Dominance for vestibular cortical function in the non-dominant hemisphere
Dominance for vestibular cortical function in the non-dominant hemisphere
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DOI：
10.1093/cercor/13.9.994
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发表时间：
2003-09-01
期刊：
影响因子：
3.7
通讯作者：
Brandt, T
中科院分区：
文献类型：
--
作者：
Dieterich, M;Bense, S;Brandt, T
这项O-15标记的H2O团注正电子发射断层扫描（PET）研究的目的是分析前庭皮质系统的半球优势。因此，在12名右利手和12名左利手健康志愿者中研究了热量前庭刺激（用44 ℃的温水冲洗右耳或左耳）对皮质和皮质下激活的不同影响。热灌注诱导旋转和眼球震颤的方向特异性感觉。在两个半球内的网络中发现了显著的局部脑血流量增加，包括上级额回/沟、中央前回和顶下小叶与缘上回。这些区域最好地对应于皮质眼运动中心，即前额叶皮质、额叶眼场和顶叶眼场，已知这些区域参与热性眼球震颤的处理。此外，在颞顶后部与邻近的上级颞回、顶下小叶和楔前叶之间，可分离出明显的颞顶激活。这些区域最适合于在猴子中鉴定的多感觉前庭皮层区域的人类同源物，并且对应于顶叶岛前庭皮层（PIVC）、视觉颞侧裂区（VTS）以及区域7和6。在前额叶、额下回和前扣带回中观察到进一步的皮质激活。壳核、丘脑和中脑的皮质下激活模式与传出眼运动通路的组织结构一致。皮质和皮质下激活所描述的领域是双边的单耳刺激，但主要是在半球同侧的刺激耳朵，并表现出显着的右半球优势的前庭和眼运动结构的右手志愿者。同样，在12名左撇子志愿者中发现了显著的左半球优势。因此，这项PET研究首次表明，前庭热量刺激引起的皮质和皮质下激活取决于（i）受试者的利手性和（ii）受刺激耳朵的一侧。因此，当非优势半球与受刺激的耳朵同侧时，即在右耳的热量灌注期间在右利手受试者的右半球中，以及在左耳的热量灌注期间在左利手受试者的左半球中，发现最大激活。利手和前庭优势在相对半球的定位可能表明，前庭系统及其半球优势，在个体发育过程中成熟较早，决定了右利手或左利手。
The aim of this O-15-labelled H2O bolus positron emission tomography (PET) study was to analyse the hemispheric dominance of the vestibular cortical system. Therefore, the differential effects of caloric vestibular stimulation (right or left ear irrigation with warm water at 44degreesC) on cortical and subcortical activation were studied in 12 right-handed and 12 left-handed healthy volunteers. Caloric irrigation induces a direction-specific sensation of rotation and nystagmus. Significant regional cerebral blood flow increases were found in a network within both hemispheres, including the superior frontal gyrus/sulcus, the precentral gyrus and the inferior parietal lobule with the supramarginal gyrus. These areas correspond best to the cortical ocular motor centres, namely the prefrontal cortex, the frontal eye field and the parietal eye field, known to be involved in the processing of caloric nystagmus. Furthermore, distinct temporo-parietal activations could be separated in the posterior part of the insula with the adjacent superior temporal gyrus, the inferior parietal lobule and precuneus. These areas fit best to the human homologues of multisensory vestibular cortex areas identified in the monkey and correspond to the parieto-insular vestibular cortex (PIVC), the visual temporal sylvian area (VTS) and areas 7 and 6. Further cortical activations were seen in the anterior insula, the inferior frontal gyrus and anterior cingulum. The subcortical activation pattern in the putamen, thalamus and midbrain is consistent with the organization of efferent ocular motor pathways. Cortical and subcortical activation of the described areas was bilateral during monaural stimulation, but predominant in the hemisphere ipsilateral to the stimulated ear and exhibited a significant right hemispheric dominance for vestibular and ocular motor structures in right-handed volunteers. Similarly, a significant left hemispheric dominance was found in the 12 left-handed volunteers. Thus, this PET study showed for the first time that cortical and subcortical activation by vestibular caloric stimulation depends (i) on the handedness of the subjects and (ii) on the side of the stimulated ear. Maximum activation was therefore found when the non-dominant hemisphere was ipsilateral to the stimulated ear, i.e. in the right hemisphere of right-handed subjects during caloric irrigation of the right ear and in the left hemisphere of left-handed subjects during caloric irrigation of the left ear. The localization of handedness and vestibular dominance in opposite hemispheres might conceivably indicate that the vestibular system and its hemispheric dominance, which matures earlier during ontogenesis, determine right- or left-handedness.