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Cholinergic systems in the rat brain: III. Projections from the pontomesencephalic tegmentum to the thalamus, tectum, basal ganglia, and basal forebrain. Brain Res Bull

Department of Psychology and Brain Research Institute University of California, Los Angeles, CA 90024 USA
Brain Research Bulletin (Impact Factor: 2.97). 06/1986; 16(5):603-37. DOI: 10.1016/0361-9230(86)90134-6
Source: PubMed

ABSTRACT The ascending cholinergic projections of the pedunculopontine and dorsolateral tegmental nuclei, referred to collectively as the pontomesencephalotegmental (PMT) cholinergic complex, were investigated by use of fluorescent tracer histology in combination with choline-O-acetyltransferase (ChAT) immunohistochemistry and acetylcholinesterase (AChE) pharmacohistochemistry. Propidium iodide, true blue, or Evans blue was infused into the anterior, reticular, mediodorsal, central medial, and posterior nuclear areas of the thalamus; the habenula; lateral geniculate; superior colliculus; pretectal/parafascicular area; subthalamic nucleus; caudate-putamen complex; globus pallidus; entopeduncular nucleus; substantia nigra; medial septal nucleus/vertical limb of the diagonal band area; magnocellular preoptic/ventral pallidal area; and lateral hypothalamus. In some animals, separate injections of propidium iodide and true blue were made into two different regions in the same rat brain, usually a dorsal and a ventral target, in order to assess collateralization patterns. Retrogradely transported fluorescent labels and ChAT and/or AChE were analyzed microscopically on the same brain section. All of the above-delimited targets were found to receive cholinergic input from the PMT cholinergic complex, but some regions were preferentially innervated by either the pedunculopontine or dorsolateral tegmental nucleus. The former subdivision of the PMT cholinergic complex projected selectively to extrapyramidal structures and the superior colliculus, whereas the dorsolateral tegmental nucleus was observed to provide cholinergic input preferentially to anterior thalamic regions and rostral portions of the basal forebrain. The PMT cholinergic neurons showed a tendency to collateralize extensively.

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    • "MS - vDBB is known to receive inputs from the pedunculopontine tegmental nucleus and laterodorsal tegmental nucleus . These cholinergic brainstem nuclei exert influence on MS - vDBB and theta generation both via direct afferents to MS - vDBB ( Woolf and Butcher , 1986 ; Hallanger and Wainer , 1988 ) and via an indirect route through the supramammillary and posterior hypothalamic nuclei ( Kirk and McNaughton , 1991 ; Oddie et al . , 1994 ) . "
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    • "Morphologically similar ChAT? neurons occur in the PPNd, but these neurons are less numerous and more widely distributed than those in the PPNc. Overall, the density of ChAT? neurons in the two parts of the PPN is lower than in the laterodorsal tegmental nucleus (LTD), a ACh brainstem nucleus that is known to innervate massively the thalamus (Sofroniew et al. 1985; Woolf and Butcher 1986; Hallanger et al. 1987; Steriade et al. 1988; Paré et al. 1988). A careful examination of coronal, sagittal and horizontal sections immunostained for ChAT has revealed that the labeled axons originating from ChAT? neurons in the PPN form a diffuse bundle that ascends within the midbrain tegmentum . "
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    • "Sources of ACh to exert this modulation are the PPN (Charara and Parent 1994; Mena-Segovia et al. 2004; Woolf and Butcher 1986) and some cholinergic neurons within or in the vicinity of the GPe (Bengtson and Osborne 2000; Rodrigo et al. 1998). PPN afferents also reach the Str (Dautan et al. 2014; Mena-Segovia et al. 2004; Woolf and Butcher 1986), although a main cholinergic source in this nucleus comes from interneurons (Wilson et al. 1990). "
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