Advances in morphological and functional studies on the paraventricular thalamic nucleus / 解剖学报

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.

AFFERENT CONNECTIONS OF THE DORSOMEDIAL NUCLEUS OF THE THALAMUS IN THE RAT WITH WGA-HRP METHOD / 解剖学报

WGA-HRP was injected into different segment of the dorsomedial nucleus (DM) of thalamus by means of microiontophoretical delivery in 19 rats to observe the afferent projections of DM. It is found that the DM received afferent projections widely from the frontal cortex, basal telecephalon, limbic system, monoaminergic neuron, reticular formation, central gray matter and superior colliculus. Furthermore, some topographical organization has also been observed. The medial segment of DM received afferent projections mainly from dorsal agranular insular cortex, infralimbic cortex, amygdaloid complex, septum, bed nucleus of the stria terminalis and raphe nuclei, related with the function of the limbic system. The central segment of DM received afferent projections from the dorsal agranular insular cortex and the prepiriform cortex, also related with the function of the limbic system. The lateral segment of DM received afferent projections mainly from the medial precentral cortex, dorsal division of anterior cingulate cortex, E-W nucleus and superior colliculus, related with the function of eye movement. In addition, all the three segments of DM received numerous afferents from the substantia innominata, nucleus tractus diagonalis (Broca), lateral preoptic area and reticular nucleus of the thalamus.

BRAINSTEM PROJECTIONS TO THE PREFRONTAL CORTEX IN THE RAT——A WGA—HRP STUDY / 解剖学报

The afferent projections of the prefrontal cortex'from the brainstem werestudied by using WGA-HRP technique in 25 rats. Following WGA-HRP injections into the dorsal part of anterior cingulate cortex, prelimbic cortex, and dorsal agranular insular cortex, three groups of retrograde labeled neurons were observed in the brainstem. First group was the monoaminergic neurons, in which the locus coeruleus, ventral tegmental area, compact part of substantia nigra, nucleus raphe dorsalis, nucleus eentralis superior, nucleus linearis caudalis widely projected to the every part of the prefrontal cortex, but the quantitative difference of the projections to different parts of the prefrontal cortex from the lateral reticular nucleus, commissural nucleus, nucleus raphe magnus, A_4, A_5, parabrachial nuclei, reticular part of substantia nigra and the nucleus linearis rostralis was also found. Second group was the nuclei related with oculomotor action, such as E-W nucleus, periventricular gray substance, reticular formation of mesencephalon and the nucleus pontis oralis. Third group was-the sensory nucleus, such as parabrachial nucleus, main sensory nucleus of the trigeminal nerve and the commissural nucleus.