Cholinergic and monoaminergic innervation of the cat's thalamus: Comparison of the lateral geniculate nucleus with other principal sensory nuclei
- 9 October 1989
- journal article
- research article
- Published by Wiley in Journal of Comparative Neurology
- Vol. 288 (4), 647-675
- https://doi.org/10.1002/cne.902880411
Abstract
The cholinergic and monoaminergic innervation of the lateral geniculate nucleus (GL) and other thalamic nuclei in the cat was examined by using immunocytochemical and tract‐tracing techniques. Cholinergic fibers, identified with an antibody to choline acetyltransferase (ChAT), are present in all layers of the GL. They are fine in caliber and exhibit numerous swellings along their lengths. The A layers, the magnocellular C layer, and the medial interlaminar nucleus are rich in cholinergic fibers that give rise to prominent clusters of boutons, while the parvicellular C layers contain fewer fibers that are more uniformly distributed. The interlaminar zones are largely devoid of ChAT‐immunoreactive fibers. Double‐label experiments show that cholinergic projections to the GL originate from two sources, the pedunculopontine reticular formation (PPT) and the parabigeminal nucleus (Pbg). The PPT contributes cholinergic fibers to all layers, while Pbg projections are limited to the parvicellular C layers. The lateral geniculate nucleus has a much greater density of cholinergic fibers than the other principal sensory nuclei: the density of fibers in the A layers is more than three times greater than that in the ventral posterior nucleus (VP) or the ventral division of the medial geniculate nucleus (GMv). In contrast, serotonin (5‐HT)‐immunoreactive fibers are distributed with equal density across the principal thalamic nuclei, while tyrosine hydroxylase (TH)‐immunoreactive fibers (presumed to contain norepinephrine) are noticeably less dense in the GL than in the others. Monoaminergic fibers also differ from cholinergic fibers in their laminar distribution within the GL: both TH‐ and 5HT‐immunoreactive fibers are distributed evenly across the layers and interlaminar zones and are slightly more abundant in the parvicellular C layers than in the other layers. Other thalamic nuclei rich in cholinergic fibers include the pulvinar nucleus, the ventral lateral geniculate nucleus, the intermediate nucleus of the lateral group, the lateral medial and suprageniculate nuclei (Graybiel and Berson: Neuroscience 5: 1175–1238, '80), and the paracentral and central‐lateral components of the intralaminar nuclei. This pattern matches the distribution of projections from the PPT and is similar, but not identical, to the pattern of acetylcholinesterase staining. The fact that most of the nuclei rich in cholinergic fibers have been implicated in visual sensory or visual motor functions suggests that cholinergic projections from the reticular formation play an especially important role in visually guided behavior.Keywords
This publication has 96 references indexed in Scilit:
- Cholinergic projections from the midbrain reticular formation and the parabigeminal nucleus to the lateral geniculate nucleus in the tree shrewJournal of Comparative Neurology, 1988
- The serotoninergic fibers in the dorsal lateral geniculate nucleus of the cat: Distribution and synaptic connections demonstrated with immunocytochemistryJournal of Comparative Neurology, 1987
- Choline acetyltransferase immunoreactivity in the rat thalamusJournal of Comparative Neurology, 1987
- Projections from the parabigeminal nucleus to the dorsal lateral geniculate nucleus in the tree shrew Tupaia glisJournal of Comparative Neurology, 1986
- Distribution of acetylcholinesterase in the geniculo striate system ofGalago senegalensis andAotus trivirgatus: Evidence for the origin of the reaction product in the lateral geniculate bodyJournal of Comparative Neurology, 1980
- Norepinephrine and serotonin: Opposite effects on the activity of lateral geniculate neurons evoked by optic pathway stimulationExperimental Neurology, 1980
- Acetylcholinesterase and the cholinergic neuronLife Sciences, 1979
- Anatomical evidence of a third ascending vestibular pathway involving the ventral lateral geniculate nucleus and the intralaminar nuclei of the catBrain Research, 1979
- Connections of the pretectum in the catJournal of Comparative Neurology, 1977
- Determination of the transfer ratio of cat's geniculate neurons through quasi-intracellular recordings and the relation with the level of alertnessExperimental Brain Research, 1972