Dynamic reorganization of digit representations in somatosensory cortex of nonhuman primates after spinal cord injury.
Dynamic reorganization of digit representations in somatosensory cortex of nonhuman primates after spinal cord injury.
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脊髓损伤后非人类灵长类动物的体感皮层中数字表示的动态重组。
DOI：
10.1523/jneurosci.1841-12.2012
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发表时间：
2012-10-17
期刊：
影响因子：
--
通讯作者：
Kaas JH
中科院分区：
文献类型：
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作者：
Chen LM;Qi HX;Kaas JH
成年灵长类动物的躯体感觉皮层在感觉丧失后会随着时间的推移重新激活。皮质重新激活的时间过程和神经机制尚不清楚。在这里，我们报告，纵向高分辨率的功能磁共振成像研究麻醉松鼠猴显示动态重组的数字激活区3b，在两个月内严重破坏传入输入后，背柱部分。我们发现，输入严重中断的数字区域表现出fMRI触觉反应。重组的特点是一个早期的远离阶段，和一个后期返回阶段，如个别数字激活中心的空间移位病变前的激活网站。随后的光学成像研究证实了功能磁共振成像激活，密集的微电极穿透确定了重新激活部位的弱神经元活动。功能磁共振成像和光学成像检测到的输入剥夺区域的激活区明显大于正常输入个位数区域，并且大于神经元尖峰活动定义的区域。这项研究捕捉了动态重组的数字表示后，背柱病变，并揭示活动成像和微电极记录地图之间的差异。我们的观察结果表明，阈下活动在去传入皮层的再激活中起重要作用，并可能促进行为恢复。
Somatosensory cortices of adult primates reactivate over time after sensory loss. The time course and the neural mechanisms underlying the cortical reactivation are not well understood. Here we report that longitudinal high-resolution fMRI studies on anesthetized squirrel monkeys revealed dynamic reorganizations of digit activations in area 3b, within two months after severely disrupting afferent inputs by dorsal column section. We found that digit regions where inputs were severely disrupted exhibited fMRI tactile responses. Reorganization was characterized by an early moving away phase, and a late returning phase, as indicated by spatial shifts of individual digit activation centers in relation to the pre-lesion activation sites. Subsequent optical imaging studies confirmed fMRI activations, and dense microelectrode penetrations identified weak neuronal activity at the reactivated sites. Activation zones detected by fMRI and optical imaging were significantly larger in input-deprived than normal input single digit regions, and were larger than regions defined by neuronal spiking activity. This study captures the dynamic reorganization of digit representations following dorsal column lesions, and reveals differences between activity imaging and microelectrode recording maps. Our observations suggest that subthreshold activity plays an important role in the reactivation of deafferented cortex, and could promote behavioral recovery.