Adaptive axonal remodeling in the midbrain auditory space map
Adaptive axonal remodeling in the midbrain auditory space map
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DOI：
10.1523/jneurosci.21-09-03161.2001
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发表时间：
2001-05-01
影响因子：
5.3
通讯作者：
Knudsen, EI
中科院分区：
文献类型：
--
作者：
DeBello, WM;Feldman, DE;Knudsen, EI
仓鸮下丘外核（ICX）的听觉空间图具有高度可塑性，特别是在生命早期。当少年猫头鹰饲养棱镜眼镜（棱镜），横向位移视野，在ICX神经元的听觉空间调谐自适应调整，以匹配视觉位移。在本研究中，我们发现，这种功能可塑性伴随着轴突重塑。ICX接受听觉输入的中央核的下丘（ICC）通过地形轴突的投影。我们使用顺行示踪剂biocytin研究经验依赖性的变化，从ICC投射到ICX的轴突的空间格局。正常成年人的投射野较正常青少年稀疏，限制性较强。棱镜饲养的成年人的投影领域更密集，更广泛的比那些在正常的成年人，并包含更多的bouton负载轴突，适当地定位在ICX传达自适应听觉空间信息。青少年和棱镜饲养猫头鹰的结果的定量比较表明，棱镜的经验导致地形适当的轴突发芽和突触。我们的结论是，这种精心制作的轴突代表了一个适应性神经回路的形成。在正常的投射区的轴突和终扣的密度被保存在棱镜饲养猫头鹰。两种不同的电路编码空间的替代地图的共存可能是棱镜饲养的猫头鹰重新适应成年正常条件的能力的基础。
The auditory space map in the external nucleus of the inferior colliculus (ICX) of barn owls is highly plastic, especially during early life. When juvenile owls are reared with prismatic spectacles (prisms) that displace the visual field laterally, the auditory spatial tuning of neurons in the ICX adjusts adaptively to match the visual displacement. In the present study, we show that this functional plasticity is accompanied by axonal remodeling.The ICX receives auditory input from the central nucleus of the inferior colliculus (ICC) via topographic axonal projections. We used the anterograde tracer biocytin to study experience-dependent changes in the spatial pattern of axons projecting from the ICC to the ICX. The projection fields in normal adults were sparser and more restricted than those in normal juveniles. The projection fields in prism-reared adults were denser and broader than those in normal adults and contained substantially more bouton-laden axons that were appropriately positioned in the ICX to convey adaptive auditory spatial information. Quantitative comparison of results from juvenile and prism-reared owls indicated that prism experience led to topographically appropriate axonal sprouting and synaptogenesis. We conclude that this elaboration of axons represents the formation of an adaptive neuronal circuit.The density of axons and boutons in the normal projection zone was preserved in prism-reared owls. The coexistence of two different circuits encoding alternative maps of space may underlie the ability of prism-reared owls to readapt to normal conditions as adults.