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Laterodorsal tegmental nucleus
About: Laterodorsal tegmental nucleus is a research topic. Over the lifetime, 420 publications have been published within this topic receiving 37189 citations.
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TL;DR: It appears that the age-related changes of memory function as well as some of the behavioral disturbances seen in the dementia of Alzheimer's Disease may be related to pathological alterations along central cholinergic pathways.
2,280 citations
TL;DR: The purpose of the present investigation was to examine the topographical organization of efferent projections from the cytoarchitectonic divisions of the mPFC (the medial precentral, dorsal anterior cingulate and prelimbic cortices) to determine whether the efferents from different regions within the prelimbics were organized topographically.
Abstract: The purpose of the present investigation was to examine the topographical organization of efferent projections from the cytoarchitectonic divisions of the mPFC (the medial precentral, dorsal anterior cingulate and prelimbic cortices). We also sought to determine whether the efferents from different regions within the prelimbic division were organized topographically. Anterograde transport of Phaseolus vulgaris leucoagglutinin was used to examine the efferent projections from restricted injection sites within the mPFC. Major targets of the prelimbic area were found to include prefrontal, cingulate, and perirhinal cortical structures, the dorsomedial and ventral striatum, basal forebrain nuclei, basolateral amygdala, lateral hypothalamus, mediodorsal, midline and intralaminar thalamic nuclei, periaqueductal gray region, ventral midbrain tegmentum, laterodorsal tegmental nucleus, and raphe nuclei. Previously unreported projections of the prelimbic region were also observed, including efferents to the anterior olfactory nucleus, the piriform cortex, and the pedunculopontine tegmental-cuneiform region. A topographical organization governed the efferent projections from the prelimbic area, such that the position of terminal fields within target structures was determined by the rostrocaudal, dorsoventral, and mediolateral placement of the injection sites. Efferent projections from the medial precentral and dorsal anterior cingulate divisions (dorsomedial PFC) were organized in a similar topographical fashion and produced a pattern of anterograde labeling different from that seen with prelimbic injection sites. Target structures innervated primarily by the dorsomedial PFC included certain neocortical fields (the motor, somatosensory, and visual cortices), the dorsolateral striatum, superior colliculus, deep mesencephalic nucleus, and the pontine and medullary reticular formation. Previously unreported projections to the paraoculomotor central gray area and the mesencephalic trigeminal nucleus were observed following dorsomedial PFC injections. These results indicate that the efferent projections of the mPFC are topographically organized within and across the cytoarchitectonic divisions of the medial wall cortex. The significance of topographically organized and restricted projections of the rat mPFC is discussed in light of behavioral and physiological studies indicating functional heterogeneity of this region.
1,621 citations
TL;DR: The correspondence of the distribution of ChAT‐labeled neurons identified by the methods to earlier immunocytochemical and acetylcholinesterase histochemical studies and to connectional studies of these groups argues for the specificity of the ChAT antibody used.
Abstract: The neuroanatomical location and cytological features of cholinergic neurons in the rat brain were determined by the immunocytochemical localization of the biosynthetic enzyme, choline acetyltransferase (ChAT). Perikarya labeled with ChAT were detected in four major cell groups: (1) the striatum, (2) the magnocellular basal nucleus, (3) the pontine tegmentum, and (4) the cranial nerve motor nuclei. Labeled neurons in the striatum were observed scattered throughout the neostriatum (caudate, putamen) and associated areas (nucleus accumbens, olfactory tubercle). Larger ChAT-labeled neurons were seen in an extensive cell system which comprises the magnocellular basal nucleus. This more or less continuous set of neuronal clusters consists of labeled neurons in the nucleus of the diagonal band (horizontal and vertical limbs), the magnocellular preoptic nucleus, the substantia innominata, and the globus pallidus. Labeled neurons in the pontine tegmentum were seen as a group of large neurons in the caudal midbrain, dorsolateral to the most caudal part of the substantia nigra, and extended in a caudodorsal direction through the midbrain reticular formation into the area surrounding the superior cerebellar peduncle. The neurons in this latter group constitute the pedunculopontine tegmental nucleus (PPT). An additional cluster of cells was observed medially adjacent to the PPT, in the lateral part of the central gray matter at the rostral end of the fourth ventricle. This group corresponds to the laterodorsal tegmental nucleus. Large ChAT-labeled neurons were also observed in all somatic and visceral motor nerve nuclei. The correspondence of the distribution of ChAT-labeled neurons identified by our methods to earlier immunocytochemical and acetylcholinesterase histochemical studies and to connectional studies of these groups argues for the specificity of the ChAT antibody used.
952 citations
TL;DR: Dynamic analyses of sequential firing rates throughout the waking-sleep cycle showed that none of the full-blown states of vigilance is associated with a uniform level of spontaneous firing rate.
Abstract: This study was performed to examine the hypothesis that thalamic-projecting neurons of mesopontine cholinergic nuclei display activity patterns that are compatible with their role in inducing and maintaining activation processes in thalamocortical systems during the states of waking (W) and rapid-eye-movement (REM) sleep associated with desynchronization of the electroencephalogram (EEG) A sample of 780 neurons located in the peribrachial (PB) area of the pedunculopontine tegmental nucleus and in the laterodorsal tegmental (LDT) nucleus were recorded extracellularly in unanesthetized, chronically implanted cats Of those neurons, 82 were antidromically invaded from medial, intralaminar, and lateral thalamic nuclei: 570 were orthodromically driven at short latencies from various thalamic sites: and 45 of the latter elements are also part of the 82 cell group, as they were activated both antidromically and synaptically from the thalamus There were no statistically significant differences between firing rates in the PB and LDT neuronal samples Rate analyses in 2 distinct groups of PB/LDT neurons, with fast (greater than 10 Hz) and slow (less than 2 Hz) discharge rates in W, indicated that (1) the fast-discharging cell group had higher firing rates in W and REM sleep compared to EEG-synchronized sleep (S), the differences between all states being significant (p less than 00005); (2) the slow-discharging cell group increased firing rates from W to S and further to REM sleep, with significant difference between W and S (p less than 001), as well as between W or S and REM sleep (p less than 00005) Interspike interval histograms of PB and LDT neurons showed that 75% of them have tonic firing patterns, with virtually no high-frequency spike bursts in any state of the wake-sleep cycle We found 22 PB cells that discharged rhythmic spike trains with recurring periods of 08-1 sec Autocorrelograms revealed that this oscillatory behavior disappeared when their firing rate increased during REM sleep Dynamic analyses of sequential firing rates throughout the waking-sleep cycle showed that none of the full-blown states of vigilance is associated with a uniform level of spontaneous firing rate Signs of decreased discharge frequencies of mesopontine neurons appeared toward the end of quiet W, preceding by about 10-20 sec the most precocious signs of EEG synchronization heralding the sleep onset During transition from S to W, rates of spontaneous discharges increased 20 sec before the onset of EEG desynchronization(ABSTRACT TRUNCATED AT 400 WORDS)
746 citations
TL;DR: A simple enzyme histochemical technique is described that detects various distinct populations of neurons in the brain that contain an extremely high activity of an endogenous enzyme, NADPH-diaphorase, that can reduce the dye nitro blue tetrazolium to a bright blue reaction product.
688 citations