Pollin B, Albe-Fessard D
Brain Res. 1979 Sep 21;173(3):431-49. doi: 10.1016/0006-8993(79)90240-3.
In an attempt to understand the modifications which appears at the thalamic level when dorsal cord sections are performed, peripheral fields of thalamic units were studied in normal and dorsal-cord sectional monkeys, totally awake and implanted with glass micropipettes. Six normal Macaca cynomolgus and 7 having received spinal sections, were studied. Ventricular radiography was performed and all the coordinates were related to new stereotaxic coordinates using the posterior commissure as the origin. Cell-bodies and axon units were recognized on the basis of the shape of the spikes. In normal animals, 972 units were studied; 307 were thalamic units with peripheral fields and 177 were derived from cell bodies. Localization of these cells was studied as a function of their peripheral field and response characteristics. The majority of ventralis posterior (VP) cell bodies were only activated by contralateral stimulation, their peripheral field being frequently found on the extremities. Somatotopic organization consisted of concentric layers rather than zones in apposition. Dorsoventral segregation of afferent modality sensitivity (movement, pressure, light touch) was observed. Somatosensory convergence was found in VP inferior (VPi) as well as convergence of different types of afferents on a few VP cells. Units responding to bilateral or ipsilateral stimulations were found only in posterior VP and in surrounding nuclei. A particular somatotopy was shown to exist in n. reticularis. A total of 838 units were studied in animals having had dorsal columns and Morin's bundle served. Only a few cells (13) responded in VPl to contralateral hindlimb stimulation. Their characteristics recall those noted in layer V spinal cord cells. The other cells (55) still driven by a hindlimb were dispersed in the nuclei just adjacent to VPl. The majority of cells found in the VPl were activated from the forelimb. They were observed in their normal VPl localization as well as in areas where hindlimb representation was found in normal animals. This change of afferent input is attributed to a reinnervation of hindlimb cells (probably at the gracilis level) by sprouting from forelimb afferent.
为了了解在进行脊髓背侧横断时丘脑水平出现的变化，在完全清醒并植入玻璃微电极的正常和脊髓背侧横断的猴子中，研究了丘脑神经元的外周视野。研究了6只正常食蟹猴和7只接受脊髓横断的猴子。进行了脑室造影，并以后连合为原点，将所有坐标与新的立体定向坐标相关联。根据峰电位的形状识别细胞体和轴突单位。在正常动物中，研究了972个单位；其中307个是具有外周视野的丘脑单位，177个来自细胞体。根据这些细胞的外周视野和反应特性研究了它们的定位。大多数腹后核（VP）细胞体仅由对侧刺激激活，其外周视野常在四肢发现。躯体定位组织由同心层组成，而不是并列的区域。观察到传入模态敏感性（运动、压力、轻触）的背腹侧分离。在腹后下核（VPi）发现了躯体感觉汇聚，以及在一些VP细胞上不同类型传入纤维的汇聚。仅在VP后部和周围核中发现对双侧或同侧刺激有反应的单位。在网状核中显示存在一种特殊的躯体定位。在脊髓背侧柱和莫林束被切断的动物中，共研究了838个单位。只有少数细胞（13个）在VPl中对侧后肢刺激有反应。它们的特征让人想起在脊髓V层细胞中观察到的特征。其他仍由后肢驱动的细胞（55个）分散在紧邻VPl的核中。在VPl中发现的大多数细胞由前肢激活。它们在正常的VPl定位以及在正常动物中发现后肢代表区的区域中被观察到。这种传入输入的变化归因于前肢传入纤维的侧支发芽对后肢细胞（可能在薄束核水平）的重新支配。
