Crowley J C, Katz L C
Howard Hughes Medical Institute and Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA.
Science. 2000 Nov 17;290(5495):1321-4. doi: 10.1126/science.290.5495.1321.
The segregation of lateral geniculate nucleus (LGN) axons into ocular dominance columns is believed to involve a prolonged, activity-dependent sorting process. However, visualization of early postnatal ferret LGN axons by direct LGN tracer injections revealed segregated ocular dominance columns <7 days after innervation of layer 4. These early columns were unaffected by experimentally induced imbalances in retinal activity, implying that different mechanisms govern initial column formation and their modification during the subsequent critical period. Instead of activity-dependent plasticity, we propose that ocular dominance column formation relies on the targeting of distinct axonal populations to defined locales in cortical layer 4.
外侧膝状体核（LGN）轴突分离成眼优势柱被认为涉及一个漫长的、依赖活动的分选过程。然而，通过直接向LGN注射示踪剂对出生后早期雪貂LGN轴突进行可视化显示，在第4层神经支配后不到7天就出现了分离的眼优势柱。这些早期的柱不受实验诱导的视网膜活动失衡的影响，这意味着不同的机制控制着初始柱的形成及其在随后关键期的修饰。我们提出，眼优势柱的形成并非依赖于活动的可塑性，而是依赖于不同轴突群体靶向皮质第4层的特定区域。
