McKenna James Timothy, Vertes Robert P
Center for Complex Systems and Brain Sciences, Florida Atlantic University, Boca Raton, Florida 33431, USA.
J Comp Neurol. 2004 Dec 6;480(2):115-42. doi: 10.1002/cne.20342.
The nucleus reuniens (RE) is the largest of the midline nuclei of the thalamus and the major source of thalamic afferents to the hippocampus and parahippocampal structures. Nucleus reuniens has recently been shown to exert powerful excitatory actions on CA1 of the hippocampus. Few reports on any species have examined afferent projections to nucleus reuniens. By using the retrograde anatomical tracer Fluorogold, we examined patterns of afferent projections to RE in the rat. We showed that RE receives a diverse and widely distributed set of afferents projections. The main sources of input to nucleus reuniens were from the orbitomedial, insular, ectorhinal, perirhinal, and retrosplenial cortices; CA1/subiculum of hippocampus; claustrum, tania tecta, lateral septum, substantia innominata, and medial and lateral preoptic nuclei of the basal forebrain; medial nucleus of amygdala; paraventricular and lateral geniculate nuclei of the thalamus; zona incerta; anterior, ventromedial, lateral, posterior, supramammillary, and dorsal premammillary nuclei of the hypothalamus; and ventral tegmental area, periaqueductal gray, medial and posterior pretectal nuclei, superior colliculus, precommissural/commissural nuclei, nucleus of the posterior commissure, parabrachial nucleus, laterodorsal and pedunculopontine tegmental nuclei, nucleus incertus, and dorsal and median raphe nuclei of the brainstem. The present findings of widespread projections to RE, mainly from limbic/limbic-associated structures, suggest that nucleus reuniens represents a critical relay in the transfer of limbic information (emotional/cognitive) from RE to its major targets, namely, to the hippocampus and orbitomedial prefrontal cortex. RE appears to be a major link in the two-way exchange of information between the hippocampus and the medial prefrontal cortex.
丘脑正中核（RE）是丘脑中线核团中最大的一个，也是丘脑向海马和海马旁结构传入纤维的主要来源。最近研究表明，丘脑正中核对海马CA1区具有强大的兴奋作用。关于任何物种向丘脑正中核传入投射的报道都很少。通过使用逆行解剖示踪剂荧光金，我们研究了大鼠丘脑正中核的传入投射模式。我们发现，丘脑正中核接受多种分布广泛的传入投射。丘脑正中核的主要输入源来自眶内侧、岛叶、嗅外、嗅周和压后皮质；海马的CA1/下托；屏状核、带状终板、外侧隔核、无名质以及基底前脑的内侧和外侧视前核；杏仁核内侧核；丘脑的室旁核和外侧膝状体核；未定带；下丘脑的前核、腹内侧核、外侧核、后核、乳头体上核和乳头体背前核；以及脑干的腹侧被盖区、导水管周围灰质、内侧和后顶盖前核、上丘、连合前/连合核、后连合核、臂旁核、外侧背核和脑桥被盖脚内核、不确定核以及背侧和中缝核。目前关于向丘脑正中核广泛投射的研究结果，主要来自边缘/边缘相关结构，表明丘脑正中核是边缘信息（情感/认知）从丘脑正中核传递到其主要靶区，即海马和眶内侧前额叶皮质的关键中继站。丘脑正中核似乎是海马和内侧前额叶皮质之间双向信息交换的主要环节。
