Allen G V, Hopkins D A
Department of Anatomy and Neurobiology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
J Comp Neurol. 1998 Aug 31;398(3):347-58. doi: 10.1002/(sici)1096-9861(19980831)398:3<347::aid-cne4>3.0.co;2-#.
To study the convergence of medial prefrontal cortex and mamillary body projections to the medial pontine nuclei, light and electron microscopic, neuroanatomical, tract-tracing experiments were performed. Injections of horseradish peroxidase conjugated to wheat germ agglutinin (WGA-HRP), biotin conjugated to dextran (BD), or rhodamine conjugated to dextran (RD) were made individually or in combinations into the cerebral cortex, hypothalamus, or pons. In addition, injections of WGA-HRP into the medial prefrontal cortex and electrolytic lesions of the mamillary body were made to study the synaptology of afferent projections to the pontine nuclei. In the light microscopic studies, injections of WGA-HRP into the rostromedial pontine nuclei produced dense, retrograde labeling both in the dorsal peduncular area of the medial prefrontal cortex and in the medial mamillary nucleus, pars medialis. Injections of the anterograde tracers BD and RD into the medial prefrontal cortex and the medial mamillary nuclei, respectively, resulted in partially overlapping terminal fields in the rostromedial pontine nuclei. In the electron microscopic studies, injections of WGA-HRP into the dorsal peduncular area and electrolytic lesions of the mamillary body produced anterogradely labeled axon terminals and degenerating axon terminals that synapsed on the same dendrites or neuronal somata in the rostromedial pontine nuclei. The results demonstrate that the medial prefrontal cortex and the medial mamillary nuclei have partially overlapping projections to the rostromedial pontine nuclei and implicate precerebellar relay nuclei in the integration of limbic and/or autonomic functions mediated by convergent projections from the cerebral cortex and the hypothalamus.
为研究内侧前额叶皮质和乳头体向脑桥内侧核的投射汇聚情况，进行了光镜和电镜神经解剖学示踪实验。将与小麦胚凝集素结合的辣根过氧化物酶（WGA-HRP）、与葡聚糖结合的生物素（BD）或与葡聚糖结合的罗丹明（RD）单独或联合注射到大脑皮质、下丘脑或脑桥。此外，向内侧前额叶皮质注射WGA-HRP并对乳头体进行电解损伤，以研究向脑桥核传入投射的突触学。在光镜研究中，向脑桥内侧核头端注射WGA-HRP，在内侧前额叶皮质的背侧脚区和乳头体内侧核内侧部产生密集的逆行标记。分别向内侧前额叶皮质和乳头体内侧核注射顺行示踪剂BD和RD，在脑桥内侧核头端产生部分重叠的终末野。在电镜研究中，向背侧脚区注射WGA-HRP并对乳头体进行电解损伤，产生顺行标记的轴突终末和变性轴突终末，它们在脑桥内侧核头端的同一树突或神经元胞体上形成突触。结果表明，内侧前额叶皮质和乳头体内侧核对脑桥内侧核头端有部分重叠的投射，并提示小脑前中继核在由大脑皮质和下丘脑的汇聚投射介导的边缘和/或自主功能整合中起作用。
