Ventral Pallidum

Using c-Fos expression as a high-resolution marker of neuronal activation, congenic mice demonstrated significantly less neuronal activity associated with ethanol withdrawal than background strain mice in the substantia nigra pars reticulata (SNr), subthalamic nucleus (STN), rostromedial lateral globus pallidus, and ventral pallidum.  

Immunohistochemical studies revealed that accumbens neurons that project to the ventral pallidum showed adenosine A(2A) receptors immunoreactivity. Moreover, activation of accumbens A(2A) receptors by local injections of CGS 21680 increased extracellular GABA levels in the ventral pallidum. Combined contralateral injections of CGS 21680 into the accumbens and the GABA(A) agonist muscimol into ventral pallidum (i.e., "disconnection" methods) also impaired response output, indicating that these structures are part of a common neural circuitry regulating the exertion of effort.  

RATIONALE: Somatostatin and its receptors have been localized in brain nuclei implicated in motor control, such as the striatum, nucleus accumbens, ventral pallidum, and globus pallidus (GP).  

The main telencephalic afferents to the septum arise ipsilaterally from the hippocampal formation, dorsolateral corticoid area, piriform cortex, amygdaloid pallium, and the ventral pallidum.  

We reveal here that the ventral pallidum (VP), a brain region reciprocally innervated by the VTA and the NAc, is a critical mediator of opiate-induced behavioral sensitization.  

The circuit-related consequences of activating the ventral pallidum (VP) are not well known, and lacking in particular is how these effects are altered in various neuropathological states.  

The reward system contains the ventral tegmental area, nucleus accumbens and ventral pallidum and finally sends information to the lateral hypothalamic area, the feeding center.  

In other examined subcortical/cerebral cortical areas dynorphin levels were normal with the striking exception of the ventral pallidum (+346%), whereas cerebral cortical metenkephalin levels were generally decreased and neurotensin variably changed. However, the human dynorphin observations parallel well animal findings and suggest that the dynorphin system is upregulated, manifested as elevated neuropeptide levels, after chronic drug exposure in striatum and ventral pallidum.  

Cocaine-primed reinstatement of drug seeking is associated with a decrease in extracellular GABA in the ventral pallidum (VP).  

A regions of interest (ROI) analysis revealed that pictures of high-calorie foods produced significantly greater activation in the obese group compared to controls in medial and lateral orbitofrontal cortex, amygdala, nucleus accumbens/ventral striatum, medial prefrontal cortex, insula, anterior cingulate cortex, ventral pallidum, caudate, putamen, and hippocampus.  

Activation of hippocampal neurons evoked by a new stimulus facilitates the appearance of responses in dopaminergic neurons as a result of disinhibition via striopallidal cells of the nucleus accumbens and ventral pallidum.  

In contrast to the LSt, Area X and surrounding MSt project to the ventral pallidum (VP) and dorsal thalamus via pallidal-like neurons.  

Instead, we describe an indirect pathway from Area X to midbrain dopaminergic neurons via a connection in the ventral pallidum (VP).  

The latter KO has reduced Oxtr binding beginning 21-28 d postnatally, leading to prominent reductions in the lateral septum, hippocampus, and ventral pallidum.  

The resulting anterograde labeling includes the olfactory tubercle, the islands of Calleja and sparse terminal fields in the shell of the nucleus accumbens and ventral pallidum. The possibility that parts of the accumbens shell and/or ventral pallidum could be included in the mammalian olfactostriatum cannot be discarded..  

Compared to the acute nicotine animals, brain activity in the sensitized animals demonstrated prolonged BOLD activation in response to nicotine in the hippocampus, nucleus accumbens, prefrontal cortex, ventral pallidum and ventral tegmentum, and more intense peak activation in the hippocampus, prefrontal cortex and ventral tegmentum.  

The ventral pallidum is a brain area that receives substantial GABAergic input from nucleus accumbens. It was hypothesized that stimulation of GABA(A) receptors in the ventral pallidum would result in behavioral effects that resemble those produced by interference with accumbens dopamine transmission. In the present experiments, infusions of the GABA(A) agonist muscimol (5.0-10.0 ng) into the ventral pallidum decreased lever pressing for preferred food, but increased consumption of the less preferred chow. Furthermore, injections of muscimol into a control site dorsal to the ventral pallidum produced no significant effects on lever pressing and chow intake. These data indicate that stimulation of GABA receptors in ventral pallidum produces behavioral effects similar to those produced by accumbens dopamine depletions. ventral pallidum appears to be a component of the brain circuitry regulating response allocation and effort-related choice behavior, and may act to convey information from nucleus accumbens to other parts of this circuitry.  

sociabilis exhibited a pattern of nucleus accumbens OTR and ventral pallidum V1aR binding different from that associated with the formation of opposite-sex pair bonds in microtine rodents.  

The neurocircuitry underlying cocaine-primed reinstatement includes a decrease in GABA in the ventral pallidum (VP) that is inhibited by a mu opioid receptor antagonist, suggesting that opioid peptides colocalized with GABA in the projection from the nucleus accumbens to the VP may mediate this effect.  

Importantly, increased activity in an large interconnected ventral pallidum/amygdala cluster to the "unseen" cocaine cues strongly predicted future positive affect to visible versions of the same cues in subsequent off-magnet testing, pointing both to the functional significance of the rapid brain response, and to shared brain substrates for appetitive motivation within and outside awareness.  

Surprisingly, neither social fidelity measured by space use nor sexual fidelity measured by paternity was associated with V1aR expression in the ventral pallidum (VPall) or lateral septum, areas causally related to pairbond formation.  

In particular, mUBPy was strongly expressed in the hippocampal formation, septal region, ventral pallidum, preoptic nucleus, periventricular nucleus of hypothalamus, compact part of the substantia nigra, ventral tegmental area, cochlear nucleus and granular cell layer of cerebellum.  

We used electron microscopic immunolabeling of NK(1) receptors and the vesicular acetylcholine transporter (VAchT) to test the hypothesis that the subcellular distributions of these receptors in cholinergic neurons of the rat ventral pallidum are subject to a similar regulation. These results provide ultrastructural evidence that NK(1) receptors in cholinergic neurons of the ventral pallidum have subcellular locations and plasticity conducive to active involvement in dopamine-dependent sensorimotor processing..  

The major source of these projections was found to be the pallidum, as both the compact and diffuse zones of this nucleus received projections from all of its structures: the entopeduncular nucleus, the globus pallidus, and the ventral pallidum.  

Forebrain neurons exhibiting both Fos and tracer immunoreactivity were enriched in both cocaine groups relative to the controls only in the globus pallidus and ventral pallidum, which, together, represented a minor part of total forebrain retrogradely labeled neurons.  

Injection of dextran-amines into the posterolateral cortical amygdaloid nucleus of rats resulted in anterograde labeling in the ventral striatum, in particular in the core of the nucleus accumbens, and in the medial olfactory tubercle including some islands of Calleja and the cell bridges across the ventral pallidum.  

Ipsi- and contralateral injections of the receptor blockers and saline had no effect on either stimulation reward efficacy or response rate, although the blockers, especially phaclofen, sometimes enhanced response rate when injected into the globus pallidus or ventral pallidum.  

Significant differences in glucose uptake were found between males in long-term pair-bonds and lone males in areas including the nucleus accumbens, ventral pallidum, medial preoptic area, medial amygdala, and the supraoptic nucleus of the hypothalamus. In paired before and after comparisons, males showed significant changes following pairing in the right nucleus accumbens and ventral pallidum but not in other areas.  

Of the labelled cell bodies in the subcortical structures, about 38.8% were located in the ipsilateral basal forebrain (10.6% in the lateral amygdala LA, 11.5% in the globus pallidus GP, 3.7% in the ventral pallidum VPa, 13.0% in the nucleus basalis NB), 13.1% in the ipsi- and contralateral diencephalon (6.4% in the posterior paraventricular thalamic nuclei, 6.7% in the hypothalamic area), and 48.1% in the midbrain (20.0% in the ipsilateral substantia nigra, 9.8% in the ipsi- and contralateral ventral tegmental area, 5.0% in the ipsi- and contralateral locus coeruleus, 13.3% the ipsi- and contralateral dorsal raphe nuclei).  

Additional significant changes were noted in the ventral pallidum, superior colliculus, dentate gyrus (increases), and red nucleus (decreases).  

Methamphetamine (METH) causes the release of serotonin (5-HT), but little is known about how repeated exposure to METH modifies serotonergic receptor function, especially in the ventral pallidum (VP), a brain region highly innervated by serotonin inputs.  

They are found in many brain regions associated with drug addiction including the nucleus accumbens, ventral tegmental area and ventral pallidum.  

We predict that the loss of intrinsic motivation in the first phase of the satiation process is correlated with a decrease in activity in brain regions associated with positive hedonic experience, such as the nucleus accumbens, the ventral pallidum, and the medial orbitofrontal cortex.  

More than half of the CTb-Fos double-labelled neurons were located in the prefrontal cortex, lateral preoptic area-lateral hypothalamus, pontomesencephalic tegmentum, dorsal raphe nucleus, ventral pallidum and nucleus accumbens.  

Previous studies have suggested that the ventral pallidum (VP) is involved in the hedonics of taste stimuli, therefore the present study investigated whether the VP is a neural substrate for the shift in preference of the CS after CTA acquisition.  

Activation of hippocampal neurons caused by new stimulus facilitates occurrence of reaction of dopaminergic cells due to their disinhibition through striatopallidal cells of nucleus accumbens and ventral pallidum. However, increase in dopamine level and activation accumbens and ventral pallidum.  

In control rats DHPG increases extracellular dopamine in NAcc and induces locomotion by activating the 'normal' circuit: NAcc-->ventral pallidum-->medial-dorsal thalamus-->prefrontal cortex, which is not activated in portacaval shunt rats.  

This experiment used intracranial administration of a selective micro-opioid receptor alkylating agent (beta-funaltrexamine (beta-FNA)) to assess the role of mu-opioid receptors in the NAc, ventral pallidum (VP), and ventral tegmental area (VTA) on the ability of heroin to alter cocaine self-administration.  

LCGU was decreased in a number of limbic (nucleus accumbens and ventral pallidum) and cortical (medial/ventral orbital and infralimbic) regions and in the raphe magnus nucleus in quinpirole-sensitized rats (P<0.05 vs.  

In the present study, the effect of repeated administration of morphine into the ventral pallidum (intra-VP) on the conditioned place preference (CPP) induced by systemic morphine injection was investigated in male Wistar rats.  

We found that the brain areas that produced ESB-induced 50-kHz calls are the areas that have previously been shown to support the most vigorous self-stimulation behavior (prefrontal cortex, nucleus accumbens, ventral pallidum, lateral preoptic area, lateral hypothalamus, ventral tegmental area, and raphe).  

We inserted cannulae in the NAcc and microdialysis probes in the NAcc, ventral pallidum (VP), substantia nigra pars reticulata (SNr), medio-dorsal thalamus (MDT), ventro-medial thalamus (VMT) or prefrontal cortex (PFCx).  

It was shown that the main source of these projections was pallidum, since the projections were directed both to the compact and diffuse parts of this nucleus from all its structures: nucleus entopeduncularis, globus pallidus and ventral pallidum.  

Anatomical tracing showed that the anterior thalamic nucleus innervates the anterior parts of the medial, dorsal, and lateral pallia and the rostralmost part of the pallium in addition to the subpallial amygdala/ventral pallidum region. Electrical stimulation of diverse sensory nerves and brain regions generated evoked potentials with distinct characteristics in the pallium, subpallial amygdala/ventral pallidum, and dorsal striatopallidum. Intracellular bimodal sensory responses were obtained in the anterior pallium, medial amygdala, ventral pallidum, and dorsal striatopallidum. Our results demonstrate that the amphibian anterior pallium, medial amygdala/ventral pallidum, and dorsal striatopallidum are multimodal sensory centers.  

Mu-opioid stimulation of cubic millimeter hedonic hotspots in either the nucleus accumbens shell (NAc) or the ventral pallidum (VP) amplifies hedonic "liking" reactions to sweetness and appetitive "wanting" for food reward.  

The reward system contains the ventral tegmental area, nucleus accumbens, and ventral pallidum; it finally sends information to the lateral hypothalamic area, the feeding center.  

The results show that the RLi heavily innervates the olfactory tubercle (mainly the polymorph layer) and the ventrolateral part of the ventral pallidum, but largely avoids the accumbens.  

High levels of oxytocin receptor (OTR) in the nucleus accumbens and high levels of vasopressin 1a receptor (V1aR) in the ventral pallidum contribute to monogamous social structure in the prairie vole.  

Among a variety of brain regions including the parabrachial nucleus, amygdala, insular cortex, supramammillary nucleus, nucleus accumbens, and ventral pallidum that are involved in different phases of CTA expression, the enhanced taste sensitivity to facilitate detection of the conditioned stimulus may originate in the central nucleus of the amygdala and the hedonic shift, from positive to negative, may originate in the basolateral nucleus of the amygdala..  

In addition, discrete groups of Drd4-EGFP labelled neurons were observed in the anterior olfactory nucleus, ventral pallidum, and lateral parabrachial nucleus.  

The present review aims to summarize recent advances in the identification of brain substrates for food 'liking' with a focus on opioid hot spots in the nucleus accumbens and ventral pallidum.  

The latter correlation was particularly impressive for the ventral pallidum and basolateral amygdala.  

The CgCtx, MPOA, ventral pallidum, and LS also showed significant sex by treatment interactions on V1a binding.  

Whereas the suggested core lies entirely within the boundary of the medial striatum, the shell seems partially to overlap the ventral pallidum.  

Intravenous administration of SSR180711 strongly increased the firing rate of single ventral pallidum neurons, extracellularly recorded in anesthetized rats.  

The role of ionotropic glutamate receptors within the ventral pallidum (VP) in the expression of conditioned place preference (CPP) and motor adaptations to morphine was evaluated.  

Neuron activity was recorded from the basal forebrain of rats, including the mixed area of the ventral pallidum, substantia innominata, and mid part of Meynert's nucleus.  

pCREB levels were decreased at 14 days withdrawal in the nucleus accumbens and ventral pallidum. Thus, only the ventral pallidum showed changes in molecular processes that consistently correlated with motor sensitization, revealing that this region may be associated with this enduring behavioral phenotype initiated by methamphetamine.  

In contrast, men show a higher gray matter concentration in the left entorhinal cortex (Brodmann's area 28), right ventral pallidum, dorsal left insular cortex and a region of the orbitofrontal cortex (Brodmann's area 25).  

Further, the rostral parts receive inputs from the substantia nigra pars reticularis and the ventral pallidum that the caudal part lacks.  

Neurons immunoreactive (+) or containing mRNAs for both ChAT and VGLUT3 were mainly localized to the ventral pallidum and more caudal BF regions; the co-immunoreactive neurons represented 31% of cholinergic neurons in the ventral pallidum and 5-9% more caudally. Twenty-five to 79% of ChAT+VGLUT3+ neurons in different BF regions were retrogradely labeled from the basolateral amygdala, up to 52% (ventral pallidum) of the retrogradely labeled ChAT+ neurons were VGLUT3+, and the largest number of amygdala-projecting ChAT+VGluT3+ neurons was found in the ventral pallidum.  

The ventral pallidum (VP) supports self-stimulation and has anatomical connections that suggest it could be linked to medial forebrain bundle (MFB) self-stimulation.  

The PL (and ventral anterior cingulate cortex) (AC) of rats is ideally positioned to integrate current and past information, including its affective qualities, and act on it through its projections to the ventral striatum/ventral pallidum.  

The ventral pallidum (VP) is a key structure in brain mesocorticolimbic reward circuits that mediate "liking" reactions to sensory pleasures.  

We recently revealed that the ventral pallidum (VP) may also be involved.  

Studies of the pedunculopontinopallidal projections of the dog brain based on the retrograde axonal transport of horseradish peroxidase demonstrated that the compact zone (PPNc) and the lateral area of the diffuse zone (PPNd) of the pedunculopontine tegmental nucleus (PPN) of the midbrain project to the globus pallidus, entopeduncular nucleus, and ventral pallidum.  

Preliminary intraperitoneal injections of some combinations of adreno- and dopaminomimetics, monoamines, and mediator amino acids (as well as of their agonists and antagonists) followed by microinjections of the same combinations into the ventral pallidum reveal differences in the functional significance of the neurochemical profile of this paleostriatum formation in realization of the anxiety states of different genesis, as manifested in the "illuminated site avoidance" and the "threatening situation" tests in rats. The pharmacological analysis based on the local injection of anxiosedative and anxioselective agents into the ventral paleostriatum showed that the antiaversive action of campirone is revealed under the conditions of dominating fear motivation, while that analogous action of chlordiazepoxide, phenibut and indoter is revealed under negative stressful zoosocial impacts and is realized by serotonin- and GABA-ergic (rather than by cathecholamine- and glutaminergic) aversive systems of the ventral pallidum..  

A previous report has demonstrated that the blockade of GABAA receptors in the ventral pallidum (VP), a target of GABAergic projection from the nucleus accumbens, greatly increases food, but not water, intake in satiated rats [ Stratford et al.  

However, an investigation of GABA and DA levels in the ventral pallidum gave no indication of changes in activity.  

Dopamine D1 receptor binding was decreased in the caudate putamen, nucleus accumbens, olfactory tubercle and ventral pallidum of D2 receptor knockout mice.  

The medial preoptic area (MPOA), ventral pallidum (VP), and nucleus accumbens (NA) receive dopaminergic afferents and are involved in maternal behavior.  

Genotype-dependent c-Fos induction was also apparent in associated circuitry including the lateral septum, the ventral tegmental area, the nucleus accumbens core, the dorsolateral caudate putamen, the substantia nigra pars compacta, the cingulate and entorhinal cortices, and the ventral pallidum.  

Here, we review evidence that changes in dopaminergic and glutamatergic transmission in limbic/basal ganglia circuits of interconnected nuclei including the medial prefrontal cortex, nucleus accumbens, ventral pallidum, amygdala, hippocampus, orbitofrontal cortex, neostriatum and thalamus underlie cocaine priming-induced reinstatement of cocaine seeking.  

Neurons in ventral pallidum fire to reward and its predictive cues. Both sensitization and acute amphetamine increased ventral pallidum firing at CS+2 (population code and rate code).  

Both mechanisms are related to a system for control and modulation of visceral function stretching from the spinal cord to the ventromedial prefrontal cortex, including the ventral striatum, ventral pallidum, and mediodorsal thalamus, the amygdala, the hypothalamus, the periaqueductal gray (PAG), and the brainstem reticular formation and autonomic nuclei.  

ventral striatum, ventral pallidum).  

In freely behaving rats, muscimol (0.25 microg) or saline was infused intracerebrally into one of four areas-the supramammillary area (SUM), nucleus accumbens (NAC), ventral pallidum (VP), and ventral tegmental area (VTA)-and righting, pain, and EEG responses were recorded following either halothane or sodium pentobarbital, representing inhalational and injectable general anesthetic, respectively.  

The study of pedunculo-pontine-pallidum projections in the dog's brain, which was performed using the method of retrograde axonal transport, has demonstrated the projections of a compact part (PPNc) and the lateral area of a diffuse part (PPNd) of midbrain pedunculo-pontine tegmental nucleus (PPN) to the globus pallidus, nucleus entopeduncularis and the ventral pallidum.  

How are natural reward functions such as sucrose hedonic impact and the motivation to eat generated within the ventral pallidum (VP)? Here, we used a novel microinjection and functional mapping procedure to neuroanatomically localize and neurochemically characterize substrates in the VP that mediate increases in eating behavior and enhancements in taste hedonic "liking" reactions.  

These findings, combined with the fact that the lateral hypothalamus receives strong inputs from the shell of the nucleus accumbens and ventral pallidum, suggest that these structures are part of integrative functional loops that control reward and appetitive behaviors..  

Similarly, the nucleus accumbens proper and the olfactostriatum show a similar pattern of efferent connections including those going to the ventral pallidum, although the olfactostriatum alone projects to the main and accessory olfactory bulbs as well as some amygdaloid nuclei. On the basis of its chemoarchitecture, the olfactostriatum resembles the mammalian ventral pallidum (but also the shell of the nucleus accumbens).  

A ventromedial cellular column forms a nucleus accumbens rostrally and continues caudally into a shell-like ventral pallidum.  

Activation of mu-opioid receptors in the ventral pallidum (VP) is important for the induction of behavioral sensitization to morphine in rats.  

The presence of CART in substance P NAcc neurons suggests that CART neurons may be a subset of the basal ganglia direct pathway or that CART neurons are involved in limbic projections of the NAcc, such as to the ventral pallidum..  

Moderate-dose ethanol (1.0 g/kg) also significantly lowered LCGU rates in many brain regions of P rats, including key limbic structures, such as the medial prefrontal cortex, olfactory tubercles, ventral tegmental area, basolateral nucleus of the amygdala, lateral septum, and ventral pallidum.  

The resulting novelty signal is conveyed through the subiculum, accumbens, and ventral pallidum to the VTA where it contributes (along with salience and goal information) to the novelty-dependent firing of these cells.  

Smaller numbers of Fos-immunoreactive cells were seen unilaterally in the bed nucleus of the stria terminalis, medial ventral pallidum, arcuate nucleus, and ventral tegmental area and bilaterally in the supraoptic and tuberomammillary nuclei.  

In contrast, higher levels of ethanol-induced FOSir were observed in the ventral pallidum (VP) and globus pallidus (GP) of MKO mice as compared to WT.  

The projection from the nucleus accumbens to the ventral pallidum regulates the reinstatement of cocaine seeking in rats extinguished from cocaine self-administration. This projection coexpresses GABA and enkephalin, posing a role for mu-opioid receptors in the ventral pallidum in mediating the reinstatement of cocaine seeking. Rats were extinguished from cocaine self-administration, and the reinstatement of active lever pressing by cocaine was blocked by intra-ventral pallidum administration of the mu receptor antagonist Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH2 (CTAP) (0.03-3.0 microg). Conversely, stimulating mu receptors with morphine (1-30 microg) in the ventral pallidum reinstated cocaine seeking. The ability of intra-ventral pallidum morphine to reinstate lever pressing was blocked by co-microinjection of the mu antagonist CTAP and was augmented by systemic cocaine administration. The reinstatement of cocaine seeking was associated with reduced extracellular GABA in the ventral pallidum, and the reduction in GABA was also prevented by blocking mu receptors with CTAP (10 microm). Although immunoblotting revealed that neither the total tissue concentration nor the membrane insertion of mu receptors in the ventral pallidum was altered by withdrawal from cocaine, the capacity of morphine (0.01-10 microm) to reduce ventral pallidum levels of extracellular GABA was augmented in rats extinguished from cocaine self-administration.  

ventral pallidum (VP) is an important source of limbic input to medial thalamus.  

The olfactostriatum projects to the main and accessory olfactory bulbs, lateral cortex, septal complex, ventral pallidum, external, ventral anterior and dorsolateral amygdalae, bed nucleus of the stria terminalis, preoptic area, lateral posterior hypothalamic nucleus, ventral tegmental area, substantia nigra and raphe nuclei.  

RATIONAL: Somatostatin and its receptors (sst(1) and sst(2)) have been localized in brain nuclei implicated in motor control, such as the nucleus accumbens, ventral pallidum (VP) and substantia innominata (SI).  

The GABA(A) receptor antagonist bicuculline (150 ng/0.2 microl per side) significantly produced repetitive jaw movements when injected bilaterally into the retrorubral field, but not the ventral pallidum. Essentially similar effects were obtained when muscimol and bicuculline were given into the ventral pallidum, a region that is also known to receive GABAergic inhibitory inputs from the nucleus accumbens. In conclusion, GABA(A) receptor blockade in the retrorubral field elicits characteristic repetitive jaw movements, and the GABA(A) receptors in that region as well as in the ventral pallidum modulate the accumbens-specific, dopamine D1/D2 receptor-mediated jaw movements..  

Sufficient evidence exists for the inclusion of the ventral pallidum (VP) into the category of a dopaminoceptive brain region.  

Terminal fields selectively labeled with DCC antibody corresponded to known nigrostriatal projections to the dorsolateral striatal patches and dorsomedial shell of the accumbens, and were also detected in prefrontal cortex, septum, lateral habenular and ventral pallidum.  

RESULTS: Lesioned animals exhibiting deficits in prepulse inhibition of the startle reflex showed a significant blood perfusion increase in the nucleus accumbens, basolateral amygdala, ventral pallidum, entorhinal-piriform cortex, orbital prefrontal cortex, and in the bed nucleus of the stria terminalis, and a decrease of perfusion in the temporal cortex.  

The ventral pallidum (VP) is involved in motivated behaviors and its function is altered by acute administration of cocaine and morphine, but the effects of repeated drug exposure remain unknown.  

Hedonic and rewarding states like these are modulated by the dopaminergic system in the nucleus accumbens, prefrontal cortex and also in the ventral pallidum and by the glutamatergic system in the neocortex and limbic system. In the present study, propofol was administered either alone or in combination with the GABAA receptor antagonist bicuculline via reverse microdialysis into the ventral pallidum of freely moving rats. Application of propofol decreased dopamine levels in the ventral pallidum. The reduced dopamine release in ventral pallidum was most probably mediated through a GABAergic feedback loop from the ventral pallidum via the nucleus accumbens to the dopaminergic neurons of the ventral tegmental area or by long loop feedback. As an increase but not a decrease of dopamine release in the ventral pallidum is involved in hedonic and rewarding properties, similar symptoms induced by propofol seem to be unrelated to an action of propofol in the ventral pallidum..  

The IEG responses of areas involved in reward (nucleus accumbens and ventral pallidum) and general stress processes (e.g.  

(-19%), glomerular layer of olfactory bulb (-18%), ventral pallidum (-14%), medial preoptic area (-16%), retrochiasmatic/arcuate hypothalamus (-18%), anteromedial thalamic n.  

Several experiments explored the roles of nucleus accumbens (NA), ventral pallidum (VP) and medial preoptic area (MPOA) in the regulation of maternal behavior in rats.  

However, repeated cocaine administration resulted in lower BOLD responses in the prefrontal cortex, agranular insular cortex, nucleus accumbens, ventral pallidum, and dorsomedial thalamus, among other brain regions.  

However, significant increases in levels of [ 3H]FNZ binding were found in the nucleus accumbens and ventral pallidum 1 h after single administration of PCP.  

Significant transport of Mn2+ was observed in olfactory structures ipsilateral to site of Mn2+ administration including the bulb, lateral olfactory tract (lo) by 12 h and in the tubercle, piriform cortex, ventral pallidum, amygdala, and in smaller structures such as the anterior commissure after 24 h post-administration.  

Results indicated that mGluR5- and GABA(A) alpha1-containing receptors were both coexpressed in limbic brain regions and colocalized on the same cells in specific brain regions including the amygdala, hippocampus, globus pallidus, and ventral pallidum.  

Studies from ours and other laboratories have shown that 5-HT1B receptors are densely expressed in the ventral pallidum, globus pallidus, substantia nigra and dorsal subiculum and moderately expressed in the cerebral cortex, the molecular layer of the hippocampus, the entopeduncular nucleus, the superficial gray layer of the superior colliculus, the caudate putamen and the deep nuclei of the cerebellum.  

We further show that, in hippocampus and ventral pallidum, spinophilin is occasionally present in dendritic shafts adjacent to gamma-aminobutyric acid-containing contacts.  

Our findings suggest the following telencephalic divisions: (1) a central amygdala-bed nucleus of the stria terminalis in the caudal midventral telencephalon, connected to visceral-autonomic centers; (2) a vomeronasal amygdala in the caudolateral ventral telencephalon receiving input from the accessory olfactory bulb and projecting mainly to the preoptic region/hypothalamus; (3) an olfactory amygdala in the caudal pole of the telencephalon lateral to the vomeronasal amygdala receiving input from the main olfactory bulb and projecting to the hypothalamus; (4) a medial amygdala receiving input from the anterior dorsal thalamus and projecting to the medial pallium, septum, and hypothalamus; (5) a ventromedial column formed by a nucleus accumbens and a ventral pallidum projecting to the central amygdala, hypothalamus, and posterior tubercle; (6) a lateral column constituting the dorsal striatum proper rostrally and the dorsal pallidum caudally, and a ventrolateral column constituting the ventral striatum.  

Neurons in this region share the chemical features of the adjacent cortex (presence of a similar proportion of parvalbumin immunoreactive neurons and minimal activity for acetylcholinesterase and tyrosine hydroxylase), unlike the adjacent putamen and ventral pallidum.  

Several lines of evidence suggest that opiate-induced disinhibition of the ventral pallidum participates in the mediation of opiate reward, though direct in vivo evidence to support this hypothesis has been lacking. Thus, heroin self-administration is associated with both decreased GABA efflux and a late phase increase in glutamate efflux in the ventral pallidum. These observations are consistent with the hypothesis that heroin self-administration results in a disinhibition and/or excitation of the ventral pallidum..  

The current study was designed to test the hypothesis that acquisition of signal-induced anticipation of self-administered ethanol and operant oral self-administration of ethanol increases the extracellular levels of dopamine in the ventral pallidum of alcohol-preferring (P) rats. The study was also designed to explore the association between behavioral activity and dopamine efflux in the ventral pallidum. The ethanol group showed significant increases in extracellular levels of dopamine in the ventral pallidum during (1). These findings support the suggestion that dopaminergic activation in the ventral pallidum is involved in ethanol-seeking and ethanol-drinking behaviors and directly implicate the mesopallidal dopamine system in the reinforcing actions of ethanol..  

Axonal transport of retrograde markers was used to study the distribution of the afferent projections of the nuclei of the pallidal complex (the globus pallidus, the entopeduncular nucleus, and the ventral pallidum) from functionally diverse cortical and subcortical structures (cortical fields, substantia nigra, ventral tegmental field, and thalamus) in the dog brain.  

A ventral pallidum, a basal cholinergic cell group, and medial and lateral bed nuclei of the stria terminalis were also recognized.  

On the other hand, only a few NK3 receptor-immunoreactive neurons showed immunoreactivity for choline acetyltransferase or parvalbumin in the substantia innominata, ventral pallidum, and globus pallidus, although the distribution of NK3 receptor-expressing neurons overlapped with those of cholinergic neurons and parvalbumin-positive neurons.  

Fos induction also occurred in limbic and reward regions, including the ventral pallidum, nucleus accumbens, and mediodorsal thalamus (MDthal). Next, we infused a selective V1aR antagonist into three candidate brain regions that seemed most likely involved in vasopressin-mediated pair bond formation: the ventral pallidum, medial amygdala, and MDthal. Blockade of V1aR in the ventral pallidum, but not in the medial amygdala or MDthal, prevented partner preference formation. Lastly, we demonstrated that the mating-induced Fos activation in the ventral pallidum was vasopressin-dependent, since over-expression of V1aR using viral vector gene transfer resulted in a proportionate increase in mating-induced Fos in the same region. This is the first study to show that vasopressin neurotransmission occurs in the ventral pallidum during mating, and that V1aR activation in this region is necessary for pair bond formation in male prairie voles.  

Neurons in the ventral pallidum (VP) exhibit robust responding to activation of dopamine (DA) receptors of the D1 class.  

Rats were trained to self-administer cocaine and the cholinergic neurotoxin 192-IgG-saporin or vehicle was then bilaterally administered into the posterior nucleus accumbens (NAcc)-ventral pallidum (VP).  

Transient inhibition of the central extended amygdala [ CEA; including the central nucleus of the amygdala (CN), ventral bed nucleus of the stria terminalis (BNSTv), and nucleus accumbens shell (NAshell)], ventral tegmental area (VTA), and motor circuitry [ including the dorsal prefrontal cortex (PFCd), nucleus accumbens core (NAcore), and ventral pallidum (VP)] blocked the ability of footshock stress to reinstate lever pressing previously associated with cocaine delivery.  

The ventral pallidum in rat is a basal forebrain structure that contains neurons that project in the limbic striatopallidal circuitry and magnocellular cholinergic corticopetal neurons. We conclude from this study that ascending 5-HT projections from the dorsal raphe could have direct and opposite effects on the activities of neurons within the limbic striatopallidal and cholinergic corticopetal circuitry in the ventral pallidum..  

We recorded neural activity in the ventral pallidum (VP) while rats learned a pavlovian reward association.  

The activity of cholinergic innervations of and/or interneurons in the olfactory tubercle, caudate putamen, diagonal band-pre-optic region, ventral pallidum, lateral and medial hypothalamus, hippocampus, ventral tegmental area and visual cortices reflected by the turnover rates of acetylcholine were significantly altered in rats self-administering cocaine compared to yoked cocaine infused controls. These changes implicate the involvement of cholinergic neurons with cell bodies in the diagonal band-pre-optic region, the medial septum and several brainstem nuclei and interneurons in the caudate-putamen and ventral pallidum in the processes underlying cocaine self-administration.  

V1aR binding was nonoverlapping with each of these markers but colocalized with iron accumulation as shown by Perls' iron stain as well as leucine-enkephalin immunoreactivity, both markers for the ventral pallidum. OTR and V1aR mRNA were also restricted within the nucleus accumbens and ventral pallidum, respectively. Immunocytochemical analysis of oxytocin and vasopressin in the ventral forebrain demonstrated the presence of oxytocin-immunoreactive fibers in the nucleus accumbens and vasopressin-immunoreactive fibers in the ventral pallidum, with males showing a greater density of vasopressin fibers than females, but there was no such sex difference in the oxytocin system.  

The ventral pallidum (VP) is a major intermediary in the prefrontal cortical circuitry regulating sensorimotor gating and locomotor behavior, both of which are potently modulated by catecholamines.  

We reported previously that the glycosaminoglycan heparin (HP) has the facility to improve learning in adult rodents when administered into the nucleus basalis of the ventral pallidum.  

It was determined that this short-term antagonism of D2-like receptors induced fiber and terminal degeneration and significantly decreased tyrosine hydroxylase (TH) and brain-derived neurotrophic factor (BDNF) immunoreactivity in the ventral pallidum (VP), as determined by optical density measurements.  

In contrast, the ventral pallidum and substantia innominata received dense CB1 receptor-ir innervation and cholinergic neurons received CB1 receptor-ir presumed synaptic contacts. VGLUT3 immunoreactivity was largely absent in ventral pallidum and substantia innominata.  

In one of them additional activation at the right nucleus accumbens/ventral striatum and right ventral pallidum was present.  

RESULTS: The sustained sadness condition was associated with a statistically significant deactivation in mu-opioid neurotransmission in the rostral anterior cingulate, ventral pallidum, amygdala, and inferior temporal cortex. The deactivation of mu-opioid neurotransmission in the rostral anterior cingulate, ventral pallidum, and amygdala was correlated with the increases in negative affect ratings and the reductions in positive affect ratings during the sustained sadness state.  

The present studies investigated the role of the GABA-ergic efferent from the nucleus accumbens to the ventral pallidum in latent inhibition. The GABA(A) agonist muscimol (4.56 ng/microl), and antagonist picrotoxin (0.2 microg/microl), were infused into the ventral pallidum, and effects on latent inhibition were assessed using a conditioned suppression procedure.  

Cocaine (200 mm) was self-administered marginally into the accumbens shell but not into the core, dorsal striatum, or ventral pallidum. In addition, cocaine injections (200 mm in 300 nl) into the tubercle but not the shell or ventral pallidum induced conditioned place preference.  

It has been hypothesized that alcohol addiction is mediated, at least in part, by specific gamma-aminobutyric acid(A) (GABA(A)) receptors within the ventral pallidum (VP).  

When the retrograde tracer was injected into the ventral pallidum, about 60% and 40% of retrogradely labeled neurons in the accumbens nucleus were immunoreactive for PPD and PPE, respectively. Although no olfactory tubercle neurons projected fibers to the mesencephalic regions, 60% and 40% of olfactory tubercle neurons projecting to the ventrolateral portion of the ventral pallidum were immunoreactive for PPD and PPE, respectively, as were the accumbens nucleus neurons. About 70% of accumbens nucleus and olfactory tubercle neurons projecting to the ventral pallidum and all accumbens nucleus neurons projecting to the ventral mesencephalic regions showed PPTA immunoreactivity. A small population (2-12%) of accumbens neurons projecting to the ventral pallidum and mesencephalic regions displayed immunoreactivity for PPTB. This suggests that the ventral striatopallidal projection system is less specialized than the dorsal striatopallidal system in terms of peptide production, or that the ventral pallidum should be compared with a combined region of the globus pallidus and entopeduncular nucleus in the dorsal system..  

Numerous PVs occupy all structures currently regarded as having a striatal composition, including the caudate-putamen, nucleus accumbens, and olfactory tubercle, as well as structures that receive outputs from these, including the globus pallidus, ventral pallidum, entopeduncular nucleus and substantia nigra reticulata.  

In addition, Fos-immunostaining induced by SKF-82958 in caudate-putamen (CPu) and nucleus accumbens (Nac) was greater in food-restricted than ad libitum-fed rats, as was staining induced by quinpirole in globus pallidus and ventral pallidum.  

the caudate-putamen), globus pallidus, ventral pallidum, and nucleus accumbens.  

Evidence suggests activity in a subcortical network involving portions of the nucleus accumbens shell, ventral pallidum, and brainstem causes 'liking' and positive affective reactions to sweet tastes. Lesions of ventral pallidum also impair normal sensory pleasure.  

They were located in the ventral pallidum, substantia innominata and the horizontal limb of the diagonal-band areas.  

The ventral pallidum receives a dense enkephalinergic projection from the nucleus accumbens and is implicated as a locus mediating the rewarding and reinforcing effects of psychostimulant and opiate drugs. Microinjection of naloxone (0.01-10 microg) into the ventral pallidum once a day for 3 days dose-dependently produced a conditioned place aversion when tested in the drug-free state 24 h after the last naloxone injection. In contrast, the locomotor activation induced by peripheral cocaine injection was unaffected by naloxone injection into the ventral pallidum.The data implicate endogenous opioid peptide systems within the ventral pallidum as regulators of hedonic status..  

In this study it was investigated whether ventral striatal dopamine-induced changes in switching to cue-directed behavioral patterns were funnelled via the rostral areas of the ventral pallidum/substantia innominata (VP/SI) complex and, if so, whether changes in switching to cue-directed behavioral patterns could be elicited in the VP/SI complex by manipulating GABAergic activity.  

In addition, interaction analyses showed that schematic versus propositional processing of happiness (compared with the neutral scenario) was associated with increased activity in the ventral striatum whereas "schematic anger" was tentatively associated with activation of the ventral pallidum..  

Cholinergic projection neurons with heterogeneous densities were found in the medial septum, vertical and horizontal diagonal bands of Broca, ventral pallidum, and magnocellular nucleus basalis (MBN)/substantia innominata (SI) complex; cholinergic interneurons were observed in the caudate nucleus, putamen, accumbens nucleus, and olfactory tubercule, whereas the globus pallidus was devoid of cholinergic nerve cells.  

The cerebral cortex, caudate putamen, ventral pallidum, and nucleus accumbens showed lower labeling.  

the central amygdaloid nucleus, field CA3 of the hippocampus, paraventricular hypothalamic nucleus, medial preoptic nucleus, interstitial nucleus of the posterior limb of the anterior commissure, lateral globus pallidus, ventral pallidum and lateral division of the bed nucleus of the stria terminalis.  

Data were collected from several key limbic (nucleus accumbens, ventral tegmental area, olfactory tubercle, amygdala, hippocampus, ventral pallidum, and septum), basal ganglia, cortical (medial prefrontal, frontal, parietal, temporal, occipital, entorhinal, piriform, and cingulate), and subcortical (thalamus, habenula, and superior colliculus) structures.  

Intense feeding responses associated with an increased duration of feeding behavior were consistently recorded after injections of MK-801 or CNQX into the medial two-thirds of the tuberculum olfactorium (TO), the ventral aspect of lobus parolfactorium (LPOv), or the ventral pallidum (VP).  

The present study examined the effects of intraperitoneal (IP) ethanol administration on the extracellular levels of dopamine in the ventral pallidum (VP) and globus pallidus (GP) of Wistar rats.  

Mesocortical (prelimbic, orbital and insular) and allocortical (entorhinal, piriform and periamygdalar) including archicortex (subicular part of hippocampal formations) fields project onto ventral pallidum. The data obtained indicate specificity of distribution of cortical afferent projectional fibres in each of nuclei studied which allows to consider globes pallidum as motor zone and ventral pallidum as limbic zone of paladial complex.  

This included innervations of the nucleus accumbens, ventral pallidum, lateral hypothalamus and the anterior and posterior cingulate, entorhinal-subicular and visual cortices.  

In sensitized rats, quinpirole decreased LCGU in the nucleus accumbens core and shell (77 and 83% of control, respectively) and ventral pallidum (82% of control) as well as in the caudate/putamen (86% of control), lateral habenula (77% of control), and motor cortex (79% of control). This suggests that decreased neuronal activity in the nucleus accumbens and ventral pallidum may underlie the augmented behavioral response to quinpirole in sensitized animals..  

In addition, we detected EGFP and S100B in forebrain neurons previously thought not to express S100B in the mouse, including neurons of primary motor and somatosensory neocortical areas, the ventral pallidum and prerubral field.  

Projections from functionally diverse cortical and subcortical structures (cortex, amygdaloid body, substantia nigra, ventral tegmental area, and thalamus) to the pallidum (globus pallidus, entopeduncular nucleus and ventral pallidum) were studied in dogs using the method of axonal transport of the retrograde markers.  

Numerous NK1R expressing neurons also occurred in both external (GPe) and internal (GPi) segments of the globus pallidus, as well as in the ventral pallidum (GPv).  

Large-sized neurons double labelled for parvalbumin and the GABA(A) receptor alpha1-subunit are also widely distributed in the neighbouring ventral pallidum.  

Furthermore, cocaine injections into the lateral or posterior tubercle produced marginal locomotion and rearing, while cocaine injections into regions just dorsal to these tubercle sites, the lateral portion of the shell or the ventral pallidum, did not produce any stimulating effect.  

We examined the effects of heparin on learning and frontal cortex acetylcholine parameters following injection of the glucosaminoglycan into the ventral pallidum.  

Dopamine terminals in the striatum and ventral pallidum, as well as dendrites of midbrain dopaminergic neurons in the ventral tegmental area and substantia nigra express the plasmalemmal dopamine transporter (DAT) and the vesicular monoamine transporter (VMAT2).  

Alpha-synuclein was not observed in perikarya, but was distributed with high intensity in nerve terminals in the caudate and putamen and ventral pallidum, where beta-synuclein was much weaker and less densely distributed in the caudate and putamen.  

Two radial maze tasks, random foraging and delayed spatial win-shift, have been used to investigate, in rats, the functions and inter-relationships of structures connected through the corticostriatal loops, such as the prelimbic cortex, nucleus accumbens, ventral pallidum and mediodorsal thalamus.  

Bilateral injections of both muscimol (25 and 50 ng/0.2 microl per side) and bicuculline (50 and 150 ng/0.2 microl per side) into the ventral pallidum, entopeduncular nucleus or dorsolateral part of the substantia nigra pars reticulata essentially inhibited dopamine receptor-mediated jaw movements to various degrees. The acetylcholine receptor-mediated jaw movements were not affected by muscimol injections into the ventral pallidum, but were inhibited by bicuculline injections. Studies on such injections into the ventral pallidum, entopeduncular nucleus or dorsolateral part of the substantia nigra pars reticulata of naive rats revealed that jaw movements of the digastric/masseter type were elicited either by muscimol injections into the dorsolateral part of the substantia nigra pars reticulata or by combined injections of muscimol and bicuculline into the entopeduncular nucleus, and that jaw movements of the digastric type were elicited only by combined injections of muscimol and bicuculline into the entopeduncular nucleus. It is suggested that the three different profiles of responses to GABAergic drugs in animals showing either dopamine receptor-mediated or acetylcholine receptor-mediated jaw movements reflect the involvement of three distinct types of output neurons of the striatum, namely: type I neurons with collateralised axons to the ventral pallidum, entopeduncular nucleus and dorsolateral part of the substantia nigra pars reticulata, mediating the dopamine receptor-mediated jaw movements; type II neurons with collateralised axons to the globus pallidus that, in turn, project to the entopeduncular nucleus and the dorsolateral part of the substantia nigra pars reticulata, mediating directly the acetylcholine receptor-mediated jaw movements; and type III neurons with a single axon to the ventral pallidum, mediating indirectly the acetylcholine receptor-mediated movements.  

Perfusion of a selective mGlu5R agonist (CHPG) in the nucleus accumbens facilitated GABA release in the ipsilateral ventral pallidum.  

We then tested the capacity of 3-PBC to block alcohol-maintained responding in the ventral pallidum (VP), a novel alcohol reward substrate, which primarily expresses the alpha1-receptor isoform.  

A systematic approach to determining those settings that maximally improve parkinsonism and suppress drug-induced dyskinesias is outlined following a clear algorithm that uses the observation that stimulation of the dorsal and ventral pallidum has been shown to have opposite motor effects in PD.  

The present study explored the possibility that excitatory amino acid (EAA) sensitivity within the ventral pallidum (VP) is altered by long-term removal of dopamine (DA).  

While comparing the effects of various drugs injected into distinct regions of the basal forebrain on cognitive and motor endpoints, we observed that the ventral pallidum (VP) appeared to be sensitive to vehicle control infusions when cognitive indices were measured.  

Since the target neurons of MCL fibers seem to be uncoupled to D-1 receptors, the medium spiny GABA neurons projecting to the ventral pallidum and ventral tegmental area (VTA) exert a weak feedback inhibition on the neurons of origin of MCL system.  

The ventral pallidum (VP) is situated at the convergence of midbrain dopamine and accumbal opioid efferent projections.  

The ventral pallidum (VP) is a basal forebrain structure that is interconnected with motor and limbic structures and may be considered as an interface between motivational and effector neural signals.  

(v) The core regions of the islands of Calleja that border the ventral pallidum (VP) sharing some of its features are invaded by myelinated fibers of the medial forebrain bundle (MFB).  

By using reverse transcription PCR combined with Southern hybridization, the long form of prolactin receptor mRNA was detected in the substantia nigra, caudate putamen, globus pallidus, and ventral pallidum in ovariectomized rats, whereas the short form was not detectable in any of these areas.  

To understand the potential contribution of the dopamine D2 receptor (D2R) to the action of dopamine in the ventral pallidum (VP), we used electron microscopic immunocytochemistry to examine the cellular and subcellular localization of an antipeptide antiserum against the D2R in both ventromedial and dorsolateral VP compartments.  

Six months later, histological analyses showed severe neurodegeneration within the lateral striatum accompanied by apparent cell loss in the ventral pallidum and entopedoncular nucleus.  

The transient inhibition of brain nuclei associated with motor systems [ including the ventral tegmental area (VTA), dorsal prefrontal cortex (dPFC), core of the nucleus accumbens (NAcore), and ventral pallidum (VP)] prevented cocaine-induced reinstatement.  

Likewise, 300 microM CP-93,129 reduced 5-HT output in substantia nigra pars reticulata, ventral pallidum, lateral habenula and the suprachiasmatic nucleus.  

The autoradiograms indicated that in the human brain, the 5-HT(1B) receptor is much more abundant than the 5-HT(1D) receptor, which seemed to occur only in low amounts mainly in the ventral pallidum.  

In rat brain, Shh transcripts were identified by double in situ hybridization in GABAergic neurons located in various basal forebrain nuclei including globus pallidus, ventral pallidum, medial septum-diagonal band complex, magnocellular preoptic nucleus and in cerebellar Purkinje cells as well as in motoneurons of several cranial nerve nuclei and of the spinal cord.  

Distribution of labelled neurons in thalamic nuclei after the marker injection into the dog brain pallidal structures (globus pallidum, entopeduncular nucleus and ventral pallidum) was studied by retrograde axonic HRP and fluorochrome transport. Analysis of the material obtained allowed to conclude that in globus pallidum projections from motor thalamic nuclei (ventral anterior, ventral lateral, ventral medial and median centre) are dominating, although in ventral pallidum projections from limbic nuclei (parafascicular and median) are predominant.  

Because the ventral pallidum is involved in reinforcement and addiction, we hypothesize that V1aR activation in this region promotes pair-bond formation via a mechanism similar to conditioning.  

The amygdala and ventral pallidum receive secondary collaterals from striatal axons of dorsal/ventral tier neurons or RRF neurons.  

Both the nucleus accumbens and ventral pallidum are key relay nuclei in the brain circuits implicated in reward, such as the mesolimbic dopamine and opioid systems.  

The distribution of SPR-like immunoreactive (SPR-LI) neurons completely overlapped with that of choline acetyltransferase (ChAT)-LI neurons in the medial septal nucleus, the nucleus of diagonal band of Broca, the magnocellular preoptic nucleus, the substantia innominata of basal forebrain, the caudate-putamen, and the ventral pallidum of the basal ganglia.  

In several limbic regions (e.g., ventral tegmental area, olfactory tubercle, medial prefrontal cortex, ventral pallidum and lateral septum), no recovery of LCGU rates was observed after 2 weeks of alcohol deprivation.  

The present article reviews our recent biochemical and microdialysis studies showing the evidence for an antagonistic CCK(B)/D(2) receptor interaction in the regulation of dopaminergic transmission in the nucleus accumbens and GABAergic transmission in the ipsilateral ventral pallidum.  

Substantial numbers of double-labeled neurons were observed in the rostral part of the lateral septum, and in a region centered on the shared boundaries of the bed nucleus of stria terminalis, ventromedial ventral pallidum, diagonal band of Broca, lateral preoptic area and rostral lateral hypothalamus.  

RESULTS: Data were collected from several key limbic (nucleus accumbens, ventral tegmental area, olfactory tubercle, amygdala, hippocampus, ventral pallidum, and septum), basal ganglia, cortical (medial prefrontal, frontal, parietal, temporal, occipital, entorhinal, pyriform, and cingulate), and subcortical (thalamus, habenula, and superior colliculus) structures.  

This study evaluated the capacity of mu-opioid and glutamate receptor agonists to differentially regulate the involvement of the GABAergic projection from the ventral pallidum to the mediodorsal thalamus in working memory and locomotor activity. Microinjection of either the ionotropic glutamate receptor agonist alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) or the mu agonist [ D-Ala(2),N-Me-Phe(4),Gly-ol(5)]enkephalin into the ventral pallidum of male Sprague-Dawley rats produced a dose-dependent impairment in working memory, estimated using a forced delayed alternation task in a T-maze. Involvement of the GABAergic projection from the ventral pallidum to the mediodorsal thalamus in mu-opioid-induced impairment of working memory was verified by showing that inhibiting GABA(B) receptors in the mediodorsal thalamus blocked the effect of [ D-Ala(2),N-Me-Phe(4),Gly-ol(5)]enkephalin in the ventral pallidum. Similarly, either glutamate or mu-opioid receptor stimulation in the ventral pallidum elicited motor activity, and the motor stimulant effect of the mu agonist was blocked, while that of AMPA is not affected by GABA(B) receptor blockade in the mediodorsal thalamus. Distinction between mu and glutamate receptor stimulation was further revealed by the fact that stimulating mu receptors in the ventral pallidum caused a dose-dependent reduction in extracellular GABA levels, while AMPA was without effect on GABA in the ventral pallidum.These data indicate that stimulating mu-opioid receptors reduces GABAergic tone in the ventral pallidum, which increases activity in the GABAergic projection to the mediodorsal thalamus, thereby impairing working memory. Moreover, it is hypothesized that mu receptors in the ventral pallidum gate the recruitment of working memory into ongoing behavioral activity..  

The ability of GABA(A) receptors in the ventral pallidum to modulate shell-specific behavior was studied. Unilateral injections of the GABA(A) receptor agonist muscimol (10, 25 and 50 ng) into the ventral pallidum dose-dependently mimicked shell-specific circling, especially when given at a level +8.6mm anterior to the interaural line; this effect was GABA(A) receptor specific, because it was prevented by the GABA(A) receptor antagonist bicuculline (150 ng). Pallidal injections of bicuculline (150 ng) produced short-lasting ipsiversive circling that was followed by contraversive pivoting.We conclude that the ventromedial portion of the ventral pallidum contains GABA(A) receptors that are crucial for the transmission of information from the shell of the nucleus accumbens via the ventral pallidum towards other brain structures; this holds especially for information about shell-specific circling elicited by carbachol. The same portion of the ventral pallidum also contains GABA(A) receptors that control the transfer of information from the nucleus accumbens towards structures outside the ventral pallidum; this holds especially for information about shell-specific pivoting elicited by dopaminergic agonists..  

In the second part of the study, we performed ibotenic acid lesions to the major output nuclei of the accumbens, the ventral pallidum, mediodorsal thalamus, ventrolateral/ventromedial thalamus and pedunculopontine tegmental nucleus, to observe their effect on locomotor activity induced by focal (+)-MK-801 (25 nmol) administration into the accumbens. In contrast, ibotenic acid lesions of the ventral pallidum and ventrolateral/ventromedial thalamus completely blocked the motor response induced by accumbens MK-801.These data indicate that the intact mediodorsal thalamus, which has been proposed as a part of the loop that relays accumbens information to the prefrontal cortex, does not seem to be a structure of primary importance in MK-801 locomotor activity.  

The subthalamic nucleus (STN), a component of the basal ganglia motor system, sends an excitatory amino acid (EAA)-containing projection to the ventral pallidum (VP), a major limbic system output region.  

In contrast, the globus pallidus, the entopeduncular nucleus, the ventral pallidum, the subthalamic nucleus, and the substantia nigra pars reticulata revealed dense networks of presumable dendrites of resident projection neurons, which were darkly labeled for subunit alpha1-, beta2-, and gamma2-immunoreactivities. The globus pallidus, ventral pallidum, entopeduncular nucleus, and substantia nigra pars reticulata, all areas receiving innervations from the striatum, displayed strong subunit gamma1-immunoreactivity compared to other brain areas.  

A corticolimbic-striatal-thalamic network (1) integrates the salient incentive context in the medial orbital cortex, amygdala, and hippocampus; (2) encodes the intensity of incentive stimuli in a motive circuit composed of the nucleus accumbens, ventral pallidum, and ventral tegmental area dopamine projection system; and (3) creates an incentive motivational state that can be transmitted to the motor system.  

Postoperatively, stimulation through macroelectrode contacts located in the posterior ventral pallidum controlled the patient's dyskinesias. We postulate stimulation of the ventral pallidum controls dyskinesias by activating large axons which inhibit GPi neurons..  

The ventral striatal lesions involved portions of ventral pallidum and thus it seems likely that they affected functions mediated by the nucleus accumbens as well as striatal areas of the tubercle.  

In addition, prefrontal limbic areas projected to two other systems of the basal forebrain, the ventral pallidum and the extended amygdala, delineated with the striatal-related markers dopamine, adenosine 3':5'-monophosphate regulated phosphoprotein of M(r) 32kDa, and the related phosphoprotein Inhibitor-1. Moreover, orbitofrontal and medial prefrontal cortices target the ventral pallidum and the extended amygdala, through which high-order association areas may activate motor autonomic structures for the expression of emotions..  

Partially overlapping distributions of neuromedin K receptor-like immunoreactive and choline acetyltransferase-positive neurons were found in the basal nucleus of Meynert, globus pallidus, ventral pallidum of the forebrain, tegmental nuclei of the pons and dorsal motor nucleus of the vagus.  

PPI was reported to be regulated by forebrain circuits, including mesolimbic cortex, nucleus accumbens, ventral pallidum, thalamus, and pedunculopontine tegmentum nucleus.  

To explore the significance of ventral pallidum (VP) during the amphetamine sensitization, we first investigated if there are neurochemical alterations in the VP during amphetamine withdrawal period.  

We employed dual probe microdialysis in the nucleus accumbens and ipsilateral ventral pallidum of the halothane anaesthetized rat to investigate the effect of intra-accumbens perfusion with the sulphated octapeptide cholecystokinin (CCK-8S, 10-1000 nM, 60 min) alone and in the presence of the selective CCK1 and CCK2 receptor antagonists L-364,718 (10 and 100 nM) and PD134308 (10 nM), tetrodotoxin (TTX, 1000 nM) and the GABA(A) receptor antagonist bicuculline (1000 nM), on dialysate GABA levels in the ventral pallidum. Intra-accumbens perfusion with the 100 and 1000 nM concentration of CCK-8S was associated with a significant decrease (-16+/-3% and -23+/-3% vs basal, respectively) in ventral pallidum GABA levels.  

Motor activity is regulated by projections from the nucleus accumbens to the ventral pallidum, but it is unclear which efferents regulate behavioral output from the ventral pallidum. Motor activity was elicited pharmacologically by microinjecting either the mu opioid receptor agonist, Tyr-D-Ala-Gly-NmePhe-Gly-OH (DAMGO) or the glutamate receptor agonist, alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate (AMPA) into the ventral pallidum. The involvement of efferent projections was determined by microinjecting the local anesthetic procaine into the mediodorsal nucleus of the thalamus (MD) or the midbrain extrapyramidal area (MEA) prior to administering DAMGO or AMPA into the ventral pallidum. These data indicate that the involvement of efferent projections from the ventral pallidum to either the MD or MEA in motor activation depends upon the type of receptor stimulated in the ventral pallidum..  

Reserpine treatment depleted endogenous dopamine by more than 90% and significantly increased the binding of [ (125)I]NCQ 298 to D2 receptors in the nucleus accumbens, ventral pallidum, and substantia nigra. Chronic stimulation of D2-like receptors with quinpirole (1 mg/kg/day) or 7-OH-DPAT (1 mg/kg/day) produced decreases in [ (125)I]NCQ 298 binding in the nucleus accumbens, ventral pallidum, and substantia nigra as expected. As with depletion, chronic stimulation elicited an opposite response from D3 receptors with significant increases observed in the ventral pallidum and substantia nigra.  

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