Quantifying and comparing the pattern of thalamic and cortical projections to the posterior auditory field in hearing and deaf cats
Quantifying and comparing the pattern of thalamic and cortical projections to the posterior auditory field in hearing and deaf cats
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DOI：
10.1002/cne.24005
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发表时间：
2016-10-15
影响因子：
2.5
通讯作者：
Lomber, Stephen G.
中科院分区：
文献类型：
--
作者：
Butler, Blake E.;Chabot, Nicole;Lomber, Stephen G.
感觉丧失后，会发生代偿性跨模式重组，从而使其余模式在功能上得到增强。例如，行为证据表明，聋哑动物的周边视觉定位比正常听力动物更好，并且这种增强是通过后听觉场（PAF）的募集介导的，后听觉场通常参与正常听力动物的声音定位。为了描述这种现象背后的解剖学变化，我们确定了听力正常的猫以及早发性和迟发性耳聋猫的丘脑和皮质对 PAF 的投射。逆行示踪剂生物素化葡聚糖胺单侧沉积在 PAF 中，以标记皮质和丘脑传入神经。早期耳聋后，对侧 PAF 的胼胝体投射显着减少。晚期失聪动物的视觉皮层区域、后外侧外侧区（EPp）和多感觉区（MZ）的投射出现小范围变化。除了这些细微的差异外，各组之间与 PAF 的连接在很大程度上相似，主要预测来自初级听觉皮层 (A1) 和内侧膝状体的腹侧部分 (MGBv)。这种大规模连接变化的缺乏表明，感觉丧失后的功能重组是由于突触强度的变化和/或阈下联运连接的暴露造成的。 J.Comp。内罗尔。 524:3042-3063，2016 年。(c) 2016 年 Wiley 期刊公司。
Following sensory loss, compensatory crossmodal reorganization occurs such that the remaining modalities are functionally enhanced. For example, behavioral evidence suggests that peripheral visual localization is better in deaf than in normal hearing animals, and that this enhancement is mediated by recruitment of the posterior auditory field (PAF), an area that is typically involved in localization of sounds in normal hearing animals. To characterize the anatomical changes that underlie this phenomenon, we identified the thalamic and cortical projections to the PAF in hearing cats and those with early- and late-onset deafness. The retrograde tracer biotinylated dextran amine was deposited in the PAF unilaterally, to label cortical and thalamic afferents. Following early deafness, there was a significant decrease in callosal projections from the contralateral PAF. Late-deaf animals showed small-scale changes in projections from one visual cortical area, the posterior ectosylvian field (EPp), and the multisensory zone (MZ). With the exception of these minor differences, connectivity to the PAF was largely similar between groups, with the principle projections arising from the primary auditory cortex (A1) and the ventral division of the medial geniculate body (MGBv). This absence of large-scale connectional change suggests that the functional reorganization that follows sensory loss results from changes in synaptic strength and/or unmasking of subthreshold intermodal connections. J. Comp. Neurol. 524:3042-3063, 2016. (c) 2016 Wiley Periodicals, Inc.