康奈爾大學的研究人員利用最新科技研究幼小斑馬魚的脊索,，結(jié)果在脊索中發(fā)現(xiàn)了一種出乎意料的功能組織類型,。
根據(jù)這篇發(fā)表于3月1日Nature的文章,，研究人員發(fā)現(xiàn)幼小斑馬魚脊索中沿背腹軸方面的神經(jīng)元位置，與斑馬魚游動速度所引起的神經(jīng)元活化,，有直接的關(guān)連性,。
電生理學和活體影像之研究顯示，游動速度較快時,，靠近斑馬魚背部的運動神經(jīng)元和激發(fā)性中間神經(jīng)元會被活化,，而斑馬魚游動速度較慢時，則會使位置更靠腹部,、朝向脊索下半部分的神經(jīng)元活化,。脊索功能的分布，能使斑馬魚游動時效率更高,。
魚類到兩棲類和哺乳動物在演化過程中，都保留了早期的脊索發(fā)育,，所以這種類型的組織可能也存在于其它動物中,。這項研究結(jié)果有助于治療脊髓受損或帕金森氏癥患者。
(資料來源 : Bio.com)
部分英文原文
Nature 446, 71-75 (1 March 2007) | doi:10.1038/nature05588; Received 16 November 2006; Accepted 10 January 2007
A topographic map of recruitment in spinal cord
David L. McLean1, Jingyi Fan2, Shin-ichi Higashijima3, Melina E. Hale2 and Joseph R. Fetcho1
Department of Neurobiology and Behavior, Cornell University, Ithaca, New York 14853, USA
Department of Organismal Biology and Anatomy, University of Chicago, Chicago, Illinois 60637, USA
National Institutes of Natural Sciences, Okazaki Institute for Integrative Bioscience and National Institute for Physiological Sciences, Myodaiji Okazaki, Aichi 444-8787, Japan
Correspondence to: Joseph R. Fetcho1 Correspondence and requests for materials should be addressed to J.R.F. (Email: [email protected]).
Animals move over a range of speeds by using rhythmic networks of neurons located in the spinal cord1, 2, 3, 4, 5, 6. Here we use electrophysiology and in vivo imaging in larval zebrafish (Danio rerio) to reveal a systematic relationship between the location of a spinal neuron and the minimal swimming frequency at which the neuron is active. Ventral motor neurons and excitatory interneurons are rhythmically active at the lowest swimming frequencies, with increasingly more dorsal excitatory neurons engaged as swimming frequency rises. Inhibitory interneurons follow the opposite pattern. These inverted patterns of recruitment are independent of cell soma size among interneurons, but may be partly explained by concomitant dorso-ventral gradients in input resistance. Laser ablations of ventral, but not dorsal, excitatory interneurons perturb slow movements, supporting a behavioural role for the topography. Our results reveal an unexpected pattern of organization within zebrafish spinal cord that underlies the production of movements of varying speeds.
