近日，美國加利福尼亞州大學圣地亞哥醫(yī)學院的科學家最新研究顯示,，鳥類掌控聽力輸入的大腦區(qū)域與人類等哺乳動物非常接近,，暗示著人類與鳥類大腦之間的相似性超出之前的觀點，同時,，這種相似性可能起源自3億年前哺乳動物和鳥類的共同祖先,。
一個世紀以來，神經(jīng)學科學家都認為人類和其它哺乳動物的的大腦與鳥類等動物的大腦存在著差異,。主要表面在大腦新皮層(neocortex)的物理結構,，該區(qū)域是大腦負責掌控復雜的認知能力,。來自加利福尼亞州大學圣地亞哥醫(yī)學院的哈維－卡爾頓(Harvey J. Karten)教授和研究同事顛覆了這一觀點,，在最新的研究中，他們使用高敏感繪圖儀等現(xiàn)代復雜的圖像技術,，繪制出鳥的大腦區(qū)域,，發(fā)現(xiàn)鳥大腦與哺乳掌控聽力的皮層非常相似,。這項發(fā)現(xiàn)證實鳥大腦皮層區(qū)域也包含著通過不同狹窄、輻射縱向細胞類型連接的薄細胞層,。
該研究顯示大腦新皮層細胞的纖薄和柱向柱狀結構并不是哺乳動物所獨有的,，或許進化于更遠古的脊椎動物祖先。
卡爾頓稱,，這一最新研究為神經(jīng)學專家提出了一個嚴峻的難題——哺乳動物大腦新皮層的進化起源,，這種復雜的新皮層最初的進化起源在哪里？他猜測可能源自3億年前哺乳動物和鳥類的共同祖先,。(生物谷Bioon.net)
生物谷推薦原文出處：
PNAS April 1, 1997 vol. 94 no. 7 2800-2804
Evolutionary developmental biology meets the brain: The origins of mammalian?cortex
Harvey J. Karten
Genes Are Highly Conserved. But Where Does Novelty Arise?
“The central problem for evolutionary biologists interested in development has been how morphology is transformed in evolution. In 1922, Walter Garstang made the very basic observation that because the morphology of animals arises anew in each generation, evolution of new animal forms has to be viewed as a problem in the evolution of development.” R. A. Raff (1)
For most of the past 100 years, the evolutionary origins of the mammalian cortex and the development of the mammalian cortex have been studied as if the two issues were completely unrelated to each other. The paper by Kuan et al. (2) in the current issue of the Proceedings raises a number of important issues for the fields of evolution and cortical development and attempts to bridge this gap. This paper also comes at a time in which molecular genetics has forced us to deal with the “meaning” of major gene families found across all vertebrates and invertebrates.
The Telencephalon of Nonmammals and the Phylogeny of Neocortex
Where Did Neocortex Come From?Until the latter part of the twentieth century, the prevailing view of the origins of the mammalian neocortex consisted of a series of loosely conceived proposals, with the common theme that the mammalian neocortex arises within the thin pallial mantle region as found in reptiles. This supposed that all the specific neurons of the cortex, including those in receipt of thalamic input, interneurons, and output neurons, were newly evolved in mammals and were constitutively organized as a laminar structure. This hypothesis also implied that the specific sensory nuclei of the thalamus that provide the inputs to the cortex were also uniquely mammalian.
