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Mofakham S, Robertson J, Lubin N, Cleri NA, Mikell CB. An Unpredictable Brain Is a Conscious, Responsive Brain. J Cogn Neurosci 2024; 36:1643-1652. [PMID: 38579270 DOI: 10.1162/jocn_a_02154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2024]
Abstract
Severe traumatic brain injuries typically result in loss of consciousness or coma. In deeply comatose patients with traumatic brain injury, cortical dynamics become simple, repetitive, and predictable. We review evidence that this low-complexity, high-predictability state results from a passive cortical state, represented by a stable repetitive attractor, that hinders the flexible formation of neuronal ensembles necessary for conscious experience. Our data and those from other groups support the hypothesis that this cortical passive state is because of the loss of thalamocortical input. We identify the unpredictability and complexity of cortical dynamics captured by local field potential as a sign of recovery from this passive coma attractor. In this Perspective article, we discuss how these electrophysiological biomarkers of the recovery of consciousness could inform the design of closed-loop stimulation paradigms to treat disorders of consciousness.
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Guerrero-Gonzalez JM, Kirk GR, Birn R, Bigler ED, Bowen K, Broman AT, Rosario BL, Butt W, Beers SR, Bell MJ, Alexander AL, Ferrazzano PA. Multi-modal MRI of hippocampal morphometry and connectivity after pediatric severe TBI. Brain Imaging Behav 2024; 18:159-170. [PMID: 37955810 PMCID: PMC10844146 DOI: 10.1007/s11682-023-00818-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/22/2023] [Indexed: 11/14/2023]
Abstract
This investigation explores memory performance using the California Verbal Learning Test in relation to morphometric and connectivity measures of the memory network in severe traumatic brain injury. Twenty-two adolescents with severe traumatic brain injury were recruited for multimodal MRI scanning 1-2 years post-injury at 13 participating sites. Analyses included hippocampal volume derived from anatomical T1-weighted imaging, fornix white matter microstructure from diffusion tensor imaging, and hippocampal resting-state functional magnetic resonance imaging connectivity as well as diffusion-based structural connectivity. A typically developing control cohort of forty-nine age-matched children also underwent scanning and neurocognitive assessment. Results showed hippocampus volume was decreased in traumatic brain injury with respect to controls. Further, hippocampal volume loss was associated with worse performance on memory and learning in traumatic brain injury subjects. Similarly, hippocampal fornix fractional anisotropy was reduced in traumatic brain injury with respect to controls, while decreased fractional anisotropy in the hippocampal fornix also was associated with worse performance on memory and learning in traumatic brain injury subjects. Additionally, reduced structural connectivity of left hippocampus to thalamus and calcarine sulcus was associated with memory and learning in traumatic brain injury subjects. Functional connectivity in the left hippocampal network was also associated with memory and learning in traumatic brain injury subjects. These regional findings from a multi-modal neuroimaging approach should not only be useful for gaining valuable insight into traumatic brain injury induced memory and learning disfunction, but may also be informative for monitoring injury progression, recovery, and for developing rehabilitation as well as therapy strategies.
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Affiliation(s)
- Jose M Guerrero-Gonzalez
- Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.
- Waisman Center, University of Wisconsin-Madison, 1500 Highland Avenue, Madison, WI, 53705, USA.
| | - Gregory R Kirk
- Waisman Center, University of Wisconsin-Madison, 1500 Highland Avenue, Madison, WI, 53705, USA
| | - Rasmus Birn
- Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Department of Psychiatry, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Erin D Bigler
- Department of Psychology and Neuroscience Center, Brigham Young University, Provo, UT, USA
- Department of Neurology & Department of Psychiatry, University of Utah, Salt Lake City, UT, USA
| | | | - Aimee T Broman
- Department of Biostatistics, University of Wisconsin-Madison, Madison, WI, USA
| | - Bedda L Rosario
- Department of Epidemiology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Warwick Butt
- Department of Critical Care, Faculty of Medicine, Melbourne University, Melbourne, Australia
| | - Sue R Beers
- Department of Psychiatry, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Michael J Bell
- Department of Pediatrics, Children's National Medical Center, Washington, DC, USA
| | - Andrew L Alexander
- Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Department of Psychiatry, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Waisman Center, University of Wisconsin-Madison, 1500 Highland Avenue, Madison, WI, 53705, USA
| | - Peter A Ferrazzano
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Waisman Center, University of Wisconsin-Madison, 1500 Highland Avenue, Madison, WI, 53705, USA
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Tauber JM, Brincat SL, Stephen EP, Donoghue JA, Kozachkov L, Brown EN, Miller EK. Propofol-mediated Unconsciousness Disrupts Progression of Sensory Signals through the Cortical Hierarchy. J Cogn Neurosci 2024; 36:394-413. [PMID: 37902596 PMCID: PMC11161138 DOI: 10.1162/jocn_a_02081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2023]
Abstract
A critical component of anesthesia is the loss of sensory perception. Propofol is the most widely used drug for general anesthesia, but the neural mechanisms of how and when it disrupts sensory processing are not fully understood. We analyzed local field potential and spiking recorded from Utah arrays in auditory cortex, associative cortex, and cognitive cortex of nonhuman primates before and during propofol-mediated unconsciousness. Sensory stimuli elicited robust and decodable stimulus responses and triggered periods of stimulus-related synchronization between brain areas in the local field potential of Awake animals. By contrast, propofol-mediated unconsciousness eliminated stimulus-related synchrony and drastically weakened stimulus responses and information in all brain areas except for auditory cortex, where responses and information persisted. However, we found stimuli occurring during spiking Up states triggered weaker spiking responses than in Awake animals in auditory cortex, and little or no spiking responses in higher order areas. These results suggest that propofol's effect on sensory processing is not just because of asynchronous Down states. Rather, both Down states and Up states reflect disrupted dynamics.
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Affiliation(s)
- John M Tauber
- Massachusetts Institute of Technology, Cambridge, MA
| | | | | | | | - Leo Kozachkov
- Massachusetts Institute of Technology, Cambridge, MA
| | - Emery N Brown
- Massachusetts Institute of Technology, Cambridge, MA
- Massachusetts General Hospital, Boston
- Harvard University, Cambridge, MA
| | - Earl K Miller
- Massachusetts Institute of Technology, Cambridge, MA
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Jang SH, Choi EB. Relationship between the consciousness level and the structural neural connectivity of the medial prefrontal cortex in hypoxic-ischemic brain injury: a pilot study. Neuroreport 2022; 33:750-755. [PMID: 36250436 PMCID: PMC9622375 DOI: 10.1097/wnr.0000000000001841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 09/11/2022] [Indexed: 11/06/2022]
Abstract
This pilot study investigated the relationship between the consciousness level and the structural neural connectivity of the medial prefrontal cortex (mPFC SNC) in patients with hypoxic-ischemic brain injury (HI-BI), using diffusion tensor tractography (DTT). Twenty-three patients with HI-BI were recruited into the study based on predefined inclusion criteria. Their consciousness levels were evaluated using the Glasgow Coma Scale (GCS) and the Coma Recovery Scale-Revised (CRS-R). Using DTT, the mPFC SNC was reconstructed for each patient. The average of the fractional anisotropy (FA), apparent diffusion coefficient (ADC), and voxel number (VN) for the mPFC SNC in both hemispheres were determined. The GCS score showed moderate positive correlations with the FA value and VN of the mPFC SNC [(FA) r = 0.439; (VN) r = 0.466; P < 0.05], and a strong negative correlation with ADC value ( r = -0.531; P < 0.05). The CRS-R score had a strong positive and negative correlation with the FA and ADC values of the mPFC SNC, respectively, [(FA) r = 0.540; (ADC) r = -0.614; P < 0.05] and a moderate positive correlation with the VN of the mPFC SNC ( r = 0.488; P < 0.05). We found that the severity of the injury to the mPFC SNC was closely related to the consciousness level. Our results suggest that the mPFC SNC appears to be a neural correlate for the control of consciousness in patients with HI-BI. Based on these results, we believe that the mPFC could be a target area for noninvasive neurostimulation therapies for patients with impaired consciousness following HI-BI.
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Affiliation(s)
- Sung Ho Jang
- Department of Physical Medicine and Rehabilitation, College of Medicine, Yeungnam University, Daegu, Republic of Korea
| | - Eun Bi Choi
- Department of Physical Medicine and Rehabilitation, College of Medicine, Yeungnam University, Daegu, Republic of Korea
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Mashour GA, Pal D, Brown EN. Prefrontal cortex as a key node in arousal circuitry. Trends Neurosci 2022; 45:722-732. [PMID: 35995629 PMCID: PMC9492635 DOI: 10.1016/j.tins.2022.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 07/02/2022] [Accepted: 07/31/2022] [Indexed: 10/15/2022]
Abstract
The role of the prefrontal cortex (PFC) in the mechanism of consciousness is a matter of active debate. Most theoretical and empirical investigations have focused on whether the PFC is critical for the content of consciousness (i.e., the qualitative aspects of conscious experience). However, there is emerging evidence that, in addition to its well-established roles in cognition, the PFC is a key regulator of the level of consciousness (i.e., the global state of arousal). In this opinion article we review recent data supporting the hypothesis that the medial PFC is a critical node in arousal-promoting networks.
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Affiliation(s)
- George A Mashour
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, USA; Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA; Center for Consciousness Science, University of Michigan, Ann Arbor, MI, USA; Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA.
| | - Dinesh Pal
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, USA; Center for Consciousness Science, University of Michigan, Ann Arbor, MI, USA; Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Emery N Brown
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA; Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA, USA; Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA; Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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Servider J, Saadon JR, Adachi J, Shen E, Mikell CB, Mofakham S. Cortical recordings reveal hidden early signs of recovery following traumatic brain injury: A case report. Brain Res 2022; 1786:147903. [PMID: 35381214 DOI: 10.1016/j.brainres.2022.147903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/29/2022] [Accepted: 03/31/2022] [Indexed: 11/02/2022]
Abstract
Prognosticating recovery of consciousness after severe traumatic brain injury (TBI) is a difficult task. Understanding the mechanism of recovery of consciousness in these patients will undoubtedly help clarify this issue. Recent research has underscored the importance of electrophysiological data in characterizing the state of the brain during this period of unconsciousness. Here, we investigated cortical electrophysiological recordings from a single TBI patient and discovered that high-frequency activity associated with the return of consciousness reappeared in a spatiotemporal fashion. We observed a shift toward higher frequencies first in the anterior cingulate cortex, and then later in the dorsolateral prefrontal cortex. This finding suggests that recovery may originate in more internal cortices and progress to superficial ones. Although this observation occurred in a single patient, it points to a potential mechanism for recovery of normal cortical activity in the return of consciousness following TBI.
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Affiliation(s)
- John Servider
- Department of Neurosurgery, Renaissance School of Medicine at Stony Brook University, Stony Brook, NY, USA
| | - Jordan R Saadon
- Department of Neurosurgery, Renaissance School of Medicine at Stony Brook University, Stony Brook, NY, USA
| | - Joseph Adachi
- Department of Neurosurgery, Renaissance School of Medicine at Stony Brook University, Stony Brook, NY, USA
| | - Erica Shen
- Department of Neurosurgery, University of Connecticut School of Medicine, Farmington, CT, USA
| | - Charles B Mikell
- Department of Neurosurgery, Renaissance School of Medicine at Stony Brook University, Stony Brook, NY, USA
| | - Sima Mofakham
- Department of Neurosurgery, Renaissance School of Medicine at Stony Brook University, Stony Brook, NY, USA; Department of Electrical and Computer Engineering, Stony Brook University, Stony Brook, NY, USA.
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