Efferent projections of the paraventricular thalamic nucleus in the rat

Abstract

The paraventricular nucleus of the thalamus (PVT) receives input from all major components of the circadian timing system, including the suprachiasmatic nucleus (SCN), the intergeniculate leaflet and the retina. For a better understanding of the role of this nucleus in circadian timing, we examined the distribution of its efferent projections using the anterograde tracer Phaseolus vulgaris leucoagglutinin (PHA-L). The efferent projections of the PVT are loosely organized along its dorsal-ventral and anterior-posterior axes. The anterior PVT sends projections to the SCN; the dorsomedial and ventromedial hypothalamic nuclei; the lateral septum; the bed nucleus of the stria terminalis; the central and basomedial amygdaloid nuclei; the anterior olfactory nucleus; the olfactory tubercle; the nucleus accumbens; the infralimbic, piriform, and perirhinal cortices; the ventral subiculum; and the endopiriform nucleus. A small PHA-L injection, restricted to the ventral portion of the anterior PVT, produces a similar pattern of labeling, except for a marked decrease in the number of labeled fibers in the hypothalamus, cortex, and lateral septum and an increase in labeling in the endopiriform nucleus and basolateral amygdaloid nucleus. The posterior PVT has a more limited efferent distribution than the anterior PVT, terminating in the anterior olfactory nucleus; the olfactory tubercle; the nucleus accumbens; and the central, basolateral, and basomedial nuclei of the amygdala. Our results show that the anterior PVT is ideally situated to relay circadian timing information from the SCN to brain areas involved in visceral and motivational aspects of behavior and to provide feedback regulation of the SCN.

Regional Differentiation of the Medial Prefrontal Cortex in Regulating Adaptive Responses to Acute Emotional Stress

“…For example, the posterior paraventricular nucleus of the thalamus (PVTp) has been implicated as a critical node in circuitry subserving decrements in HPA output (habituation) commonly seen on repeated exposure to the same stressor, as well as the exaggerated responses to introduction of a novel challenge (facilitation) (Bhatnagar and Dallman, 1998;Bhatnagar et al, 2002). The PVTp projection to mPFC targets IL in a highly preferential manner (Moga et al, 1995), warranting consideration of this region in the adaptive adjustments of the axis to chronic stress. From a pathological perspective, neuroimaging studies reveal functional impairment and shrinkage of mPFC in posttraumatic stress disorder (PTSD) (Rauch et al, 2003;Shin et al, 2005) that find a parallel in reports of dendritic atrophy and synapse loss after chronic emotional stress in rodents (Cook and Wellman, 2004;Radley et al, 2004Radley et al, , 2006.…”

Central neural distribution of immunoreactive Fos and CRH in relation to plasma ACTH and corticosterone during sepsis in the rat

“…Furthermore, chronic cold exposure activates cholecystokinin-containing pathways from the parabrachial region to the PVT that suppress the ACTH response to acute restraint (Bhatnagar et al, 2000). The PVT and its sites of projection that include the hypothalamic dorsomedial nucleus, amygdala, bed nucleus of stria terminalis, and infralimbic cortex (Moga et al, 1995) can modulate the PVH (Sawchenko and Swanson, 1983). Projections through the amygdala (Xu, et al, 1999) and the bed nucleus (Crane, et al, 2003) participate in the acute response of ACTH to systemic interleukin-1.…”

Vesicular glutamate transporter 3-immunoreactive pericellular baskets ensheath a distinct population of neurons in the lateral septum

“…Existence of VGLUT3-mRNA was repeatedly reported to be absent from the thalamus, and there are some controversial descriptions for the hypothalamus and ventral pallidum (Fremeau et al, 2002;Herzog et al, 2004;Schäfer et al, 2002). The thalamic afferents are probably represented by VGLUT2-ir as all thalamic subnuclei projecting to the LS express VGLUT2-ir and -mRNA (Fremeau et al, 2001;Herzog et al, 2001;Hur and Zaborszky, 2005;Kaneko et al, 2002;Moga et al, 1995;Staiger and Nürnberger, 1989). It remains to be elucidated whether the different VGLUT2-labeling pattern, i.e.…”