Electron-microscopic analysis of synaptic input from the perigeniculate nucleus to the A-laminae of the lateral geniculate nucleus in cats

1991 ◽  
Vol 310 (3) ◽  
pp. 316-336 ◽  
Author(s):  
Josephine B. Cucchiaro ◽  
Daniel J. Uhlrich ◽  
S. Murray Sherman
Keyword(s):  
Lateral Geniculate Nucleus ◽  
Synaptic Input ◽  
Microscopic Analysis ◽  
Electron Microscopic Analysis ◽  
Electron Microscopic ◽  
Perigeniculate Nucleus ◽  
Lateral Geniculate

Quantitative light- and electron-microscopic analysis of cytochrome-oxidase distribution in neurons of the lateral geniculate nucleus of the adult monkey

1990 ◽  
Vol 4 (3) ◽  
pp. 269-287 ◽  
Author(s):  
Suyan Liu ◽  
Margaret Wong-Riley
Keyword(s):  
Cytochrome Oxidase ◽  
Cell Density ◽  
Lateral Geniculate Nucleus ◽  
Metabolic Activity ◽  
Microscopic Analysis ◽  
Electron Microscopic ◽  
Lateral Geniculate ◽  
Quantitative Analyses ◽  
Contralateral Eye ◽  
Relay Neurons

AbstractThe distribution of cytochrome oxidase (CO) in the lateral geniculate nucleus (LGN) of normal adult macaque monkeys was analyzed in quantitative light- and electron-microscope (EM) studies. Both reactive and nonreactive neurons were found throughout laminae 1–6. Darkly reactive neurons were more numerous in laminae 1, 2, and 6. Within each lamina, there was a positive correlation between cell size and level of CO activity in neurons. The cell density was greater in laminae 1, 4, and 6, which received input from the contralateral eye, than in corresponding laminae representing the ipsilateral eye (2, 3, and 5). The cell density in each of the magnocellular laminae was less than that in each of the parvicellular laminae.Three types of neurons could be distinguished within magnocellular laminae at the EM level. Types I and II were interpreted to be relay neurons, while the small size of type III qualified them to be interneurons. Two populations were found within parvicellular laminae, corresponding to relay neurons and interneurons, respectively. EM quantitative analyses revealed that the darkly reactive neurons contained a high proportion of moderate to darkly reactive mitochondria, which comprised 44.2%, 42.5%, and 39.2% of the mitochondrial population within neurons of laminae 1, 2, and 6 respectively. In contrast, a relatively low proportion of reactive mitochondria were found in neurons within laminae 3 (22.8%), 4 (26.4%), and 5 (32.4%). Moreover, magnocellular laminae contained a higher density of synapses on cell bodies than parvicellular laminae. All laminae, except layer 5, contained predominantly symmetric synapses on cell bodies. However, the proportion of symmetrical synapses in the magnocellular laminae (65.6%) was greater than that in the parvicellular laminae (59%).Our quantitative light and EM results indicate that the level of metabolic activity in neurons of the monkey LGN is higher in magnocellular, ON-center, and contralateral than in parvicellular, OFF-center, and ipsilateral visual pathways, respectively. The metabolic activity of neurons is likely to reflect the chronic level of spontaneous and synaptically evoked discharges of these cells.

Quantitative immunogold evidence for enrichment of glutamate but not aspartate in synaptic terminals of retino-geniculate, geniculo-cortical, and cortico-geniculate axons in the cat

1994 ◽  
Vol 11 (4) ◽  
pp. 675-681 ◽  
Author(s):  
Vicente M. Montero
Keyword(s):  
Lateral Geniculate Nucleus ◽  
Glial Cells ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Electron Microscopic ◽  
Thin Sections ◽  
Selective Enrichment ◽  
Perigeniculate Nucleus ◽  
Synaptic Terminals ◽  
Lateral Geniculate ◽  
Dorsal Lateral Geniculate

AbstractA postembedding immunogold procedure was used on thin sections of the dorsal lateral geniculate nucleus (LGN) and perigeniculate nucleus (PGN) of the cat to estimate qualitatively and quantitatively, at the electron-microscopic (EM) level, the intensity of glutamate or aspartate immunoreactivities on identifiable synaptic terminals and other profiles of the neuropil. On sections incubated with a glutamate antibody, terminals of retinal and cortical axons in the LGN, and of collaterals of geniculo-cortical axons in the PGN, contain significantly higher density of immunogold particles than GABAergic terminals, glial cells, dendrites, and cytoplasm of geniculate cells. By contrast, in sections incubated with an aspartate antibody, terminals of retino-geniculate, cortico-geniculate, and geniculo-cortical axons did not show a selective enrichment of immunoreactivity, but instead the density of immunogold particles was generally low in the different profiles of the neuropil, with the exception of nucleoli. These results suggest that glutamate, but not aspartate, is a neurotransmitter candidate in the retino-geniculo-cortical pathways.

Sign in / Sign up

Export Citation Format

Share Document