Multisensory integration in primary auditory (A1), visual (V1), and somatosensory cortex (S1) is substantially mediated by their direct interconnections and by thalamic inputs across the sensory modalities. We have previously shown in rodents (Mongolian gerbils) that during postnatal development, the anatomical and functional strengths of these crossmodal and also of sensory matched connections are determined by early auditory, somatosensory, and visual experience. Because supragranular layer III pyramidal neurons are major targets of corticocortical and thalamocortical connections, we investigated in this follow-up study how the loss of early sensory experience changes their dendritic morphology. Gerbils were sensory deprived early in development by either bilateral sciatic nerve transection at postnatal day (P) 5, ototoxic inner hair cell damage at P10, or eye enucleation at P10. Sholl and branch order analyses of Golgi-stained layer III pyramidal neurons at P28, which demarcates the end of the sensory critical period in this species, revealed that visual and somatosensory deprivation leads to a general increase of apical and basal dendritic branching in A1, V1, and S1. In contrast, dendritic branching, particularly of apical dendrites, decreased in all three areas following auditory deprivation. Generally, the number of spines, and consequently spine density, along the apical and basal dendrites decreased in both sensory deprived and non-deprived cortical areas. Therefore, we conclude that the loss of early sensory experience induces a refinement of corticocortical crossmodal and other cortical and thalamic connections by pruning of dendritic spines at the end of the critical period. Based on present and previous own results and on findings from the literature, we propose a scenario for multisensory development following early sensory loss.

中文翻译：

---

早期的感觉丧失会改变啮齿类动物初级感觉皮质中的树突状锥体神经元的树突分支和脊柱密度。

初级听觉（A1），视觉（V1）和体感皮层（S1）中的多感官整合基本上是由它们的直接互连和通过丘脑输入的感觉模态介导的。我们先前在啮齿动物（蒙古沙鼠）中发现，在产后发育过程中，这些交叉峰态以及感觉匹配连接的解剖学和功能强度是由早期的听觉，体感和视觉经验决定的。由于肾上皮层III锥体神经元是皮层皮质和丘脑皮质连接的主要目标，因此我们在此后续研究中调查了早期感觉体验的丧失如何改变其树突形态。出生后（P）5日，双侧坐骨神经横断，沙鼠在发育早期被感觉剥夺，5 在P10发生耳毒性内毛细胞损伤，或在P10发生眼睛摘除。在P28处高尔基染色的III层锥体神经元的触角和分支顺序分析界定了该物种的感官关键期的结束，表明视觉和体感的剥夺导致A1，V1的根尖和基底树突分支普遍增加。和S1。相反，听觉剥夺后，所有三个区域的树突分支，特别是顶端树突分支均减少。通常，在感觉剥夺的皮层区域和非剥夺的皮层区域中，沿着根尖和基底树突的脊椎数量减少，因此脊柱密度降低。因此，我们得出的结论是，在关键时期结束时，通过修剪树突棘，丧失了早期的感觉体验，从而导致了皮质皮质交叉峰态以及其他皮质和丘脑连接的细化。基于目前和以前的研究结果以及文献中的发现，我们提出了在早期感觉丧失后进行多感觉发展的方案。