151
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Crone JS, Lutkenhoff ES, Bio BJ, Laureys S, Monti MM. Testing Proposed Neuronal Models of Effective Connectivity Within the Cortico-basal Ganglia-thalamo-cortical Loop During Loss of Consciousness. Cereb Cortex 2017; 27:2727-2738. [PMID: 27114177 DOI: 10.1093/cercor/bhw112] [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] [Indexed: 12/17/2022] Open
Abstract
In recent years, a number of brain regions and connectivity patterns have been proposed to be crucial for loss and recovery of consciousness but have not been compared in detail. In a 3 T resting-state functional magnetic resonance imaging paradigm, we test the plausibility of these different neuronal models derived from theoretical and empirical knowledge. Specifically, we assess the fit of each model to the dynamic change in effective connectivity between specific cortical and subcortical regions at different consecutive levels of propofol-induced sedation by employing spectral dynamic causal modeling. Surprisingly, our findings indicate that proposed models of impaired consciousness do not fit the observed patterns of effective connectivity. Rather, the data show that loss of consciousness, at least in the context of propofol-induced sedation, is marked by a breakdown of corticopetal projections from the globus pallidus. Effective connectivity between the globus pallidus and the ventral posterior cingulate cortex, present during wakefulness, fades in the transition from lightly sedated to full loss of consciousness and returns gradually as consciousness recovers, thereby, demonstrating the dynamic shift in brain architecture of the posterior cingulate "hub" during changing states of consciousness. These findings highlight the functional role of a previously underappreciated direct pallido-cortical connectivity in supporting consciousness.
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Affiliation(s)
- Julia Sophia Crone
- Department of Psychology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Evan Scott Lutkenhoff
- Department of Psychology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Branden Joseph Bio
- Department of Psychology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Steven Laureys
- Coma Science Group, Cyclotron Research Center, University of Liège, 4000 Liège, Belgium
| | - Martin Max Monti
- Department of Psychology, University of California Los Angeles, Los Angeles, CA 90095, USA.,Brain Injury Research Center, Department of Neurosurgery, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA 90095, USA
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152
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Ben Simon E, Maron-Katz A, Lahav N, Shamir R, Hendler T. Tired and misconnected: A breakdown of brain modularity following sleep deprivation. Hum Brain Mapp 2017; 38:3300-3314. [PMID: 28370703 DOI: 10.1002/hbm.23596] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 02/10/2017] [Accepted: 03/20/2017] [Indexed: 12/18/2022] Open
Abstract
Sleep deprivation (SD) critically affects a range of cognitive and affective functions, typically assessed during task performance. Whether such impairments stem from changes to the brain's intrinsic functional connectivity remain largely unknown. To examine this hypothesis, we applied graph theoretical analysis on resting-state fMRI data derived from 18 healthy participants, acquired during both sleep-rested and sleep-deprived states. We hypothesized that parameters indicative of graph connectivity, such as modularity, will be impaired by sleep deprivation and that these changes will correlate with behavioral outcomes elicited by sleep loss. As expected, our findings point to a profound reduction in network modularity without sleep, evident in the limbic, default-mode, salience and executive modules. These changes were further associated with behavioral impairments elicited by SD: a decrease in salience module density was associated with worse task performance, an increase in limbic module density was predictive of stronger amygdala activation in a subsequent emotional-distraction task and a shift in frontal hub lateralization (from left to right) was associated with increased negative mood. Altogether, these results portray a loss of functional segregation within the brain and a shift towards a more random-like network without sleep, already detected in the spontaneous activity of the sleep-deprived brain. Hum Brain Mapp 38:3300-3314, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Eti Ben Simon
- Functional Brain Center, Wohl Institute for Advanced Imaging Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Adi Maron-Katz
- Functional Brain Center, Wohl Institute for Advanced Imaging Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Nir Lahav
- Department of Physics, Bar-Ilan University, Ramat Gan, Israel
| | - Ron Shamir
- Blavatnik School of Computer Science, Tel-Aviv University, Tel-Aviv, Israel
| | - Talma Hendler
- Functional Brain Center, Wohl Institute for Advanced Imaging Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,School of Psychological Sciences, Tel Aviv University, Tel-Aviv, Israel.,Sagol school of Neuroscience, Tel Aviv University, Tel Aviv, Israel
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153
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Weng L, Xie Q, Zhao L, Zhang R, Ma Q, Wang J, Jiang W, He Y, Chen Y, Li C, Ni X, Xu Q, Yu R, Huang R. Abnormal structural connectivity between the basal ganglia, thalamus, and frontal cortex in patients with disorders of consciousness. Cortex 2017; 90:71-87. [PMID: 28365490 DOI: 10.1016/j.cortex.2017.02.011] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 09/28/2016] [Accepted: 02/20/2017] [Indexed: 12/17/2022]
Abstract
Consciousness loss in patients with severe brain injuries is associated with reduced functional connectivity of the default mode network (DMN), fronto-parietal network, and thalamo-cortical network. However, it is still unclear if the brain white matter connectivity between the above mentioned networks is changed in patients with disorders of consciousness (DOC). In this study, we collected diffusion tensor imaging (DTI) data from 13 patients and 17 healthy controls, constructed whole-brain white matter (WM) structural networks with probabilistic tractography. Afterward, we estimated and compared topological properties, and revealed an altered structural organization in the patients. We found a disturbance in the normal balance between segregation and integration in brain structural networks and detected significantly decreased nodal centralities primarily in the basal ganglia and thalamus in the patients. A network-based statistical analysis detected a subnetwork with uniformly significantly decreased structural connections between the basal ganglia, thalamus, and frontal cortex in the patients. Further analysis indicated that along the WM fiber tracts linking the basal ganglia, thalamus, and frontal cortex, the fractional anisotropy was decreased and the radial diffusivity was increased in the patients compared to the controls. Finally, using the receiver operating characteristic method, we found that the structural connections within the NBS-derived component that showed differences between the groups demonstrated high sensitivity and specificity (>90%). Our results suggested that major consciousness deficits in DOC patients may be related to the altered WM connections between the basal ganglia, thalamus, and frontal cortex.
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Affiliation(s)
- Ling Weng
- Center for the Study of Applied Psychology, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, Institute of Brain Science and Rehabilitation, South China Normal University, Guangzhou 510631, PR China
| | - Qiuyou Xie
- Centre for Hyperbaric Oxygen and Neurorehabilitation, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou 510010, PR China
| | - Ling Zhao
- Center for the Study of Applied Psychology, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, Institute of Brain Science and Rehabilitation, South China Normal University, Guangzhou 510631, PR China
| | - Ruibin Zhang
- Department of Psychology, The University of Hong Kong, Hong Kong, PR China
| | - Qing Ma
- Centre for Hyperbaric Oxygen and Neurorehabilitation, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou 510010, PR China
| | - Junjing Wang
- Center for the Study of Applied Psychology, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, Institute of Brain Science and Rehabilitation, South China Normal University, Guangzhou 510631, PR China
| | - Wenjie Jiang
- Center for the Study of Applied Psychology, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, Institute of Brain Science and Rehabilitation, South China Normal University, Guangzhou 510631, PR China
| | - Yanbin He
- Centre for Hyperbaric Oxygen and Neurorehabilitation, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou 510010, PR China
| | - Yan Chen
- Centre for Hyperbaric Oxygen and Neurorehabilitation, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou 510010, PR China
| | - Changhong Li
- Center for the Study of Applied Psychology, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, Institute of Brain Science and Rehabilitation, South China Normal University, Guangzhou 510631, PR China
| | - Xiaoxiao Ni
- Centre for Hyperbaric Oxygen and Neurorehabilitation, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou 510010, PR China
| | - Qin Xu
- Center for the Study of Applied Psychology, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, Institute of Brain Science and Rehabilitation, South China Normal University, Guangzhou 510631, PR China
| | - Ronghao Yu
- Centre for Hyperbaric Oxygen and Neurorehabilitation, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou 510010, PR China.
| | - Ruiwang Huang
- Center for the Study of Applied Psychology, Guangdong Key Laboratory of Mental Health and Cognitive Science, School of Psychology, Institute of Brain Science and Rehabilitation, South China Normal University, Guangzhou 510631, PR China.
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154
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Havlík M. Missing piece of the puzzle in the science of consciousness: Resting state and endogenous correlates of consciousness. Conscious Cogn 2017; 49:70-85. [DOI: 10.1016/j.concog.2017.01.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 12/19/2016] [Accepted: 01/22/2017] [Indexed: 10/20/2022]
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155
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Executive attention deficits after traumatic brain injury reflect impaired recruitment of resources. NEUROIMAGE-CLINICAL 2017; 14:233-241. [PMID: 28180082 PMCID: PMC5288490 DOI: 10.1016/j.nicl.2017.01.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 12/13/2016] [Accepted: 01/11/2017] [Indexed: 11/24/2022]
Abstract
Deficits in attention are a common and devastating consequence of traumatic brain injury (TBI), leading to functional impairments, rehabilitation barriers, and long-term disability. While such deficits are well documented, little is known about their underlying pathophysiology hindering development of effective and targeted interventions. Here we evaluate the integrity of brain systems specific to attentional functions using quantitative assessments of electroencephalography recorded during performance of the Attention Network Test (ANT), a behavioral paradigm that separates alerting, orienting, and executive components of attention. We studied 13 patients, at least 6 months post-TBI with cognitive impairments, and 24 control subjects. Based on performance on the ANT, TBI subjects showed selective impairment in executive attention. In TBI subjects, principal component analysis combined with spectral analysis of the EEG after target appearance extracted a pattern of increased frontal midline theta power (2.5–7.5 Hz) and suppression of frontal beta power (12.5–22.5 Hz). Individual expression of this pattern correlated (r = − 0.67, p < 0.001) with executive attention impairment. The grading of this pattern of spatiotemporal dynamics with executive attention deficits reflects impaired recruitment of anterior forebrain resources following TBI; specifically, deafferentation and variable disfacilitation of medial frontal neuronal populations is proposed as the basis of our findings. Electrophysiological correlate of impaired executive attention after Traumatic Brain Injury is derived. Theta increases in medial frontal and beta suppression in frontal regions is linked to behavioral performance. Individual-specific pathophysiology allows for tracking of recovery/interventions and studies of function-structure.
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156
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Jang SH, Lee HD. Recovery of multiply injured ascending reticular activating systems in a stroke patient. Neural Regen Res 2017; 12:671-672. [PMID: 28553350 PMCID: PMC5436368 DOI: 10.4103/1673-5374.205109] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Sung Ho Jang
- Department of Physical Medicine and Rehabilitation, College of Medicine, Yeungnam University, Daemyungdong, Namgu, Daegu, Republic of Korea
| | - Han Do Lee
- Department of Physical Medicine and Rehabilitation, College of Medicine, Yeungnam University, Daemyungdong, Namgu, Daegu, Republic of Korea
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157
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Wallace R. Sleep, Psychopathology, and Culture. COMPUTATIONAL PSYCHIATRY 2017. [DOI: 10.1007/978-3-319-53910-2_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/26/2023]
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158
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Distinctive time-lagged resting-state networks revealed by simultaneous EEG-fMRI. Neuroimage 2017; 145:1-10. [DOI: 10.1016/j.neuroimage.2016.09.027] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 09/09/2016] [Accepted: 09/13/2016] [Indexed: 11/21/2022] Open
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159
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Cain SM, Ahn S, Garcia E, Zhang Y, Waheed Z, Tyson JR, Yang Y, Van Sung T, Phillips AG, Snutch TP. Heantos-4, a natural plant extract used in the treatment of drug addiction, modulates T-type calcium channels and thalamocortical burst-firing. Mol Brain 2016; 9:94. [PMID: 27919294 PMCID: PMC5139062 DOI: 10.1186/s13041-016-0274-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 11/21/2016] [Indexed: 11/10/2022] Open
Abstract
Heantos-4 is a refined combination of plant extracts currently approved to treat opiate addiction in Vietnam. In addition to its beneficial effects on withdrawal and prevention of relapse, reports of sedation during clinical treatment suggest that arousal networks in the brain may be recruited during Heantos administration. T-type calcium channels are implicated in the generation of sleep rhythms and in this study we examined whether a Heantos-4 extraction modulates T-type calcium channel currents generated by the Cav3.1, Cav3.2 and Ca3.3 subtypes. Utilizing whole-cell voltage clamp on exogenously expressed T-type calcium channels we find that Heantos inhibits Cav3.1 and Cav3.3 currents, while selectively potentiating Cav3.2 currents. We further examined the effects of Heantos-4 extract on low-threshold burst-firing in thalamic neurons which contribute to sleep oscillations. Using whole-cell current clamp in acute thalamic brain slices Heantos-4 suppressed rebound burst-firing in ventrobasal thalamocortical neurons, which express primarily Cav3.1 channels. Conversely, Heantos-4 had no significant effect on the burst-firing properties of thalamic reticular neurons, which express a mixed population of Cav3.2 and Cav3.3 channels. Examining Heantos-4 effects following oral administration in a model of absence epilepsy revealed the potential to exacerbate seizure activity. Together, the findings indicate that Heantos-4 has selective effects both on specific T-type calcium channel isoforms and distinct populations of thalamic neurons providing a putative mechanism underlying its effects on sedation and on the thalamocortical network.
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Affiliation(s)
- Stuart M Cain
- Michael Smith Laboratories and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 219-2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Soyon Ahn
- Department of Psychiatry, University of British Columbia, Vancouver, Canada
| | - Esperanza Garcia
- Michael Smith Laboratories and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 219-2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Yiming Zhang
- Michael Smith Laboratories and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 219-2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Zeina Waheed
- Michael Smith Laboratories and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 219-2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
| | - John R Tyson
- Michael Smith Laboratories and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 219-2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Yi Yang
- Michael Smith Laboratories and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 219-2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Tran Van Sung
- Institute of Chemistry, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - Anthony G Phillips
- Department of Psychiatry, University of British Columbia, Vancouver, Canada
| | - Terrance P Snutch
- Michael Smith Laboratories and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 219-2185 East Mall, Vancouver, BC, V6T 1Z4, Canada. .,Department of Psychiatry, University of British Columbia, Vancouver, Canada.
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160
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Wallace R. High metabolic demand in neural tissues: Information and control theory perspectives on the synergism between rate and stability. J Theor Biol 2016; 409:86-96. [PMID: 27582301 DOI: 10.1016/j.jtbi.2016.08.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 01/13/2016] [Accepted: 08/23/2016] [Indexed: 10/21/2022]
Abstract
Evolutionary process has been selected for inherently unstable systems in higher animals that can react swiftly to changing patterns of threat or opportunity, for example blood pressure, the immune response, and gene expression. However, these require continual strict regulation: uncontrolled blood pressure is fatal, immune cells can attack 'self' tissues, and improper gene expression triggers developmental disorders. Consciousness in particular demands high rates of metabolic free energy to both operate and regulate the fundamental biological machinery: both the 'stream of consciousness' and the 'riverbanks' that confine it to useful realms are constructed and reconstructed moment-by-moment in response to highly dynamic internal and environmental circumstances. We develop powerful necessary conditions models for such phenomena based on the Data Rate Theorem linking control and information theories in the context of inherent instability. The synergism between conscious action and its regulation underlies the ten-fold higher rate of metabolic energy consumption in human neural tissues and implies a close, culturally modulated relation between sleep disorders and certain psychopathologies.
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Affiliation(s)
- Rodrick Wallace
- Division of Epidemiology, The New York State Psychiatric Institute, United States.
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161
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Sekulic S, Gebauer-Bukurov K, Cvijanovic M, Kopitovic A, Ilic D, Petrovic D, Capo I, Pericin-Starcevic I, Christ O, Topalidou A. Appearance of fetal pain could be associated with maturation of the mesodiencephalic structures. J Pain Res 2016; 9:1031-1038. [PMID: 27881927 PMCID: PMC5115678 DOI: 10.2147/jpr.s117959] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Fetal pain remains a controversial subject both in terms of recognizing its existence and the time-frame within which it appears. This article investigates the hypothesis that pain perception during development is not related to any determined structures of the central nervous system (CNS), on the contrary, the process of perception could be made with any structure satisfying conditions that the perception of pain is the organization, identification, and interpretation of sensory information in order to represent and understand the environment. According to this definition, chronic decerebrate and decorticate experimental animals, anencephalic, and hydranencephalic patients demonstrate that the basic, most general, appropriate interaction with the environment can be achieved with a functional mesodiencephalon (brain stem, and diencephalon) as the hierarchically highest structure of the CNS during development. In intact fetuses, this structure shows signs of sufficient maturation starting from the 15th week of gestation. Bearing in mind the dominant role of the reticular formation of the brain stem, which is marked by a wide divergence of afferent information, a sense of pain transmitted through it is diffuse and can dominate the overall perception of the fetus. The threshold for tactile stimuli is lower at earlier stages of gestation. The pain inhibition mechanisms are not sufficiently developed during intrauterine development, which is another factor that leads to increased intensity of pain in the fetus. As a conclusion it could be proposed that the fetus is exposed to rudimentary painful stimuli starting from the 15th gestation week and that it is extremely sensitive to painful stimuli.
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Affiliation(s)
- Slobodan Sekulic
- Department of Neurology, Faculty of Medicine Novi Sad, University of Novi Sad
| | | | - Milan Cvijanovic
- Department of Neurology, Faculty of Medicine Novi Sad, University of Novi Sad
| | | | - Djordje Ilic
- Department of Obstetrics and Gynecology, Faculty of Medicine Novi Sad, University of Novi Sad
| | - Djordje Petrovic
- Department of Obstetrics and Gynecology, Faculty of Medicine Novi Sad, University of Novi Sad
| | - Ivan Capo
- Department of Histology and Embryology, Faculty of Medicine Novi Sad, University of Novi Sad
| | - Ivana Pericin-Starcevic
- Department of Developmental Neurology and Epilepsy, Institute for Child and Youth Health Care of Vojvodina, Faculty of Medicine Novi Sad, University of Novi Sad, Novi Sad, Serbia
| | - Oliver Christ
- School of Applied Psychology, Institute Humans in Complex Systems, Olten, Switzerland
| | - Anastasia Topalidou
- Department of Orthopaedics and Traumatology, University Hospital of Heraklion, Faculty of Medicine, University of Crete, Heraklion, Greece
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162
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Cunningham SI, Tomasi D, Volkow ND. Structural and functional connectivity of the precuneus and thalamus to the default mode network. Hum Brain Mapp 2016; 38:938-956. [PMID: 27739612 DOI: 10.1002/hbm.23429] [Citation(s) in RCA: 134] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 08/15/2016] [Accepted: 09/27/2016] [Indexed: 12/17/2022] Open
Abstract
Neuroimaging studies have identified functional interactions between the thalamus, precuneus, and default mode network (DMN) in studies of consciousness. However, less is known about the structural connectivity of the precuneus and thalamus to regions within the DMN. We used diffusion tensor imaging (DTI) to parcellate the precuneus and thalamus based on their probabilistic white matter connectivity to each other and DMN regions of interest (ROIs) in 37 healthy subjects from the Human Connectome Database. We further assessed resting-state functional connectivity (RSFC) among the precuneus, thalamus, and DMN ROIs. The precuneus was found to have the greatest structural connectivity with the thalamus, where connection fractional anisotropy (FA) increased with age. The precuneus also showed significant structural connectivity to the hippocampus and middle pre-frontal cortex, but minimal connectivity to the angular gyrus and midcingulate cortex. In contrast, the precuneus exhibited significant RSFC with the thalamus and the strongest RSFC with the AG. Significant symmetrical structural connectivity was found between the thalamus and hippocampus, mPFC, sFG, and precuneus that followed known thalamocortical pathways, while thalamic RSFC was strongest with the precuneus and hippocampus. Overall, these findings reveal high levels of structural and functional connectivity linking the thalamus, precuneus, and DMN. Differences between structural and functional connectivity (such as between the precuneus and AG) may be interpreted to reflect dynamic shifts in RSFC for cortical hub-regions involved with consciousness, but could also reflect the limitations of DTI to detect superficial white matter tracts that connect cortico-cortical regions. Hum Brain Mapp 38:938-956, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
| | - Dardo Tomasi
- National Institutes of Health, NIAAA, Bethesda, Maryland
| | - Nora D Volkow
- National Institutes of Health, NIAAA, Bethesda, Maryland.,National Institute of Health, NIDA, Bethesda, Maryland
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163
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Bichler EK, Elder CC, García PS. Clarithromycin increases neuronal excitability in CA3 pyramidal neurons through a reduction in GABAergic signaling. J Neurophysiol 2016; 117:93-103. [PMID: 27733592 DOI: 10.1152/jn.00134.2016] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 10/07/2016] [Indexed: 01/24/2023] Open
Abstract
Antibiotics are used in the treatment and prevention of bacterial infections, but effects on neuron excitability have been documented. A recent study demonstrated that clarithromycin alleviates daytime sleepiness in hypersomnia patients (Trotti LM, Saini P, Freeman AA, Bliwise DL, García PS, Jenkins A, Rye DB. J Psychopharmacol 28: 697-702, 2014). To explore the potential application of clarithromycin as a stimulant, we performed whole cell patch-clamp recordings in rat pyramidal cells from the CA3 region of hippocampus. In the presence of the antibiotic, rheobase current was reduced by 50%, F-I relationship (number of action potentials as a function of injected current) was shifted to the left, and the resting membrane potential was more depolarized. Clarithromycin-induced hyperexcitability was dose dependent; doses of 30 and 300 μM clarithromycin significantly increased the firing frequency and membrane potential compared with controls (P = 0.003, P < 0.0001). We hypothesized that clarithromycin enhanced excitability by reducing GABAA receptor activation. Clarithromycin at 30 μM significantly reduced (P = 0.001) the amplitude of spontaneous miniature inhibitory GABAergic currents and at 300 μM had a minor effect on action potential width. Additionally, we tested the effect of clarithromycin in an ex vivo seizure model by evaluating its effect on spontaneous local field potentials. Bath application of 300 μM clarithromycin enhanced burst frequency twofold compared with controls (P = 0.0006). Taken together, these results suggest that blocking GABAergic signaling with clarithromycin increases cellular excitability and potentially serves as a stimulant, facilitating emergence from anesthesia or normalizing vigilance in hypersomnia and narcolepsy. However, the administration of clarithromycin should be carefully considered in patients with seizure disorders. NEW & NOTEWORTHY Clinical administration of the macrolide antibiotic clarithromycin has been associated with side effects such as mania, agitation, and delirium. Here, we investigated the adverse effects of this antibiotic on CA3 pyramidal cell excitability. Clarithromycin induces hyperexcitability in single neurons and is related to a reduction in GABAergic signaling. Our results support a potentially new application of clarithromycin as a stimulant to facilitate emergence from anesthesia or to normalize vigilance.
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Affiliation(s)
- Edyta K Bichler
- Department of Anesthesiology, Emory University School of Medicine, Atlanta, Georgia; .,Anesthesiology and Research Divisions, Atlanta VA Medical Center, Decatur, Georgia; and
| | | | - Paul S García
- Department of Anesthesiology, Emory University School of Medicine, Atlanta, Georgia.,Anesthesiology and Research Divisions, Atlanta VA Medical Center, Decatur, Georgia; and
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164
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Xiao M, Ge H, Khundrakpam BS, Xu J, Bezgin G, Leng Y, Zhao L, Tang Y, Ge X, Jeon S, Xu W, Evans AC, Liu S. Attention Performance Measured by Attention Network Test Is Correlated with Global and Regional Efficiency of Structural Brain Networks. Front Behav Neurosci 2016; 10:194. [PMID: 27777556 PMCID: PMC5056177 DOI: 10.3389/fnbeh.2016.00194] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Accepted: 09/27/2016] [Indexed: 01/12/2023] Open
Abstract
Functional neuroimaging studies have indicated the involvement of separate brain areas in three distinct attention systems: alerting, orienting, and executive control (EC). However, the structural correlates underlying attention remains unexplored. Here, we utilized graph theory to examine the neuroanatomical substrates of the three attention systems measured by attention network test (ANT) in 65 healthy subjects. White matter connectivity, assessed with diffusion tensor imaging deterministic tractography was modeled as a structural network comprising 90 nodes defined by the automated anatomical labeling (AAL) template. Linear regression analyses were conducted to explore the relationship between topological parameters and the three attentional effects. We found a significant positive correlation between EC function and global efficiency of the whole brain network. At the regional level, node-specific correlations were discovered between regional efficiency and all three ANT components, including dorsolateral superior frontal gyrus, thalamus and parahippocampal gyrus for EC, thalamus and inferior parietal gyrus for alerting, and paracentral lobule and inferior occipital gyrus for orienting. Our findings highlight the fundamental architecture of interregional structural connectivity involved in attention and could provide new insights into the anatomical basis underlying human behavior.
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Affiliation(s)
- Min Xiao
- Research Center for Sectional Imaging Anatomy, Shandong Provincial Key Laboratory of Mental Disorders, School of Medicine, Shandong UniversityJinan, China; Montreal Neurological Institute, McGill University, MontrealQC, Canada
| | - Haitao Ge
- Research Center for Sectional Imaging Anatomy, Shandong Provincial Key Laboratory of Mental Disorders, School of Medicine, Shandong University Jinan, China
| | | | - Junhai Xu
- Research Center for Sectional Imaging Anatomy, Shandong Provincial Key Laboratory of Mental Disorders, School of Medicine, Shandong University Jinan, China
| | - Gleb Bezgin
- Montreal Neurological Institute, McGill University, Montreal QC, Canada
| | - Yuan Leng
- Research Center for Sectional Imaging Anatomy, Shandong Provincial Key Laboratory of Mental Disorders, School of Medicine, Shandong University Jinan, China
| | - Lu Zhao
- Laboratory of Neuroimaging, Institute of Neuroimaging and Informatics, Keck School of Medicine, University of Southern California, Los Angeles CA, USA
| | - Yuchun Tang
- Research Center for Sectional Imaging Anatomy, Shandong Provincial Key Laboratory of Mental Disorders, School of Medicine, Shandong University Jinan, China
| | - Xinting Ge
- Research Center for Sectional Imaging Anatomy, Shandong Provincial Key Laboratory of Mental Disorders, School of Medicine, Shandong University Jinan, China
| | - Seun Jeon
- Montreal Neurological Institute, McGill University, Montreal QC, Canada
| | - Wenjian Xu
- Department of Radiology, Affiliated Hospital of Qingdao University Qingdao, China
| | - Alan C Evans
- Montreal Neurological Institute, McGill University, Montreal QC, Canada
| | - Shuwei Liu
- Research Center for Sectional Imaging Anatomy, Shandong Provincial Key Laboratory of Mental Disorders, School of Medicine, Shandong University Jinan, China
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165
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Zheng ZS, Reggente N, Lutkenhoff E, Owen AM, Monti MM. Disentangling disorders of consciousness: Insights from diffusion tensor imaging and machine learning. Hum Brain Mapp 2016; 38:431-443. [PMID: 27622575 DOI: 10.1002/hbm.23370] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 07/27/2016] [Accepted: 08/25/2016] [Indexed: 11/07/2022] Open
Abstract
Previous studies have suggested that disorders of consciousness (DOC) after severe brain injury may result from disconnections of the thalamo-cortical system. However, thalamo-cortical connectivity differences between vegetative state (VS), minimally conscious state minus (MCS-, i.e., low-level behavior such as visual pursuit), and minimally conscious state plus (MCS+, i.e., high-level behavior such as language processing) remain unclear. Probabilistic tractography in a sample of 25 DOC patients was employed to assess whether structural connectivity in various thalamo-cortical circuits could differentiate between VS, MCS-, and MCS+ patients. First, the thalamus was individually segmented into seven clusters based on patterns of cortical connectivity and tested for univariate differences across groups. Second, reconstructed whole-brain thalamic tracks were used as features in a multivariate searchlight analysis to identify regions along the tracks that were most informative in distinguishing among groups. At the univariate level, it was found that VS patients displayed reduced connectivity in most thalamo-cortical circuits of interest, including frontal, temporal, and sensorimotor connections, as compared with MCS+, but showed more pulvinar-occipital connections when compared with MCS-. Moreover, MCS- exhibited significantly less thalamo-premotor and thalamo-temporal connectivity than MCS+. At the multivariate level, it was found that thalamic tracks reaching frontal, parietal, and sensorimotor regions, could discriminate, up to 100% accuracy, across each pairwise group comparison. Together, these findings highlight the role of thalamo-cortical connections in patients' behavioral profile and level of consciousness. Diffusion tensor imaging combined with machine learning algorithms could thus potentially facilitate diagnostic distinctions in DOC and shed light on the neural correlates of consciousness. Hum Brain Mapp 38:431-443, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Zhong S Zheng
- Department of Psychology, University of California Los Angeles, Los Angeles, California
| | - Nicco Reggente
- Department of Psychology, University of California Los Angeles, Los Angeles, California
| | - Evan Lutkenhoff
- Department of Psychology, University of California Los Angeles, Los Angeles, California
| | - Adrian M Owen
- The Brain and Mind Institute, University of Western Ontario, London, Ontario, Canada
| | - Martin M Monti
- Department of Psychology, University of California Los Angeles, Los Angeles, California.,Department of Neurosurgery, University of California Los Angeles, Los Angeles, California
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166
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McKinnon MC, Boyd JE, Frewen PA, Lanius UF, Jetly R, Richardson JD, Lanius RA. A review of the relation between dissociation, memory, executive functioning and social cognition in military members and civilians with neuropsychiatric conditions. Neuropsychologia 2016; 90:210-34. [DOI: 10.1016/j.neuropsychologia.2016.07.017] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 06/16/2016] [Accepted: 07/16/2016] [Indexed: 01/01/2023]
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167
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Calderon DP, Kilinc M, Maritan A, Banavar JR, Pfaff D. Generalized CNS arousal: An elementary force within the vertebrate nervous system. Neurosci Biobehav Rev 2016; 68:167-176. [PMID: 27216213 PMCID: PMC5003634 DOI: 10.1016/j.neubiorev.2016.05.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Revised: 05/19/2016] [Accepted: 05/19/2016] [Indexed: 01/13/2023]
Abstract
Why do animals and humans do anything at all? Arousal is the most powerful and essential function of the brain, a continuous function that accounts for the ability of animals and humans to respond to stimuli in the environment by producing muscular responses. Following decades of psychological, neurophysiological and molecular investigations, generalized CNS arousal can now be analyzed using approaches usually applied to physical systems. The concept of "criticality" is a state that illustrates an advantage for arousal systems poised near a phase transition. This property provides speed and sensitivity and facilitates the transition of the system into different brain states, especially as the brain crosses a phase transition from less aroused to more aroused states. In summary, concepts derived from applied mathematics of physical systems will now find their application in this area of neuroscience, the neurobiology of CNS arousal.
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Affiliation(s)
- D P Calderon
- Laboratory for Neurobiology and Behavior, the Rockefeller University, New York, NY 10065, United States; Department of Anaesthesiology, Weill Cornell Medical College, New York, NY 10021, United States.
| | - M Kilinc
- Laboratory for Neurobiology and Behavior, the Rockefeller University, New York, NY 10065, United States
| | - A Maritan
- Department of Physics, University of Padova, Istituto Nazionale di Fisica Nucleare and Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, 35131 Padova, Italy
| | - J R Banavar
- Department of Physics, University of Maryland, College Park, MD 20742, United States
| | - D Pfaff
- Laboratory for Neurobiology and Behavior, the Rockefeller University, New York, NY 10065, United States
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168
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Baker JL, Ryou JW, Wei XF, Butson CR, Schiff ND, Purpura KP. Robust modulation of arousal regulation, performance, and frontostriatal activity through central thalamic deep brain stimulation in healthy nonhuman primates. J Neurophysiol 2016; 116:2383-2404. [PMID: 27582298 DOI: 10.1152/jn.01129.2015] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 08/08/2016] [Indexed: 11/22/2022] Open
Abstract
The central thalamus (CT) is a key component of the brain-wide network underlying arousal regulation and sensory-motor integration during wakefulness in the mammalian brain. Dysfunction of the CT, typically a result of severe brain injury (SBI), leads to long-lasting impairments in arousal regulation and subsequent deficits in cognition. Central thalamic deep brain stimulation (CT-DBS) is proposed as a therapy to reestablish and maintain arousal regulation to improve cognition in select SBI patients. However, a mechanistic understanding of CT-DBS and an optimal method of implementing this promising therapy are unknown. Here we demonstrate in two healthy nonhuman primates (NHPs), Macaca mulatta, that location-specific CT-DBS improves performance in visuomotor tasks and is associated with physiological effects consistent with enhancement of endogenous arousal. Specifically, CT-DBS within the lateral wing of the central lateral nucleus and the surrounding medial dorsal thalamic tegmental tract (DTTm) produces a rapid and robust modulation of performance and arousal, as measured by neuronal activity in the frontal cortex and striatum. Notably, the most robust and reliable behavioral and physiological responses resulted when we implemented a novel method of CT-DBS that orients and shapes the electric field within the DTTm using spatially separated DBS leads. Collectively, our results demonstrate that selective activation within the DTTm of the CT robustly regulates endogenous arousal and enhances cognitive performance in the intact NHP; these findings provide insights into the mechanism of CT-DBS and further support the development of CT-DBS as a therapy for reestablishing arousal regulation to support cognition in SBI patients.
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Affiliation(s)
- Jonathan L Baker
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York;
| | - Jae-Wook Ryou
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York
| | - Xuefeng F Wei
- College of New Jersey, Department of Biomedical Engineering, Ewing Township, New Jersey; and
| | - Christopher R Butson
- University of Utah, Scientific Computing & Imaging (SCI) Institute, Department of Bioengineering, Salt Lake City, Utah
| | - Nicholas D Schiff
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York
| | - Keith P Purpura
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York
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169
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Chica AB, Bayle DJ, Botta F, Bartolomeo P, Paz-Alonso PM. Interactions between phasic alerting and consciousness in the fronto-striatal network. Sci Rep 2016; 6:31868. [PMID: 27555378 PMCID: PMC4995394 DOI: 10.1038/srep31868] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 07/27/2016] [Indexed: 11/24/2022] Open
Abstract
Only a small fraction of all the information reaching our senses can be the object of conscious report or voluntary action. Although some models propose that different attentional states (top-down amplification and vigilance) are necessary for conscious perception, few studies have explored how the brain activations associated with different attentional systems (such as top-down orienting and phasic alerting) lead to conscious perception of subsequent visual stimulation. The aim of the present study was to investigate the neural mechanisms associated with endogenous spatial attention and phasic alertness, and their interaction with the conscious perception of near-threshold stimuli. The only region demonstrating a neural interaction between endogenous attention and conscious perception was the thalamus, while a larger network of cortical and subcortical brain activations, typically associated with phasic alerting, was highly correlated with participants' conscious reports. Activation of the anterior cingulate cortex, supplementary motor area, frontal eye fields, thalamus, and caudate nucleus was related to perceptual consciousness. These data suggest that not all attentional systems are equally effective in enhancing conscious perception, highlighting the importance of thalamo-cortical circuits on the interactions between alerting and consciousness.
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Affiliation(s)
- Ana B. Chica
- Department of Experimental Psychology, and Brain, Mind, and Behavior Research Center (CIMCYC), University of Granada, Spain
| | - Dimitri J. Bayle
- Sport and Movement Research Center (CeRSM, EA 2931), Université Paris Ouest-La Défense, Nanterre, France
- INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, and Université Pierre et Marie Curie-Paris 6, UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013 Paris, France
| | - Fabiano Botta
- Department of Experimental Psychology, and Brain, Mind, and Behavior Research Center (CIMCYC), University of Granada, Spain
| | - Paolo Bartolomeo
- INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, and Université Pierre et Marie Curie-Paris 6, UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013 Paris, France
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170
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Hazell AS. The Vegetative State and Stem Cells: Therapeutic Considerations. Front Neurol 2016; 7:118. [PMID: 27602016 PMCID: PMC4993988 DOI: 10.3389/fneur.2016.00118] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 07/07/2016] [Indexed: 01/20/2023] Open
Abstract
The vegetative state (VS), also known as “unresponsive wakefulness syndrome,” is considered one of the most devastating outcomes of acquired brain injury. While diagnosis of this condition is generally well-defined clinically, patients often appear to be awake despite an absence of behavioral signs of awareness, which to the family can be confusing, leading them to believe the loved one is aware of their surroundings. This inequality of agreement can be very distressing. Currently, no cure for the VS is available; as a result, patients may remain in this condition for the rest of their lives, which in some cases amount to decades. Recent advances in stem cell approaches for the treatment of other neurological conditions may now provide an opportunity to intervene in this syndrome. This mini review will address the development of VS, its diagnosis, affected cerebral structures, and the underlying basis of how stem cells can offer therapeutic promise that would take advantage of the often long-term features associated with this maladie to effect a repair of the severely damaged circuitry. In addition, current limitations of this treatment strategy, including a lack of animal models, few long-term clinical studies that might identify benefits of stem cell treatment, and the potential for development of tumors are considered.
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Affiliation(s)
- Alan S Hazell
- Department of Medicine, University of Montreal, Montreal, Quebec, Canada; Programa de Postgrado en Fisiopatología Médica, Universidade Estadual de Campinas (UNICAMP), Campinas, São Paulo, Brazil
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171
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Caliandro P, Vecchio F, Miraglia F, Reale G, Della Marca G, La Torre G, Lacidogna G, Iacovelli C, Padua L, Bramanti P, Rossini PM. Small-World Characteristics of Cortical Connectivity Changes in Acute Stroke. Neurorehabil Neural Repair 2016; 31:81-94. [PMID: 27511048 DOI: 10.1177/1545968316662525] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background After cerebral ischemia, disruption and subsequent reorganization of functional connections occur both locally and remote to the lesion. Recently, complexity of brain connectivity has been described using graph theory, a mathematical approach that depicts important properties of complex systems by quantifying topologies of network representations. Functional and dynamic changes of brain connectivity can be reliably analyzed via electroencephalography (EEG) recordings even when they are not yet reflected in structural changes of connections. Objective We tested whether and how ischemic stroke in the acute stage may determine changes in small-worldness of cortical networks as measured by cortical sources of EEG. Methods Graph characteristics of EEG of 30 consecutive stroke patients in acute stage (no more than 5 days after the event) were examined. Connectivity analysis was performed using eLORETA in both hemispheres. Results Network rearrangements were mainly detected in delta, theta, and alpha bands when patients were compared with healthy subjects. In delta and alpha bands similar findings were observed in both hemispheres regardless of the side of ischemic lesion: bilaterally decreased small-worldness in the delta band and bilaterally increased small-worldness in the alpha2 band. In the theta band, bilaterally decreased small-worldness was observed only in patients with stroke in the left hemisphere. Conclusions After an acute stroke, brain cortex rearranges its network connections diffusely, in a frequency-dependent modality probably in order to face the new anatomical and functional frame.
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Affiliation(s)
- Pietro Caliandro
- Catholic University, Rome, Italy .,Fondazione Don Carlo Gnocchi Onlus, Milan, Italy
| | | | | | | | | | | | | | - Chiara Iacovelli
- Catholic University, Rome, Italy.,Fondazione Don Carlo Gnocchi Onlus, Milan, Italy
| | - Luca Padua
- Catholic University, Rome, Italy.,Fondazione Don Carlo Gnocchi Onlus, Milan, Italy
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172
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Vanzan S, Wilkinson D, Ferguson H, Pullicino P, Sakel M. Behavioural improvement in a minimally conscious state after caloric vestibular stimulation: evidence from two single case studies. Clin Rehabil 2016; 31:500-507. [PMID: 27121862 DOI: 10.1177/0269215516646167] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To investigate whether caloric vestibular stimulation, a non-invasive form of neuro-modulation, alters the level of awareness in people residing in a minimally conscious state. DESIGN Single-case ( n = 2), prospective, controlled (ABAB) efficacy study. SETTING Tertiary, neuro-rehabilitation inpatient ward within a university hospital. PARTICIPANTS Two individuals in a minimally conscious state. INTERVENTION Left ear caloric vestibular stimulation was performed in two four/five-week blocks interleaved with two four/five-week blocks of sham stimulation. Session duration and frequency gradually increased within each block from once per day for 10 minutes (Week 1) to once per day for 20 minutes (Week 2) to 20 minutes twice per day in the remaining weeks. MEASURES Wessex Head Injury Matrix, JFK Coma Recovery Scale - Revised. RESULTS Both participants' Wessex Head Injury Matrix scores indicated a transition from involuntary (i.e. mechanical vocalization) to voluntary (i.e. gesture making, selective responses to family members) behaviour that was time-locked to the onset of active stimulation. In one participant, this improvement persisted for at least four weeks after active stimulation, while in the other it diminished two weeks after stimulation. Allied, although less dramatic, changes were seen on the arousal and auditory subscales of the JFK Coma Recovery Scale - Revised. CONCLUSION The data provide the first evidence that vestibular stimulation may help improve outcome in a low awareness state, although further studies are needed to replicate effect and determine longer-term benefit.
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Affiliation(s)
- Serena Vanzan
- 1 School of Psychology, University of Kent, Canterbury, UK
| | | | | | - Patrick Pullicino
- 2 KentHealth, University of Kent, Canterbury, UK.,3 Department of Neurology, East Kent Hospitals University NHS Foundation Trust, Kent, UK
| | - Mohamed Sakel
- 4 East Kent Neuro-Rehabilitation Service, East Kent Hospitals University NHS Foundation Trust, Kent, UK
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173
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Effects of Ketamine on Neuronal Spontaneous Excitatory Postsynaptic Currents and Miniature Excitatory Postsynaptic Currents in the Somatosensory Cortex of Rats. IRANIAN JOURNAL OF MEDICAL SCIENCES 2016; 41:275-82. [PMID: 27365548 PMCID: PMC4912645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Ketamine is a commonly used intravenous anesthetic which produces dissociation anesthesia, analgesia, and amnesia. The mechanism of ketamine-induced synaptic inhibition in high-level cortical areas is still unknown. We aimed to elucidate the effects of different concentrations of ketamine on the glutamatergic synaptic transmission of the neurons in the primary somatosensory cortex by using the whole-cell patch-clamp method. METHODS Sprague-Dawley rats (11-19 postnatal days, n=36) were used to obtain brain slices (300 μM). Spontaneous excitatory postsynaptic currents (data from 40 neurons) were recorded at a command potential of -70 mV in the presence of bicuculline (a competitive antagonist of GABAA receptors, 30 μM) and strychnine (glycine receptor antagonist, 30 μM). Miniature excitatory postsynaptic currents (data from 40 neurons) were also recorded when 1 μM of tetrodotoxin was added into the artificial cerebrospinal fluid. We used GraphPad Prism5for statistical analysis. Significant differences in the mean amplitude and frequency were tested using the Student paired 2-tailed t test. Values of P<0.05 were considered significant. RESULTS Different concentrations of ketamine inhibited the frequency and amplitude of the spontaneous excitatory postsynaptic currents as well as the amplitude of the miniature excitatory postsynaptic currents in a concentration-dependent manner, but they exerted no significant effect on the frequency of the miniature excitatory postsynaptic currents. CONCLUSION Ketamine inhibited the excitatory synaptic transmission of the neurons in the primary somatosensory cortex. The inhibition may have been mediated by a reduction in the sensitivity of the postsynaptic glutamatergic receptors.
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174
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Neural correlates of consciousness in patients who have emerged from a minimally conscious state: a cross-sectional multimodal imaging study. Lancet Neurol 2016; 15:830-842. [DOI: 10.1016/s1474-4422(16)00111-3] [Citation(s) in RCA: 150] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 02/17/2016] [Accepted: 03/02/2016] [Indexed: 01/02/2023]
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175
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Piarulli A, Bergamasco M, Thibaut A, Cologan V, Gosseries O, Laureys S. EEG ultradian rhythmicity differences in disorders of consciousness during wakefulness. J Neurol 2016; 263:1746-60. [DOI: 10.1007/s00415-016-8196-y] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 06/03/2016] [Accepted: 06/04/2016] [Indexed: 10/21/2022]
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176
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Central thalamic deep brain stimulation to support anterior forebrain mesocircuit function in the severely injured brain. J Neural Transm (Vienna) 2016; 123:797-806. [PMID: 27113938 DOI: 10.1007/s00702-016-1547-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 04/02/2016] [Indexed: 10/21/2022]
Abstract
This integrative review frames a general rationale for the use of central thalamic deep brain stimulation (CT-DBS) to support arousal regulation mechanisms in the severely injured brain. The organizing role of the anterior forebrain mesocircuit in recovery mechanisms following widespread deafferentation produced by multi-focal structural brain injuries is emphasized. The mesocircuit model provides the conceptual foundation for the key role of the central thalamus as a privileged node for neuromodulation to support forebrain arousal regulation. In this context, cellular mechanisms arising at the neocortical, striatal, and thalamic population level are considered in the assessment of an individual patient's capacity for harboring underlying reserve that could be recruited for further recovery. Recent preclinical studies and pilot clinical results are compared to frame the detailed rationale for CT-DBS. Application of CT-DBS across the range of outcomes following severe-to-moderate brain injuries is discussed with the aim of improving consciousness and cognition in patients with non-progressive brain injuries.
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177
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Sun D, Lee TMC, Wang Z, Chan CCH. Unfolding the Spatial and Temporal Neural Processing of Making Dishonest Choices. PLoS One 2016; 11:e0153660. [PMID: 27096474 PMCID: PMC4838301 DOI: 10.1371/journal.pone.0153660] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 04/01/2016] [Indexed: 12/30/2022] Open
Abstract
To understand the neural processing that underpins dishonest behavior in an economic exchange game task, this study employed both functional magnetic resonance imaging (fMRI) and event-related potential (ERP) methodologies to examine the neural conditions of 25 participants while they were making either dishonest or honest choices. It was discovered that dishonest choices, contrary to honest choices, elicited stronger fMRI activations in bilateral striatum and anterior insula. It also induced fluctuations in ERP amplitudes within two time windows, which are 270–30 milliseconds before and 110–290 milliseconds after the response, respectively. Importantly, when making either dishonest or honest choices, human and computer counterparts were associated with distinct fMRI activations in the left insula and different ERP amplitudes at medial and right central sites from 80 milliseconds before to 250 milliseconds after the response. These results support the hypothesis that there would be distinct neural processing during making dishonest decisions, especially when the subject considers the interests of the counterpart. Furthermore, the fMRI and ERP findings, together with ERP source reconstruction, clearly delineate the temporal sequence of the neural processes of a dishonest decision: the striatum is activated before response, then the left insula is involved around the time of response, and finally the thalamus is activated after response.
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Affiliation(s)
- Delin Sun
- Laboratory of Neuropsychology, The University of Hong Kong, Hong Kong, China
- Laboratory of Cognitive Affective Neuroscience, The University of Hong Kong, Hong Kong, China
| | - Tatia M. C. Lee
- Laboratory of Neuropsychology, The University of Hong Kong, Hong Kong, China
- Laboratory of Cognitive Affective Neuroscience, The University of Hong Kong, Hong Kong, China
- The State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong, China
- * E-mail: (TMCL); (CCHC)
| | - Zhaoxin Wang
- Key Laboratory of Brain Functional Genomics (MOE & STCSM), Institute of Cognitive Neuroscience, School of Psychology and Cognitive Science, East China Normal University, Shanghai, China
| | - Chetwyn C. H. Chan
- Applied Cognitive Neuroscience Laboratory, Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hong Kong, China
- * E-mail: (TMCL); (CCHC)
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178
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The application of a mathematical model linking structural and functional connectomes in severe brain injury. NEUROIMAGE-CLINICAL 2016; 11:635-647. [PMID: 27200264 PMCID: PMC4864323 DOI: 10.1016/j.nicl.2016.04.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 04/08/2016] [Accepted: 04/10/2016] [Indexed: 11/25/2022]
Abstract
Following severe injuries that result in disorders of consciousness, recovery can occur over many months or years post-injury. While post-injury synaptogenesis, axonal sprouting and functional reorganization are known to occur, the network-level processes underlying recovery are poorly understood. Here, we test a network-level functional rerouting hypothesis in recovery of patients with disorders of consciousness following severe brain injury. This hypothesis states that the brain recovers from injury by restoring normal functional connections via alternate structural pathways that circumvent impaired white matter connections. The so-called network diffusion model, which relates an individual's structural and functional connectomes by assuming that functional activation diffuses along structural pathways, is used here to capture this functional rerouting. We jointly examined functional and structural connectomes extracted from MRIs of 12 healthy and 16 brain-injured subjects. Connectome properties were quantified via graph theoretic measures and network diffusion model parameters. While a few graph metrics showed groupwise differences, they did not correlate with patients' level of consciousness as measured by the Coma Recovery Scale — Revised. There was, however, a strong and significant partial Pearson's correlation (accounting for age and years post-injury) between level of consciousness and network diffusion model propagation time (r = 0.76, p < 0.05, corrected), i.e. the time functional activation spends traversing the structural network. We concluded that functional rerouting via alternate (and less efficient) pathways leads to increases in network diffusion model propagation time. Simulations of injury and recovery in healthy connectomes confirmed these results. This work establishes the feasibility for using the network diffusion model to capture network-level mechanisms in recovery of consciousness after severe brain injury. A “functional rerouting” hypothesis in recovery from brain injury is tested. The connectome-based network diffusion model measures functional rerouting. Recovery in severe brain injury correlates with a network diffusion model parameter. Simulation in healthy connectomes independently validates the results in patients.
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179
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Changes in Neurocognitive Architecture in Patients with Obstructive Sleep Apnea Treated with Continuous Positive Airway Pressure. EBioMedicine 2016; 7:221-9. [PMID: 27322475 PMCID: PMC4909326 DOI: 10.1016/j.ebiom.2016.03.020] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Revised: 03/07/2016] [Accepted: 03/12/2016] [Indexed: 12/30/2022] Open
Abstract
Background Obstructive sleep apnea (OSA) is a chronic, multisystem disorder that has a bidirectional relationship with several major neurological disorders, including Alzheimer's dementia. Treatment with Continuous Positive Airway Pressure (CPAP) offers some protection from the effects of OSA, although it is still unclear which populations should be targeted, for how long, and what the effects of treatment are on different organ systems. We investigated whether cognitive improvements can be achieved as early as one month into CPAP treatment in patients with OSA. Methods 55 patients (mean (SD) age: 47.6 (11.1) years) with newly diagnosed moderate–severe OSA (Oxygen Desaturation Index: 36.6 (25.2) events/hour; Epworth sleepiness score (ESS): 12.8 (4.9)) and 35 matched healthy volunteers were studied. All participants underwent neurocognitive testing, neuroimaging and polysomnography. Patients were randomized into parallel groups: CPAP with best supportive care (BSC), or BSC alone for one month, after which they were re-tested. Findings One month of CPAP with BSC resulted in a hypertrophic trend in the right thalamus [mean difference (%): 4.04, 95% CI: 1.47 to 6.61], which was absent in the BSC group [− 2.29, 95% CI: − 4.34 to − 0.24]. Significant improvement was also recorded in ESS, in the CPAP plus BSC group, following treatment [mean difference (%): − 27.97, 95% CI: − 36.75 to − 19.19 vs 2.46, 95% CI: − 5.23 to 10.15; P = 0.012], correlated to neuroplastic changes in brainstem (r = − 0.37; P = 0.05), and improvements in delayed logical memory scores [57.20, 95% CI: 42.94 to 71.46 vs 23.41, 95% CI: 17.17 to 29.65; P = 0.037]. Interpretation One month of CPAP treatment can lead to adaptive alterations in the neurocognitive architecture that underlies the reduced sleepiness, and improved verbal episodic memory in patients with OSA. We propose that partial neural recovery occurs during short periods of treatment with CPAP. One month of CPAP treatment leads to adaptive alterations in the neuroanatomy and neurocognition in patients with OSA. Improvements in sleepiness and verbal episodic memory were demonstrable following only one month of treatment with CPAP. Our findings support the clinical rationale for the use of CPAP treatment to relieve sleepiness, even for a short duration.
Obstructive sleep apnea (OSA) is a highly prevalent sleep disorder that has been linked with dementia, stroke and increased risks of cardiovascular disease. Continuous positive airway pressure (CPAP) treatment has been shown to be effective in reducing sleepiness in moderate to severe OSA. However, the evidence for its use to reverse or slow the rate of cognitive decline is unclear. Our findings show that one month of CPAP treatment in patients with moderate to severe OSA leads to adaptive alterations in the brain networks associated with reduced sleepiness and improved memory.
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180
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A large-scale perspective on stress-induced alterations in resting-state networks. Sci Rep 2016; 6:21503. [PMID: 26898227 PMCID: PMC4761902 DOI: 10.1038/srep21503] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 01/05/2016] [Indexed: 02/06/2023] Open
Abstract
Stress is known to induce large-scale neural modulations. However, its neural effect once the stressor is removed and how it relates to subjective experience are not fully understood. Here we used a statistically sound data-driven approach to investigate alterations in large-scale resting-state functional connectivity (rsFC) induced by acute social stress. We compared rsfMRI profiles of 57 healthy male subjects before and after stress induction. Using a parcellation-based univariate statistical analysis, we identified a large-scale rsFC change, involving 490 parcel-pairs. Aiming to characterize this change, we employed statistical enrichment analysis, identifying anatomic structures that were significantly interconnected by these pairs. This analysis revealed strengthening of thalamo-cortical connectivity and weakening of cross-hemispheral parieto-temporal connectivity. These alterations were further found to be associated with change in subjective stress reports. Integrating report-based information on stress sustainment 20 minutes post induction, revealed a single significant rsFC change between the right amygdala and the precuneus, which inversely correlated with the level of subjective recovery. Our study demonstrates the value of enrichment analysis for exploring large-scale network reorganization patterns, and provides new insight on stress-induced neural modulations and their relation to subjective experience.
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181
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Prasad JA, Abela AR, Chudasama Y. Midline thalamic reuniens lesions improve executive behaviors. Neuroscience 2016; 345:77-88. [PMID: 26868974 DOI: 10.1016/j.neuroscience.2016.01.071] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Revised: 01/25/2016] [Accepted: 01/27/2016] [Indexed: 12/29/2022]
Abstract
The role of the thalamus in complex cognitive behavior is a topic of increasing interest. Here we demonstrate that lesions of the nucleus reuniens (NRe), a midline thalamic nucleus interconnected with both hippocampal and prefrontal circuitry, lead to enhancement of executive behaviors typically associated with the prefrontal cortex. Rats were tested on four behavioral tasks: (1) the combined attention-memory (CAM) task, which simultaneously assessed attention to a visual target and memory for that target over a variable delay; (2) spatial memory using a radial arm maze, (3) discrimination and reversal learning using a touchscreen operant platform, and (4) decision-making with delayed outcomes. Following NRe lesions, the animals became more efficient in their performance, responding with shorter reaction times but also less impulsively than controls. This change, combined with a decrease in perseverative responses, led to focused attention in the CAM task and accelerated learning in the visual discrimination task. There were no observed changes in tasks involving either spatial memory or value-based decision making. These data complement ongoing efforts to understand the role of midline thalamic structures in human cognition, including the development of thalamic stimulation as a therapeutic strategy for acquired cognitive disabilities (Schiff, 2008; Mair et al., 2011), and point to the NRe as a potential target for clinical intervention.
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Affiliation(s)
- J A Prasad
- Department of Psychology, McGill University, Montreal, QC, H3A 1B1, Canada
| | - A R Abela
- Department of Psychology, McGill University, Montreal, QC, H3A 1B1, Canada
| | - Y Chudasama
- Department of Psychology, McGill University, Montreal, QC, H3A 1B1, Canada.
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182
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Henriques J, Pazart L, Grigoryeva L, Muzard E, Beaussant Y, Haffen E, Moulin T, Aubry R, Ortega JP, Gabriel D. Bedside Evaluation of the Functional Organization of the Auditory Cortex in Patients with Disorders of Consciousness. PLoS One 2016; 11:e0146788. [PMID: 26789734 PMCID: PMC4720275 DOI: 10.1371/journal.pone.0146788] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 12/22/2015] [Indexed: 11/18/2022] Open
Abstract
To measure the level of residual cognitive function in patients with disorders of consciousness, the use of electrophysiological and neuroimaging protocols of increasing complexity is recommended. This work presents an EEG-based method capable of assessing at an individual level the integrity of the auditory cortex at the bedside of patients and can be seen as the first cortical stage of this hierarchical approach. The method is based on two features: first, the possibility of automatically detecting the presence of a N100 wave and second, in showing evidence of frequency processing in the auditory cortex with a machine learning based classification of the EEG signals associated with different frequencies and auditory stimulation modalities. In the control group of twelve healthy volunteers, cortical frequency processing was clearly demonstrated. EEG recordings from two patients with disorders of consciousness showed evidence of partially preserved cortical processing in the first patient and none in the second patient. From these results, it appears that the classification method presented here reliably detects signal differences in the encoding of frequencies and is a useful tool in the evaluation of the integrity of the auditory cortex. Even though the classification method presented in this work was designed for patients with disorders of consciousness, it can also be applied to other pathological populations.
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Affiliation(s)
- Julie Henriques
- Laboratoire de Mathématiques de Besançon, Besançon, France
- Cegos Deployment, Besançon, France
| | - Lionel Pazart
- INSERM CIC 1431 Centre d’Investigation Clinique en Innovation Technologique, CHU de Besançon, Besançon, France
- EA 481 Laboratoire de Neurosciences de Besançon, Besançon, France
| | | | - Emelyne Muzard
- Service de neurologie, CHU de Besançon, Besançon, France
| | - Yvan Beaussant
- Département douleur soins palliatifs, CHU de Besançon, Besançon, France
| | - Emmanuel Haffen
- INSERM CIC 1431 Centre d’Investigation Clinique en Innovation Technologique, CHU de Besançon, Besançon, France
- EA 481 Laboratoire de Neurosciences de Besançon, Besançon, France
- Service de Psychiatrie de l’adulte, CHU de Besançon, Besançon, France
| | - Thierry Moulin
- INSERM CIC 1431 Centre d’Investigation Clinique en Innovation Technologique, CHU de Besançon, Besançon, France
- EA 481 Laboratoire de Neurosciences de Besançon, Besançon, France
- Service de neurologie, CHU de Besançon, Besançon, France
| | - Régis Aubry
- INSERM CIC 1431 Centre d’Investigation Clinique en Innovation Technologique, CHU de Besançon, Besançon, France
- EA 481 Laboratoire de Neurosciences de Besançon, Besançon, France
- Département douleur soins palliatifs, CHU de Besançon, Besançon, France
| | - Juan-Pablo Ortega
- Laboratoire de Mathématiques de Besançon, Besançon, France
- Centre National de la Recherche Scientifique (CNRS), Paris, France
| | - Damien Gabriel
- INSERM CIC 1431 Centre d’Investigation Clinique en Innovation Technologique, CHU de Besançon, Besançon, France
- EA 481 Laboratoire de Neurosciences de Besançon, Besançon, France
- * E-mail:
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183
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Liu J, Lee HJ, Weitz AJ, Fang Z, Lin P, Choy M, Fisher R, Pinskiy V, Tolpygo A, Mitra P, Schiff N, Lee JH. Frequency-selective control of cortical and subcortical networks by central thalamus. eLife 2015; 4:e09215. [PMID: 26652162 PMCID: PMC4721962 DOI: 10.7554/elife.09215] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 11/06/2015] [Indexed: 12/29/2022] Open
Abstract
Central thalamus plays a critical role in forebrain arousal and organized behavior. However, network-level mechanisms that link its activity to brain state remain enigmatic. Here, we combined optogenetics, fMRI, electrophysiology, and video-EEG monitoring to characterize the central thalamus-driven global brain networks responsible for switching brain state. 40 and 100 Hz stimulations of central thalamus caused widespread activation of forebrain, including frontal cortex, sensorimotor cortex, and striatum, and transitioned the brain to a state of arousal in asleep rats. In contrast, 10 Hz stimulation evoked significantly less activation of forebrain, inhibition of sensory cortex, and behavioral arrest. To investigate possible mechanisms underlying the frequency-dependent cortical inhibition, we performed recordings in zona incerta, where 10, but not 40, Hz stimulation evoked spindle-like oscillations. Importantly, suppressing incertal activity during 10 Hz central thalamus stimulation reduced the evoked cortical inhibition. These findings identify key brain-wide dynamics underlying central thalamus arousal regulation. DOI:http://dx.doi.org/10.7554/eLife.09215.001 The ability to wake up every morning and to fall asleep at night is something that most people take for granted. However, damage to a brain region called the central thalamus can cause a range of consciousness-related disorders, including memory problems, excessive sleeping, and even comas. For example, cell death within the central thalamus has been associated with severely disabled patients following traumatic brain injury. Previous studies have found that electrically stimulating the neurons in the central thalamus can change whether an animal is drowsy or awake and alert. However, it was not clear whether a single group of neurons in the central thalamus was responsible for switching the brain’s state between sleep and wakefulness, or how this would work. Liu, Lee, Weitz, Fang et al. have now used a technique called optogenetics to stimulate specific neurons in the central thalamus of rats, by using flashes of light. Stimulation was combined with several techniques to monitor the response of other brain regions, including fMRI imaging that shows the activity of the entire brain. The results showed that rapidly stimulating the neurons in the central thalamus – 40 or 100 times a second – led to widespread brain activity and caused sleeping rats to wake up. In contrast, stimulating the neurons of the central thalamus more slowly – around 10 times a second – suppressed the activity of part of the brain called the sensory cortex and caused rats to enter a seizure-like state of unconsciousness. Further investigation identified a group of inhibitory neurons that the central thalamus interacts with to carry out this suppression. The results suggest that the central thalamus can either power the brain to an “awake” state or promote a state of unconsciousness, depending on how rapidly its neurons are stimulated. Future work will seek to translate these results to the clinic and investigate how stimulation of the central thalamus can be optimized to reduce cognitive deficits in animal models of traumatic brain injury. DOI:http://dx.doi.org/10.7554/eLife.09215.002
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Affiliation(s)
- Jia Liu
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, United States
| | - Hyun Joo Lee
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, United States
| | - Andrew J Weitz
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, United States.,Department of Bioengineering, Stanford University, Stanford, United States
| | - Zhongnan Fang
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, United States.,Department of Electrical Engineering, Stanford University, Stanford, United States
| | - Peter Lin
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, United States
| | - ManKin Choy
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, United States
| | - Robert Fisher
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, United States
| | - Vadim Pinskiy
- Cold Spring Harbor Laboratory, Cold Spring Harbor, United States
| | | | - Partha Mitra
- Cold Spring Harbor Laboratory, Cold Spring Harbor, United States
| | - Nicholas Schiff
- Department of Neurology, Weill Cornell Medical College, New York, United States
| | - Jin Hyung Lee
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, United States.,Department of Bioengineering, Stanford University, Stanford, United States.,Department of Electrical Engineering, Stanford University, Stanford, United States.,Department of Neurosurgery, Stanford University, Stanford, United States
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184
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Peter-Derex L, Magnin M, Bastuji H. Heterogeneity of arousals in human sleep: A stereo-electroencephalographic study. Neuroimage 2015. [DOI: 10.1016/j.neuroimage.2015.07.057] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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185
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Nigri A, Ferraro S, Bruzzone MG, Nava S, D'Incerti L, Bertolino N, Sattin D, Leonardi M, Lundström JN. Central olfactory processing in patients with disorders of consciousness. Eur J Neurol 2015; 23:605-12. [DOI: 10.1111/ene.12907] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 10/01/2015] [Indexed: 02/02/2023]
Affiliation(s)
- A. Nigri
- Neuroradiology Department Foundation IRCCS Neurological Institute ‘Carlo Besta’ MilanItaly
| | - S. Ferraro
- Neuroradiology Department Foundation IRCCS Neurological Institute ‘Carlo Besta’ MilanItaly
| | - M. G. Bruzzone
- Neuroradiology Department Foundation IRCCS Neurological Institute ‘Carlo Besta’ MilanItaly
| | - S. Nava
- Neuroradiology Department Foundation IRCCS Neurological Institute ‘Carlo Besta’ MilanItaly
| | - L. D'Incerti
- Neuroradiology Department Foundation IRCCS Neurological Institute ‘Carlo Besta’ MilanItaly
| | - N. Bertolino
- Health Department Foundation IRCCS Neurological Institute ‘Carlo Besta’ MilanItaly
| | - D. Sattin
- Neurology, Public Health and Disability Unit Scientific Department Foundation IRCCS Neurological Institute ‘Carlo Besta’ Milan Italy
| | - M. Leonardi
- Neurology, Public Health and Disability Unit Scientific Department Foundation IRCCS Neurological Institute ‘Carlo Besta’ Milan Italy
| | - J. N. Lundström
- Department of Clinical Neuroscience Karolinska Institutet Stockholm Sweden
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186
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Lant ND, Gonzalez-Lara LE, Owen AM, Fernández-Espejo D. Relationship between the anterior forebrain mesocircuit and the default mode network in the structural bases of disorders of consciousness. NEUROIMAGE-CLINICAL 2015; 10:27-35. [PMID: 26693399 PMCID: PMC4660379 DOI: 10.1016/j.nicl.2015.11.004] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 10/22/2015] [Accepted: 11/07/2015] [Indexed: 12/01/2022]
Abstract
The specific neural bases of disorders of consciousness (DOC) are still not well understood. Some studies have suggested that functional and structural impairments in the default mode network may play a role in explaining these disorders. In contrast, others have proposed that dysfunctions in the anterior forebrain mesocircuit involving striatum, globus pallidus, and thalamus may be the main underlying mechanism. Here, we provide the first report of structural integrity of fiber tracts connecting the nodes of the mesocircuit and the default mode network in 8 patients with DOC. We found evidence of significant damage to subcortico-cortical and cortico-cortical fibers, which were more severe in vegetative state patients and correlated with clinical severity as determined by Coma Recovery Scale-Revised (CRS-R) scores. In contrast, fiber tracts interconnecting subcortical nodes were not significantly impaired. Lastly, we found significant damage in all fiber tracts connecting the precuneus with cortical and subcortical areas. Our results suggest a strong relationship between the default mode network - and most importantly the precuneus - and the anterior forebrain mesocircuit in the neural basis of the DOC.
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Affiliation(s)
- Nicholas D Lant
- The Brain and Mind Institute, The University of Western Ontario, London, ON N6A 5B7, Canada
| | - Laura E Gonzalez-Lara
- The Brain and Mind Institute, The University of Western Ontario, London, ON N6A 5B7, Canada
| | - Adrian M Owen
- The Brain and Mind Institute, The University of Western Ontario, London, ON N6A 5B7, Canada
| | - Davinia Fernández-Espejo
- The Brain and Mind Institute, The University of Western Ontario, London, ON N6A 5B7, Canada ; School of Psychology, University of Birmingham, Birmingham, B15 2TT, UK
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187
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Basal forebrain control of wakefulness and cortical rhythms. Nat Commun 2015; 6:8744. [PMID: 26524973 PMCID: PMC4659943 DOI: 10.1038/ncomms9744] [Citation(s) in RCA: 191] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 09/25/2015] [Indexed: 02/07/2023] Open
Abstract
Wakefulness, along with fast cortical rhythms and associated cognition, depend on the basal forebrain (BF). BF cholinergic cell loss in dementia and the sedative effect of anti-cholinergic drugs have long implicated these neurons as important for cognition and wakefulness. The BF also contains intermingled inhibitory GABAergic and excitatory glutamatergic cell groups whose exact neurobiological roles are unclear. Here we show that genetically targeted chemogenetic activation of BF cholinergic or glutamatergic neurons in behaving mice produced significant effects on state consolidation and/or the electroencephalogram but had no effect on total wake. Similar activation of BF GABAergic neurons produced sustained wakefulness and high-frequency cortical rhythms, whereas chemogenetic inhibition increased sleep. Our findings reveal a major contribution of BF GABAergic neurons to wakefulness and the fast cortical rhythms associated with cognition. These findings may be clinically applicable to manipulations aimed at increasing forebrain activation in dementia and the minimally conscious state. The mammalian basal forebrain controls cortical rhythm and wake-sleep. Anaclet et al. use genetically-targeted chemogenetic systems to activate or inhibit cholinergic, glutamatergic or GABAergic neurons in this region, and reveal their contributions to behavioral and electrocortical arousal in behaving mice.
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188
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Lewis LD, Voigts J, Flores FJ, Schmitt LI, Wilson MA, Halassa MM, Brown EN. Thalamic reticular nucleus induces fast and local modulation of arousal state. eLife 2015; 4:e08760. [PMID: 26460547 PMCID: PMC4686423 DOI: 10.7554/elife.08760] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 09/24/2015] [Indexed: 02/06/2023] Open
Abstract
During low arousal states such as drowsiness and sleep, cortical neurons exhibit rhythmic slow wave activity associated with periods of neuronal silence. Slow waves are locally regulated, and local slow wave dynamics are important for memory, cognition, and behaviour. While several brainstem structures for controlling global sleep states have now been well characterized, a mechanism underlying fast and local modulation of cortical slow waves has not been identified. Here, using optogenetics and whole cortex electrophysiology, we show that local tonic activation of thalamic reticular nucleus (TRN) rapidly induces slow wave activity in a spatially restricted region of cortex. These slow waves resemble those seen in sleep, as cortical units undergo periods of silence phase-locked to the slow wave. Furthermore, animals exhibit behavioural changes consistent with a decrease in arousal state during TRN stimulation. We conclude that TRN can induce rapid modulation of local cortical state. DOI:http://dx.doi.org/10.7554/eLife.08760.001 We usually think of sleep as a global state: that the entire brain is either asleep or awake. However, recent evidence has suggested that smaller regions of the brain can show sleep-like activity while the rest of the brain remains awake. It is not clear why or how these sleep-like patterns of brain activity appear, and whether they are related to the drowsy behaviour that occurs when one is about to fall asleep. Lewis, Voigts et al. investigated how this process works in mice using a technique called optogenetics. This technique makes it possible to genetically engineer mice so that the activity of particular areas of the brain can be switched on or off by light. Lewis, Voigts et al. used light to stimulate different regions of the brain and tracked the resulting brain activity using tiny electrodes that are capable of detecting the activity of individual neurons. The experiments show that stimulating one part of a deep brain structure called the thalamic reticular nucleus causes just one small part of the brain to switch from being awake to producing sleep-like brain wave patterns. When a larger area is stimulated, the whole brain switches into this sleep-like pattern. Stimulation of the thalamic reticular nucleus also caused the animals to become drowsy and they were more likely to fall asleep, which suggests that sleep-like activity in small parts of the brain may contribute to drowsiness. Lewis, Voigts et al.’s findings identify a brain switch that can influence whether an animal is awake or asleep. Importantly, they show that sleep can be independently controlled in small brain regions, and that the thalamic reticular nucleus contains a ‘map’ that allows it to induce sleep in just one region, or across the whole brain. Memories are strengthened during sleep, so the next challenge is to study whether the thalamic reticular nucleus influences memory formation. The findings also suggest that further study of this brain region may be useful for understanding how the sleep and awake states are controlled by particular neurons. DOI:http://dx.doi.org/10.7554/eLife.08760.002
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Affiliation(s)
- Laura D Lewis
- Society of Fellows, Harvard University, Cambridge, United States.,Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, United States.,Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Jakob Voigts
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Francisco J Flores
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States.,Department of Anesthesia, Harvard Medical School, Boston, United States.,Department of Anesthesia, Massachusetts General Hospital, Boston, United States
| | - L Ian Schmitt
- Neuroscience Institute, New York University, New York, United States
| | - Matthew A Wilson
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States.,Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, United States
| | - Michael M Halassa
- Neuroscience Institute, New York University, New York, United States
| | - Emery N Brown
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States.,Department of Anesthesia, Harvard Medical School, Boston, United States.,Department of Anesthesia, Massachusetts General Hospital, Boston, United States.,Harvard-MIT Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, United States.,Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, United States
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189
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Jang SH, Kwon HG. The direct pathway from the brainstem reticular formation to the cerebral cortex in the ascending reticular activating system: A diffusion tensor imaging study. Neurosci Lett 2015; 606:200-3. [DOI: 10.1016/j.neulet.2015.09.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Revised: 08/24/2015] [Accepted: 09/06/2015] [Indexed: 02/06/2023]
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190
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Nakane T, Miyakoshi M, Nakai T, Naganawa S. How the Non-attending Brain Hears Its Owner's Name. Cereb Cortex 2015; 26:3889-904. [PMID: 26374785 DOI: 10.1093/cercor/bhv184] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We used functional magnetic resonance imaging to investigate how attended and non-attended hearing of a subject's own name (SON) captures his or her attention. It has been reported that SON presentation activates the medial prefrontal cortex (mPFC), which is considered to be the key region for self-recognition. However, it remains unclear whether non-attended SON presentation also activates the mPFC. We hypothesized that an attended SON should activate mPFC more than a non-attended SON. To test this hypothesis, we designed an experiment in which we manipulated the task-relevance of SON; in a name-detection task, SON was a target stimulus, whereas in a tone-judgment task, SON was unrelated to the task. In each condition, identical sets of sound stimuli were presented. SON activated mPFC in the name-detection task but not in the tone-judgment task, supporting our hypothesis. In contrast, non-attended SON activated midbrain reticular formation, thalamus, insula, auditory cortex, and precuneus. We interpreted these to be related to low-level, automatic SON detection. Thus, hearing one's own name in a non-attended condition does not primarily engage the mPFC, but recruits a cortico-subcortical auditory attention network; this may account for the oft-observed salience of SON.
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Affiliation(s)
- Toshiki Nakane
- Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
| | - Makoto Miyakoshi
- Swartz Center for Computational Neuroscience, Institute for Neural Computation, University of California San Diego 0559, La Jolla, CA 92093-0559, USA Japan Society for the Promotion of Science, Tokyo, Japan
| | - Toshiharu Nakai
- Laboratory for Neuroimaging and Informatics, National Center for Geriatrics and Gerontology, Ohbu, Aichi 474-8522, Japan
| | - Shinji Naganawa
- Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Aichi 466-8550, Japan
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191
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Aleksandrova EV, Zaytsev OS, Potapov AA. [Clinical syndromes of neurotransmitter system dysfunction in severe brain injury]. Zh Nevrol Psikhiatr Im S S Korsakova 2015; 115:40-46. [PMID: 26356514 DOI: 10.17116/jnevro20151157140-46] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
AIM To explore neurotransmitter system dysfunctions involved in maintaining of consciousness and motor functions in patients with severe traumatic brain injury (TBI) and to assess their severity and predictive value. MATERIAL AND METHODS Authors examined 100 patients (34 women and 66 men), aged 32.0 ± 13.0 years, with severe TBI. Eighty-eight patients (31 women and 57 men) were studied in the acute stage (1-15 days, mean 5.8 ± 3.7 days) and 70 patients (24 women and 46 men) in the subacute stage (18-70 days, mean 30.4 ± 12.7 days). Inclusion criteria were: severe TBI with depression of consciousness (≤ 7 scores on the Glasgow Coma Scale), admission to the hospital in acute and subacute stages. Outcome of TBI was evaluated using the Glasgow Outcome Scale. RESULTS AND CONCLUSION The following clinical syndromes of neurotransmitter system dysfunction were singled out: excess or insufficiency of glutamate, cholinergic deficit, excess or insufficiency of dopamine. Their transformation during disease was identified. Predictive value of neurotransmitter dysfunctions for TBI is emphasized.
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Affiliation(s)
- E V Aleksandrova
- Burdenko Research Institute of Neurosurgery, Russian Academy Sciences, Moscow
| | - O S Zaytsev
- Burdenko Research Institute of Neurosurgery, Russian Academy Sciences, Moscow
| | - A A Potapov
- Burdenko Research Institute of Neurosurgery, Russian Academy Sciences, Moscow
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192
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Jerath R, Crawford MW, Barnes VA. A unified 3D default space consciousness model combining neurological and physiological processes that underlie conscious experience. Front Psychol 2015; 6:1204. [PMID: 26379573 PMCID: PMC4550793 DOI: 10.3389/fpsyg.2015.01204] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 07/29/2015] [Indexed: 12/28/2022] Open
Abstract
The Global Workspace Theory and Information Integration Theory are two of the most currently accepted consciousness models; however, these models do not address many aspects of conscious experience. We compare these models to our previously proposed consciousness model in which the thalamus fills-in processed sensory information from corticothalamic feedback loops within a proposed 3D default space, resulting in the recreation of the internal and external worlds within the mind. This 3D default space is composed of all cells of the body, which communicate via gap junctions and electrical potentials to create this unified space. We use 3D illustrations to explain how both visual and non-visual sensory information may be filled-in within this dynamic space, creating a unified seamless conscious experience. This neural sensory memory space is likely generated by baseline neural oscillatory activity from the default mode network, other salient networks, brainstem, and reticular activating system.
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Affiliation(s)
| | | | - Vernon A Barnes
- Department of Pediatrics, Georgia Prevention Institute, Georgia Regents University Augusta, GA, USA
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193
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Huang Y, He J, Green AL, Aziz TZ, Stein JF, Wang S. Characteristics of thalamic local field potentials in patients with disorders of consciousness. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2015; 2015:3779-82. [PMID: 26737116 DOI: 10.1109/embc.2015.7319216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A functioning thalamus is essential for treatment of patients with disorders of consciousness (DOC) using deep brain stimulation (DBS). This work aims to identify the potential biomarkers related to consciousness from the thalamic deep brain local field potentials (LFPs) in DOC patients. The frequency features of central thalamic LFPs were characterized with spectral analysis. The features were further compared to those of LFPs from the ventroposterior lateral nucleus of the thalamus (VPL) in patients with pain. There are several distinct characteristics of thalamic LFPs found in patients with DOC. The most important feature is the oscillation around 10Hz which could be relevant to the existence of residual consciousness, whereas high power below 8Hz seemed to be associated with loss of consciousness. The invasive deep brain recording tool opens a unique way to explore the brain function in consciousness, awareness and alertness and clarify the potential mechanisms of thalamic stimulation in DOC.
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194
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Tseng WL, Thomas LA, Harkins E, Pine DS, Leibenluft E, Brotman MA. Neural correlates of masked and unmasked face emotion processing in youth with severe mood dysregulation. Soc Cogn Affect Neurosci 2015; 11:78-88. [PMID: 26137973 DOI: 10.1093/scan/nsv087] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 06/26/2015] [Indexed: 01/29/2023] Open
Abstract
Reproducibility of results is important in improving the robustness of conclusions drawn from research, particularly in functional magnetic resonance imaging (fMRI). In this study, we aim to replicate a previous study on the neural correlates of face emotion processing above and below awareness level using an independent sample of youth with severe mood dysregulation (SMD) and healthy volunteers (HV). We collected fMRI data in 17 SMD and 20 HV, using an affective priming paradigm with masked (17 ms) and unmasked (187 ms) faces (angry, happy, neutral, blank oval). When processing masked and unmasked angry faces, SMD patients exhibited increased activation in the parahippocampal gyrus (PHG) and superior temporal gyrus relative to HV. When processing masked and unmasked happy faces, SMD patients showed decreased activation in the insula, PHG and thalamus compared with HV. During masked face processing in general across emotions, youth with SMD showed greater ventromedial prefrontal cortex (vmPFC) activation relative to HV. Perturbed activation in emotion processing areas (e.g. insula, PHG, superior temporal gyrus and thalamus) manifests as hyper-sensitivity toward negative emotions and hypo-sensitivity toward positive emotions may be important in the etiology and maintenance of irritability, aggression and depressive symptoms in SMD. vmPFC dysfunction may mediate over-reactivity to face emotions associated with irritability.
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Affiliation(s)
- Wan-Ling Tseng
- Emotion and Development Branch, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, USA and
| | - Laura A Thomas
- War Related Illness and Injury Study Center, Veterans Affairs Medical Center, Washington, DC, USA
| | - Elizabeth Harkins
- Emotion and Development Branch, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, USA and
| | - Daniel S Pine
- Emotion and Development Branch, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, USA and
| | - Ellen Leibenluft
- Emotion and Development Branch, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, USA and
| | - Melissa A Brotman
- Emotion and Development Branch, National Institute of Mental Health, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, USA and
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195
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Cruse D, Norton L, Gofton T, Young GB, Owen AM. Positive prognostication from median-nerve somatosensory evoked cortical potentials. Neurocrit Care 2015; 21:238-44. [PMID: 24865267 DOI: 10.1007/s12028-014-9982-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND The bilateral absence of the cortical N20 median-nerve somatosensory evoked potential (SSEP) is a strong predictor of poor outcome from coma. However, when N20s are present, accurate prognostication is challenging. Here, we investigated the potential for later SSEP components to help disambiguate outcome in these cases. METHODS In a retrospective review of data from two intensive care units, the amplitudes and latencies of the N20, P25, and N35 components of 28 patients in coma were quantified and related to outcome at discharge from primary care (average 1-month post-injury). Only patients who had survived primary care were included in order to avoid self-fulfilling prophecies, and to focus outcome prediction on those patients with relatively present SSEPs. RESULTS The amplitudes of the N20 and N35 components (averaged across hemispheres) significantly predicted the range of outcomes beyond death. Abnormal amplitudes of the N20 and N35--as derived from a healthy control group--were significantly associated with poor outcome. The relative latencies of the cortical components were not related to outcome. CONCLUSIONS While it is well documented that absent SSEPs are highly predictive of poor outcome, the current data indicate that the relative preservation (absolute amplitude) of "present" N20 and N35 SSEP components can also provide predictive value and thereby inform clinicians and families with decision-making in coma. Further prospective study will elucidate the relative contributions of etiology to the predictive power of these SSEP measures.
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Affiliation(s)
- Damian Cruse
- Brain and Mind Institute, Western University, Natural Sciences Centre Room 237, London, ON, N6A 5B7, Canada,
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196
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Lutkenhoff ES, Chiang J, Tshibanda L, Kamau E, Kirsch M, Pickard JD, Laureys S, Owen AM, Monti MM. Thalamic and extrathalamic mechanisms of consciousness after severe brain injury. Ann Neurol 2015; 78:68-76. [PMID: 25893530 DOI: 10.1002/ana.24423] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2014] [Revised: 04/03/2015] [Accepted: 04/07/2015] [Indexed: 01/14/2023]
Abstract
OBJECTIVE What mechanisms underlie the loss and recovery of consciousness after severe brain injury? We sought to establish, in the largest cohort of patients with disorders of consciousness (DOC) to date, the link between gold standard clinical measures of awareness and wakefulness, and specific patterns of local brain pathology-thereby possibly providing a mechanistic framework for patient diagnosis, prognosis, and treatment development. METHODS Structural T1-weighted magnetic resonance images were collected, in a continuous sample of 143 severely brain-injured patients with DOC (and 96 volunteers), across 2 tertiary expert centers. Brain atrophy in subcortical regions (bilateral thalamus, basal ganglia, hippocampus, basal forebrain, and brainstem) was assessed across (1) healthy volunteers and patients, (2) clinical entities (eg, vegetative state, minimally conscious state), (3) clinical measures of consciousness (Coma Recovery Scale-Revised), and (4) injury etiology. RESULTS Compared to volunteers, patients exhibited significant atrophy across all structures (p < 0.05, corrected). Strikingly, we found almost no significant differences across clinical entities. Nonetheless, the clinical measures of awareness and wakefulness upon which differential diagnosis rely were systematically associated with tissue atrophy within thalamic and basal ganglia nuclei, respectively; the basal forebrain was atrophied in proportion to patients' response to sensory stimulation. In addition, nontraumatic injuries exhibited more extensive thalamic atrophy. INTERPRETATION These findings provide, for the first time, a grounding in pathology for gold standard behavior-based clinical measures of consciousness, and reframe our current models of DOC by stressing the different links tying thalamic mechanisms to willful behavior and extrathalamic mechanisms to behavioral (and electrocortical) arousal.
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Affiliation(s)
- Evan S Lutkenhoff
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA
| | - Jeffrey Chiang
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA
| | - Luaba Tshibanda
- Coma Science Group, Cyclotron Research Center and Neurology Department, University and University Hospital of Liège, Liège, Belgium
| | - Evelyn Kamau
- Division of Neurosurgery, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Murielle Kirsch
- Coma Science Group, Cyclotron Research Center and Neurology Department, University and University Hospital of Liège, Liège, Belgium.,Department of Anesthesia and Intensive Care Medicine, Liège University Hospital, Liège, Belgium
| | - John D Pickard
- Division of Neurosurgery, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Steven Laureys
- Coma Science Group, Cyclotron Research Center and Neurology Department, University and University Hospital of Liège, Liège, Belgium
| | - Adrian M Owen
- Brain and Mind Institute, University of Western Ontario, London, Ontario, Canada
| | - Martin M Monti
- Department of Psychology, University of California, Los Angeles, Los Angeles, CA.,Brain Injury Research Center, Department of Neurosurgery, Geffen School of Medicine at University of California, Los Angeles, Los Angeles, CA
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197
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Hippocampal-prefrontal circuit and disrupted functional connectivity in psychiatric and neurodegenerative disorders. BIOMED RESEARCH INTERNATIONAL 2015; 2015:810548. [PMID: 25918722 PMCID: PMC4396015 DOI: 10.1155/2015/810548] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 03/09/2015] [Accepted: 03/19/2015] [Indexed: 11/17/2022]
Abstract
In rodents, the hippocampus has been studied extensively as part of a brain system responsible for learning and memory, and the prefrontal cortex (PFC) participates in numerous cognitive functions including working memory, flexibility, decision making, and rewarding learning. The neuronal projections from the hippocampus, either directly or indirectly, to the PFC, referred to as the hippocampal-prefrontal cortex (Hip-PFC) circuit, play a critical role in cognitive and emotional regulation and memory consolidation. Although in certain psychiatric and neurodegenerative diseases, structural connectivity viewed by imaging techniques has been consistently found to be associated with clinical phenotype and disease severity, the focus has moved towards the investigation of connectivity correlates of molecular pathology and coupling of oscillation. Moreover, functional and structural connectivity measures have been emerging as potential intermediate biomarkers for neuronal disorders. In this review, we summarize progress on the anatomic, molecular, and electrophysiological characters of the Hip-PFC circuit in cognition and emotion processes with an emphasis on oscillation and functional connectivity, revealing a disrupted Hip-PFC connectivity and electrical activity in psychiatric and neurodegenerative disorders as a promising candidate of neural marker for neuronal disorders.
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198
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Ma N, Dinges DF, Basner M, Rao H. How acute total sleep loss affects the attending brain: a meta-analysis of neuroimaging studies. Sleep 2015; 38:233-40. [PMID: 25409102 DOI: 10.5665/sleep.4404] [Citation(s) in RCA: 150] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 10/15/2014] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVES Attention is a cognitive domain that can be severely affected by sleep deprivation. Previous neuroimaging studies have used different attention paradigms and reported both increased and reduced brain activation after sleep deprivation. However, due to large variability in sleep deprivation protocols, task paradigms, experimental designs, characteristics of subject populations, and imaging techniques, there is no consensus regarding the effects of sleep loss on the attending brain. The aim of this meta-analysis was to identify brain activations that are commonly altered by acute total sleep deprivation across different attention tasks. DESIGN Coordinate-based meta-analysis of neuroimaging studies of performance on attention tasks during experimental sleep deprivation. METHODS The current version of the activation likelihood estimation (ALE) approach was used for meta-analysis. The authors searched published articles and identified 11 sleep deprivation neuroimaging studies using different attention tasks with a total of 185 participants, equaling 81 foci for ALE analysis. RESULTS The meta-analysis revealed significantly reduced brain activation in multiple regions following sleep deprivation compared to rested wakefulness, including bilateral intraparietal sulcus, bilateral insula, right prefrontal cortex, medial frontal cortex, and right parahippocampal gyrus. Increased activation was found only in bilateral thalamus after sleep deprivation compared to rested wakefulness. CONCLUSION Acute total sleep deprivation decreases brain activation in the fronto-parietal attention network (prefrontal cortex and intraparietal sulcus) and in the salience network (insula and medial frontal cortex). Increased thalamic activation after sleep deprivation may reflect a complex interaction between the de-arousing effects of sleep loss and the arousing effects of task performance on thalamic activity.
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Affiliation(s)
- Ning Ma
- Center for Functional Neuroimaging, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - David F Dinges
- Division of Sleep and Chronobiology, Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Mathias Basner
- Division of Sleep and Chronobiology, Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Hengyi Rao
- Center for Functional Neuroimaging, Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.,Division of Sleep and Chronobiology, Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
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199
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Mair RG, Miller RLA, Wormwood BA, Francoeur MJ, Onos KD, Gibson BM. The neurobiology of thalamic amnesia: Contributions of medial thalamus and prefrontal cortex to delayed conditional discrimination. Neurosci Biobehav Rev 2015; 54:161-74. [PMID: 25616180 DOI: 10.1016/j.neubiorev.2015.01.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 12/18/2014] [Accepted: 01/12/2015] [Indexed: 11/16/2022]
Abstract
Although medial thalamus is well established as a site of pathology associated with global amnesia, there is uncertainty about which structures are critical and how they affect memory function. Evidence from human and animal research suggests that damage to the mammillothalamic tract and the anterior, mediodorsal (MD), midline (M), and intralaminar (IL) nuclei contribute to different signs of thalamic amnesia. Here we focus on MD and the adjacent M and IL nuclei, structures identified in animal studies as critical nodes in prefrontal cortex (PFC)-related pathways that are necessary for delayed conditional discrimination. Recordings of PFC neurons in rats performing a dynamic delayed non-matching-to position (DNMTP) task revealed discrete populations encoding information related to planning, execution, and outcome of DNMTP-related actions and delay-related activity signaling previous reinforcement. Parallel studies recording the activity of MD and IL neurons and examining the effects of unilateral thalamic inactivation on the responses of PFC neurons demonstrated a close coupling of central thalamic and PFC neurons responding to diverse aspects of DNMTP and provide evidence that thalamus interacts with PFC neurons to give rise to complex goal-directed behavior exemplified by the DNMTP task.
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Affiliation(s)
- Robert G Mair
- Department of Psychology, University of New Hampshire, Durham, NH 03824, United States.
| | - Rikki L A Miller
- Department of Psychology, University of New Hampshire, Durham, NH 03824, United States
| | - Benjamin A Wormwood
- Department of Psychology, University of New Hampshire, Durham, NH 03824, United States
| | - Miranda J Francoeur
- Department of Psychology, University of New Hampshire, Durham, NH 03824, United States
| | - Kristen D Onos
- Department of Psychology, University of New Hampshire, Durham, NH 03824, United States
| | - Brett M Gibson
- Department of Psychology, University of New Hampshire, Durham, NH 03824, United States
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200
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Altered activity in the central medial thalamus precedes changes in the neocortex during transitions into both sleep and propofol anesthesia. J Neurosci 2015; 34:13326-35. [PMID: 25274812 DOI: 10.1523/jneurosci.1519-14.2014] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
How general anesthetics cause loss of consciousness is unknown. Some evidence points toward effects on the neocortex causing "top-down" inhibition, whereas other findings suggest that these drugs act via subcortical mechanisms, possibly selectively stimulating networks promoting natural sleep. To determine whether some neuronal circuits are affected before others, we used Morlet wavelet analysis to obtain high temporal resolution in the time-varying power spectra of local field potentials recorded simultaneously in discrete brain regions at natural sleep onset and during anesthetic-induced loss of righting reflex in rats. Although we observed changes in the local field potentials that were anesthetic-specific, there were some common changes in high-frequency (20-40 Hz) oscillations (reductions in frequency and increases in power) that could be detected at, or before, sleep onset and anesthetic-induced loss of righting reflex. For propofol and natural sleep, these changes occur first in the thalamus before changes could be detected in the neocortex. With dexmedetomidine, the changes occurred simultaneously in the thalamus and neocortex. In addition, the phase relationships between the low-frequency (1-4 Hz) oscillations in thalamic nuclei and neocortical areas are essentially the same for natural sleep and following dexmedetomidine administration, but a sudden change in phase, attributable to an effect in the central medial thalamus, occurs at the point of dexmedetomidine loss of righting reflex. Our data are consistent with the central medial thalamus acting as a key hub through which general anesthesia and natural sleep are initiated.
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