Functional topography of the secondary somatosensory cortex for nonpainful and painful stimuli: an fMRI study
Functional topography of the secondary somatosensory cortex for nonpainful and painful stimuli: an fMRI study
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DOI：
10.1016/j.neuroimage.2003.07.004
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发表时间：
2003-11-01
期刊：
影响因子：
5.7
通讯作者：
Romani, GL
中科院分区：
文献类型：
--
作者：
Ferretti, A;Babiloni, C;Romani, GL
采用功能磁共振成像（fMRI）技术研究了正中神经在5个强度水平（从无痛运动阈值到中度疼痛）刺激时对侧初级（SI）和双侧次级（SII）体感区的区域活动。目的是表征SII的功能地形，与SI相比，作为刺激强度的函数。结果表明，电刺激正中神经在所有刺激强度下均能激活对侧侧单侧脑区。当被视为一个单一区域时，SII在对侧半球的激活比在同侧半球的激活更强烈。当对SII反应进行更精细的空间分析时，与非疼痛刺激相比，疼痛刺激的活动定位在更后的位置。这是关于暂态电刺激的SII分离的第一篇报道。该后区活动（相对信号强度）随刺激强度的增加而增加。这些结果表明，处理由背柱-内侧小网膜（非疼痛信号）和新脊髓丘脑（疼痛信号）通路传递的信号的神经群在空间上存在分离。在涉及感觉运动整合、学习和记忆需求的任务中，进一步的fMRI实验应该评估这两个SII亚区的功能特性。(C) 2003 Elsevier Inc.版权所有。
The regional activity of the contralateral primary (SI) and the bilateral secondary (SII) somatosensory areas during median nerve stimulations at five intensity levels (ranging from nonpainful motor threshold to moderate pain) was studied by means of functional magnetic resonance imaging (fMRI). The aim was to characterize the functional topography of SII compared to SI as a function of the stimulus intensity. Results showed that the galvanic stimulation of the median nerve activated the contralateral SI at all stimulus intensities. When considered as a single region, SII was more strongly activated in the contralateral than in the ipsilateral hemisphere. When a finer spatial analysis of the SII responses was performed, the activity for the painful stimulation was localized more posteriorly compared to that for the nonpainful stimulation. This is the first report on such a SII segregation for transient galvanic stimulations. The activity (relative signal intensity) of this posterior area increased with the increase of the stimulus intensity. These results suggest a spatial segregation of the neural populations that process signals conveyed by dorsal column-medial lemniscus (nonpainful signals) and neospinothalamic (painful signals) pathways. Further fMRI experiments should evaluate the functional properties of these two SII subregions during tasks involving sensorimotor integration, learning, and memory demands. (C) 2003 Elsevier Inc. All rights reserved.