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Qin P, Duncan NW, Chen DYT, Chen CJ, Huang LK, Huang Z, Lin CYE, Wiebking C, Yang CM, Northoff G, Lane TJ. Vascular-metabolic and GABAergic Inhibitory Correlates of Neural Variability Modulation. A Combined fMRI and PET Study. Neuroscience 2018. [PMID: 29530810 DOI: 10.1016/j.neuroscience.2018.02.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Neural activity varies continually from moment to moment. Such temporal variability (TV) has been highlighted as a functionally specific brain property playing a fundamental role in cognition. We sought to investigate the mechanisms involved in TV changes between two basic behavioral states, namely having the eyes open (EO) or eyes closed (EC) in vivo in humans. To these ends we acquired BOLD fMRI, ASL, and [18F]-fluoro-deoxyglucose PET in a group of healthy participants (n = 15), along with BOLD fMRI and [18F]-flumazenil PET in a separate group (n = 19). Focusing on an EO- vs EC-sensitive region in the occipital cortex (identified in an independent sample), we show that TV is constrained in the EO condition compared to EC. This reduction is correlated with an increase in energy consumption and with regional GABAA receptor density. This suggests that the modulation of TV by behavioral state involves an increase in overall neural activity that is related to an increased effect from GABAergic inhibition in addition to any excitatory changes. These findings contribute to our understanding of the mechanisms underlying activity variability in the human brain and its control.
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Affiliation(s)
- Pengmin Qin
- Guangdong Key Laboratory of Mental Health and Cognitive Science, South China Normal University, Guangzhou, China; Graduate Institute of Humanities in Medicine, Taipei Medical University, Taipei, Taiwan; Brain and Consciousness Research Centre, Taipei Medical University-Shuang Ho Hospital, New Taipei City, Taiwan; Centre for Studies of Psychological Applications, South China Normal University, Guangzhou, China; School of Psychology, South China Normal University, Guangzhou, China
| | - Niall W Duncan
- Graduate Institute of Humanities in Medicine, Taipei Medical University, Taipei, Taiwan; Brain and Consciousness Research Centre, Taipei Medical University-Shuang Ho Hospital, New Taipei City, Taiwan; Centre for Cognition and Brain Disorders, Hangzhou Normal University, Hangzhou, China.
| | - David Yen-Ting Chen
- Brain and Consciousness Research Centre, Taipei Medical University-Shuang Ho Hospital, New Taipei City, Taiwan; Department of Radiology, Taipei Medical University-Shuang Ho Hospital, New Taipei City, Taiwan
| | - Chi-Jen Chen
- Department of Radiology, Taipei Medical University-Shuang Ho Hospital, New Taipei City, Taiwan
| | - Li-Kai Huang
- Department of Neurology, Taipei Medical University-Shuang Ho Hospital, New Taipei City, Taiwan
| | - Zirui Huang
- Mind, Brain Imaging and Neuroethics Research Unit, Institute of Mental Health Research, University of Ottawa, Ottawa, Canada
| | | | - Christine Wiebking
- Applied Emotion and Motivation Research, Institute for Psychology and Education, Universität Ulm, Ulm, Germany
| | - Che-Ming Yang
- Department of Nuclear Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan
| | - Georg Northoff
- Graduate Institute of Humanities in Medicine, Taipei Medical University, Taipei, Taiwan; Brain and Consciousness Research Centre, Taipei Medical University-Shuang Ho Hospital, New Taipei City, Taiwan; Department of Neurology, Taipei Medical University-Shuang Ho Hospital, New Taipei City, Taiwan; University of Ottawa Brain and Mind Research Institute, Centre for Neural Dynamics, Faculty of Medicine, University of Ottawa, Ottawa, Canada; Mental Health Centre, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, China
| | - Timothy J Lane
- Graduate Institute of Humanities in Medicine, Taipei Medical University, Taipei, Taiwan; Brain and Consciousness Research Centre, Taipei Medical University-Shuang Ho Hospital, New Taipei City, Taiwan; Research Center for Mind, Brain, and Learning, National Chengchi University, Taipei, Taiwan.
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Volberg G, Wutz A, Greenlee MW. Top-down control in contour grouping. PLoS One 2013; 8:e54085. [PMID: 23326575 PMCID: PMC3542329 DOI: 10.1371/journal.pone.0054085] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 12/10/2012] [Indexed: 11/21/2022] Open
Abstract
Human observers tend to group oriented line segments into full contours if they follow the Gestalt rule of 'good continuation'. It is commonly assumed that contour grouping emerges automatically in early visual cortex. In contrast, recent work in animal models suggests that contour grouping requires learning and thus involves top-down control from higher brain structures. Here we explore mechanisms of top-down control in perceptual grouping by investigating synchronicity within EEG oscillations. Human participants saw two micro-Gabor arrays in a random order, with the task to indicate whether the first (S1) or the second stimulus (S2) contained a contour of collinearly aligned elements. Contour compared to non-contour S1 produced a larger posterior post-stimulus beta power (15–21 Hz). Contour S2 was associated with a pre-stimulus decrease in posterior alpha power (11–12 Hz) and in fronto-posterior theta (4–5 Hz) phase couplings, but not with a post-stimulus increase in beta power. The results indicate that subjects used prior knowledge from S1 processing for S2 contour grouping. Expanding previous work on theta oscillations, we propose that long-range theta synchrony shapes neural responses to perceptual groupings regulating lateral inhibition in early visual cortex.
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Affiliation(s)
- Gregor Volberg
- Institut für Psychologie, Universität Regensburg, Regensburg, Germany.
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Mao R, Schummers J, Knoblich U, Lacey CJ, Van Wart A, Cobos I, Kim C, Huguenard JR, Rubenstein JLR, Sur M. Influence of a subtype of inhibitory interneuron on stimulus-specific responses in visual cortex. ACTA ACUST UNITED AC 2011; 22:493-508. [PMID: 21666125 DOI: 10.1093/cercor/bhr057] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Inhibition modulates receptive field properties and integrative responses of neurons in cortical circuits. The contribution of specific interneuron classes to cortical circuits and emergent responses is unknown. Here, we examined neuronal responses in primary visual cortex (V1) of adult Dlx1(-/-) mice, which have a selective reduction in cortical dendrite-targeting interneurons (DTIs) that express calretinin, neuropeptide Y, and somatostatin. The V1 neurons examined in Dlx1(-/-) mice have reduced orientation selectivity and altered firing rates, with elevated late responses, suggesting that local inhibition at dendrites has a specific role in modulating neuronal computations. We did not detect overt changes in the physiological properties of thalamic relay neurons and features of thalamocortical projections, such as retinotopic maps and eye-specific inputs, in the mutant mice, suggesting that the defects are cortical in origin. These experimental results are well explained by a computational model that integrates broad tuning from dendrite-targeting and narrower tuning from soma-targeting interneuron subclasses. Our findings suggest a key role for DTIs in the fine-tuning of stimulus-specific cortical responses.
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Affiliation(s)
- Rong Mao
- Picower Institute for Learning and Memory, Cambridge, MA 02139, USA.
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The environmental pollutant endosulfan disrupts cerebral cortical function at low doses. Neurotoxicology 2010; 32:31-7. [PMID: 21144862 DOI: 10.1016/j.neuro.2010.12.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 11/20/2010] [Accepted: 12/01/2010] [Indexed: 11/21/2022]
Abstract
Endosulfan can induce convulsions that could lead to brain damage. The variability and lack of specificity of neurological signs and symptoms in the pre-convulsive stages makes early diagnosis difficult. We sought to determine if electrophysiological exploration of the cerebral cortex could yield objective signs of endosulfan intoxication at levels that do not elicit convulsions. Endosulfan was administered intravenously to Sprague-Dawley adult rats under urethane anesthesia at doses from 0.5 to 4mg/kg. EEG power and the evoked potentials (EP) to forepaw electrical stimulation were studied over the contralateral (S1CL) and homolateral (S1HL) cortical somatosensory areas and the contralateral visual area (V1CL). At each area, five EP waves were measured. Arterial blood pressure, heart rate and body temperature were also recorded. Endosulfan induced a dose-related increase in EPs at all sites. At S1CL, EP peak amplitude was greater than baseline at 1, 2 and 4mg/kg for the first negative, second positive and third negative waves, and at 2 and 4mg/kg for the first and third positive waves. Similar but less marked trends were observed at S1HL and V1CL. A shift of EEG power to higher frequencies (alpha and beta EEG bands) was only present at 4mg/kg. In conclusion, endosulfan induced a large increase of cortical evoked potentials amplitudes at doses that did not elicit convulsions. These responses could be used as a non-invasive diagnostic tool to detect low-level endosulfan intoxication in humans and to help establish the NOAEL and LOAEL levels of this pollutant.
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Abstract
Excitatory synapses arising from local neurons in the cat visual cortex are much more numerous than the thalamocortical synapses, which provide the primary sensory input. Many of these local circuit synapses are involved in the connections between cortical layers, but lateral connections within layers provide a major component of the local circuit synapses. We tested the influence of these lateral connections in the primary visual cortex of cats by inactivating small patches of cortex about 450 microm lateral from the recording pipette. By use of the neurotransmitter gamma-aminobutyric acid (GABA), small patches of cortex were inhibited and released from inhibition in seconds. Orientation tuning curves derived from responses to oriented drifting gratings were obtained during short control periods interleaved with periods of GABA inactivation. About 30% of the cells (18/62, recorded in all layers) changed their orientation tuning when a small portion of their lateral input was silenced. There was no broadening of the orientation tuning curve during lateral inactivation. Instead, the recorded cells shifted their preferred orientation towards the orientation of the inactivated site. One explanation is that the GABA inactivation alters the balance of excitatory and inhibitory inputs to a cell, which results in a shift of the cell's preferred orientation.
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Affiliation(s)
- Cyrille C Girardin
- Institute of Neuroinformatics, ETH/University of Zurich, Zurich, Switzerland.
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