脳画像解析により言語特異的な脳ネットワークを解明(Brain Scans Reveal Language-Specific Brain Networks)

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2026-08-13 スタンフォード大学

米国のStanford Universityの研究チームは、言語処理を担う脳内ネットワークが、従来考えられていたような汎用的な仕組みではなく、言語ごとの特徴に応じて異なる構造や活動パターンを示すことを明らかにした。研究では脳画像解析などを用いて複数言語話者の脳活動を比較し、言語ごとの文法構造や表現様式の違いが脳内ネットワークの形成や利用方法に反映されることを示した。この結果は、人間の脳に共通する言語処理基盤が存在する一方で、個々の言語経験が神経回路の組織化に大きな影響を与えることを示唆している。研究成果は、言語習得や多言語教育の理解を深めるだけでなく、失語症などの言語障害の診断・リハビリテーション手法の改善にも貢献する可能性がある。また、脳と言語の関係を再考する重要な知見として注目される。

Four 3D brain models show regions of activity highlighted in blue and red.
The language networks of two different individuals (top and bottom) were identified using two different methods (left and right). Scans identified the blue networks when the individuals were not performing language-related tasks and the red networks when they read sentences and then nonsense words. This illustrates how the language network can vary between individuals and how it can be identified without having an individual speak, read, or write. | Courtesy Stanford H&S

<関連情報>

任意のタスクを実行する1199人の人間の脳の個別化された機能的コネクトームにおける言語ネットワーク A language network in the individualized functional connectomes of 1199 human brains doing arbitrary tasks

Cory Shain & Evelina Fedorenko
Nature Communications  Published:13 August 2026
DOI:https://doi.org/10.1038/s41467-026-75745-8

Abstract

A century and a half of neuroscience has yielded many divergent theories of the neurobiology of language. Two factors that likely contribute to this situation include (a) conceptual disagreement about language and its component processes, and (b) intrinsic inter-individual variability in the topography of language areas. Recent functional magnetic resonance imaging (fMRI) studies of small numbers of intensively scanned individuals have argued that a language-selective brain network emerges bottom-up from correlations (individualized functional connectomics, iFC) in task-free (e.g., rest) or task-regressed activation timecourses. Here we tested this hypothesis at scale and evaluated its practical utility for task-agnostic language localization: we apply iFC separately to each of 1,957 (fMRI) scanning sessions (1,199 unique brains), each consisting of diverse tasks. We found that iFC indeed revealed a largely left-hemisphere-dominant frontotemporal network that was more stable within individuals than between them, robust to the granularity of the parcellation, and selective for language. These results support the hypothesis that this network is a key structure in the functional organization of the adult brain and show that it can be recovered retrospectively from arbitrary imaging data, with implications for neuroscience, neurosurgery, and neural engineering.

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