Intrinsic Variability of Ocular Dominance Column Periodicity in Normal Macaque Monkeys

AbstractWe analyzed the immunohistochemical distribution of the two calcium-binding proteins, parvalbumin (PV) and calbindin D-28k (CB), in the primary visual cortex and lateral dorsal geniculate nucleus (dLGN) of monocularly enucleated macaque monkeys (Macaca fascicularis and Macaca nemestrind) in order to determine how the expression of PV and CB is affected by functional inactivity. The monkeys survived 1–17 weeks after monocular enucleation. The distribution pattern of each of the proteins was examined immunocytochemically using monoclonal antibodies and compared with that of the metabolic marker cytochrome oxidase (CO). We recorded manually the number of immunostained neurons and estimated the concentration of immunoreactive staining product using a computerized image-acquisition system. Our results indicate a decrease of approximately 30% in the labeling of PV-immunoreactive (ir) neuropil particularly in those layers of denervated ocular-dominance columns receiving the geniculocortical input. There was no change in the number of PV-ir neurons in any compartment irrespective of the enucleation interval. For CB-ir, we found a 20% decrease in the neuropil labeling in layer 2/3 of the denervated ocular-dominance columns. In addition, a subset of pyramidal CB-ir neurons in layers 2 and 4B, which are weakly stained in control animals, showed decreased labeling. In the dLGN of enucleated animals, PV-ir and CB-ir were decreased only in the neuropil of the denervated layers.From these results, we conclude that cortical interneurons and geniculate projection neurons still express PV and CB in their cell bodies after disruption of the direct functional input from one eye. The only distinct decrease of PV and CB expression is seen in axon terminals from retinal ganglion cells in the dLGN, and in the axons and terminals of both geniculocortical projection cells and cortical interneurons in the cerebral cortex.

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Analysis of the postnatal growth of visual cortex

Visual Neuroscience ◽

10.1017/s0952523898155049 ◽

1998 ◽

Vol 15 (5) ◽

pp. 831-839 ◽

Cited By ~ 21

Author(s):

KEVIN R. DUFFY ◽

KATHRYN M. MURPHY ◽

DAVID G. JONES

Keyword(s):

Visual Cortex ◽

Mammalian Species ◽

Ocular Dominance ◽

Postnatal Growth ◽

Global Features ◽

Macaque Monkeys ◽

Dimensional Shape ◽

Visual Cortical ◽

Isotropic Expansion ◽

Retinotopic Map

Development and growth of V1 begins during embryogenesis and continues postnatally. The growth of V1 has direct implications on the organization of features such as the retinotopic map and the pattern of visual cortical columns. We have examined the postnatal growth and two-dimensional shape of V1 in macaque monkeys, cats, and rats. The perimeter, area, and anterior–posterior length of V1 were measured from unfolded and flattened sections from neonatal and adult animals from each of these species. Although there were substantial differences in the overall amount of postnatal growth, from 18% in macaque monkeys to more than 100% in cats, in all three species the shape of V1 did not change during development. Thus, growth of the mammalian visual cortex is well described as an isotropic expansion, so the layout of the global features, such as the arrangement of ocular dominance columns and the retinotopic map, does not need to change during development. Furthermore, quantification of the shape confirms the observations that there is a similar, egg-like oval shape to the visual cortex of these mammalian species.

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