ABSTRACT
Paraventricular thalamic nucleus (PVT) is an essential component of the midline thalamus, which has been regarded as a transmit relay nucleus and an integrated center in multiple behaviors including wakefulness, food intake, addiction, reward and fear memory. PVT is predominantly populated with glutaminergic excitatory neurons expressing vesicular glutamate transporter-2 (VGluT2) but without GABAergic inhibitory neurons. Therefore, based on the paradox of its multiplexed roles in different behaviors and its comparatively simplex excitatory nature, more specific subclassification of excitatory PVT neurons is required in studies in this field. In the present review, morphological and electrophysiological characteristics, efferent and afferent connections, and morphological and functional distinctions in anterior subregion and posterior subregion of PVT are summarized. In addition, neural connections and neurochemical properties are used as subclassification criteria in PVT neurons. This review might explain the integrated role of PVT in different behaviors, which would be helpful for further studies on the PVT.
ABSTRACT
The projections of the hippocampus onto the cerebral cortex were studied in 31 rats after injections of horseradish peroxidase(HRP) into the parietal, frontal, and temporal lobes of the cerebral cortex respectively. The results were as follows:1) HRP labelled pyramidal cells were found in the CA1~CA3 of the dorsal and ventral hippocampus on both sides, more numerous on the ipsi-lateral side in all the cases. However, no HRP labelled cells could be identified in the CA4 or dentate gyrus in any case.2) Labelled neusons of hippocampo-temporal projection were more numerous than those of hippocampo-parietal or hippocampo-frontal projection. However, no difference could be revealed between those of hippocampo-parietal and hippocampo-frontal projections.The anatomical and functional significance of our findings were discussed
ABSTRACT
WGA-HRP was injected into the dorsomedial nucleus of thalamus (DM)by means of microiontophoretical delivery in 19 rats, and into the dorsal division of anterior cingulate cortex (ACd), the prelimbic area (PL), the dorsal agranular insular area (AId) of prefrontal cortex by using microinjective system in 17 rats to observe the efferent projections of the DM.It was found that the DM projected to a large part of the prefrontal cortex including the medial precentral area (PCm), ACd, PL, AId, ventral agranular insular area (AIv), medial orbital area (MO), ventral orbital area (VO), ventrolateral orbital area (VLO), and some topographical organizations were also found. The lateral segment of DM projects to the ACd, PCm, PL, AId, AIv and VLO. The intermediate segment of DM projects to the AId and AIv. The medial segment of DM projects to the AId, PL, IL, AIv, MO and VO. Furthermore, the DM also projects to some subcortical nuclei, such as the reticular nucleus of thalamus (R), the lateral preoptic area (LPO), the lateral hypothalamic area (LHA), the caudoputamen, the nucleus accumbens and the parafascicular nucleus of thalamus. In addition, some reciprocal connections between the DM and the ACd, PCm, PL, IL, AId, R, LPO and LHA were observed.