Chabot Nicole, Butler Blake E, Lomber Stephen G
Cerebral Systems Laboratory, University of Western Ontario, London, Ontario, Canada, N6A 5C2.
Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada, N6A 5C1.
J Comp Neurol. 2015 Oct 15;523(15):2297-320. doi: 10.1002/cne.23790. Epub 2015 May 12.
Following sensory deprivation, primary somatosensory and visual cortices undergo crossmodal plasticity, which subserves the remaining modalities. However, controversy remains regarding the neuroplastic potential of primary auditory cortex (A1). To examine this, we identified cortical and thalamic projections to A1 in hearing cats and those with early- and late-onset deafness. Following early deafness, inputs from second auditory cortex (A2) are amplified, whereas the number originating in the dorsal zone (DZ) decreases. In addition, inputs from the dorsal medial geniculate nucleus (dMGN) increase, whereas those from the ventral division (vMGN) are reduced. In late-deaf cats, projections from the anterior auditory field (AAF) are amplified, whereas those from the DZ decrease. Additionally, in a subset of early- and late-deaf cats, area 17 and the lateral posterior nucleus (LP) of the visual thalamus project concurrently to A1. These results demonstrate that patterns of projections to A1 are modified following deafness, with statistically significant changes occurring within the auditory thalamus and some cortical areas. Moreover, we provide anatomical evidence for small-scale crossmodal changes in projections to A1 that differ between early- and late-onset deaf animals, suggesting that potential crossmodal activation of primary auditory cortex differs depending on the age of deafness onset.
感觉剥夺后，初级躯体感觉皮层和视觉皮层会发生跨模态可塑性，以服务于其余的感觉模态。然而，关于初级听觉皮层（A1）的神经可塑性潜力仍存在争议。为了对此进行研究，我们确定了听力正常的猫以及早发性和迟发性耳聋猫中投射到A1的皮层和丘脑投射。早发性耳聋后，来自第二听觉皮层（A2）的输入会增强，而起源于背侧区（DZ）的输入数量会减少。此外，来自背内侧膝状核（dMGN）的输入增加，而来自腹侧部（vMGN）的输入减少。在迟发性耳聋的猫中，来自前听觉场（AAF）的投射会增强，而来自DZ的投射会减少。此外，在一部分早发性和迟发性耳聋的猫中，视皮层17区和视觉丘脑的外侧后核（LP）会同时投射到A1。这些结果表明，耳聋后投射到A1的模式会发生改变，在听觉丘脑和一些皮层区域会出现具有统计学意义的变化。此外，我们为投射到A1的小规模跨模态变化提供了解剖学证据，这些变化在早发性和迟发性耳聋动物之间有所不同，这表明初级听觉皮层的潜在跨模态激活因耳聋发作的年龄而异。
