深層の皮質内ニューロンによって制御される感覚刺激のデンドリティック・エンコーディング
Masanori Murayama1, Enrique Pérez-Garci, Thomas Nevian
1Physiologisches Institut, Universität Bern, Bühlplatz 5, CH-3012 Bern, Switzerland.
Nature
|January 20, 2009
まとめ
層5 (L5) のピラミッド型のニューロンのアクティブデンドリティック伝導性は,コンピューティング能力を高めます. 抑制は,L5ピラミッド型デンドライトによる感覚エンコーディングを制御し,線形ダイナミックレンジの適応を可能にします.
科学分野:
- 神経科学は神経科学である.
- 計算神経科学とは
- 細胞神経科学は細胞神経科学である.
背景:
- アクティブなデンドリティック伝導性は,神経の計算能力とスパイク活動を大幅に高めます.
- 層5 (L5) のピラミッド型ニューロンは,プレートポテンシャルのためのアピカルデンドリートカルシウムチャネルを利用し,入力/出力獲得とバースト発火に影響を与えます.
研究 の 目的:
- 様々なインプットが活性の dendritic 特性 in vivo にどのように影響するかを調査する.
- L5ピラミッド型デンドライトにおける感覚刺激の強さのエンコーディングを調査する.
- dendritic 活動を調節する阻害性ニューロンの役割を明らかにする.
主な方法:
- L5のピラミッド型デンドライトのデンドリットカルシウム変化を記録するために,新しい光ファイバー方法を使用しました.
- 覚醒状態と麻酔状態のラットにおけるL5ピラミッド型デンドライトの集団における記録された活動.
- シングルアピカル・タフト・デンドライトから in vitro 記録を行いました.
主要な成果:
- 感覚刺激の強さは,L5ピラミッド細胞の集団デンドリットカルシウム反応によって段階的にコードされます.
- L5シナプス入力によって活性化される特定の抑制性ニューロンのサブセットは,刺激-応答関数の傾きを制御します.
- 内部ニューロンによる局所的抑制は,隣接するL5ピラミッドニューロンにおける dendritic calcium spikeの開始をブロックする.
結論:
- 目覚めた動物の皮質のマイクロ回路は,活性なL5ピラミッド型デンドライト特性と抑制に対する感受性に依存しています.
- このマイクロ回路は,アピカルデンドライトの地元の集団が,ダイナミックレンジ全体で感覚刺激を線形にコードすることを可能にします.
- 阻害制御は,皮質回路における適応的感覚エンコーディングに不可欠である.
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