The projection of the lateral geniculate nucleus to area 17 of the rat cerebral cortex. I. General description

Peters, Alan; Feldman, Martin L.

doi:10.1007/bf01176183

Cited by 295 publications

(148 citation statements)

References 47 publications

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“…Their experimental estimates of the thalamic component were in good agreement with theoretical estimates of Peters and Payne (1993). The approximation used by Peters and Feldman (1976) and Peters and Payne (1993) is now referred to as Peters's rule (Braitenberg and Schüz, 1991). They assumed that axons simply connect in direct proportion to the occurrence of all synaptic targets in the neuropil.…”

Section: Introductionsupporting

confidence: 69%

A Quantitative Map of the Circuit of Cat Primary Visual Cortex

Binzegger¹,

Douglas²,

Martin³

2004

J. Neurosci.

801

996

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We developed a quantitative description of the circuits formed in cat area 17 by estimating the "weight" of the projections between different neuronal types. To achieve this, we made three-dimensional reconstructions of 39 single neurons and thalamic afferents labeled with horseradish peroxidase during intracellular recordings in vivo. These neurons served as representatives of the different types and provided the morphometrical data about the laminar distribution of the dendritic trees and synaptic boutons and the number of synapses formed by a given type of neuron. Extensive searches of the literature provided the estimates of numbers of the different neuronal types and their distribution across the cortical layers. Applying the simplification that synapses between different cell types are made in proportion to the boutons and dendrites that those cell types contribute to the neuropil in a given layer, we were able to estimate the probable source and number of synapses made between neurons in the six layers. The predicted synaptic maps were quantitatively close to the estimates derived from the experimentalelectronmicroscopicstudiesforthecaseofthemainsourcesofexcitatoryandinhibitoryinputtothespinystellatecells,whichform a major target of layer 4 afferents. The map of the whole cortical circuit shows that there are very few "strong" but many "weak" excitatory projections, each of which may involve only a few percentage of the total complement of excitatory synapses of a single neuron.

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Section: Introductionsupporting

confidence: 69%

A Quantitative Map of the Circuit of Cat Primary Visual Cortex

Binzegger¹,

Douglas²,

Martin³

2004

J. Neurosci.

801

996

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“…In addition, we discovered a triad of synaptic elements in which an immunopositive bouton and an unstained bouton invariably contacted the neck or head of the same spine ( Fig. 2 a- WM type traditionally associated with excitatory inputs-e.g., thalamo-cortical (16,17) or cortico-cortical (16,18) afferents. We almost never observed a DA-positive axospine synapse without encountering the unstained asymmetric member ofthe triadic complex in the same or nearby sections.…”

Section: Resultsmentioning

confidence: 99%

Dopamine synaptic complex with pyramidal neurons in primate cerebral cortex.

Goldman‐Rakic

Leranth²,

Williams³

et al. 1989

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

390

242

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Dopamine (DA)-containing projections to the cerebral cortex are considered to play an important role in cognitive processes. Using a recently developed monoclonal antiserum directed against DA and an antibody directed against tyrosine hydroxylase in combination with Golgi impregnation and electron microscopy, we have observed that DA and tyrosine hydroxylase afferents establish symmetric membrane specializations with the soma, dendritic shafts, and spines of identified pyramidal cells in the prefrontal, cingulate, and motor cortex of primates. The axospinous contacts invariably formed part of a synaptic complex in which the dendritic spine of a pyramidal neuron was the target of both a DApositive symmetric and an unlabeled asymmetric bouton. This arrangement allows direct DA modulation of the overall excitability of cortical projection neurons by altering local spine responses to excitatory inputs. Dopamine (DA) has been implicated in a wide range of cognitive and affective behaviors and its importance for diseases affecting thought processes, such as schizophrenia, has been repeatedly stressed (1). Although the highest brain concentrations of DA are found in the caudate nucleus, this neurotransmitter is also present in the cerebral cortex, particularly in areas like the prefrontal cortex (2, 3) that are involved in emotional and cognitive processing. In rodents (4) and nonhuman primates (5), experimental depletion of DA has, in fact, been shown to result in cognitive deficits.A more complete understanding of DA's role in cortical function will require detailed knowledge about the cortical targets of DA afferents. The DA innervation of the primate prefrontal cortex has so far been studied only at the light microscopic level (6, 7). These studies reveal rich plexuses of DA-containing fibers in specific layers of the prefrontal cortex in monkeys (6, 7) and humans (8). However, definitive information on the postsynaptic structures innervated by these fibers is lacking. Accordingly, the goal of the present study was to provide ultrastructural data on the nature, distribution, and postsynaptic targets of dopaminergic boutons in the primate neocortex. We have used a recently available monoclonal antiserum directed against DA developed in one of our laboratories (9) as well as an antibody to its rate-limiting enzyme, tyrosine hydroxylase (TH) (10), and combined these methods with Golgi impregnation and electron microscopy (EM) to visualize DA synapses in the primate cortex. MATERIALS AND METHODSFive adult male rhesus monkey (Macaca mulatta) were deeply anesthetized and transcardially perfused using the fixative of Van Eden et al. (11) for DA and that of Somogyi and Takagi (12) for TH. After perfusion, blocks of tissue were taken from the dorsal bank of the principal sulcus (Walker's area 46), the anterior cingulate gyrus (Brodmann's area 24), and the primary motor cortex (Brodmann's area 4) (see Fig. 1) and were then sectioned perpendicular to the pial surface on a vibratome or cryostat. The sections were stai...

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“…However, as degeneration proceeds, the boutons become darker and smaller and synaptic constituents are less evident. Eventually the dcgcnerating structures are engulfed and disappear (see Peters and Feldman, 1976). …”

Section: Methodsmentioning

confidence: 99%

Effect of testosterone on input received by an identified neuron type of the canary song system: a Golgi/electron microscopy/degeneration study

et al. 1988

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Combinations of the Golgi stain, anterograde degeneration, and electron microscopy are used to further characterize the hormone-sensitive “type IV” neuron of the forebrain nucleus robustus archistriatalis (RA) of adult female canaries. Anterograde degeneration was used to “stain,” at the electron-microscopic level, the axon terminals of neurons projecting to RA from hyperstriatum ventralis, pars caudalis (HVc) and from the lateral magnocellular nucleus of the anterior neostriatum (L- MAN). The HVc neurons projecting to RA type IV cells form synapses predominantly on the dendritic spines of those cells, while L-MAN neurons that project to RA type IV cells form a 2.5:1 mixture of shaft and spine synapses. There were about 1000 synapses from HVc neurons (about 30% of all spine synapses) on typical type IV cells and about 50 synapses from L-MAN neurons. Earlier work had shown that in female canaries the dendrites of type IV neurons of the avian song control nucleus RA increase in total length after systemic testosterone treatment, and that this increase in dendritic length was accompanied by the development of malelike song. We now show that testosterone treatment also increases the number of dendritic spines present in type IV neurons. Presumably this is accompanied by an increase in the number of synaptic inputs received by type IV cells. Earlier evidence suggested that the testosterone-induced addition of extra dendritic length to type IV cells occurred at existing dendritic tips. We tested the hypothesis that these added peripheral ends received a special subset of inputs, which might then account for the change in behavior, and found it to be false. Mapping and counts of degenerating synapses resulting from lesion of HVc and L-MAN suggest that under the influence of hormone, new synapses are added throughout the dendritic tree, with no special distribution or change in ratio of inputs occurring at the tip of dendrites. Under the influence of testosterone, each type IV cell may receive only “more of the same” inputs it received before onset of treatment. We speculate on how such changes in circuitry may relate to song stability and learning.

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The projection of the lateral geniculate nucleus to area 17 of the rat cerebral cortex. I. General description

Cited by 295 publications

References 47 publications

A Quantitative Map of the Circuit of Cat Primary Visual Cortex

A Quantitative Map of the Circuit of Cat Primary Visual Cortex

Dopamine synaptic complex with pyramidal neurons in primate cerebral cortex.

Effect of testosterone on input received by an identified neuron type of the canary song system: a Golgi/electron microscopy/degeneration study

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