Rhomboid Nucleus Of Thalamus

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.  

The thalamic regions with the strongest effects of muscle input were the VL bilaterally and the VPL contralaterally (increase in c-Fos expression) as well as the rhomboid nucleus (decrease in c-Fos expression)..  

Both controls and pilocarpine-treated animals presented neo-Timm staining in the anterodorsal nucleus, laterodorsal nucleus, reticular nucleus, most intralaminar nuclei, nucleus reuniens, and rhomboid nucleus of the thalamus, as well as in the zona incerta. The intensity of neo-Timm staining was similar in control and pilocarpine-treated rats, except for the nucleus reuniens and the rhomboid nucleus, which had a lower intensity of staining in the epileptic group.  

The basic organization of an exceptionally complex pattern of axonal projections from one distinct cell group of the bed nuclei of the stria terminalis, the rhomboid nucleus (BSTrh), was analyzed with the PHAL anterograde tract-tracing method in rats.  

The following groups can be discerned: (1) a dorsal group, consisting of the paraventricular, parataenial and intermediodorsal nuclei, involved in viscero-limbic functions; (2) a lateral group, comprising the central lateral and paracentral nuclei and the anterior part of the central medial nucleus, involved in cognitive functions; (3) a ventral group, made up of the reuniens and rhomboid nucleus and the posterior part of the central medial nucleus, involved in multimodal sensory processing; (4) a posterior group, consisting of the centre médian and parafascicular nuclei, involved in limbic motor functions..  

A band of labeled cells involving CL, central medial nucleus (CM) and rhomboid nucleus (Rh) formed a halo around the periphery of submedial (gelatinosus) nucleus (Sm).  

The main findings of this study are as follows: (1) few double-labeled cells were found after two injections in different sectors of the caudate nucleus; (2) double-labeled neurons were more abundant after adjacent injections and they were mainly located in the caudal intralaminar nuclei, in the rhomboid nucleus and in the dorsal mediodorsal nucleus; and (3) there were variations in the spatial organization of the thalamostriatal neurons projecting to various sectors of the caudate nucleus in the different thalamic nuclei known to project to this part of the striatum..  

(4) Many retrogradely labeled neurons were consistently found in the lateral wing of the rhomboid nucleus after injections into the CN.  

The central region of the ventral striatum, including the dorsal part of the core of the nucleus accumbens, receives a limited projection from the midline thalamic, predominantly from the rhomboid nucleus.  

The most medial band included area 6-projecting neurons in the anterior nuclei, the rhomboid nucleus, the ventral anterior nucleus (VA), ventromedial nucleus (VM) and mediodorsal nucleus (MD).  

A moderate density of dopamine-beta-hydroxylase immunoreactive processes were found in the rhomboid nucleus and zona incerta whereas little dopamine-beta-hydroxylase immunoreactivity was found in the fields of Forel, nucleus reuniens, or subthalamic nucleus.  

In contrast to the other midline nuclei, the rhomboid nucleus projects to widespread cortical areas.  

The projection of the rhomboid nucleus is restricted to the rostrolateral extreme of the striatum.  

Direct projections from the nucleus reuniens (Re) and the rhomboid nucleus (Rh) in the midline of the thalamus were examined in the rat by utilizing anterograde axonal transport of Phaseolus vulgaris leukoagglutinin (PHA-L).  

The most dense collection of perikarya containing CCK-IR was seen in the rostral group of the intralaminar nuclei, in rostral parts of the rhomboid nucleus and the anterodorsal nucleus.  

After injection of HRP into the head of the caudate nucleus (Cd), thalamic neurons labeled with HRP were observed mainly in the rhomboid nucleus (Rh), central medial nucleus (Ce), centre médian-parafascicular complex (CM-Pf) as well as in the midline and intralaminar regions surrounding the mediodorsal nucleus (MD).  

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