Hayama T, Hashimoto K, Ogawa H
Department of Physiology, Kumamoto University School of Medicine, Japan.
Neurosci Res. 1994 Jan;18(4):291-9. doi: 10.1016/0168-0102(94)90165-1.
To locate a taste-related region in the thalamic reticular nucleus (Rt), we explored a reticular region having connections with the thalamic taste relay and the cortical taste area (CTA), by neuronal tracing methods using HRP, WGA-HRP and biocytin. Tracer injections at the thalamic taste relay, i.e., the parvicellular part of the thalamic posteromedial ventral nucleus (VPMpc), labeled cell bodies and axon terminals in a confined portion of the ipsilateral Rt. This was located at the ventromedial-most portion of the nucleus at the level of approx. 1.2 mm rostral to the rostral end of the VPMpc. Tracer injections at the CTA ipsilaterally labeled axon terminals in the same region of the Rt, as did the thalamic injections. When WGA-HRP was injected at this taste-related region in the Rt, we observed labeled cell bodies in layer VI in the CTA; in the VPMpc we saw densely labeled axon terminals but few, if any, labeled cell bodies. The results indicated that the taste-related region in the Rt receives input from the VPMpc and CTA, and sends output to the VPMpc. They also showed that the reticulo-thalamic projections were much heavier than the thalamo-reticular ones in the taste system.
为了在丘脑网状核（Rt）中定位与味觉相关的区域，我们通过使用辣根过氧化物酶（HRP）、小麦胚凝集素-辣根过氧化物酶（WGA-HRP）和生物胞素的神经元追踪方法，探索了一个与丘脑味觉中继和皮质味觉区（CTA）有联系的网状区域。在丘脑味觉中继处注射示踪剂，即丘脑后内侧腹侧核（VPMpc）的小细胞部分，标记了同侧Rt特定区域内的细胞体和轴突终末。该区域位于核的最腹内侧部分，在VPMpc嘴侧端嘴侧约1.2mm处。在CTA同侧注射示踪剂，与丘脑注射一样，标记了Rt相同区域内的轴突终末。当在Rt中这个与味觉相关的区域注射WGA-HRP时，我们在CTA的VI层观察到标记的细胞体；在VPMpc中，我们看到密集标记的轴突终末，但标记的细胞体很少（如果有的话）。结果表明，Rt中与味觉相关的区域接受来自VPMpc和CTA的输入，并向VPMpc发送输出。结果还表明，在味觉系统中，网状丘脑投射比丘脑网状投射要多得多。
