Matelli M, Luppino G, Fogassi L, Rizzolatti G
Istituto di Fisiologia Umana, Università di Parma, Italy.
J Comp Neurol. 1989 Feb 15;280(3):468-88. doi: 10.1002/cne.902800311.
Recent cytoarchitectonic, histochemical, and hodological studies in primates have shown that area 6 is formed by three main sectors: the supplementary motor area, superior area 6, which lies medial to the spur of the arcuate sulcus, and inferior area 6, which is located lateral to it. Inferior area 6 has been further subdivided into two histochemical areas: area F5, located along the inferior limb of the arcuate sulcus, and area F4, located between area F5 and area 4 (area F1). The present study traced the thalamocortical projections of inferior area 6 and the adjacent part of area 4 by injecting small amounts of WGA-HRP in specific sectors of the agranular frontal cortex. Our data showed that each histochemical area receives a large projection from one nucleus of the ventrolateral thalamus (motor thalamus) and additional projections from other nuclei of this thalamic sector. Area F5 receives a large projection from area X of Olszewski ('52) and additional projections from the caudal part of the nucleus ventralis posterior lateralis, pars oralis (VPLo), and the nucleus ventralis lateralis, pars caudalis (VLc) (VPLo-VLc complex). Area F4 receives a large projection from the nucleus ventralis lateralis, pars oralis (VLo), and additional projections from area X and the VPLo-VLc complex. The rostral part of area F1 is innervated chiefly by VLo, plus smaller contributions from rostral VPLo and the VPLo-VLc complex. The caudal part of F1 receives its greatest input from VPLo, with a small contribution from VLo. In addition, each histochemical area receives projections originating from the intralaminar thalamic nuclei, the posterior thalamus, and--for area F4 and area F5--also from the nucleus medialis dorsalis (MD). Analysis of the physiological properties of the various histochemical areas in relation to their main thalamic input showed that those cortical fields in which distal movements are predominant (area F5, caudal part of area F1) are innervated chiefly by area X and VPLo, whereas those cortical fields in which proximal movements are predominant receive their main input from VLo. Because VPLo and area X are targets of cerebellothalamic pathways, whereas VLo receives a pallidal input, we propose that the cortical fields in which distal movements are most heavily represented are mainly under the influence of the cerebellum, whereas the cortical fields in which proximal movements are most heavily represented are mainly under the influence of the basal ganglia.
近期针对灵长类动物的细胞构筑学、组织化学和神经通路学研究表明，6区由三个主要部分构成：辅助运动区、位于弓状沟 spur 内侧的6区上部，以及位于其外侧的6区下部。6区下部又进一步细分为两个组织化学区域：位于弓状沟下肢的F5区，以及位于F5区和4区（F1区）之间的F4区。本研究通过在颗粒状额叶皮质的特定区域注射少量WGA - HRP，追踪了6区下部及4区相邻部分的丘脑皮质投射。我们的数据显示，每个组织化学区域都从腹外侧丘脑（运动丘脑）的一个核团接收大量投射，并从该丘脑区域的其他核团接收额外投射。F5区从奥尔谢夫斯基（1952年）的X区接收大量投射，并从腹后外侧核口部尾侧部分（VPLo）和腹外侧核尾部（VLc）（VPLo - VLc复合体）接收额外投射。F4区从腹外侧核口部（VLo）接收大量投射，并从X区和VPLo - VLc复合体接收额外投射。F1区的前部主要由VLo支配，还有来自VPLo前部和VPLo - VLc复合体的较小贡献。F1区的后部最大输入来自VPLo，VLo有少量贡献。此外，每个组织化学区域都接收来自丘脑板内核、丘脑后部的投射，对于F4区和F5区，还接收来自背内侧核（MD）的投射。对各组织化学区域与其主要丘脑输入相关的生理特性分析表明，那些以远端运动为主的皮质区域（F5区、F1区后部）主要由X区和VPLo支配，而那些以近端运动为主的皮质区域主要输入来自VLo。由于VPLo和X区是小脑 - 丘脑通路的靶点，而VLo接收苍白球输入，我们提出，那些远端运动占主导的皮质区域主要受小脑影响，而那些近端运动占主导的皮质区域主要受基底神经节影响。
