Vertes Robert P, Hoover Walter B, Do Valle Angela Cristina, Sherman Alexandra, Rodriguez J J
Center for Complex Systems and Brain Sciences, Florida Atlantic University, Boca Raton, Florida 33431, USA.
J Comp Neurol. 2006 Dec 10;499(5):768-96. doi: 10.1002/cne.21135.
The nucleus reuniens (RE) is the largest of the midline nuclei of the thalamus and exerts strong excitatory actions on the hippocampus and medial prefrontal cortex. Although RE projections to the hippocampus have been well documented, no study using modern tracers has examined the totality of RE projections. With the anterograde anatomical tracer Phaseolus vulgaris leuccoagglutinin, we examined the efferent projections of RE as well as those of the rhomboid nucleus (RH) located dorsal to RE. Control injections were made in the central medial nucleus (CEM) of the thalamus. We showed that the output of RE is almost entirely directed to the hippocampus and "limbic" cortical structures. Specifically, RE projects strongly to the medial frontal polar, anterior piriform, medial and ventral orbital, anterior cingulate, prelimbic, infralimbic, insular, perirhinal, and entorhinal cortices as well as to CA1, dorsal and ventral subiculum, and parasubiculum of the hippocampus. RH distributes more widely than RE, that is, to several RE targets but also significantly to regions of motor, somatosensory, posterior parietal, retrosplenial, temporal, and occipital cortices; to nucleus accumbens; and to the basolateral nucleus of amygdala. The ventral midline thalamus is positioned to exert significant control over fairly widespread regions of the cortex (limbic, sensory, motor), hippocampus, dorsal and ventral striatum, and basal nuclei of the amygdala, possibly to coordinate limbic and sensorimotor functions. We suggest that RE/RH may represent an important conduit in the exchange of information between subcortical-cortical and cortical-cortical limbic structures potentially involved in the selection of appropriate responses to specific and changing sets of environmental conditions.
reunions核（RE）是丘脑中线核中最大的核，对海马体和内侧前额叶皮质具有强烈的兴奋作用。尽管RE向海马体的投射已有充分记录，但尚无使用现代示踪剂的研究考察过RE投射的全貌。我们使用顺行性解剖示踪剂菜豆白细胞凝集素，研究了RE以及位于RE背侧的菱形核（RH）的传出投射。在丘脑中央内侧核（CEM）进行对照注射。我们发现，RE的输出几乎完全指向海马体和“边缘”皮质结构。具体而言，RE强烈投射至内侧额极、前梨状、内侧和腹侧眶额、前扣带回、前边缘、下边缘、岛叶、嗅周和内嗅皮质，以及海马体的CA1区、背侧和腹侧海马下托及副海马下托。RH的分布比RE更广泛，即除了几个RE的投射靶点外，还显著投射至运动、体感、顶叶后部、压后皮质、颞叶和枕叶皮质区域；伏隔核；以及杏仁核的基底外侧核。腹侧中线丘脑能够对皮质（边缘、感觉、运动）、海马体、背侧和腹侧纹状体以及杏仁核的基底核等相当广泛的区域施加显著控制，可能是为了协调边缘和感觉运动功能。我们认为，RE/RH可能是皮层下-皮层和皮层-皮层边缘结构之间信息交换的重要通道，这些结构可能参与对特定且不断变化的环境条件选择适当反应。
