意識障害において脳が臨界状態から逸脱する仕組みを解明 (Scientists Identify How Brain Deviates from Criticality in Disorders of Consciousness)

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2026-08-07 中国科学院(CAS)

中国科学院生物物理研究所と首都医科大学北京天壇医院の共同研究チームは、重度脳損傷による意識障害(DoC)患者において、脳活動が健常者にみられる「臨界状態(criticality)」からどのように逸脱しているかを解明した。研究では、安静時機能的MRI(rs-fMRI)とPETを組み合わせて解析し、無反応覚醒症候群(UWS)の患者は最小意識状態(MCS)の患者よりも臨界状態から大きく外れ、神経活動が抑制された「サブクリティカル状態」にあることを示した。この状態では脳内の広域情報伝達や統合能力が低下し、意識の維持が困難になる。また、臨界性指標の変化は脳内グルコース代謝低下と有意に関連していた。さらに、複数の臨界性指標を用いた機械学習モデルは、UWSとMCSを92.31%の精度で識別し、予後予測でも高い性能を示した。研究成果は、意識障害の神経機構の理解を深めるとともに、客観的な診断・予後評価技術の開発につながる可能性がある。


Study workflow (Image by LIU Ning’s group)

<関連情報>

脳の臨界状態は、意識障害における異常な神経ダイナミクスと代謝を特徴づける Brain criticality characterizes abnormal neural dynamics and metabolism in disorder of consciousness

Qianqian Ge,Yumeng Xin,Chen He,Shuai Han,Xiaoli Geng,Xueling Chen,Shan Yu,Jianghong He,Ning Liu & Long Xu
Communications Biology  Published:20 July 2026
DOI:https://doi.org/10.1038/s42003-026-10713-y  Unedited version

Abstract

Revealing how disrupted brain dynamics lead to altered consciousness levels remains a central challenge in understanding the neural mechanisms underlying consciousness. The brain criticality framework offers a promising perspective, in which optimal neural integration and information processing occur when the brain operates near a critical point, while also reflecting fundamental neural processes such as excitation/inhibition balance. Here, we combined resting-state functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) to systematically assess brain criticality in disorder of consciousness (DoC) patients. Our results revealed that patients in an unresponsive wakefulness state (UWS) exhibited significantly greater power-law scaling exponents in co-activation clusters, higher Ising energy, and lower phase synchronization compared to those in a minimally conscious state (MCS). These findings suggest a greater deviation from critical brain dynamics in UWS, reflecting diminished neural integration and increased disorder. The extent of these deviations correlated with metabolic deficits measured by PET, highlighting the functional relevance of altered neural dynamics. Importantly, critical metrics were significantly associated with clinical scores and outperformed PET in both diagnosis and prognosis. Together, our findings advance understanding of the neural mechanisms underlying consciousness and highlight the potential of criticality-based metrics for characterizing brain states and informing prognosis in DoC.

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