A basic study of the motor disturbance in basal ganglia diseases

我们计划研究投射到纹状体的大鼠丘脑束旁核(PF)的突触组织与束旁传入的关系。将生物素标记的葡聚糖胺(BDA)注入上丘(SC)或桥脑脚被盖核(PPN)后，在PF的外侧部出现了大量BDA标记的轴突和轴突终末。电子显微镜下，所有标记的轴突终末均含有圆形突触小泡并形成不对称突触。比较SC和PPN传入终末，前者似乎比后者大，而且SC终末比PPN终末更靠近树突的近端。将辣根过氧化物酶标记的麦芽凝集素(WGA-HRP)和BDA分别注入纹状体和SC，观察到BDA标记的终末与WGA-HRP标记的PF神经元突触。从而证实了丘脑-束旁-纹状体的连续投射。当WGA-HKP和BDA分别注射到SC和PPN时，观察到两个核团的轴突终末与PF神经元的单一树突突触。这意味着SC和PPN传入会聚到一个单一的PF神经元上。这是不可能的，因此，SC功能的眼动和定向运动以及PPN功能的运动都整合在PF中。然后，这种信息可能被发送到纹状体，并通过基底节回路传递到运动皮质。现在我们可以解释PF函数的一部分。

We planned to study the synaptic organization of the rat parafascicular nucleus (Pf) of the thalamus, which projects to the striatum, in relation to parafascicular afferents. After injections of biotinylated dextran amine (BDA) into the superior colliculus (SC) or the pedunculopontine tegmental nucleus (PPN), both of which are main afferent sources of the Pf, numerous BDA-labeled axons and axon terminals appeared in the lateral part of the Pf. Electron microscopically all of the labeled axon terminals contained round synaptic vesicles and made asymmetric synapses. Comparing SC and PPN afferent terminals, the former seemed larger than the latter, and SC terminals tended to be located at more proximal portion of dendrites than PPN terminals. When wheatgerm agglutinin conjugated to horseradish peroxidase (WGA-HRP) and BDA were injected into the striatum and SC, respectively, BDA-labeled terminals were observed to synapse with WGA-HRP labeled Pf neurons. Thus, the serial colliculo-parafasciculo-striatal projection was proved. When WGA-HKP and BDA were injected into the SC and PPN, respectively, axon terminals from both nuclei observed to synapse with a single dendrite of Pf neurons. This fact means that SC and PPN afferents converged onto a single Pf neuron. It is conceirvable, therefore, both ocular and orientation movements of the SC function, and locomotion of the PPN function are integrated in the Pf. Then this kind of information might be sent to the striatum, and conveyed to the motor cortex via the basal ganglia circuitry. Now we could explain a part of the Pf function.