Neuronal and synaptic organization of the normal dorsal lateral geniculate nucleus of the squirrel monkey,Saimiri sciureus

1972 ◽  
Vol 144 (1) ◽  
pp. 25-59 ◽  
Author(s):  
Margaret T. T. Wong-Riley
Keyword(s):  
Squirrel Monkey ◽  
Lateral Geniculate Nucleus ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Saimiri Sciureus ◽  
Synaptic Organization ◽  
Lateral Geniculate ◽  
Dorsal Lateral Geniculate

Quantitative analyses of synaptic contacts of interneurons in the dorsal lateral geniculate nucleus of the squirrel monkey

1996 ◽  
Vol 13 (6) ◽  
pp. 1129-1142 ◽  
Author(s):  
James R. Wilson ◽  
Donna M. Forestner ◽  
Ryan P. Cramer
Keyword(s):  
Squirrel Monkey ◽  
Lateral Geniculate Nucleus ◽  
Receptive Fields ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Saimiri Sciureus ◽  
Projection Neurons ◽  
Parvocellular Pathway ◽  
Synaptic Contacts ◽  
Lateral Geniculate ◽  
Dorsal Lateral Geniculate

AbstractThree interneurons were recorded from and then injected with horseradish peroxidase in the parvocellular laminae of the squirrel monkey's (Saimiri sciureus) dorsal lateral geniculate nucleus. They were then examined using the electron microscope for their synaptic contacts, both the afferent contacts onto their dendrites and their presynaptic dendritic contacts onto presumptive projection (relay) neuron dendrites. The somata of these interneurons were small (mean = 178 μm2), but the dendritic trees were large compared with those of projection neurons. All three interneurons had similar synaptic patterns onto their dendrites with about equal numbers of retinal, cortical, and GABAergic contacts. The distribution of these contacts was more uniform compared with the same types of contacts made onto projection neurons. The presynaptic dendrites were observed to contact only the dendrites of presumptive projection neurons, and these contacts were nearly all in the form of geniculate triads. None of the three interneurons displayed an axon. The receptive fields of these interneurons were similar to those of projection cells, but were larger and had center-response signs that were the opposite of the projection neurons around them (e.g. OFF center for the dorsal part of the parvocellular mass where ON-center projection neurons reside). The squirrel monkey data provides additional evidence that one aspect of the laminar pattern observed in the parvocellular pathway of the primate's dLGN might be related to a segregation of projection neurons of one center-response sign with interneurons of the opposite center-response sign.

How much feedback from visual cortex to lateral geniculate nucleus in cat: A perspective

2004 ◽  
Vol 21 (4) ◽  
pp. 487-500 ◽  
Author(s):  
JULIAN M.L. BUDD
Keyword(s):  
Lateral Geniculate Nucleus ◽  
Sensory Information ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Synaptic Organization ◽  
Lateral Geniculate ◽  
Order Of Magnitude ◽  
Efferent Neurons ◽  
Cortical Synapses ◽  
Corticothalamic Feedback ◽  
Dorsal Lateral Geniculate

Corticothalamic feedback is believed to play an important role in selectively regulating the flow of sensory information from thalamus to cortex. But despite its importance, the size and nature of corticothalamic pathway connectivity is not fully understood. In light of recent empirical data, the aim of this paper was to quantify the contribution of area 17 axon connectivity to the synaptic organization of A-laminae in dorsal lateral geniculate nucleus (dLGN) in cat, the best studied corticothalamic pathway. Numerical constraints indicate that most corticogeniculate synapses are not formed with inhibitory interneurons. However, the main finding is that there was an order of magnitude difference between estimates of the mean number of cortical synapses per A-laminae neuron based on individual corticogeniculate axon data (12,000–16,000 cortical synapses per cell) than that previously derived from partial reconstructions of the synaptic input to two physiologically identified relay cells (1200–1500 cortical synapses per cell). In an attempt to reconcile these different estimates, parameter variation and comparative analyses suggest that previous work may have overestimated the density of corticogeniculate efferent neurons and underestimated the total number of synapses per geniculate neuron. But as this analysis did not include area 18 corticogeniculate axons innervating A-laminae, the discrepancy between different estimates may be greater and require further explanation. Thus, the analysis presented here suggests geniculate neurons receive on average a greater number of cortical synapses per cell but from far fewer corticogeniculate axons than previously thought.

scholarly journals Synaptic organization of thalamocortical axon collaterals in the perigeniculate nucleus and dorsal lateral geniculate nucleus

2008 ◽  
Vol 508 (2) ◽  
pp. 264-285 ◽  
Author(s):  
Martha E. Bickford ◽  
Haiyang Wei ◽  
Michael A. Eisenback ◽  
Ranida D. Chomsung ◽  
Arkadiusz S. Slusarczyk ◽  
...  
Keyword(s):  
Lateral Geniculate Nucleus ◽  
Dorsal Lateral Geniculate Nucleus ◽  
Synaptic Organization ◽  
Perigeniculate Nucleus ◽  
Lateral Geniculate ◽  
Axon Collaterals ◽  
Dorsal Lateral Geniculate
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