A PHA‐L analysis of ascending projections of the dorsal raphe nucleus in the rat
- 22 November 1991
- journal article
- research article
- Published by Wiley in Journal of Comparative Neurology
- Vol. 313 (4), 643-668
- https://doi.org/10.1002/cne.903130409
Abstract
Ascending projections from the dorsal raphe nucleus (DR) were examined in the rat by using the anterograde anatomical tracer, Phaseolus vulgaris leucoagglutinin (PHA-L). The majority of labeled fibers from the DR ascended through the forebrain within the medial forebrain bundle. DR fibers were found to terminate heavily in several subcortical as well as cortical sites. The following subcortical nuclei receive dense projections from the DR: ventral regions of the midbrain central gray including the ‘supraoculomotor central gray’ region, the ventral tegmental area, the substantia nigra-pars compacta, midline and intralaminar nuclei of the thalamus including the posterior paraventricular, the parafascicular, reuniens, rhomboid, intermediodorsal/mediodorsal, and central medial thalamic nuclei, the central, lateral and basolateral nuclei of the amygdala, posteromedial regions of the striatum, the bed nucleus of the stria terminalis, the lateral septal nucleus, the lateral preoptic area, the substantia innominata, the magnocellular preoptic nucleus, the endopiriform nucleus, and the ventral pallidum. The following subcortical nuclei receive moderately dense projections from the DR: the median raphe nucleus, the midbrain reticular formation, the cuneiform/pedunculopontine tegmental area, the retrorubral nucleus, the supramammillary nucleus, the lateral hypothalamus, the paracentral and central lateral intralaminar nuclei of the thalamus, the globus pallidus, the medial preoptic area, the vertical and horizontal limbs of the diagonal band nuclei, the claustrum, the nucleus accumbens, and the olfactory tubercle. The piriform, insular and frontal cortices receive dense projections from the DR; the occipital, entorhinal, perirhinal, frontal orbital, anterior cingulate, and infralimbic cortices, as well as the hippocampal formation, receive moderately dense projections from the DR. Some notable differences were observed in projections from the caudal DR and the rostral DR. For example, the hippocampal formation receives moderately dense projections from the caudal DR and essentially none from the rostral DR. On the other hand, virtually all neocortical regions receive significantly denser projections from the rostral than from the caudal DR. The present results demonstrate that dorsal raphe fibers project significantly throughout widespread regions of the midbrain and forebrain.Keywords
This publication has 100 references indexed in Scilit:
- Dorsal raphe serotoninergic branching neurons projecting both to the lateral geniculate body and superior colliculus: A combined retrograde tracing–immunohistochemical study in the ratJournal of Comparative Neurology, 1988
- Serotoninergic innervation of the cat cerebral cortexJournal of Comparative Neurology, 1988
- Brainstem afferents to the magnocellular basal forebrain studied by axonal transport, immunohistochemistry, and electrophysiology in the ratJournal of Comparative Neurology, 1988
- The entorhinal cortex of the monkey: III. Subcortical afferentsJournal of Comparative Neurology, 1987
- The afferent connections of the substantia innominata in the monkey,Macaca fascicularisJournal of Comparative Neurology, 1985
- Subcortical projections to lateral geniculate and thalamic reticular nuclei in the hooded ratJournal of Comparative Neurology, 1983
- The distribution and origin of serotonin‐containing fibers in the septal area: A combined immunohistochemical and fluorescent retrograde tracing study in the ratJournal of Comparative Neurology, 1982
- Organization of diencephalic and brainstem afferent projections to the lateral septum in the ratNeuroscience Letters, 1982
- Evidence for two organizational plans within the somatic sensory‐motor cortex of the ratJournal of Comparative Neurology, 1979
- Superior colliculus connections with the extraocular motor nuclei in the catJournal of Comparative Neurology, 1978