Electrocorticography reveals thalamic control of cortical dynamics following traumatic brain injury

Mofakham, Sima; Fry, Adam; Adachi, Joseph; Stefancin, Patricia; Duong, Timothy Q.; Saadon, Jordan R; Winans, Nathan J.; Sharma, Himanshu; Feng, Guanchao; Djurić, Petar M.; Mikell, Charles B.

doi:10.1038/s42003-021-02738-2

Cited by 23 publications

(12 citation statements)

References 61 publications

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“…We believe that those drivers might be linked both to the regions participating in the RAS system (Intralaminar Thalamus, Raphe Nuclei, and Locus Coeruleus) [4, 16] and to the dorsal nuclei of the thalamus that are implicated in the relay of sensory information and have also been tightly linked to the generation of oscillatory behavior in the cortex in slow waves [63–66]. This would support the view of the thalamus as a driver and controller of cortical dynamics [6, 25, 67–69].…”

Section: Discussionmentioning

confidence: 82%

Modeling the role of the thalamus in resting-state functional connectivity: nature or structure

Cabrera-Álvarez¹,

Doorn²,

Maestú³

et al. 2023

Preprint

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The thalamus is a central brain structure that serves as a relay station for sensory inputs from the periphery to the cortex and regulates cortical arousal. Traditionally, it has been regarded as a passive relay that transmits information between brain regions. However, recent studies have suggested that the thalamus may also play a role in shaping functional connectivity (FC) in a task-based context. Based on this idea, we hypothesized that due to its centrality in the network and its involvement in cortical activation, the thalamus may also contribute to resting-state FC, a key neurological biomarker widely used to characterize brain function in health and disease. To investigate this hypothesis, we constructed ten in-silico brain network models based on neuroimaging data (MEG, MRI, and dwMRI), and simulated them including and excluding the thalamus. and raising the noise into thalamus to represent the afferences related to the reticular activating system (RAS) and the relay of peripheral sensory inputs. We simulated brain activity and compared the resulting FC to their empirical MEG counterparts to evaluate model's performance. Results showed that a parceled version of the thalamus with higher noise, able to drive damped cortical oscillators, enhanced the match to empirical FC. However, with an already active self-oscillatory cortex, no impact on the dynamics was observed when introducing the thalamus. We also demonstrated that the enhanced performance was not related to the structural connectivity of the thalamus, but to its higher noisy inputs. Additionally, we highlighted the relevance of a balanced signal-to-noise ratio in thalamus to allow it to propagate its own dynamics. In conclusion, our study sheds light on the role of the thalamus in shaping brain dynamics and FC in resting-state and allowed us to discuss the general role of criticality in the brain at the mesoscale level.

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Section: Discussionmentioning

confidence: 82%

Modeling the role of the thalamus in resting-state functional connectivity: nature or structure

Cabrera-Álvarez¹,

Doorn²,

Maestú³

et al. 2023

Preprint

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“…Furthermore, phase- and amplitude-coupling patterns may partly reflect different neuronal mechanisms ( Siems and Siegel, 2020 ; Duclos et al, 2021 ). In general, the presence of high-frequency oscillations, corticocortical and thalamocortical connections (structural and functional) is associated with higher levels of consciousness ( Mofakham et al, 2021 ; Oberto et al, 2022 ). Delta activity and synchronization appear to be higher when the cortical arousal is at a lower level ( Sitt et al, 2014 ; Frohlich et al, 2021 ).…”

Section: Discussionmentioning

confidence: 99%

EEG Evidence Reveals Zolpidem-Related Alterations and Prognostic Value in Disorders of Consciousness

et al. 2022

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Effective treatment and accurate long-term prognostication of patients with disorders of consciousness (DOC) remain pivotal clinical issues and challenges in neuroscience. Previous studies have shown that zolpidem produces paradoxical recovery and induces similar change patterns in specific electrophysiological features in some DOC (∼6%). However, whether these specific features are neural markers of responders, and how neural features evolve over time remain unclear. Here, we capitalized on static and dynamic EEG analysis techniques to fully uncover zolpidem-induced alterations in eight patients with DOC and constructed machine-learning models to predict long-term outcomes at the single-subject level. We observed consistent patterns of change across all patients in several static features (e.g., decreased relative theta power and weakened alpha-band functional connectivity) after zolpidem administration, albeit none zolpidem responders. Based on the current evidence, previously published electrophysiological features are not neural markers for zolpidem responders. Moreover, we found that the temporal dynamics of the brain slowed down after zolpidem intake. Brain states before and after zolpidem administration could be completely characterized by the EEG features. Furthermore, long-term outcomes were accurately predicted using connectivity features. Our findings suggest that EEG neural signatures have huge potential to assess consciousness states and predict fine-grained outcomes. In summary, our results extend the understanding of the effects of zolpidem on the brain and open avenues for the application prospect of zolpidem and EEG in patients with DOC.

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“… 14 More recently, our work has demonstrated that DTI can be used to assess the structural integrity of thalamocortical projections and that preservation of these connections is associated with earlier command following after severe TBI. 33 - 35 Therefore, structural imaging methods can assess injuries to areas critical to consciousness and provide valuable prognostic information.…”

Section: Neuroimagingmentioning

confidence: 99%

“…Our observations in patients with severe TBI and in silico have demonstrated that thalamic injury results in dysfunctional cortical networks with simplistic and repetitive characteristics, supporting the idea that thalamic input is crucial for the content of consciousness. 33 …”

Section: Areas Of Controversymentioning

confidence: 99%

Brain Circuitry of Consciousness: A Review of Current Models and a Novel Synergistic Model With Clinical Application

Gammel

Alkadaa

Saadon

et al. 2023

Neurosurgery Practice

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How consciousness arises in the brain has important implications for clinical decision-making. We summarize recent findings in consciousness studies to provide a toolkit for clinicians to assess deficits in consciousness and predict outcomes after brain injury. Commonly encountered disorders of consciousness are highlighted, followed by the clinical scales currently used to diagnose them. We review recent evidence describing the roles of the thalamocortical system and brainstem arousal nuclei in supporting awareness and arousal and discuss the utility of various neuroimaging studies in evaluating disorders of consciousness. We explore recent theoretical progress in mechanistic models of consciousness, focusing on 2 major models, the global neuronal workspace and integrated information theory, and review areas of controversy. Finally, we consider the potential implications of recent research for the day-to-day decision-making of clinical neurosurgeons and propose a simple “three-strikes” model to infer the integrity of the thalamocortical system, which can guide prognosticating return to consciousness.

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Electrocorticography reveals thalamic control of cortical dynamics following traumatic brain injury

Cited by 23 publications

References 61 publications

Modeling the role of the thalamus in resting-state functional connectivity: nature or structure

Modeling the role of the thalamus in resting-state functional connectivity: nature or structure

EEG Evidence Reveals Zolpidem-Related Alterations and Prognostic Value in Disorders of Consciousness

Brain Circuitry of Consciousness: A Review of Current Models and a Novel Synergistic Model With Clinical Application

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