Abnormal access of axial vibrotactile input to deafferented somatosensory cortex in human upper limb amputees
Abnormal access of axial vibrotactile input to deafferented somatosensory cortex in human upper limb amputees
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DOI：
10.1152/jn.1997.77.5.2753
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发表时间：
1997-05-01
影响因子：
2.5
通讯作者：
Brooks, DJ
中科院分区：
文献类型：
--
作者：
Kew, JJM;Halligan, PW;Brooks, DJ
我们研究了两个人类受试者总deafferentation的一个上肢继发于创伤性多颈根撕脱。两名受试者都出现了幻肢，并对麻痹的、传入神经切断的肢体进行了选择性截肢。心理物理学研究显示，在每一个主题的皮肤面积在同侧的截肢，振动触觉刺激（VS）引起的涉及的感觉（RS）在幻肢的胸肌区。正电子发射断层扫描，然后被用来测量区域脑血流变化在VS的同侧截肢与RS和VS的同源部分的胸肌区邻近的完整的手臂没有RS。随后使用基于体素的相关性分析来研究功能连接。VS的胸区相邻的完整的手臂与激活的背侧部分的对侧初级体感皮层（S1）的位置与S1躯干区一致。相比之下，VS的胸肌区同侧截肢与RS与激活对侧S1延伸的躯干代表腹侧的距离分别为20和12毫米，在这两个主题。在VS的手指在正常对照受试者的S1区激活与腹侧S1区在VS的异位幻影表示在两个截肢者异常激活，这表明，deafferented手指或手/臂区已被激活的感觉输入从胸肌区。相关性分析显示，一个异常的模式内在的连接在去传入的S1手/手臂面积的截肢者。在一个主题中，去传入的S1功能连接的S1体素是正常传入的S1的3倍。这种异常的功能连接延伸在这两个rostrocaudal和ventrodorthoral尺寸。结果表明，感官输入传递到轴向体表可能会获得进入S1手/手臂区域在一些人谁遭受了广泛的deafferentation这一地区。研究结果是一致的假设，deafferentation的一个地区的S1可能会导致激活以前休眠的输入从身体表面表示在紧邻的S1部分。这些结果也提供了证据表明，这些相邻的皮质区域之间的功能连接的变化在躯体位置重组中发挥了作用。
We studied two human subjects with total deafferentation of one upper limb secondary to traumatic multiple cervical root avulsions. Both subjects developed a phantom limb and underwent elective amputation of the paralyzed, deafferentated limb. Psychophysical study revealed in each subject an area of skin in the pectoral region ipsilateral to the amputation where vibrotactile stimulation (VS) elicited referred sensations (RS) in the phantom limb. Positron emission tomography was then used to measure regional cerebral blood flow changes during VS of the pectoral region ipsilateral to the amputation with RS and during VS of a homologous part of the pectoral region adjacent to the intact arm without RS. A voxel-based correlation analysis was subsequently used to study functional connectivity. VS of the pectoral region adjacent to the intact arm was associated with activation of the dorsal part of the contralateral primary somatosensory cortex (S1) in a position consistent with the S1 trunk area. In contrast, VS of the pectoral region ipsilateral to the amputation with RS was associated with activation of the contralateral S1 that extended from the level of the trunk representation ventrally over distances of 20 and 12 mm, respectively, in the two subjects. The area of S1 activated during VS of the digits in a normal control subject was coextensive with the ventral S1 region abnormally activated during VS of the ectopic phantom representation in the two amputees, suggesting that the deafferented digit or hand/arm area had been activated by sensory input from the pectoral region. Correlation analysis showed an abnormal pattern of intrinsic connectivity within the deafferented S1 hand/arm area of both amputees. In one subject, the deafferented S1 was functionally connected with 3 times as many S1 voxels as the normally afferented S1. This abnormal functional connectivity extended in both the rostrocaudal and ventrodorsal dimensions. The results demonstrate that sensory input delivered to the axial body surface may gain access to the S1 hand/arm area in some humans who have suffered extensive deafferentation of this area. The findings are consistent with the hypothesis that deafferentation of an area of S1 may result in activation of previously dormant inputs from body surfaces represented in immediately adjacent parts of S1. The results also provide evidence that changes in functional connectivity between these adjacent areas of the cortex play a role in the somatotopic reorganization.