哺乳類の脳の起源に関する化石の証拠
Timothy B Rowe1, Thomas E Macrini, Zhe-Xi Luo
1Jackson School of Geosciences, University of Texas, C1100, Austin, TX 78712, USA. rowe@mail.utexas.edu
Science (New York, N.Y.)
|May 21, 2011
まとめ
初期の哺乳類は,嗅覚,触覚の感度,および調整の強化によって駆動された進化的なパルスを通して,大きな脳を進化させた. これらの変化は,現代の哺乳類の脳の複雑さへの道を開いた.
科学分野:
- パレオントロジー・パレオントロジー
- 進化生物学の進化生物学について
- 神経科学は神経科学である.
背景:
- 哺乳類の脳の初期の進化は,多くの仮説の主題である.
- 脳の進化の軌道を理解することは,哺乳類の起源を解読する上で極めて重要です.
研究 の 目的:
- 化石の証拠を用いて哺乳類の脳の初期の進化を調査する.
- 初期の哺乳類における脳のサイズ拡大の背後にある重要な進化的出来事とドライバーを特定する.
主な方法:
- X線トモグラフィーは,ジュラ紀初期哺乳類,特にモルガヌコドン (Morganucodon) とハドロコジウム (Hadrocodium) の頭蓋骨内皮を研究するために使用されました.
- 分析は,脳の相対的なサイズと,嗅覚球,新皮質,嗅覚皮質,小脳を含む特定の脳の領域の割合に焦点を当てた.
主要な成果:
- これらの初期の形態の脳の相対的な大きさは哺乳類のレベルに達し,膨張した嗅覚球,新皮質,嗅覚皮質,小脳が特徴でした.
- 脳の膨張は少なくとも2つの異なる進化パルスで発生しました.
- 最初のパルスは,嗅覚,触覚の感度,神経筋肉の調整の改善と関連しており,その後に嗅覚の強化の2番目のパルスが続いた.
結論:
- 早期の哺乳類の脳進化には,特に嗅覚領域において,異なるパルスで発生する,顕著な拡張が含まれていた.
- 皇冠哺乳類の骨化エトモイドタービナルの発達は,大きな嗅覚受容体ゲノムと相関する嗅覚能力をさらにサポートしました.
- これらの発見は,哺乳類の出現を特徴とした神経解剖学的適応の洞察を提供します.
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