Abstract
The paraventricular nucleus of the thalamus (PVT) sends a very dense projection to the nucleus accumbens. This area of the striatum plays a key role in motivation and recent experimental evidence indicates that the PVT may have a similar function. It is well known that a dopaminergic projection from the ventral tegmental area (VTA) to the nucleus accumbens is a key regulator of motivation and reward-related behavior. Dopamine (DA) fibers have also been localized in the PVT but the source of these fibers in the rat has not been unequivocally identified. The present study was done to re-examine this question. Small iontophoretic injections of cholera toxin B (CTb) were made in the PVT to retrogradely label tyrosine hydroxylase (TH) neurons. Neurons that were double-labeled for TH/CTb were found scattered in DA cell groups of the hypothalamus (ventrorostral A10, A11, A13, A15 DA cell groups) and the midbrain (dorsocaudal A10 embedded in the periaqueductal gray). In contrast, double-labeled neurons were absent in the retrorubral field (A8), substantia nigra (A9) and VTA (A10) of the midbrain. We conclude that DA fibers in the PVT do not originate from VTA but from a heterogeneous population of DA neurons located in the hypothalamus and periaqueductal gray.
Highlights
The paraventricular nucleus of the thalamus (PVT) is a member of a group of midline and intralaminar thalamic nuclei that are believed to be involved in cognition, attention and arousal (Groenewegen and Berendse, 1994; Van der Werf et al, 2002)
The PVT is of special interest because of its dense projection to the nucleus accumbens of the ventral striatum (Li and Kirouac, 2008; Vertes and Hoover, 2008), Abbreviations: 3V, 3rd ventricle; A8, retrorubral dopamine group; A9, substantia nigra; A10, ventral tegmental area; A10dc, periaqueductal gray matter; A10vr, A10 ventrorostral dopamine group; A11, A11 dopamine group; A13, A13 dopamine group; Aq, aqueduct; CM, central medial thalamic nucleus; cp, cerebral peduncle; DA, dopamine; f, fornix; fr, fasciculus retroflexus; Hb, habenular; IMD, intermediodorsal thalamic nucleus; MD, mediodorsal thalamic nucleus; ml, medial lemniscus; mt, mammillothalamic tract; opt, optic tract; PT, paratenial thalamic nucleus; PVT, paraventricular thalamic nucleus; Rt, reticular thalamic nucleus; sm, stria medullaris of the thalamus; VTA, ventral tegmental area; xscp, decussation sup cereballar ped; ZI, zona incerta
Most of the tyrosine hydroxylase (TH)/cholera toxin B (CTb) double-labeled neurons were found in the A10vr, A11, A13, A15 DA cell groups of the hypothalamus and A10dc of the periaqueductal gray
Summary
The paraventricular nucleus of the thalamus (PVT) is a member of a group of midline and intralaminar thalamic nuclei that are believed to be involved in cognition, attention and arousal (Groenewegen and Berendse, 1994; Van der Werf et al, 2002). Each member of this group has circumscribed projections to unique regions of the cerebral cortex and the striatum. An increase in cFos was found in the PVT following contextand cue-induced reinstatement of alcohol seeking in rodents (Wedzony et al, 2003; Dayas et al, 2008; Perry and Mcnally, 2013) while inactivation of the PVT was reported to attenuate context-induced reinstatement of ethanol
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
