On the structure of the human striate area. Lamina IVc?

1978 ◽  
Vol 188 (2) ◽  
Author(s):  
E. Braak
Keyword(s):  
Striate Area

Development of synapses in macaque monkey striate cortex

1992 ◽  
Vol 8 (6) ◽  
pp. 491-504 ◽  
Author(s):  
B. S. Zielinski ◽  
A. E. Hendrickson
Keyword(s):  
Striate Cortex ◽  
World Monkey ◽  
Macaque Monkey ◽  
Cortical Plate ◽  
Electron Microscopic ◽  
Synaptic Density ◽  
Synaptic Contacts ◽  
Layer 2 ◽  
Before And After ◽  
Striate Area

AbstractA quantitative electron-microscopic (EM) analysis of the development of synaptic density (number of synapses/100 μm neuropil) has been done in primary visual cortex (striate, area 17) of the Old World monkey Macaca nemesthna. A comparative EM morphological study of developing synaptic contacts also was done in the same tissue. We find that a few immature synaptic contacts are present at fetal (F) 75 days either in the marginal zone, which becomes layer 1, or in the deepest portion of the cortical plate, the future layer 6. At F90–140 days synaptic contacts are found throughout the cortical plate, but their density remains higher in lower cortical layers. By F140 days synaptic density averaged for all layers (10.9) is three times higher than at F90 days. Just before and after birth, synaptic density rises very rapidly to peak at postnatal (P)12 weeks (63) and then declines slowly to reach adult values (37.7) between 2–6 years. This pattern was further tested by comparing synaptic density in layer 2 which contains the last cells generated in the striate cortex to that in layer 6 which contains the first cells generated in the striate cortex. Layer 6 contained the first synapses, and had a higher density up to F140 days (an “inside-to-outside” distribution). Synaptic density was equal in the two layers at F152 days and P2 days, but by P12 weeks synaptic density in layer 2 was 27% higher than that in layer 6 (an “outside-to-inside” distribution). After P12 weeks, the synaptic density declined 51% in layer 2 and 21% in layer 6 so that both layers achieved similar densities by P6 years.A light and EM comparison of neuropil and synaptic contact morphology finds that, at each age up to birth, synapses in layer 2 are generally less mature than those in layer 6, but these differences disappear shortly after birth. Between P6–24 weeks, synaptic contacts throughout the cortex acquire a mature morphology that clearly differentiates between asymmetric and symmetric types, although asymmetric contacts continue to acquire more postsynaptic density until adulthood.This complex developmental pattern suggests a sequence for synaptic developments which is more related to neuron birthdate than to the arrival of extrinsic pathways or developmental events occurring in specific laminae.

The striate area of primates

1942 ◽  
Vol 77 (2) ◽  
pp. 405-429 ◽  
Author(s):  
Gerhardt von Bonin
Keyword(s):  
Striate Area

scholarly journals Asymmetrical representation of the upper and lower visual fields in oculomotor maps

2016 ◽  
Author(s):  
Zhiguo Wang ◽  
Benchi Wang ◽  
Matthew Finkbeiner
Keyword(s):  
Visual Field ◽  
Visual Fields ◽  
Saccade Target ◽  
Lower Visual Field ◽  
Visually Guided ◽  
Fixation Stimulus ◽  
Visual Distractor ◽  
Upper Visual Field ◽  
Striate Area

The striate area devoted to the lower visual field (LVF) is larger than that devoted to the upper visual field (UVF). A similar anatomical asymmetry also exists in the LGN. Here we take advantage of two experimental tasks that are known to modulate the direction and amplitude of saccades to demonstrate a visual field asymmetry in oculomotor maps. Participants made visually guided saccades. In Experiment 1, the saccade target was accompanied by a visual distractor. The distractor's presence modulated the direction of saccades, and this effect was much stronger for LVF targets. In Experiment 2, the temporal gap between the offset of the fixation stimulus and the onset of the saccade target was manipulated. This manipulation modulated the amplitude of saccades and this modulation was stronger for saccades towards UVF targets. Taken together, these results suggest that the representation of both meridians and eccentricities in the LVF is compressed in oculomotor maps.

The topography and variability of the primary visual cortex in man

1974 ◽  
Vol 40 (6) ◽  
pp. 747-755 ◽  
Author(s):  
Suzanne S. Stensaas ◽  
Donald K. Eddington ◽  
William H. Dobelle
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Occipital Lobe ◽  
Quantitative Information ◽  
Visual Prosthesis ◽  
Content Type ◽  
Topographical Anatomy ◽  
Calcarine Fissure ◽  
Conservative Values ◽  
Striate Area

✓ The topographical anatomy of the primary visual cortex in man was studied by macroscopic identification and measurement of the line of Gennari on coronal sections from 52 hemispheres collected at autopsy. Computer analysis of these data provided detailed, quantitative information concerning the amount, variability, and distribution of the striate area on the surface of the occipital lobe, and within the calcarine fissure and other sulci. This information is particularly applicable to the development of a functional visual prosthesis for the blind based on stimulation of the visual cortex. Taking conservative values for two-point discrimination (3 mm) on the cortex based on previous observations made during neurosurgical operations, and the surgically accessible areas available for stimulation reported in this study, it seems clear that a useful number of electrodes could be implanted in virtually every patient.

Large layer VI neurons of monkey striate cortex (Meynert cells) project to the superior colliculus

1983 ◽  
Vol 219 (1214) ◽  
pp. 53-59 ◽  
Keyword(s):  
Visual Cortex ◽  
Superior Colliculus ◽  
Striate Cortex ◽  
Pyramidal Cells ◽  
Different Populations ◽  
The Common ◽  
Layer V ◽  
Laminar Specificity ◽  
Layer Vi ◽  
Striate Area

After injections of the enzyme horseradish peroxidase (HRP) into the superior colliculus of macaque monkeys, labelled cells in the neocortex were found to be restricted to layer V in all areas except striate visual cortex. In striate visual cortex, cortico-tectal cells were found both in layer V and in layer VI. The labelled cells in the two layers belonged to morphologically different populations: those of layer V were the common pyramidal cells and those of layer VI were identified as solitary cells of Meynert. This finding may provide new insights into the physiology of the cortico-collicular pathways. It also shows that the striate area in primates differs, with respect to cortico-tectal laminar specificity, from other neocortex.

Sign in / Sign up

Export Citation Format

Share Document