Fabri M, Polonara G, Mascioli G, Paggi A, Salvolini U, Manzoni T
Dipartimento di Neuroscienze, Sezione di Fisiologia, Università Politecnica delle Marche, Via Tronto 10/A, 60020 Ancona, Torrette, Italy.
Eur J Neurosci. 2006 Jun;23(11):3139-48. doi: 10.1111/j.1460-9568.2006.04823.x.
Human brain studies have shown that the cutaneous receptors of trunk regions close to the midline are represented in the first somatosensory cortex (SI) of both hemispheres. The present study aims to establish whether in humans, as in non-human primates, the bilateral representation of the trunk midline in area SI depends on the corpus callosum. Data were obtained from eight callosotomized patients: three with complete callosal resection, one with a partial posterior resection including the splenium and the callosal trunk, and four with partial anterior resections sparing the splenium and in one case also the posterior part of the callosal trunk. The investigation was carried out with functional magnetic resonance imaging. Unilateral tactile stimulation was applied by rubbing ventral trunk regions close to the midline (about 20 x 10 cm in width) with a soft cotton pad (frequency 1 Hz). Cortical activation foci elicited by unilateral stimulation of cutaneous regions adjacent to the midline were detected in the contralateral post-central gyrus (PCG), in a region corresponding to the trunk ventral midline representation zone of area SI, as described in a previous study of intact subjects. In most patients, activation foci were also found in the ipsilateral PCG, again as in subjects with an intact corpus callosum. The data confirm that the skin regions adjacent to the trunk midline are represented bilaterally in SI, and indicate that ipsilateral activation is at least partially independent of the corpus callosum.
对人类大脑的研究表明，靠近中线的躯干区域的皮肤感受器在两个半球的第一体感皮层（SI）中都有代表。本研究旨在确定在人类中，如同在非人类灵长类动物中一样，SI区中躯干中线的双侧代表是否依赖于胼胝体。数据来自八名胼胝体切开术患者：三名进行了完全胼胝体切除术，一名进行了包括压部和胼胝体干的部分后部切除术，四名进行了保留压部且在一例中还保留了胼胝体干后部的部分前部切除术。研究采用功能磁共振成像进行。用柔软的棉垫（频率1赫兹）摩擦靠近中线的腹侧躯干区域（宽度约20×10厘米）进行单侧触觉刺激。如先前对完整受试者的研究所描述，在对侧中央后回（PCG）中检测到由单侧刺激中线附近皮肤区域引起的皮质激活灶，该区域对应于SI区的躯干腹侧中线代表区。在大多数患者中，同侧PCG中也发现了激活灶，同样如同胼胝体完整的受试者。数据证实，靠近躯干中线的皮肤区域在SI区中双侧代表，并表明同侧激活至少部分独立于胼胝体。
