The pedunculopontine tegmental nucleus (PPTg) in the brainstem plays a role in controlling reinforcement learning and executing conditioned behavior. We previously examined the activity of PPTg neurons in monkeys during a reward-conditioned, visually guided saccade task, and reported that a population of these neurons exhibited tonic responses throughout the task period. These tonic responses m...

Gamma rhythms have been proposed to promote the feed forward or "bottom-up" flow of information from lower to higher regions in the brain during perception. On the other hand, beta rhythms have been proposed to represent feed back or "top-down" influence from higher regions to lower. The pedunculopontine nucleus (PPN) has been implicated in sleep-wake control and arousal, and is part of the ret...

Previous studies in our laboratory have shown that microinjection of acetylcholine and nonN-methyl-D-aspartate (NMDA) glutamate agonists into the pontine inhibitory area (PIA) induce muscle atonia. The present experiment was designed to identify the PIA afferents that could be responsible for these effects, by use of retrograde transport of wheat germ agglutinin conjugated horseradish peroxidas...

Urotensin II (UII) is a cyclic neuropeptide with strong vasoconstrictive activity in the peripheral vasculature. UII receptor mRNA is also expressed in the CNS, in particular in cholinergic neurons located in the mesopontine tegmental area, including the pedunculopontine tegmental (PPT) and lateral dorsal tegmental nuclei. This distribution suggests that the UII system is involved in functions ...

The symptom of Parkinson's disease that is most disabling and difficult to treat is akinesia. We have previously shown that low-frequency stimulation of the pedunculopontine nucleus can alleviate such akinesia in a macaque rendered Parkinsonian using 1-methyl 4-phenyl 1,2,3,6-tetrahydropyridine. Here, we have extended that study to show that adding stimulation of the pedunculopontine nucleus to...

The opponent-process theory posits that the aversive state of acute opiate withdrawal is a consequence of, and depends on, the previous rewarding state evoked by acute morphine reward. Although the brainstem tegmental pedunculopontine nucleus (TPP) is crucial for the rewarding component of morphine, the source of the later aversive component is not known. It is possible that (i) the second aver...

The recent development of deep brain stimulation (DBS) of the pedunculopontine nucleus (PPN) for the treatment of parkinsonian patients, particularly those in advanced stages with axial symptoms, has ignited interest into the study of this brain nucleus. In contrast to the extensively studied alterations of neural activity that occur in the basal ganglia in Parkinson's disease (PD), our underst...

The pedunculopontine nucleus (PPN) has long been considered an interface between the basal ganglia and motor systems, and its ability to regulate arousal states puts the PPN in a key position to modulate behavior. Despite the large amount of data obtained over recent decades, a unified theory of its function is still incomplete. By putting together classical concepts and new evidence that disse...

Benzodiazepines have been reported to induce eating when administered into the brainstem of rats (either the fourth ventricle or the parabrachial nucleus). Benzodiazepines in the brainstem also have been reported to enhance the hedonic impact of taste, as measured by hedonic/aversive taste reactivity patterns, when administered to the fourth ventricle. The present study examined whether the par...