Transient callosal projections of L4 neurons are eliminated for the acquisition of local connectivity
Transient callosal projections of L4 neurons are eliminated for the acquisition of local connectivity
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DOI：
10.1038/s41467-019-12495-w
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发表时间：
2019-10-07
影响因子：
16.6
通讯作者：
Nieto, M.
中科院分区：
文献类型：
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作者：
De Leon Reyes, N. S.;Mederos, S.;Nieto, M.
胼胝体(CC)的半球间轴突促进大脑皮层的高级功能。根据目前的观点，神经元出生后很早就决定了各自的命运，某些群体，如初级躯体感觉桶(S1)的皮层(L)4兴奋性神经元，只投射同侧。使用一种新的轴突追溯策略和以GFP为目标的Rorb(+)神经元的可视化，我们相反地证明了L4神经元发展了一过性的半球间轴突。在出生后发育过程中，当活跃的对侧轴突以特定区域和特定层的方式细化时，局部限制的L4连接出现。对感觉回路的外科和遗传学干预表明，精确率取决于来自感觉特异性丘脑核团的不同输入。减少依赖输入的精化导致成熟的功能性大脑半球间的高度连接，展示了L4神经元的可塑性和真正的膝盖骨潜力。因此，L4神经元按照丘脑输入的指示丢弃交替的半球间回路。这可以确保最佳布线。
Interhemispheric axons of the corpus callosum (CC) facilitate the higher order functions of the cerebral cortex. According to current views, callosal and non-callosal fates are determined early after a neuron's birth, and certain populations, such as cortical layer (L) 4 excitatory neurons of the primary somatosensory (S1) barrel, project only ipsilaterally. Using a novel axonal-retrotracing strategy and GFP-targeted visualization of Rorb(+) neurons, we instead demonstrate that L4 neurons develop transient interhemispheric axons. Locally restricted L4 connectivity emerges when exuberant contralateral axons are refined in an area-and layer-specific manner during postnatal development. Surgical and genetic interventions of sensory circuits demonstrate that refinement rates depend on distinct inputs from sensory-specific thalamic nuclei. Reductions in input-dependent refinement result in mature functional interhemispheric hyperconnectivity, demonstrating the plasticity and bona fide callosal potential of L4 neurons. Thus, L4 neurons discard alternative interhemispheric circuits as instructed by thalamic input. This may ensure optimal wiring.