発達中の第一視野皮質におけるタラモコルチカル可塑性がない場合に,急速な小粒外可塑性
J T Trachtenberg1, C Trepel, M P Stryker
1W. M. Keck Foundation Center for Integrative Neuroscience and Department of Physiology, University of California, San Francisco, CA 94143-0444, USA.
まとめ
早期の視覚欠乏は脳の視覚皮質を再構成し,神経細胞が欠乏した眼に反応しないようにします. この研究は,可塑性が,タラモコルチカルシナプスではなく,より高い皮質層で発生することを明らかにしています.
科学分野:
- 神経科学は神経科学である.
- 発達神経科学とは
- 視覚システムの可塑性 視覚システムの可塑性
背景:
- 発達初期におけるモノキュラー欠乏は,主視野皮質 (V1) の回路を変更する.
- ニューロンは通常,この期間を経て,欠けている目の刺激に対する反応が低下することを示します.
- この生理学的変化は,剥奪された目からの入力の解剖学的損失と関連しており,潜在的にタラモコルチカルシナプスから始まる可能性があります.
研究 の 目的:
- 短期 (24時間) の単眼剥奪の後,主視野皮質の眼優位性可塑性を調査する.
- この可塑性が起こる視覚野内の特定の層を決定する.
- 甲状腺皮質の組織が,より高い皮質段階の変化によって導かれるという仮説を検証する.
主な方法:
- 視覚皮質の活動を分析するために,内在信号光学画像を用いた.
- 標的型細胞外ユニット記録は,ニューロンの応答を評価するために使用されました.
- これらの方法は,細胞レベルで目の優位性変化の検査を可能にしました.
主要な成果:
- 欠乏した眼に対する反応性は,主視野皮質の粒外層で有意に失われていました.
- 単眼の欠乏にもかかわらず,正常な双眼,特に層IVでは,保存されました.
- これらの発見は,初期の視覚体験の層特異的な効果を示しています.
結論:
- タラモコルチカルシナプスではなく,エクストラグラニュラルの層で観察された可塑性は,以前の仮説に異議を唱える.
- これは,より高いレベルの皮質処理段階が,タラモコルクスの入力組織を導く可能性があることを示唆しています.
- 初期の視覚体験は,層に依存した方法で皮質回路を決定的に形作ります.
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