EFFECTS OF BINOCULAR DEPRIVATION ON THE DEVELOPMENT OF CLUSTERED HORIZONTAL CONNECTIONS IN CAT STRIATE CORTEX
EFFECTS OF BINOCULAR DEPRIVATION ON THE DEVELOPMENT OF CLUSTERED HORIZONTAL CONNECTIONS IN CAT STRIATE CORTEX
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DOI：
10.1073/pnas.88.3.745
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发表时间：
1991-02-01
影响因子：
11.1
通讯作者：
KATZ, LC
中科院分区：
文献类型：
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作者：
CALLAWAY, EM;KATZ, LC
内在的水平轴突侧支在成年猫的纹状皮质，特别是链接列具有相同的首选方向，因此，逆行示踪剂注射的内在标记，是急剧聚集的结果。 我们以前已经表明，这个电路的正常发展涉及到在出生后第二周从非集群模式中出现粗集群。 粗簇后来细化到成人水平的特异性轴突乔木，最初项目不正确的方向列的选择性重排。 在这里，我们报告说，剥夺动物的模式化的视觉经验，双眼眼睑缝合之前，自然睁开眼睛没有明显的影响出现的原油集群。与此相反，集群细化显着影响双眼剥夺。 在双眼剥夺> 1个月的动物的纹状皮质中注射逆行示踪剂，仅显示出粗糙的簇，表明投射到不正确方向柱的水平轴突侧支保留了很长时间，超过了它们通常会被消除的年龄。 第2/3层锥体细胞从6周龄的双眼剥夺动物有异常分布的内在水平轴突侧支，反映了缺乏集群细化。 水平侧支的放射状聚集远不如正常精确。 然而，这些细胞，开发了许多功能的正常成熟乔木，包括远端轴突分支没有看到乔木从年轻的动物具有正常的视觉经验。 总之，这些结果表明，轴突重排发生，但特异性降低。 因此，双眼剥夺并没有简单地阻止这种方向特异性回路在不成熟状态下的发展，而是限制了轴突侧支增加或消除的准确性。 我们认为，这种方向特异性电路的发展，如眼优势柱分离，可能取决于时间相关的活动调节轴突重排。 在双眼剥夺猫重排的特异性可能会下降，因为他们没有经历过尖锐的视觉刺激，同时激活相同的方向列。
Intrinsic horizontal axon collaterals in the striate cortex of adult cats specifically link columns having the same preferred orientation; consequently, retrograde tracer injections result in intrinsic labeling that is sharply clustered. We have previously shown that the normal development of this circuitry involves the emergence of crude clusters from an unclustered pattern during the second postnatal week. Crude clusters are later refined to the adult level of specificity by the selective rearrangement of axonal arbors that initially project to incorrect orientation columns. Here we report that depriving animals of patterned visual experience by binocular lid suture prior to natural eye opening had no discernible effect on the emergence of crude clusters. In contrast, cluster refinement was dramatically affected by binocular deprivation. Injections of retrograde tracers in the striate cortex of animals binocularly deprived for > 1 month revealed only crude clusters, indicating that horizontal axon collaterals projecting to incorrect orientation columns were retained well past the age when they normally would have been eliminated. Layer 2/3 pyramidal cells from 6-week-old binocularly deprived animals had abnormal distributions of intrinsic horizontal axon collaterals that mirrored the lack of cluster refinement. The radial clustering of their horizontal collaterals was considerably less precise than normal. These cells, nevertheless, developed many of the features of normal mature arbors, including the distal axonal branches not seen in arbors from younger animals with normal visual experience. Together, these results indicate that axonal rearrangements occurred, but with reduced specificity. Thus binocular deprivation did not simply arrest the development of this orientation-specific circuit at an immature state but limited the accuracy with which axon collaterals were added or eliminated. We suggest that development of this orientation-specific circuitry, like ocular dominance column segregation, may depend on temporal correlation of activity for regulation of axonal rearrangement. The specificity of rearrangement may be degraded in binocularly deprived cats because they do not experience sharply oriented visual stimuli necessary for concurrent activation of same-orientation columns.