000 9482 7121Department of Neurosurgery, University of Texas Southwestern, Dallas, TX USA
| | - Michael R. Sperling
- grid.265008.90000 0001 2166 5843Department of Neurology, Thomas Jefferson University, Philadelphia, PA USA
| | - Gregory A. Worrell
- grid.66875.3a0000 0004 0459 167XDepartment of Neurology, Mayo Clinic, Rochester, MN USA
| | - Robert E. Gross
- grid.189967.80000 0001 0941 6502Department of Neurosurgery, Emory School of Medicine, Atlanta, GA USA
| | - Barbara C. Jobst
- grid.413480.a0000 0004 0440 749XDepartment of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, NH USA
| | - Sameer A. Sheth
- grid.239585.00000 0001 2285 2675Department of Neurosurgery, Columbia University Medical Center, New York, NY USA
| | - Kareem A. Zaghloul
- grid.94365.3d0000 0001 2297 5165Surgical Neurology Branch, National Institutes of Health, Bethesda, MD USA
| | - Joel M. Stein
- grid.411115.10000 0004 0435 0884Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, PA USA
| | - Michael J. Kahana
- grid.25879.310000 0004 1936 8972Department of Psychology, University of Pennsylvania, Philadelphia, PA USA
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8
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Salamanca-Giron RF, Raffin E, Zandvliet SB, Seeber M, Michel CM, Sauseng P, Huxlin KR, Hummel FC. Enhancing visual motion discrimination by desynchronizing bifocal oscillatory activity. Neuroimage 2021; 240:118299. [PMID: 34171500 DOI: 10.1016/j.neuroimage.2021.118299] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 06/11/2021] [Accepted: 06/20/2021] [Indexed: 11/17/2022] Open
Abstract
Visual motion discrimination involves reciprocal interactions in the alpha band between the primary visual cortex (V1) and mediotemporal areas (V5/MT). We investigated whether modulating alpha phase synchronization using individualized multisite transcranial alternating current stimulation (tACS) over V5 and V1 regions would improve motion discrimination. We tested 3 groups of healthy subjects with the following conditions: (1) individualized In-Phase V1alpha-V5alpha tACS (0° lag), (2) individualized Anti-Phase V1alpha-V5alpha tACS (180° lag) and (3) sham tACS. Motion discrimination and EEG activity were recorded before, during and after tACS. Performance significantly improved in the Anti-Phase group compared to the In-Phase group 10 and 30 min after stimulation. This result was explained by decreases in bottom-up alpha-V1 gamma-V5 phase-amplitude coupling. One possible explanation of these results is that Anti-Phase V1alpha-V5alpha tACS might impose an optimal phase lag between stimulation sites due to the inherent speed of wave propagation, hereby supporting optimized neuronal communication.
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Affiliation(s)
- Roberto F Salamanca-Giron
- Defitech Chair in Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, Swiss Federal Institute of Technology (EPFL), Campus Biotech, Room H4.3.132.084, Chemin des Mines 9, Geneva, Switzerland; Defitech Chair in Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, Clinique Romande de Readaptation (CRR), EPFL Valais, Sion, Switzerland
| | - Estelle Raffin
- Defitech Chair in Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, Swiss Federal Institute of Technology (EPFL), Campus Biotech, Room H4.3.132.084, Chemin des Mines 9, Geneva, Switzerland; Defitech Chair in Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, Clinique Romande de Readaptation (CRR), EPFL Valais, Sion, Switzerland
| | - Sarah B Zandvliet
- Defitech Chair in Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, Swiss Federal Institute of Technology (EPFL), Campus Biotech, Room H4.3.132.084, Chemin des Mines 9, Geneva, Switzerland; Defitech Chair in Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, Clinique Romande de Readaptation (CRR), EPFL Valais, Sion, Switzerland
| | - Martin Seeber
- Functional Brain Mapping Lab, Department of Fundamental Neurosciences, University of Geneva, Campus Biotech, Chemin des Mines 9, 1202, Geneva, Switzerland
| | - Christoph M Michel
- Functional Brain Mapping Lab, Department of Fundamental Neurosciences, University of Geneva, Campus Biotech, Chemin des Mines 9, 1202, Geneva, Switzerland; Lemanic Biomedical Imaging Centre (CIBM), Lausanne, Geneva, Switzerland
| | - Paul Sauseng
- Department of Psychology, LMU Munich, Leopoldstr. 13, Munich 80802, Germany
| | - Krystel R Huxlin
- The Flaum Eye Institute and Center for Visual Science, University of Rochester, Rochester, NY, USA
| | - Friedhelm C Hummel
- Defitech Chair in Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, Swiss Federal Institute of Technology (EPFL), Campus Biotech, Room H4.3.132.084, Chemin des Mines 9, Geneva, Switzerland; Defitech Chair in Clinical Neuroengineering, Center for Neuroprosthetics and Brain Mind Institute, Clinique Romande de Readaptation (CRR), EPFL Valais, Sion, Switzerland; Clinical Neuroscience, University of Geneva Medical School, Geneva, Switzerland.
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9
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Wason TD. A model integrating multiple processes of synchronization and coherence for information instantiation within a cortical area. Biosystems 2021; 205:104403. [PMID: 33746019 DOI: 10.1016/j.biosystems.2021.104403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 03/05/2021] [Indexed: 12/14/2022]
Abstract
What is the form of dynamic, e.g., sensory, information in the mammalian cortex? Information in the cortex is modeled as a coherence map of a mixed chimera state of synchronous, phasic, and disordered minicolumns. The theoretical model is built on neurophysiological evidence. Complex spatiotemporal information is instantiated through a system of interacting biological processes that generate a synchronized cortical area, a coherent aperture. Minicolumn elements are grouped in macrocolumns in an array analogous to a phased-array radar, modeled as an aperture, a "hole through which radiant energy flows." Coherence maps in a cortical area transform inputs from multiple sources into outputs to multiple targets, while reducing complexity and entropy. Coherent apertures can assume extremely large numbers of different information states as coherence maps, which can be communicated among apertures with corresponding very large bandwidths. The coherent aperture model incorporates considerable reported research, integrating five conceptually and mathematically independent processes: 1) a damped Kuramoto network model, 2) a pumped area field potential, 3) the gating of nearly coincident spikes, 4) the coherence of activity across cortical lamina, and 5) complex information formed through functions in macrocolumns. Biological processes and their interactions are described in equations and a functional circuit such that the mathematical pieces can be assembled the same way the neurophysiological ones are. The model can be conceptually convolved over the specifics of local cortical areas within and across species. A coherent aperture becomes a node in a graph of cortical areas with a corresponding distribution of information.
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Affiliation(s)
- Thomas D Wason
- North Carolina State University, Department of Biological Sciences, Meitzen Laboratory, Campus Box 7617, 128 David Clark Labs, Raleigh, NC 27695-7617, USA.
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10
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van Kempen J, Gieselmann MA, Boyd M, Steinmetz NA, Moore T, Engel TA, Thiele A. Top-down coordination of local cortical state during selective attention. Neuron 2021; 109:894-904.e8. [PMID: 33406410 PMCID: PMC7927916 DOI: 10.1016/j.neuron.2020.12.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 11/20/2020] [Accepted: 12/16/2020] [Indexed: 11/30/2022]
Abstract
Spontaneous fluctuations in cortical excitability influence sensory processing and behavior. These fluctuations, long thought to reflect global changes in cortical state, were recently found to be modulated locally within a retinotopic map during spatially selective attention. We report that periods of vigorous (On) and faint (Off) spiking activity, the signature of cortical state fluctuations, are coordinated across brain areas with retinotopic precision. Top-down attention enhanced interareal local state coordination, traversing along the reverse cortical hierarchy. The extent of local state coordination between areas was predictive of behavioral performance. Our results show that cortical state dynamics are shared across brain regions, modulated by cognitive demands and relevant for behavior.
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Affiliation(s)
- Jochem van Kempen
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE1 7RU, UK.
| | - Marc A Gieselmann
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Michael Boyd
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Nicholas A Steinmetz
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - Tirin Moore
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Tatiana A Engel
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Alexander Thiele
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
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11
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Krug K. Coding Perceptual Decisions: From Single Units to Emergent Signaling Properties in Cortical Circuits. Annu Rev Vis Sci 2020; 6:387-409. [PMID: 32600168 DOI: 10.1146/annurev-vision-030320-041223] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Spiking activity in single neurons of the primate visual cortex has been tightly linked to perceptual decisions. Any mechanism that reads out these perceptual signals to support behavior must respect the underlying neuroanatomy that shapes the functional properties of sensory neurons. Spatial distribution and timing of inputs to the next processing levels are critical, as conjoint activity of precursor neurons increases the spiking rate of downstream neurons and ultimately drives behavior. I set out how correlated activity might coalesce into a micropool of task-sensitive neurons signaling a particular percept to determine perceptual decision signals locally and for flexible interarea transmission depending on the task context. As data from more and more neurons and their complex interactions are analyzed, the space of computational mechanisms must be constrained based on what is plausible within neurobiological limits. This review outlines experiments to test the new perspectives offered by these extended methods.
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Affiliation(s)
- Kristine Krug
- Lehrstuhl für Sensorische Physiologie, Institut für Biologie, Otto-von-Guericke-Universität Magdeburg, 39120 Magdeburg, Germany; .,Leibniz-Institut für Neurobiologie, 39118 Magdeburg, Germany.,Department of Physiology, Anatomy, and Genetics, Oxford University, Oxford OX1 3PT, United Kingdom
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12
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Gravel N, Renken RJ, Harvey BM, Deco G, Cornelissen FW, Gilson M. Propagation of BOLD Activity Reveals Task-dependent Directed Interactions Across Human Visual Cortex. Cereb Cortex 2020; 30:5899-5914. [PMID: 32577717 DOI: 10.1093/cercor/bhaa165] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 03/13/2020] [Accepted: 05/02/2020] [Indexed: 11/14/2022] Open
Abstract
It has recently been shown that large-scale propagation of blood-oxygen-level-dependent (BOLD) activity is constrained by anatomical connections and reflects transitions between behavioral states. It remains to be seen, however, if the propagation of BOLD activity can also relate to the brain's anatomical structure at a more local scale. Here, we hypothesized that BOLD propagation reflects structured neuronal activity across early visual field maps. To explore this hypothesis, we characterize the propagation of BOLD activity across V1, V2, and V3 using a modeling approach that aims to disentangle the contributions of local activity and directed interactions in shaping BOLD propagation. It does so by estimating the effective connectivity (EC) and the excitability of a noise-diffusion network to reproduce the spatiotemporal covariance structure of the data. We apply our approach to 7T fMRI recordings acquired during resting state (RS) and visual field mapping (VFM). Our results reveal different EC interactions and changes in cortical excitability in RS and VFM, and point to a reconfiguration of feedforward and feedback interactions across the visual system. We conclude that the propagation of BOLD activity has functional relevance, as it reveals directed interactions and changes in cortical excitability in a task-dependent manner.
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Affiliation(s)
- Nicolás Gravel
- Neural Dynamics of Visual Cognition Group, Department of Education and Psychology, Freie University Berlin, 14195 Berlin, Germany.,Laboratory of Experimental Ophthalmology, University Medical Center Groningen, University of Groningen, 9713 GZ Groningen, The Netherlands
| | - Remco J Renken
- Laboratory of Experimental Ophthalmology, University Medical Center Groningen, University of Groningen, 9713 GZ Groningen, The Netherlands.,Cognitive Neuroscience Center, University Medical Center Groningen, University of Groningen, 9713 GZ Groningen, The Netherlands
| | - Ben M Harvey
- Experimental Psychology, Helmholtz Institute, Utrecht University, 3584 CS Utrecht, The Netherlands
| | - Gustavo Deco
- Center for Brain and Cognition, Computational Neuroscience Group, Department of Information and Communication Technologies, Universitat Pompeu Fabra, 08018 Barcelona, Spain.,Institució Catalana de la Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain.,Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, 04103 Leipzig, Germany.,School of Psychological Sciences, Monash University, VIC 3800 Melbourne, Australia
| | - Frans W Cornelissen
- Laboratory of Experimental Ophthalmology, University Medical Center Groningen, University of Groningen, 9713 GZ Groningen, The Netherlands
| | - Matthieu Gilson
- Center for Brain and Cognition, Computational Neuroscience Group, Department of Information and Communication Technologies, Universitat Pompeu Fabra, 08018 Barcelona, Spain
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13
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van den Brink RL, Pfeffer T, Donner TH. Brainstem Modulation of Large-Scale Intrinsic Cortical Activity Correlations. Front Hum Neurosci 2019; 13:340. [PMID: 31649516 PMCID: PMC6794422 DOI: 10.3389/fnhum.2019.00340] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 09/17/2019] [Indexed: 12/22/2022] Open
Abstract
Brain activity fluctuates continuously, even in the absence of changes in sensory input or motor output. These intrinsic activity fluctuations are correlated across brain regions and are spatially organized in macroscale networks. Variations in the strength, topography, and topology of correlated activity occur over time, and unfold upon a backbone of long-range anatomical connections. Subcortical neuromodulatory systems send widespread ascending projections to the cortex, and are thus ideally situated to shape the temporal and spatial structure of intrinsic correlations. These systems are also the targets of the pharmacological treatment of major neurological and psychiatric disorders, such as Parkinson's disease, depression, and schizophrenia. Here, we review recent work that has investigated how neuromodulatory systems shape correlations of intrinsic fluctuations of large-scale cortical activity. We discuss studies in the human, monkey, and rodent brain, with a focus on non-invasive recordings of human brain activity. We provide a structured but selective overview of this work and distil a number of emerging principles. Future efforts to chart the effect of specific neuromodulators and, in particular, specific receptors, on intrinsic correlations may help identify shared or antagonistic principles between different neuromodulatory systems. Such principles can inform models of healthy brain function and may provide an important reference for understanding altered cortical dynamics that are evident in neurological and psychiatric disorders, potentially paving the way for mechanistically inspired biomarkers and individualized treatments of these disorders.
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Affiliation(s)
- R. L. van den Brink
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - T. Pfeffer
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - T. H. Donner
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Department of Psychology, University of Amsterdam, Amsterdam, Netherlands
- Amsterdam Center for Brain and Cognition, Institute for Interdisciplinary Studies, Amsterdam, Netherlands
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14
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Brunet NM, Fries P. Human visual cortical gamma reflects natural image structure. Neuroimage 2019; 200:635-643. [PMID: 31247299 PMCID: PMC6703910 DOI: 10.1016/j.neuroimage.2019.06.051] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 06/18/2019] [Accepted: 06/20/2019] [Indexed: 11/29/2022] Open
Abstract
Many studies have reported visual cortical gamma-band activity related to stimulus processing and cognition. Most respective studies used artificial stimuli, and the few studies that used natural stimuli disagree. Electrocorticographic (ECoG) recordings from awake macaque areas V1 and V4 found gamma to be abundant during free viewing of natural images. In contrast, a study using ECoG recordings from V1 of human patients reported that many natural images induce no gamma and concluded that it is not necessary for seeing. To reconcile these apparently disparate findings, we reanalyzed those same human ECoG data recorded during presentation of natural images. We find that the strength of gamma is positively correlated with different image-computable metrics of image structure. This holds independently of the precise metric used to quantify gamma. In fact, an average of previously used gamma metrics reflects image structure most robustly. Gamma was sufficiently diagnostic of image structure to differentiate between any possible pair of images with >70% accuracy. Thus, while gamma might be weak for some natural images, the graded strength of gamma reflects the graded degree of image structure, and thereby conveys functionally relevant stimulus properties.
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Affiliation(s)
- Nicolas M Brunet
- Millsaps College, Department of Psychology and Neuroscience, 1701 North State Street, Jackson, MS, 39210, USA
| | - Pascal Fries
- Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, Deutschordenstraße 46, 60528, Frankfurt, Germany; Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Kapittelweg 29, 6525 EN, Nijmegen, Netherlands.
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15
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Perceptual phenomena in destructured sensory fields: Probing the brain’s intrinsic functional architectures. Neurosci Biobehav Rev 2019; 98:265-286. [DOI: 10.1016/j.neubiorev.2019.01.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Revised: 01/13/2019] [Accepted: 01/14/2019] [Indexed: 12/20/2022]
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16
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McAfee SS, Liu Y, Dhamala M, Heck DH. Thalamocortical Communication in the Awake Mouse Visual System Involves Phase Synchronization and Rhythmic Spike Synchrony at High Gamma Frequencies. Front Neurosci 2018; 12:837. [PMID: 30524224 PMCID: PMC6262025 DOI: 10.3389/fnins.2018.00837] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 10/26/2018] [Indexed: 11/21/2022] Open
Abstract
In the neocortex, communication between neurons is heavily influenced by the activity of the surrounding network, with communication efficacy increasing when population patterns are oscillatory and coherent. Less is known about whether coherent oscillations are essential for conveyance of thalamic input to the neocortex in awake animals. Here we investigated whether visual-evoked oscillations and spikes in the primary visual cortex (V1) were aligned with those in the visual thalamus (dLGN). Using simultaneous recordings of visual-evoked activity in V1 and dLGN we demonstrate that thalamocortical communication involves synchronized local field potential oscillations in the high gamma range (50-90 Hz) which correspond uniquely to precise dLGN-V1 spike synchrony. These results provide evidence of a role for high gamma oscillations in mediating thalamocortical communication in the visual pathway of mice, analogous to beta oscillations in primates.
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Affiliation(s)
- Samuel S McAfee
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, United States
- Department of Diagnostic Imaging, St. Jude Children's Research Hospital, Memphis, TN, United States
| | - Yu Liu
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Mukesh Dhamala
- Department of Physics and Astronomy, Neuroscience Institute, Georgia State University, Atlanta, GA, United States
| | - Detlef H Heck
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, United States
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17
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Farahmand S, Sobayo T, Mogul DJ. Noise-Assisted Multivariate EMD-Based Mean-Phase Coherence Analysis to Evaluate Phase-Synchrony Dynamics in Epilepsy Patients. IEEE Trans Neural Syst Rehabil Eng 2018; 26:2270-2279. [PMID: 30452374 DOI: 10.1109/tnsre.2018.2881606] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Spatiotemporal evolution of synchrony dynamics among neuronal populations plays an important role in decoding complicated brain function in normal cognitive processing as well as during pathological conditions such as epileptic seizures. In this paper, a non-linear analytical methodology is proposed to quantitatively evaluate the phase-synchrony dynamics in epilepsy patients. A set of finite neuronal oscillators was adaptively extracted from a multi-channel electrocorticographic (ECoG) dataset utilizing noise-assisted multivariate empirical mode de-composition (NA-MEMD). Next, the instantaneous phases of the oscillatory functions were extracted using the Hilbert transform in order to be utilized in the mean-phase coherence analysis. The phase-synchrony dynamics were then assessed using eigenvalue decomposition. The extracted neuronal oscillators were grouped with respect to their frequency range into wideband (1-600 Hz), ripple (80-250 Hz), and fast-ripple (250-600 Hz) bands in order to investigate the dynamics of ECoG activity in these frequency ranges as seizures evolve. Drug-refractory patients with frontal and temporal lobe epilepsy demonstrated a reduction in phase-synchrony around seizure onset. However, the network phase-synchrony started to increase toward seizure end and achieved its maximum level at seizure offset for both types of epilepsy. This result suggests that hyper-synchronization of the epileptic network may be an essential self-regulatory mechanism by which the brain terminates seizures.
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18
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Rohenkohl G, Bosman CA, Fries P. Gamma Synchronization between V1 and V4 Improves Behavioral Performance. Neuron 2018; 100:953-963.e3. [PMID: 30318415 DOI: 10.1016/j.neuron.2018.09.019] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 08/09/2018] [Accepted: 09/11/2018] [Indexed: 10/28/2022]
Abstract
Behavior is often driven by visual stimuli, relying on feedforward communication from lower to higher visual areas. Effective communication depends on enhanced interareal coherence, but it remains unclear whether this coherence occurs at an optimal phase relation that actually improves stimulus transmission to behavioral report. We recorded local field potentials from V1 and V4 of macaques performing an attention task during which they reported changes in the attended stimulus. V1-V4 gamma synchronization immediately preceding the stimulus change partly predicted subsequent reaction times (RTs). RTs slowed systematically as trial-by-trial interareal gamma phase relations deviated from the phase relation at which V1 and V4 synchronized on average. V1-V4 gamma phase relations accounted for RT differences of 13-31 ms. Effects were specific to the attended stimulus and not explained by local power or phase. Thus, interareal gamma synchronization occurs at the optimal phase relation for transmission of sensory inputs to motor responses.
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Affiliation(s)
- Gustavo Rohenkohl
- Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, 60528 Frankfurt, Germany
| | - Conrado Arturo Bosman
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6525 EN Nijmegen, the Netherlands; Swammerdam Institute for Life Sciences, Center for Neuroscience, Faculty of Science, University of Amsterdam, 1098 XH Amsterdam, the Netherlands
| | - Pascal Fries
- Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, 60528 Frankfurt, Germany; Donders Institute for Brain, Cognition and Behaviour, Radboud University, 6525 EN Nijmegen, the Netherlands.
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19
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Maksimenko VA, Runnova AE, Frolov NS, Makarov VV, Nedaivozov V, Koronovskii AA, Pisarchik A, Hramov AE. Multiscale neural connectivity during human sensory processing in the brain. Phys Rev E 2018; 97:052405. [PMID: 29906840 DOI: 10.1103/physreve.97.052405] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Indexed: 11/07/2022]
Abstract
Stimulus-related brain activity is considered using wavelet-based analysis of neural interactions between occipital and parietal brain areas in alpha (8-12 Hz) and beta (15-30 Hz) frequency bands. We show that human sensory processing related to the visual stimuli perception induces brain response resulted in different ways of parieto-occipital interactions in these bands. In the alpha frequency band the parieto-occipital neuronal network is characterized by homogeneous increase of the interaction between all interconnected areas both within occipital and parietal lobes and between them. In the beta frequency band the occipital lobe starts to play a leading role in the dynamics of the occipital-parietal network: The perception of visual stimuli excites the visual center in the occipital area and then, due to the increase of parieto-occipital interactions, such excitation is transferred to the parietal area, where the attentional center takes place. In the case when stimuli are characterized by a high degree of ambiguity, we find greater increase of the interaction between interconnected areas in the parietal lobe due to the increase of human attention. Based on revealed mechanisms, we describe the complex response of the parieto-occipital brain neuronal network during the perception and primary processing of the visual stimuli. The results can serve as an essential complement to the existing theory of neural aspects of visual stimuli processing.
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Affiliation(s)
- Vladimir A Maksimenko
- Yuri Gagarin State Technical University of Saratov, REC "Artificial Intelligence Systems and Neurotechnologies", Saratov, 410054, Russia
| | - Anastasia E Runnova
- Yuri Gagarin State Technical University of Saratov, REC "Artificial Intelligence Systems and Neurotechnologies", Saratov, 410054, Russia
| | - Nikita S Frolov
- Yuri Gagarin State Technical University of Saratov, REC "Artificial Intelligence Systems and Neurotechnologies", Saratov, 410054, Russia
| | - Vladimir V Makarov
- Yuri Gagarin State Technical University of Saratov, REC "Artificial Intelligence Systems and Neurotechnologies", Saratov, 410054, Russia
| | - Vladimir Nedaivozov
- Yuri Gagarin State Technical University of Saratov, REC "Artificial Intelligence Systems and Neurotechnologies", Saratov, 410054, Russia
| | - Alexey A Koronovskii
- Saratov State University, Faculty of Nonlinear Processes, Saratov, 410012, Russia
| | - Alexander Pisarchik
- Yuri Gagarin State Technical University of Saratov, REC "Artificial Intelligence Systems and Neurotechnologies", Saratov, 410054, Russia.,Technical University of Madrid, Campus Montegancedo, E-Madrid 28223, Spain
| | - Alexander E Hramov
- Yuri Gagarin State Technical University of Saratov, REC "Artificial Intelligence Systems and Neurotechnologies", Saratov, 410054, Russia.,Saratov State University, Faculty of Nonlinear Processes, Saratov, 410012, Russia
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20
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Breshears JD, Hamilton LS, Chang EF. Spontaneous Neural Activity in the Superior Temporal Gyrus Recapitulates Tuning for Speech Features. Front Hum Neurosci 2018; 12:360. [PMID: 30279650 PMCID: PMC6153351 DOI: 10.3389/fnhum.2018.00360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Accepted: 08/21/2018] [Indexed: 11/26/2022] Open
Abstract
Background: Numerous studies have demonstrated that individuals exhibit structured neural activity in many brain regions during rest that is also observed during different tasks, however it is still not clear whether and how resting state activity patterns may relate to underlying tuning for specific stimuli. In the posterior superior temporal gyrus (STG), distinct neural activity patterns are observed during the perception of specific linguistic speech features. We hypothesized that spontaneous resting-state neural dynamics of the STG would be structured to reflect its role in speech perception, exhibiting an organization along speech features as seen during speech perception. Methods: Human cortical local field potentials were recorded from the superior temporal gyrus (STG) in 8 patients undergoing surgical treatment of epilepsy. Signals were recorded during speech perception and rest. Patterns of neural activity (high gamma power: 70–150 Hz) during rest, extracted with spatiotemporal principal component analysis, were compared to spatiotemporal neural responses to speech features during perception. Hierarchical clustering was applied to look for patterns in rest that corresponded to speech feature tuning. Results: Significant correlations were found between neural responses to speech features (sentence onsets, consonants, and vowels) and the spontaneous neural activity in the STG. Across subjects, these correlations clustered into five groups, demonstrating tuning for speech features—most robustly for acoustic onsets. These correlations were not seen in other brain areas, or during motor and spectrally-rotated speech control tasks. Conclusions: In this study, we present evidence that the RS structure of STG activity robustly recapitulates its stimulus-evoked response to acoustic onsets. Further, secondary patterns in RS activity appear to correlate with stimulus-evoked responses to speech features. The role of these spontaneous spatiotemporal activity patterns remains to be elucidated.
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Affiliation(s)
- Jonathan D. Breshears
- Department of Neurosurgery, University of California, San Francisco, San Francisco, CA, United States
| | - Liberty S. Hamilton
- Department of Neurosurgery, University of California, San Francisco, San Francisco, CA, United States
- Department of Communication Sciences and Disorders, University of Texas at Austin, Austin, TX, United States
- Department of Neurology, Dell Medical School, University of Texas at Austin, Austin, TX, United States
| | - Edward F. Chang
- Department of Neurosurgery, University of California, San Francisco, San Francisco, CA, United States
- *Correspondence: Edward F. Chang
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21
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Abstract
Theta rhythms, ≈3–8 Hz, have been found in many different parts of the brain. They are predominant in the rodent hippocampus, yet have also been described in the neocortex, primarily in frontal and parietal areas in relation to executive functions. Here, we show a ≈4-Hz theta rhythm in awake macaque monkey area V4 and primary visual cortex. This theta rhythm was spatially coextensive with visually induced gamma-band activity, and gamma power was modulated by theta phase. The strength of theta and of theta-rhythmic gamma modulation was markedly reduced by selective attention. Theta rhythmicity has been observed in microsaccade sequences, and microsaccades influence early visual activity. Yet, removing (the effects of) microsaccades did not influence the results. Theta rhythms govern rodent sniffing and whisking, and human language processing. Human psychophysics suggests a role for theta also in visual attention. However, little is known about theta in visual areas and its attentional modulation. We used electrocorticography (ECoG) to record local field potentials (LFPs) simultaneously from areas V1, V2, V4, and TEO of two macaque monkeys performing a selective visual attention task. We found a ≈4-Hz theta rhythm within both the V1–V2 and the V4–TEO region, and theta synchronization between them, with a predominantly feedforward directed influence. ECoG coverage of large parts of these regions revealed a surprising spatial correspondence between theta and visually induced gamma. Furthermore, gamma power was modulated with theta phase. Selective attention to the respective visual stimulus strongly reduced these theta-rhythmic processes, leading to an unusually strong attention effect for V1. Microsaccades (MSs) were partly locked to theta. However, neuronal theta rhythms tended to be even more pronounced for epochs devoid of MSs. Thus, we find an MS-independent theta rhythm specific to visually driven parts of V1–V2, which rhythmically modulates local gamma and entrains V4–TEO, and which is strongly reduced by attention. We propose that the less theta-rhythmic and thereby more continuous processing of the attended stimulus serves the exploitation of this behaviorally most relevant information. The theta-rhythmic and thereby intermittent processing of the unattended stimulus likely reflects the ecologically important exploration of less relevant sources of information.
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22
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Abstract
PURPOSE OF REVIEW The computational power of the brain arises from the complex interactions between neurons. One straightforward method to quantify the strength of neuronal interactions is by measuring correlation and coherence. Efforts to measure correlation have been advancing rapidly of late, spurred by the development of advanced recording technologies enabling recording from many neurons and brain areas simultaneously. This review highlights recent results that provide clues into the principles of neural coordination, connections to cognitive and neurological phenomena, and key directions for future research. RECENT FINDINGS The correlation structure of neural activity in the brain has important consequences for the encoding properties of neural populations. Recent studies have shown that this correlation structure is not fixed, but adapts in a variety of contexts in ways that appear beneficial to task performance. By studying these changes in biological neural networks and computational models, researchers have improved our understanding of the principles guiding neural communication. SUMMARY Correlation and coherence are highly informative metrics for studying coding and communication in the brain. Recent findings have emphasized how the brain modifies correlation structure dynamically in order to improve information-processing in a goal-directed fashion. One key direction for future research concerns how to leverage these dynamic changes for therapeutic purposes.
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Affiliation(s)
- Adam C. Snyder
- Dept. of Electrical and Computer Engineering, Carnegie Mellon Univ., Pittsburgh, PA, USA
- Dept. of Ophthalmology, Univ. of Pittsburgh, Pittsburgh, PA, USA
- Center for the Neural Basis of Cognition, Univ. of Pittsburgh, Pittsburgh, PA, USA
| | - Matthew A. Smith
- Dept. of Ophthalmology, Univ. of Pittsburgh, Pittsburgh, PA, USA
- Center for the Neural Basis of Cognition, Univ. of Pittsburgh, Pittsburgh, PA, USA
- Dept. of Bioengineering, Univ. of Pittsburgh, Pittsburgh, PA, USA
- Fox Center for Vision Restoration, Univ. of Pittsburgh, Pittsburgh, PA, USA
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23
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Kadipasaoglu CM, Conner CR, Baboyan VG, Rollo M, Pieters TA, Tandon N. Network dynamics of human face perception. PLoS One 2017; 12:e0188834. [PMID: 29190811 PMCID: PMC5708727 DOI: 10.1371/journal.pone.0188834] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Accepted: 11/14/2017] [Indexed: 11/19/2022] Open
Abstract
Prevailing theories suggests that cortical regions responsible for face perception operate in a serial, feed-forward fashion. Here, we utilize invasive human electrophysiology to evaluate serial models of face-processing via measurements of cortical activation, functional connectivity, and cortico-cortical evoked potentials. We find that task-dependent changes in functional connectivity between face-selective regions in the inferior occipital (f-IOG) and fusiform gyrus (f-FG) are bidirectional, not feed-forward, and emerge following feed-forward input from early visual cortex (EVC) to both of these regions. Cortico-cortical evoked potentials similarly reveal independent signal propagations between EVC and both f-IOG and f-FG. These findings are incompatible with serial models, and support a parallel, distributed network underpinning face perception in humans.
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Affiliation(s)
- Cihan Mehmet Kadipasaoglu
- Vivian Smith Department of Neurosurgery, Univ. of Texas Medical School at Houston, Houston, Texas, United States of America
| | - Christopher Richard Conner
- Vivian Smith Department of Neurosurgery, Univ. of Texas Medical School at Houston, Houston, Texas, United States of America
| | - Vatche George Baboyan
- Vivian Smith Department of Neurosurgery, Univ. of Texas Medical School at Houston, Houston, Texas, United States of America
| | - Matthew Rollo
- Vivian Smith Department of Neurosurgery, Univ. of Texas Medical School at Houston, Houston, Texas, United States of America
| | - Thomas Allyn Pieters
- Vivian Smith Department of Neurosurgery, Univ. of Texas Medical School at Houston, Houston, Texas, United States of America
| | - Nitin Tandon
- Vivian Smith Department of Neurosurgery, Univ. of Texas Medical School at Houston, Houston, Texas, United States of America
- Memorial Hermann Hospital, Texas Medical Center, Houston, Texas, United States of America
- * E-mail:
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24
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Scheeringa R, Fries P. Cortical layers, rhythms and BOLD signals. Neuroimage 2017; 197:689-698. [PMID: 29108940 PMCID: PMC6666418 DOI: 10.1016/j.neuroimage.2017.11.002] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 10/16/2017] [Accepted: 11/01/2017] [Indexed: 12/22/2022] Open
Abstract
This review investigates how laminar fMRI can complement insights into brain function derived from the study of rhythmic neuronal synchronization. Neuronal synchronization in various frequency bands plays an important role in neuronal communication between brain areas, and it does so on the backbone of layer-specific interareal anatomical projections. Feedforward projections originate predominantly in supragranular cortical layers and terminate in layer 4, and this pattern is reflected in inter-laminar and interareal directed gamma-band influences. Thus, gamma-band synchronization likely subserves feedforward signaling. By contrast, anatomical feedback projections originate predominantly in infragranular layers and terminate outside layer 4, and this pattern is reflected in inter-laminar and interareal directed alpha- and/or beta-band influences. Thus, alpha-beta band synchronization likely subserves feedback signaling. Furthermore, these rhythms explain part of the BOLD signal, with independent contributions of alpha-beta and gamma. These findings suggest that laminar fMRI can provide us with a potentially useful method to test some of the predictions derived from the study of neuronal synchronization. We review central findings regarding the role of layer-specific neuronal synchronization for brain function, and regarding the link between neuronal synchronization and the BOLD signal. We discuss the role that laminar fMRI could play by comparing it to invasive and non-invasive electrophysiological recordings. Compared to direct electrophysiological recordings, this method provides a metric of neuronal activity that is slow and indirect, but that is uniquely non-invasive and layer-specific with potentially whole brain coverage.
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Affiliation(s)
- René Scheeringa
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Kapittelweg 29, 6525 EN Nijmegen, The Netherlands; Institut National De La Santé Et De La Recherche Médicale U1028, Centre National De La Recherche Scientifique UMR S5292, Centre De Recherche En Neurosciences De Lyon, Bron, France
| | - Pascal Fries
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Kapittelweg 29, 6525 EN Nijmegen, The Netherlands; Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, Deutschordenstraße 46, 60528 Frankfurt, Germany.
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25
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Provencher D, Bizeau A, Gilbert G, Bérubé-Lauzière Y, Whittingstall K. Structural impacts on the timing and amplitude of the negative BOLD response. Magn Reson Imaging 2017; 45:34-42. [PMID: 28917813 DOI: 10.1016/j.mri.2017.09.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Revised: 09/12/2017] [Accepted: 09/12/2017] [Indexed: 01/18/2023]
Abstract
The positive (PBR) and negative BOLD responses (NBR) arising in task-fMRI display varying magnitudes and dynamics across voxels. While the effects of structure, particularly of veins, on the PBR have been studied, little is known of NBR-structure relationships. Like the PBR, the NBR is often used as a surrogate marker of neuronal activation in both basic and clinical research and assessing its relationship with cortical structure may help interpret group differences. We therefore investigated how local structure affects BOLD amplitude and timing in PBR and NBR areas using multi-band fMRI during visual stimulation to obtain high temporal resolution (TR=0.45s) data combined with T1 imaging and susceptibility-weighted imaging (SWI) to quantify the local densities of gray/white matter and veins, respectively. In both PBRs and NBRs, larger venous density was consistently associated with larger BOLD amplitude and delay, up to 1-2s larger relative to areas devoid of large veins. Both binary and sinusoidal visual stimulus modulation yielded similar activation maps and results, suggesting that underlying vasculature affects PBR and NBR temporal dynamics in the same manner. Accounting for structural impacts on PBR and NBR magnitude and timing could help enhance activation map accuracy, better assess functional connectivity, and better characterize neurovascular coupling.
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Affiliation(s)
- David Provencher
- Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke J1H 5N4, Canada.
| | - Alexandre Bizeau
- Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke J1H 5N4, Canada
| | - Guillaume Gilbert
- MR Clinical Science, Philips Healthcare, 281 Hillmount road, Markham L6C 2S3, Canada
| | - Yves Bérubé-Lauzière
- Department of Electrical and Computer Engineering, Université de Sherbrooke, 2500, boul. de l'Université, Sherbrooke J1K 2R1, Canada; Sherbrooke Molecular Imaging Center, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke J1H 5N4, Canada
| | - Kevin Whittingstall
- Sherbrooke Molecular Imaging Center, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke J1H 5N4, Canada; Department of Diagnostic Radiology, Université de Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke J1H 5N4, Canada
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26
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Gravel N, Harvey BM, Renken RJ, Dumoulin SO, Cornelissen FW. Phase-synchronization-based parcellation of resting state fMRI signals reveals topographically organized clusters in early visual cortex. Neuroimage 2017; 170:424-433. [PMID: 28867341 DOI: 10.1016/j.neuroimage.2017.08.063] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 08/02/2017] [Accepted: 08/28/2017] [Indexed: 01/29/2023] Open
Abstract
Resting-state fMRI is widely used to study brain function and connectivity. However, interpreting patterns of resting state (RS) fMRI activity remains challenging as they may arise from different neuronal mechanisms than those triggered by exogenous events. Currently, this limits the use of RS-fMRI for understanding cortical function in health and disease. Here, we examine the phase synchronization (PS) properties of blood-oxygen level dependent (BOLD) signals obtained during visual field mapping (VFM) and RS with 7T fMRI. This data-driven approach exploits spatiotemporal covariations in the phase of BOLD recordings to establish the presence of clusters of synchronized activity. We find that, in both VFM and RS data, selecting the most synchronized neighboring recording sites identifies spatially localized PS clusters that follow the topographic organization of the visual cortex. However, in activity obtained during VFM, PS is spatially more extensive than in RS activity, likely reflecting stimulus-driven interactions between local responses. Nevertheless, the similarity of the PS clusters obtained for RS and stimulus-driven fMRI suggest that they share a common neuroanatomical origin. Our finding justifies and facilitates direct comparison of RS and stimulus-evoked activity.
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Affiliation(s)
- Nicolás Gravel
- Laboratory of Experimental Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
| | - Ben M Harvey
- Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, The Netherlands; Faculty of Psychology and Education Sciences, University of Coimbra, Coimbra, Portugal
| | - Remco J Renken
- NeuroImaging Center, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Serge O Dumoulin
- Faculty of Psychology and Education Sciences, University of Coimbra, Coimbra, Portugal
| | - Frans W Cornelissen
- Laboratory of Experimental Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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27
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Mellem MS, Wohltjen S, Gotts SJ, Ghuman AS, Martin A. Intrinsic frequency biases and profiles across human cortex. J Neurophysiol 2017; 118:2853-2864. [PMID: 28835521 DOI: 10.1152/jn.00061.2017] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 08/09/2017] [Accepted: 08/22/2017] [Indexed: 11/22/2022] Open
Abstract
Recent findings in monkeys suggest that intrinsic periodic spiking activity in selective cortical areas occurs at timescales that follow a sensory or lower order-to-higher order processing hierarchy (Murray JD, Bernacchia A, Freedman DJ, Romo R, Wallis JD, Cai X, Padoa-Schioppa C, Pasternak T, Seo H, Lee D, Wang XJ. Nat Neurosci 17: 1661-1663, 2014). It has not yet been fully explored if a similar timescale hierarchy is present in humans. Additionally, these measures in the monkey studies have not addressed findings that rhythmic activity within a brain area can occur at multiple frequencies. In this study we investigate in humans if regions may be biased toward particular frequencies of intrinsic activity and if a full cortical mapping still reveals an organization that follows this hierarchy. We examined the spectral power in multiple frequency bands (0.5-150 Hz) from task-independent data using magnetoencephalography (MEG). We compared standardized power across bands to find regional frequency biases. Our results demonstrate a mix of lower and higher frequency biases across sensory and higher order regions. Thus they suggest a more complex cortical organization that does not simply follow this hierarchy. Additionally, some regions do not display a bias for a single band, and a data-driven clustering analysis reveals a regional organization with high standardized power in multiple bands. Specifically, theta and beta are both high in dorsal frontal cortex, whereas delta and gamma are high in ventral frontal cortex and temporal cortex. Occipital and parietal regions are biased more narrowly toward alpha power, and ventral temporal lobe displays specific biases toward gamma. Thus intrinsic rhythmic neural activity displays a regional organization but one that is not necessarily hierarchical.NEW & NOTEWORTHY The organization of rhythmic neural activity is not well understood. Whereas it has been postulated that rhythms are organized in a hierarchical manner across brain regions, our novel analysis allows comparison of full cortical maps across different frequency bands, which demonstrate that the rhythmic organization is more complex. Additionally, data-driven methods show that rhythms of multiple frequencies or timescales occur within a particular region and that this nonhierarchical organization is widespread.
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Affiliation(s)
- Monika S Mellem
- Section on Cognitive Neuropsychology, Laboratory of Brain and Cognition, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland; and
| | - Sophie Wohltjen
- Section on Cognitive Neuropsychology, Laboratory of Brain and Cognition, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland; and
| | - Stephen J Gotts
- Section on Cognitive Neuropsychology, Laboratory of Brain and Cognition, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland; and
| | - Avniel Singh Ghuman
- Section on Cognitive Neuropsychology, Laboratory of Brain and Cognition, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland; and.,Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Alex Martin
- Section on Cognitive Neuropsychology, Laboratory of Brain and Cognition, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland; and
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28
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Chen Y, Crawford JD. Cortical Activation during Landmark-Centered vs. Gaze-Centered Memory of Saccade Targets in the Human: An FMRI Study. Front Syst Neurosci 2017; 11:44. [PMID: 28690501 PMCID: PMC5481872 DOI: 10.3389/fnsys.2017.00044] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Accepted: 06/06/2017] [Indexed: 11/13/2022] Open
Abstract
A remembered saccade target could be encoded in egocentric coordinates such as gaze-centered, or relative to some external allocentric landmark that is independent of the target or gaze (landmark-centered). In comparison to egocentric mechanisms, very little is known about such a landmark-centered representation. Here, we used an event-related fMRI design to identify brain areas supporting these two types of spatial coding (i.e., landmark-centered vs. gaze-centered) for target memory during the Delay phase where only target location, not saccade direction, was specified. The paradigm included three tasks with identical display of visual stimuli but different auditory instructions: Landmark Saccade (remember target location relative to a visual landmark, independent of gaze), Control Saccade (remember original target location relative to gaze fixation, independent of the landmark), and a non-spatial control, Color Report (report target color). During the Delay phase, the Control and Landmark Saccade tasks activated overlapping areas in posterior parietal cortex (PPC) and frontal cortex as compared to the color control, but with higher activation in PPC for target coding in the Control Saccade task and higher activation in temporal and occipital cortex for target coding in Landmark Saccade task. Gaze-centered directional selectivity was observed in superior occipital gyrus and inferior occipital gyrus, whereas landmark-centered directional selectivity was observed in precuneus and midposterior intraparietal sulcus. During the Response phase after saccade direction was specified, the parietofrontal network in the left hemisphere showed higher activation for rightward than leftward saccades. Our results suggest that cortical activation for coding saccade target direction relative to a visual landmark differs from gaze-centered directional selectivity for target memory, from the mechanisms for other types of allocentric tasks, and from the directionally selective mechanisms for saccade planning and execution.
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Affiliation(s)
- Ying Chen
- Center for Vision Research, York University, TorontoON, Canada.,Departments of Psychology, Biology, and Kinesiology and Health Science, York University, TorontoON, Canada.,Canadian Action and Perception Network, TorontoON, Canada
| | - J D Crawford
- Center for Vision Research, York University, TorontoON, Canada.,Departments of Psychology, Biology, and Kinesiology and Health Science, York University, TorontoON, Canada.,Canadian Action and Perception Network, TorontoON, Canada.,Vision: Science to Applications Program, York University, TorontoON, Canada
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29
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Lu KH, Jeong JY, Wen H, Liu Z. Spontaneous activity in the visual cortex is organized by visual streams. Hum Brain Mapp 2017; 38:4613-4630. [PMID: 28608643 DOI: 10.1002/hbm.23687] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Revised: 06/05/2017] [Accepted: 06/07/2017] [Indexed: 12/12/2022] Open
Abstract
Large-scale functional networks have been extensively studied using resting state functional magnetic resonance imaging (fMRI). However, the pattern, organization, and function of fine-scale network activity remain largely unknown. Here, we characterized the spontaneously emerging visual cortical activity by applying independent component (IC) analysis to resting state fMRI signals exclusively within the visual cortex. In this subsystem scale, we observed about 50 spatially ICs that were reproducible within and across subjects, and analyzed their spatial patterns and temporal relationships to reveal the intrinsic parcellation and organization of the visual cortex. The resulting visual cortical parcels were aligned with the steepest gradient of cortical myelination, and were organized into functional modules segregated along the dorsal/ventral pathways and foveal/peripheral early visual areas. Cortical distance could partly explain intra-hemispherical functional connectivity, but not interhemispherical connectivity; after discounting the effect of anatomical affinity, the fine-scale functional connectivity still preserved a similar visual-stream-specific modular organization. Moreover, cortical retinotopy, folding, and cytoarchitecture impose limited constraints to the organization of resting state activity. Given these findings, we conclude that spontaneous activity patterns in the visual cortex are primarily organized by visual streams, likely reflecting feedback network interactions. Hum Brain Mapp 38:4613-4630, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Kun-Han Lu
- School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana.,Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana
| | - Jun Young Jeong
- School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana
| | - Haiguang Wen
- School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana.,Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana
| | - Zhongming Liu
- School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana.,Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, Indiana.,Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana
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30
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Abstract
Several recent studies have demonstrated that the bottom-up signaling of a visual stimulus is subserved by interareal gamma-band synchronization, whereas top-down influences are mediated by alpha-beta band synchronization. These processes may implement top-down control of stimulus processing if top-down and bottom-up mediating rhythms are coupled via cross-frequency interaction. To test this possibility, we investigated Granger-causal influences among awake macaque primary visual area V1, higher visual area V4, and parietal control area 7a during attentional task performance. Top-down 7a-to-V1 beta-band influences enhanced visually driven V1-to-V4 gamma-band influences. This enhancement was spatially specific and largest when beta-band activity preceded gamma-band activity by ∼0.1 s, suggesting a causal effect of top-down processes on bottom-up processes. We propose that this cross-frequency interaction mechanistically subserves the attentional control of stimulus selection.SIGNIFICANCE STATEMENT Contemporary research indicates that the alpha-beta frequency band underlies top-down control, whereas the gamma-band mediates bottom-up stimulus processing. This arrangement inspires an attractive hypothesis, which posits that top-down beta-band influences directly modulate bottom-up gamma band influences via cross-frequency interaction. We evaluate this hypothesis determining that beta-band top-down influences from parietal area 7a to visual area V1 are correlated with bottom-up gamma frequency influences from V1 to area V4, in a spatially specific manner, and that this correlation is maximal when top-down activity precedes bottom-up activity. These results show that for top-down processes such as spatial attention, elevated top-down beta-band influences directly enhance feedforward stimulus-induced gamma-band processing, leading to enhancement of the selected stimulus.
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31
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Hacker CD, Snyder AZ, Pahwa M, Corbetta M, Leuthardt EC. Frequency-specific electrophysiologic correlates of resting state fMRI networks. Neuroimage 2017; 149:446-457. [PMID: 28159686 PMCID: PMC5745814 DOI: 10.1016/j.neuroimage.2017.01.054] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Revised: 01/12/2017] [Accepted: 01/22/2017] [Indexed: 11/29/2022] Open
Abstract
Resting state functional MRI (R-fMRI) studies have shown that slow (< 0.1 Hz), intrinsic fluctuations of the blood oxygen level dependent (BOLD) signal are temporally correlated within hierarchically organized functional systems known as resting state networks (RSNs) (Doucet et al., 2011). Most broadly, this hierarchy exhibits a dichotomy between two opposed systems (Fox et al., 2005). One system engages with the environment and includes the visual, auditory, and sensorimotor (SMN) networks as well as the dorsal attention network (DAN), which controls spatial attention. The other system includes the default mode network (DMN) and the fronto-parietal control system (FPC), RSNs that instantiate episodic memory and executive control, respectively. Here, we test the hypothesis, based on the spectral specificity of electrophysiologic responses to perceptual vs. memory tasks (Klimesch, 1999; Pfurtscheller and Lopes da Silva, 1999), that these two large-scale neural systems also manifest frequency specificity in the resting state. We measured the spatial correspondence between electrocorticographic (ECoG) band-limited power (BLP) and R-fMRI correlation patterns in awake, resting, human subjects. Our results show that, while gamma BLP correspondence was common throughout the brain, theta (4–8 Hz) BLP correspondence was stronger in the DMN and FPC, whereas alpha (8–12 Hz) correspondence was stronger in the SMN and DAN. Thus, the human brain, at rest, exhibits frequency specific electrophysiology, respecting both the spectral structure of task responses and the hierarchical organization of RSNs.
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Affiliation(s)
- Carl D Hacker
- Department of Neurosurgery, Washington University School of Medicine, Campus Box 8225, United States.
| | - Abraham Z Snyder
- Department of Radiology, Washington University School of Medicine, Campus Box 8225, United States; Department of Neurology, Washington University School of Medicine, Campus Box 8225, United States
| | - Mrinal Pahwa
- Department of Neurosurgery, Washington University School of Medicine, Campus Box 8225, United States
| | - Maurizio Corbetta
- Department of Neurology, Washington University School of Medicine, Campus Box 8225, United States
| | - Eric C Leuthardt
- Department of Neurosurgery, Washington University School of Medicine, Campus Box 8225, United States
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32
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Mapping human temporal and parietal neuronal population activity and functional coupling during mathematical cognition. Proc Natl Acad Sci U S A 2016; 113:E7277-E7286. [PMID: 27821758 DOI: 10.1073/pnas.1608434113] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Brain areas within the lateral parietal cortex (LPC) and ventral temporal cortex (VTC) have been shown to code for abstract quantity representations and for symbolic numerical representations, respectively. To explore the fast dynamics of activity within each region and the interaction between them, we used electrocorticography recordings from 16 neurosurgical subjects implanted with grids of electrodes over these two regions and tracked the activity within and between the regions as subjects performed three different numerical tasks. Although our results reconfirm the presence of math-selective hubs within the VTC and LPC, we report here a remarkable heterogeneity of neural responses within each region at both millimeter and millisecond scales. Moreover, we show that the heterogeneity of response profiles within each hub mirrors the distinct patterns of functional coupling between them. Our results support the existence of multiple bidirectional functional loops operating between discrete populations of neurons within the VTC and LPC during the visual processing of numerals and the performance of arithmetic functions. These findings reveal information about the dynamics of numerical processing in the brain and also provide insight into the fine-grained functional architecture and connectivity within the human brain.
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Vinck M, Bosman CA. More Gamma More Predictions: Gamma-Synchronization as a Key Mechanism for Efficient Integration of Classical Receptive Field Inputs with Surround Predictions. Front Syst Neurosci 2016; 10:35. [PMID: 27199684 PMCID: PMC4842768 DOI: 10.3389/fnsys.2016.00035] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 04/04/2016] [Indexed: 11/15/2022] Open
Abstract
During visual stimulation, neurons in visual cortex often exhibit rhythmic and synchronous firing in the gamma-frequency (30–90 Hz) band. Whether this phenomenon plays a functional role during visual processing is not fully clear and remains heavily debated. In this article, we explore the function of gamma-synchronization in the context of predictive and efficient coding theories. These theories hold that sensory neurons utilize the statistical regularities in the natural world in order to improve the efficiency of the neural code, and to optimize the inference of the stimulus causes of the sensory data. In visual cortex, this relies on the integration of classical receptive field (CRF) data with predictions from the surround. Here we outline two main hypotheses about gamma-synchronization in visual cortex. First, we hypothesize that the precision of gamma-synchronization reflects the extent to which CRF data can be accurately predicted by the surround. Second, we hypothesize that different cortical columns synchronize to the extent that they accurately predict each other’s CRF visual input. We argue that these two hypotheses can account for a large number of empirical observations made on the stimulus dependencies of gamma-synchronization. Furthermore, we show that they are consistent with the known laminar dependencies of gamma-synchronization and the spatial profile of intercolumnar gamma-synchronization, as well as the dependence of gamma-synchronization on experience and development. Based on our two main hypotheses, we outline two additional hypotheses. First, we hypothesize that the precision of gamma-synchronization shows, in general, a negative dependence on RF size. In support, we review evidence showing that gamma-synchronization decreases in strength along the visual hierarchy, and tends to be more prominent in species with small V1 RFs. Second, we hypothesize that gamma-synchronized network dynamics facilitate the emergence of spiking output that is particularly information-rich and sparse.
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Affiliation(s)
- Martin Vinck
- School of Medicine, Yale University New Haven, CT, USA
| | - Conrado A Bosman
- Cognitive and Systems Neuroscience Group, Swammerdam Institute, Center for Neuroscience, University of AmsterdamAmsterdam, Netherlands; Facultad de Ciencias de la Salud, Universidad Autónoma de ChileSantiago, Chile
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Foster BL, He BJ, Honey CJ, Jerbi K, Maier A, Saalmann YB. Spontaneous Neural Dynamics and Multi-scale Network Organization. Front Syst Neurosci 2016; 10:7. [PMID: 26903823 PMCID: PMC4746329 DOI: 10.3389/fnsys.2016.00007] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 01/19/2016] [Indexed: 11/16/2022] Open
Abstract
Spontaneous neural activity has historically been viewed as task-irrelevant noise that should be controlled for via experimental design, and removed through data analysis. However, electrophysiology and functional MRI studies of spontaneous activity patterns, which have greatly increased in number over the past decade, have revealed a close correspondence between these intrinsic patterns and the structural network architecture of functional brain circuits. In particular, by analyzing the large-scale covariation of spontaneous hemodynamics, researchers are able to reliably identify functional networks in the human brain. Subsequent work has sought to identify the corresponding neural signatures via electrophysiological measurements, as this would elucidate the neural origin of spontaneous hemodynamics and would reveal the temporal dynamics of these processes across slower and faster timescales. Here we survey common approaches to quantifying spontaneous neural activity, reviewing their empirical success, and their correspondence with the findings of neuroimaging. We emphasize invasive electrophysiological measurements, which are amenable to amplitude- and phase-based analyses, and which can report variations in connectivity with high spatiotemporal precision. After summarizing key findings from the human brain, we survey work in animal models that display similar multi-scale properties. We highlight that, across many spatiotemporal scales, the covariance structure of spontaneous neural activity reflects structural properties of neural networks and dynamically tracks their functional repertoire.
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Affiliation(s)
| | - Biyu J. He
- Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of HealthMD, USA
| | | | - Karim Jerbi
- Department of Psychology, University of MontrealQC, Canada
| | | | - Yuri B. Saalmann
- Department of Psychology, University of Wisconsin - MadisonWI, USA
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