Hemispheric lateralization of somatosensory processing
Hemispheric lateralization of somatosensory processing
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DOI：
10.1152/jn.2001.85.6.2602
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发表时间：
2001-06-01
影响因子：
2.5
通讯作者：
Iadarola, MJ
中科院分区：
文献类型：
--
作者：
Coghill, RC;Gilron, I;Iadarola, MJ
疼痛和非疼痛的躯体感觉信息的处理通常被认为是由大脑区域主要是对侧的刺激身体区域。然而，有报道称，右侧后顶叶皮层的损伤会产生单侧触觉忽视综合征，这表明躯体感觉信息的成分优先在右半脑处理。为了更好地表征躯体感觉处理的右半球偏侧化，使用脑血流的（H2O）-O-15正电子发射断层扫描（PET）来映射右手受试者的左臂和右臂的接触热刺激产生的脑激活。为了允许直接评估激活的偏侧化，在单独的PET扫描期间递送左侧和右侧刺激。无害（35 ℃）和疼痛（49 ℃）刺激，以确定是否发生偏侧处理的方式与感知疼痛强度。受试者在非刺激的休息条件下进行扫描，以表征与感知疼痛强度无关的激活。疼痛强度依赖性和独立的激活的变化被确定在单独的多元回归分析。无论刺激的一侧，疼痛强度依赖性激活定位于初级体感皮层，次级体感皮层，岛叶皮层，小脑，壳核，丘脑，前扣带皮层和额叶盖的双侧区域的对侧区域。没有检测到疼痛强度依赖性处理的半球偏侧化。与此形成鲜明对比的是，部分丘脑，下顶叶皮层（BA 40），背外侧前额叶皮层（BA 9/46），背侧额叶皮层（BA 6）表现出右侧激活过程中无害和痛苦的刺激，无论刺激的一面。因此，从身体表面产生的信息成分部分地由右侧化系统处理，类似于那些处理来自外部空间的听觉和视觉空间信息的系统。这种右侧化的处理可以解释由于右大脑半球内的脑区域的损伤而引起的左侧躯体感觉忽视。
Processing of both painful and nonpainful somatosensory information is generally thought to be subserved by brain regions predominantly contralateral to the stimulated body region. However, lesions to right, but not left, posterior parietal cortex have been reported to produce a unilateral tactile neglect syndrome, suggesting that components of somatosensory information are preferentially processed in the right half of the brain. To better characterize right hemispheric lateralization of somatosensory processing, (H2O)-O-15 positron emission tomography (PET) of cerebral blood flow was used to map brain activation produced by contact thermal stimulation of both the left and right arms of right-handed subjects. To allow direct assessment of the lateralization of activation, left- and right-sided stimuli were delivered during separate PET scans. Both innocuous (35 degreesC) and painful (49 degreesC) stimuli were employed to determine whether lateralized processing occurred in a manner related to perceived pain intensity. Subjects were also scanned during a nonstimulated rest condition to characterize activation that was not related to perceived pain intensity. Pain intensity-dependent and -independent changes in activation were identified in separate multiple regression analyses. Regardless of the side of stimulation, pain intensity-dependent activation was localized to contralateral regions of the primary somatosensory cortex, secondary somatosensory cortex, insular cortex, and bilateral regions of the cerebellum, putamen, thalamus, anterior cingulate cortex, and frontal operculum. No hemispheric lateralization of pain intensity-dependent processing was detected. In sharp contrast, portions of the thalamus, inferior parietal cortex (BA 40), dorsolateral prefrontal cortex (BA 9/46), and dorsal frontal cortex (BA 6) exhibited right lateralized activation during both innocuous and painful stimulation, regardless of the side of stimulation. Thus components of information arising from the body surface are processed, in part, by right lateralized systems analogous to those that process auditory and visual spatial information arising from extrapersonal space. Such right lateralized processing can account for the left somatosensory neglect arising from injury to brain regions within the right cerebral hemisphere.