Kingsbury Marcy A, Lettman Nadine A, Finlay Barbara L
Department of Psychology, Cornell University, Ithaca, NY, USA.
Brain Res Dev Brain Res. 2002 Sep 20;138(1):35-43. doi: 10.1016/s0165-3806(02)00456-x.
The functional specificity of mammalian isocortex requires that precise connections be established between cortical areas and their targets. While recent studies of cortical development have focused on intrinsic specification, the role of extrinsic factors has received considerably less attention. In the present study, we examined how early removal of thalamic input affects the development of visual corticocortical connections. Hamster pups received ablations of visual thalamic nuclei on the day of birth. At 30 days of age, an injection of horseradish peroxidase (HRP) was placed into the area of cortex deafferented by the early thalamic ablation to retrogradely label adult corticocortical connections. Ablated animals displayed a significant increase in the number of corticocortical connections compared to control animals. The increased connectivity in ablated animals was primarily due to a significant increase in the number of corticocortical projections arising from non-visual areas. These results demonstrate that an intact thalamocortical projection is necessary for the development of normal cortical connectivity.
哺乳动物同型皮质的功能特异性要求在皮质区域与其靶标之间建立精确的连接。虽然最近关于皮质发育的研究集中在内在特化上，但外在因素的作用受到的关注要少得多。在本研究中，我们研究了早期去除丘脑输入如何影响视觉皮质-皮质连接的发育。仓鼠幼崽在出生当天接受视觉丘脑核的切除。在30日龄时，将辣根过氧化物酶（HRP）注射到因早期丘脑切除而传入神经阻滞的皮质区域，以逆行标记成年皮质-皮质连接。与对照动物相比，切除动物的皮质-皮质连接数量显著增加。切除动物中连接性的增加主要是由于非视觉区域产生的皮质-皮质投射数量显著增加。这些结果表明，完整的丘脑-皮质投射对于正常皮质连接性的发育是必要的。
