注意シフト時に視覚感度が能動的に調節されることを発見(Scientists Discover Active Modulation of Visual Sensitivity During Attention Shifts)

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2026-07-13 中国科学院(CAS)

中国科学院生物物理研究所の何生(HE Sheng)教授らの研究チームは、注意(アテンション)が対象や位置から別の対象へ移る瞬間に、脳が視覚感度を一時的に能動的に低下させることを明らかにした。この研究はPNASに掲載された。従来、眼球運動時には視覚情報が抑制されることが知られていたが、眼球を動かさない「潜在的注意(covert attention)」の切り替えでも同様の現象が起こるかは不明だった。研究では、注意の周期的な揺らぎ(注意振動)を利用して注意転換のタイミングをミリ秒精度で推定し、その過程を妨げない無関係な視覚刺激を提示したうえで、瞳孔反応(瞳孔計測)と脳磁図(MEG)を用いて視覚感度の変化を解析した。その結果、注意が切り替わる直前後に視覚感度が一時的に低下し、この抑制は特に頭頂葉を中心とする高次皮質で生じることが判明した。これらの知見は、注意の切り替え時に不要な情報処理を抑えることで、脳が安定かつ効率的に外界や内部情報を処理する仕組みを示すものであり、知覚や認知制御の神経メカニズムの理解に重要な成果となる。

<関連情報>

注意の切り替え時の感度抑制 Sensitivity suppression during attention shifts

Zixiao Zhang, Sheng He, and Jiedong Zhang
Proceedings of the National Academy of Sciences  Published:June 30, 2026
DOI:https://doi.org/10.1073/pnas.2530939123

Abstract

The brain possesses the remarkable ability to suppress undesirable signals generated by our own actions to ensure accurate perception, like the suppression of retinal motion signals during rapid eye movements, known as saccadic suppression. Attention, often referred to as the “mind’s eye,” undergoes rapid and frequent shifts, often occurring in the absence of explicit motor actions. Is visual processing similarly suppressed during attention shifts? In this study, we employed pupillometry and magnetoencephalography (MEG) to assess visual sensitivity across different attentional states. Our results revealed a reduced or suppressed visual sensitivity during attention shifts through an attentional oscillation paradigm. Such suppression was not due to microsaccades and was absent during rhythmic attentional sampling without spatial shift. MEG data further indicated that the suppression was more pronounced in parietal channels, manifesting at a relatively late stage (150 to 200 ms) of visual processing and suggesting a distinct neural mechanism compared to saccadic suppression. Our findings indicate that suppression mechanisms operate not only when there are spurious signals generated due to the movements of the sensors, but also during transitional states in the allocation of cognitive resources within representational space, thereby supporting stability of visual processing.

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