Takada M, Nambu A, Hatanaka N, Tachibana Y, Miyachi S, Taira M, Inase M
Tokyo Metropolitan Institute for Neuroscience, Tokyo Metropolitan Organization for Medical Research, Fuchu, Tokyo 183-8526, Japan.
Eur J Neurosci. 2004 Jun;19(12):3328-42. doi: 10.1111/j.0953-816X.2004.03425.x.
Linkage between the prefrontal cortex and the primary motor cortex is mediated by nonprimary motor-related areas of the frontal lobe. In an attempt to analyse the organization of the prefrontal outflow from area 46 toward the frontal motor-related areas, we investigated the pattern of projections involving the higher-order motor-related areas, such as the presupplementary motor area (pre-SMA) and the rostral cingulate motor area (CMAr). Tracer injections were made into these motor-related areas (their forelimb representation) on the medial wall that had been identified electrophysiologically. The following data were obtained from a series of tract-tracing experiments in Japanese monkeys. (i) Only a few neurons in area 46 were retrogradely labelled from the pre-SMA and CMAr; (ii) terminal labelling from area 46 occurred sparsely in the pre-SMA and CMAr; (iii) a dual labelling technique revealed that the sites of overlap of anterograde labelling from area 46 and retrograde labelling from the pre-SMA and CMAr were evident in the rostral parts of the dorsal and ventral premotor cortices (PMdr and PMvr); (iv) and tracer injections into the PMdr produced neuronal cell labelling in area 46 and terminal labelling in the pre-SMA and CMAr. The present results indicate that a large portion of the prefrontal signals from area 46 is not directly conveyed to the pre-SMA and CMAr, but rather indirectly by way of the PMdr and PMvr. This suggests that area 46 exerts its major influence on the cortical motor system via these premotor areas.
前额叶皮质与初级运动皮质之间的联系是由额叶的非初级运动相关区域介导的。为了分析从46区向前额叶运动相关区域的前额叶传出纤维的组织情况，我们研究了涉及高阶运动相关区域的投射模式，如补充运动前区（pre-SMA）和吻侧扣带运动区（CMAr）。将示踪剂注射到内侧壁上这些已通过电生理学方法确定的运动相关区域（其前肢代表区）。以下数据来自对日本猕猴进行的一系列示踪实验。（i）从补充运动前区和吻侧扣带运动区逆行标记的46区神经元只有少数；（ii）46区的终末标记在补充运动前区和吻侧扣带运动区稀疏出现；（iii）双重标记技术显示，46区顺行标记与补充运动前区和吻侧扣带运动区逆行标记的重叠部位在背侧和腹侧运动前皮质（PMdr和PMvr）的吻侧部分很明显；（iv）向背侧运动前皮质注射示踪剂会在46区产生神经元细胞标记，并在补充运动前区和吻侧扣带运动区产生终末标记。目前的结果表明，来自46区的大部分前额叶信号不是直接传递到补充运动前区和吻侧扣带运动区，而是通过背侧和腹侧运动前皮质间接传递。这表明46区通过这些运动前区对皮质运动系统发挥主要影响。
