Damage to primary visual cortex (VC) in young cats
leads to severe retrograde degeneration of the dorsal lateral
geniculate nucleus (dLGN) and selective transneuronal retrograde
degeneration of a class of retinal ganglion cells (RGCs)
that have a medium-size soma. Previous studies have shown
that “programmed” RGC death associated with
normal development in one eye can be attenuated by removal
of the other eye, suggesting that binocular interactions
can influence developmental RGC death. The present study
investigated whether removal of one eye also attenuates
the ganglion cell loss that accompanies an early VC lesion.
Five one-week-old cats received a unilateral VC lesion
(areas 17, 18, and 19), and three of these cats also underwent
monocular enucleation at the same time. Two normal control
animals also were examined. RGC measurements were made
from flat-mounted retinae when the animals were 5 weeks
old. Sampling was restricted to a retinal area corresponding
to the retinotopic representation included in the VC lesion.
Results indicate that there is a marked loss of medium-size
RGCs in the hemiretinae projecting to the damaged hemisphere
in cats that received a VC lesion alone. However, there
is no such loss in VC-lesion animals that also have a monocular
enucleation. These results indicate that the transneuronal
RGC loss that occurs after an early visual cortex lesion
can be influenced by binocular interactions.
Functional organization of the cat's visual cortex after prenatal interruption of binocular interactions.
