Conti F, Fabri M, Manzoni T
Somatosens Res. 1986;3(4):273-89. doi: 10.3109/07367228609144588.
Experiments were performed in order to study the receptive field (RF) organization and the callosal connectivity of the trunk representation zone in areas 3b and 1 of the postcentral cortex of macaque monkeys. Multiunit microelectrode recordings showed that neurons responding to tactile stimulation of bilateral RFs across the midline of the body were contained in three topographically distinct zones of the trunk map. In one zone, at the junction between cytoarchitectonic areas 3b and 1, RFs straddled the dorsal midline of the trunk. In the other two zones, one located caudally in area 1 in front of the postcentral dimple, and the other rostrally in area 3b in the depth of the posterior bank of the central sulcus, RFs straddled the ventral midline of the trunk. The first one and the other two zones are referred to here as the dorsal and the ventral midline representation zones, respectively. Elsewhere in the trunk map, neurons responded only to stimulation of contralateral RFs. The callosal connectivity of the trunk map was studied by means of the transport of horseradish peroxidase (HRP). Multiple injections of HRP in electrophysiologically identified sites of the trunk representation in one hemisphere labeled both callosal fiber terminals and callosally projecting neurons in the contralateral homotopic cortex. Dense patches of callosal neurons intensely labeled with HRP were present in the cortical regions representing the body midlines and were distributed for the most part in layer III. Some neurons lightly labeled with HRP were scattered in other zones of the trunk map. Callosal terminations were densest within the midline zones and very sparse or absent in the lateral trunk zones. Correlation of physiological and anatomical data obtained either separately or from the same animal demonstrated that cortical regions containing bilateral-field neurons also contained the highest density of labeled callosal terminations and neurons. This correlation suggests a role for the corpus callosum in the perception of the body midline, either by generating the bilateral RFs of these neurons or by coordinating the activity of the regions containing neurons with thalamically generated bilateral RFs.
进行了实验以研究猕猴中央后皮质3b区和1区中躯干表征区的感受野（RF）组织和胼胝体连接性。多单位微电极记录显示，对身体中线两侧的双侧RF进行触觉刺激有反应的神经元包含在躯干图的三个地形上不同的区域中。在一个区域，即在细胞构筑区3b和1的交界处，RF跨越躯干的背中线。在另外两个区域，一个位于中央后凹前方的1区尾部，另一个位于中央沟后壁深处的3b区头部，RF跨越躯干的腹中线。这里将第一个区域和另外两个区域分别称为背中线表征区和腹中线表征区。在躯干图的其他地方，神经元仅对同侧RF的刺激有反应。通过辣根过氧化物酶（HRP）运输研究了躯干图的胼胝体连接性。在一个半球中电生理确定的躯干表征部位多次注射HRP，标记了对侧同型皮质中的胼胝体纤维终末和胼胝体投射神经元。用HRP强烈标记的胼胝体神经元密集斑块存在于代表身体中线的皮质区域，并且大部分分布在III层。一些用HRP轻度标记的神经元散布在躯干图的其他区域。胼胝体终末在中线区域最密集，而在外侧躯干区域非常稀疏或不存在。分别或从同一动物获得的生理和解剖数据的相关性表明，包含双侧视野神经元的皮质区域也包含标记的胼胝体终末和神经元的最高密度。这种相关性表明胼胝体在身体中线感知中起作用，要么通过产生这些神经元的双侧RF，要么通过协调包含具有丘脑产生的双侧RF的神经元的区域的活动。
