Moga M M, Weis R P, Moore R Y
Department of Psychiatry, University of Pittsburgh Medical Center, Pennsylvania 15261, USA.
J Comp Neurol. 1995 Aug 21;359(2):221-38. doi: 10.1002/cne.903590204.
The paraventricular nucleus of the thalamus (PVT) receives input from all major components of the circadian timing system, including the suprachiasmatic nucleus (SCN), the intergeniculate leaflet and the retina. For a better understanding of the role of this nucleus in circadian timing, we examined the distribution of its efferent projections using the anterograde tracer Phaseolus vulgaris leucoagglutinin (PHA-L). The efferent projections of the PVT are loosely organized along its dorsal-ventral and anterior-posterior axes. The anterior PVT sends projections to the SCN; the dorsomedial and ventromedial hypothalamic nuclei; the lateral septum; the bed nucleus of the stria terminalis; the central and basomedial amygdaloid nuclei; the anterior olfactory nucleus; the olfactory tubercle; the nucleus accumbens; the infralimbic, piriform, and perirhinal cortices; the ventral subiculum; and the endopiriform nucleus. A small PHA-L injection, restricted to the ventral portion of the anterior PVT, produces a similar pattern of labeling, except for a marked decrease in the number of labeled fibers in the hypothalamus, cortex, and lateral septum and an increase in labeling in the endopiriform nucleus and basolateral amygdaloid nucleus. The posterior PVT has a more limited efferent distribution than the anterior PVT, terminating in the anterior olfactory nucleus; the olfactory tubercle; the nucleus accumbens; and the central, basolateral, and basomedial nuclei of the amygdala. Our results show that the anterior PVT is ideally situated to relay circadian timing information from the SCN to brain areas involved in visceral and motivational aspects of behavior and to provide feedback regulation of the SCN.
丘脑室旁核（PVT）接收来自昼夜节律系统所有主要组成部分的输入，包括视交叉上核（SCN）、膝间小叶和视网膜。为了更好地理解该核在昼夜节律中的作用，我们使用顺行示踪剂菜豆白细胞凝集素（PHA-L）研究了其传出投射的分布。PVT的传出投射沿其背腹轴和前后轴呈松散排列。PVT前部向SCN、下丘脑背内侧核和腹内侧核、外侧隔、终纹床核、杏仁中央核和基底内侧核、前嗅核、嗅结节、伏隔核、边缘下皮质、梨状皮质和嗅周皮质、腹侧海马下脚以及内梨状核发出投射。在前部PVT腹侧部分进行的小剂量PHA-L注射产生了类似的标记模式，但下丘脑、皮质和外侧隔中标记纤维的数量显著减少，而内梨状核和基底外侧杏仁核中的标记增加。与前部PVT相比，后部PVT的传出分布更有限，其投射终止于前嗅核、嗅结节、伏隔核以及杏仁核的中央核、基底外侧核和基底内侧核。我们的结果表明，前部PVT处于理想位置，可将昼夜节律信息从SCN传递至参与行为内脏和动机方面的脑区，并对SCN进行反馈调节。
