Cells of different sizes in the ventral nuclei project to different layers of the somatic cortex in the cat

Penny, G.R.; Itoh, Kazuyoshi; Diamond, Irving T.

doi:10.1016/0006-8993(82)90495-4

Cited by 76 publications

(27 citation statements)

References 22 publications

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“…In contrast, the mean sizes of Nissl-stained neurons in the ventral posterior nucleus range from 252 to 308 pm2 in the cat and from 178 to 198 pm2 in Galago. These values for average sizes of Nissl-stained neurons in the cat are somewhat smaller than those we have reported previously (Penny et al, 1982a). We attribute this result to differences in methods of fixation and tissue processing used in the two studies.…”

Section: Resultscontrasting

confidence: 73%

“…Small projection cells lack the thicker primary processes characteristic of the GAD-immunoreactive neurons and display no varicosities. Based on their size and cell body shape, the smallest projection neurons are very likely the same as those we earlier identified as having projections to the superficial layers of the somatic cortex (Penny et al, 1982a).…”

Section: Resultsmentioning

confidence: 61%

“…We have found evidence that small projection neurons in the ventral group of thalamic nuclei, including the ventral posterior nucleus, arborize in more superficial layers of the somatic cortex than do larger neurons (Penny et al 1982a).…”

mentioning

confidence: 78%

“…This would not permit us to argue that the cells do not project to other areas of the cortex or other centers. However, the possibility that GAD-immunoreactive cells project to other subdivisions of the somatic cortex is unlikely on the evidence from the studies of anterograde and retrograde transport (Jones and Powell, 1969;Jones, 1975a;Friedman and Jones, 1980;Koser and Hand, 1981;Spreafico et al, 1981;Penny et al, 1982a). The possibility of a projection from the GAD-positive cells of the ventral posterior nucleus to the reticular nucleus remains viable (Schiebel and Schiebel, 1966;Jones, 1975b).…”

Section: Discussionmentioning

confidence: 99%

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Glutamic acid decarboxylase-immunoreactive neurons and horseradish peroxidase-labeled projection neurons in the ventral posterior nucleus of the cat and Galago senegalensis

Penny¹,

Fitzpatrick²,

Schmechel³

et al. 1983

J. Neurosci.

116

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Immunocytochemical methods were used to identify neurons in the ventral posterior nucleus of the cat and Galago senegalensis that contain glutamic acid decarboxylase (GAD), the synthetic enzyme for the inhibitory neurotransmitter, GABA. In both species GAD-immunoreactive neurons make up about 30% of the total neurons in the ventral posterior nucleus and form a distinct class of small cells. After cortical injections of horseradish peroxidase (HRP), GAD-immunoreactive cells are not labeled with HRP and may, therefore, be GABAergic local circuit neurons. Comparison of the dendritic morphology of GAD-immunoreactive neurons with that of HRP-filled projection neurons reveals that the morphology of the GAD-containing neurons is distinct and, in particular, that the GAD-immunoreactive neurons display fewer primary dendrites. The relay neurons, in turn, can be divided into classes based on dendritic morphology and cell body size.The idea that thalamic neurons could be divided into classes based on morphological criteria has a long history. According to Rambn y Cajal (1909, the most fundamental distinction was between the neurons with long axons that project to the cerebral cortex and neurons with short axons that were thought to be local circuit neurons. Cajal found the neurons with short axons or "cellules 6 cylindre-axe court" to be distributed widely in the nervous system and to be especially numerous in the thalamus and neocortex of higher mammals. The neurons with long axons (or projection neurons) could be further subdivided into classes based on their appearance in Golgi material. T6mb61 recently (1967) identified at least two classes in the case of the somatosensory ventral posterior nucleus of the cat.

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Section: Resultscontrasting

confidence: 73%

Section: Resultsmentioning

confidence: 61%

mentioning

confidence: 78%

Section: Discussionmentioning

confidence: 99%

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Glutamic acid decarboxylase-immunoreactive neurons and horseradish peroxidase-labeled projection neurons in the ventral posterior nucleus of the cat and Galago senegalensis

Penny¹,

Fitzpatrick²,

Schmechel³

et al. 1983

J. Neurosci.

116

View full text Add to dashboard Cite

show abstract

“…The method was to restrict horseradish peroxidase (HRP) either to the superficial layers (I-III) or to layer IV and then identify cells labeled by retrograde transport of HRP. The results showed that the size of labeled neurons in VP clearly depended on the layer of their cortical target-small cells were identified after injections in cortical layer I, large cells were labeled after injections in cortical layer IV (10). Further, after an injection in the superficial layers of the striate cortex of galago, only small cells were labeled, which is to say GL layers 4 and 5 and small cells between layers (3).…”

mentioning

confidence: 94%

Calcium binding proteins distinguish large and small cells of the ventral posterior and lateral geniculate nuclei of the prosimian galago and the tree shrew (Tupaia belangeri).

Diamond

Fitzpatrick

Schmechel

1993

Proc. Natl. Acad. Sci. U.S.A.

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Two different cell types were identified in the thalamus of galago and Tupaia by using antibodies to two calcium binding proteins, calbindin and parvalbumin. In each species studied, the lateral geniculate nucleus consists of six layers, two of which have smaller relay celis. Previous studies have shown that the small cell layers receive fibers from the superior colliculus and project to the superficial layers of the striate cortex. These are the only geniculate layers that react to a calbindin antibody but not parvalbumin. The ventral posterior nucleus was included in the study and the results for both nuclei show that calbindin is a marker for thalamic cells that receive small fibers and project to superficial layers of koniocortex.

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Pallidal afferent territory of the Macaca mulatta thalamus: Neuronal and synaptic organization of the VAdc

Kultas‐Ilinsky

Reising

et al. 1997

J. Comp. Neurol.

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Ventral anterior thalamic nucleus pars densicellularis (VAdc) as delineated earlier (Ilinsky and Kultas-Ilinsky [1987] J. Comp. Neurol. 262:331-364) was analyzed by using qualitative and quantitative neuroanatomical techniques. Projection neurons (PN), retrogradely labeled with wheat germ agglutinin conjugated horseradish peroxidase from the cortex, were small to medium in size (mean area, 312 microm2) with numerous primary dendrites displaying a tufted branching pattern. Local circuit neurons (LCN), immunoreactive for gamma-aminobutyric acid (GABA) and glutamic acid decarboxylase, were small (mean area, 110 microm2), and gave off few dendrites. Two subpopulations of GABA positive boutons (F1 type) were distinguished: large (mean area, 2.6 microm2) terminals with symmetric synapses containing few pleomorphic vesicles and numerous mitochondria densely covered proximal PN sites; smaller F1 boutons with a slightly different morphology contacted mostly distal PN dendrites. Two subpopulations of terminals containing round vesicles and forming asymmetric synapses were distinguished by bouton size (mean areas, 0.4 microm2 and 1.6 microm2, respectively). These targeted mainly distal PN dendrites, but some synapsed proximally next to large F1 boutons. On distal dendrites, representatives of both types were labeled from the cortex. The density of boutons with symmetric and asymmetric synapses (the number of boutons per 100 microm of PN membrane length) was 3.3:0.2 on primary, 2.5:1.2 on secondary, and 0.8:12 on distal dendrites. The numerical density of synapses formed by presynaptic LCN dendrites on all PN levels was 20 to 40 times less than that of axon terminals at the same sites. Afferent input to LCN from boutons of all types, including that from 50% of labeled cortical boutons, mainly targeted distal dendrites. Overall, the findings suggest that PN in VAdc receive massive inhibitory input proximally intermingled with some presumably excitatory input, and that LCN contribution to PN inhibition is modest.

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Cells of different sizes in the ventral nuclei project to different layers of the somatic cortex in the cat

Cited by 76 publications

References 22 publications

Glutamic acid decarboxylase-immunoreactive neurons and horseradish peroxidase-labeled projection neurons in the ventral posterior nucleus of the cat and Galago senegalensis

Glutamic acid decarboxylase-immunoreactive neurons and horseradish peroxidase-labeled projection neurons in the ventral posterior nucleus of the cat and Galago senegalensis

Calcium binding proteins distinguish large and small cells of the ventral posterior and lateral geniculate nuclei of the prosimian galago and the tree shrew (Tupaia belangeri).

Pallidal afferent territory of the Macaca mulatta thalamus: Neuronal and synaptic organization of the VAdc

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