BrainGateコンソーシアムに関連する新しい研究は、人間がどのように学習し、長期記憶を形成するかについて重要な手がかりを与えました。この発見は、麻痺のある人のための支援ツールの開発者に洞察を与える可能性があります。 A new study associated with the BrainGate consortium offered significant clues about how humans learn and form long-term memories; the findings could provide insights for developers of assistive tools for people with paralysis.
2022-06-29 ブラウン大学
研究チームは、人間の運動皮質(運動を司る脳領域)で再生が起こるかどうかを調べるため、脊髄損傷により上肢と下肢を動かすことができない四肢麻痺(四肢麻痺ともいう)の36歳の男性を被験者としました。
ゲームでは、色のついた光の点滅パターンを観察し、そのパターンを思い出して再現する。彼は、自分の手の動きを考えるだけで、コンピューター画面上のカーソルを操作することができた。T11の運動野に埋め込まれたセンサーがニューロンの発火パターンを測定し、それが彼の意図する手の動きを反映していたため、彼は画面上でカーソルを動かしたり、好きな場所でクリックしたりすることができたのだ。この脳信号は記録され、無線でコンピューターに送られた。
睡眠中のニューロン発火のパターンが、その日の初めに記憶合わせのゲームをしているときに起こったパターンと正確に一致していることを指摘しました。
ヒトの睡眠中に運動皮質から再生されたことを示す最も直接的な証拠です」とルービンは述べています。この研究で検出されたリプレイのほとんどは、徐波睡眠(深い眠りの段階)で生じたものである。興味深いことに、T11がレム睡眠(夢を見る段階)にあるときには、リプレイが検出される可能性は非常に低かった。研究チームは、今回の研究が、人間の学習・記憶における再生とその役割について、より深く知るための基礎となると考えている。
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学習した運動パターンが睡眠中にヒトの運動皮質で再生される Learned Motor Patterns Are Replayed in Human Motor Cortex during Sleep
Daniel B. Rubin, Tommy Hosman, Jessica N. Kelemen, Anastasia Kapitonava, Francis R. Willett, Brian F. Coughlin, Eric Halgren, Eyal Y. Kimchi, Ziv M. Williams, John D. Simeral, Leigh R. Hochberg and Sydney S. Cash
Journal of Neuroscience Published:22 June 2022
DOI: https://doi.org/10.1523/JNEUROSCI.2074-21.2022
Abstract
Consolidation of memory is believed to involve offline replay of neural activity. While amply demonstrated in rodents, evidence for replay in humans, particularly regarding motor memory, is less compelling. To determine whether replay occurs after motor learning, we sought to record from motor cortex during a novel motor task and subsequent overnight sleep. A 36-year-old man with tetraplegia secondary to cervical spinal cord injury enrolled in the ongoing BrainGate brain–computer interface pilot clinical trial had two 96-channel intracortical microelectrode arrays placed chronically into left precentral gyrus. Single- and multi-unit activity was recorded while he played a color/sound sequence matching memory game. Intended movements were decoded from motor cortical neuronal activity by a real-time steady-state Kalman filter that allowed the participant to control a neurally driven cursor on the screen. Intracortical neural activity from precentral gyrus and 2-lead scalp EEG were recorded overnight as he slept. When decoded using the same steady-state Kalman filter parameters, intracortical neural signals recorded overnight replayed the target sequence from the memory game at intervals throughout at a frequency significantly greater than expected by chance. Replay events occurred at speeds ranging from 1 to 4 times as fast as initial task execution and were most frequently observed during slow-wave sleep. These results demonstrate that recent visuomotor skill acquisition in humans may be accompanied by replay of the corresponding motor cortex neural activity during sleep.
SIGNIFICANCE STATEMENT Within cortex, the acquisition of information is often followed by the offline recapitulation of specific sequences of neural firing. Replay of recent activity is enriched during sleep and may support the consolidation of learning and memory. Using an intracortical brain–computer interface, we recorded and decoded activity from motor cortex as a human research participant performed a novel motor task. By decoding neural activity throughout subsequent sleep, we find that neural sequences underlying the recently practiced motor task are repeated throughout the night, providing direct evidence of replay in human motor cortex during sleep. This approach, using an optimized brain–computer interface decoder to characterize neural activity during sleep, provides a framework for future studies exploring replay, learning, and memory.
