Abstract
Purpose: :
During visual system development, sensitivity to motion and fine detail acquisition are separated, with quality of vision having a key role in structuring the neuronal circuitry. Monocular deprivation early in life results in acuity deficits, while early binocular deprivation severely impairs motion perception. Binocular pattern deprivation is nevertheless reflected by long-lasting anatomical changes in the neuronal circuitry of the central retina. Under normal circumstances the central retina is predominantly associated with acuity, while the peripheral retina is associated with motion. Consequently damaging central retina leads to dramatic acuity deficits, while the outcome for motion has not yet been described.
Methods: :
Motion and acuity thresholds were established after central retinal lesions in two groups of adult cats. Controls had normal visual experience prior to the induction of central retinal lesions and completed extended motion training (more than one year). Binocular-deprived cats (6 months mask-rearing from eyelid opening) displayed severe motion perception deficits as demonstrated by performance in motion training. All animals were familiarized to the stationary acuity tests the week before lesioning. Two weeks post-lesion, regular visual testing started for 3 months. The performance on three familiar motion tasks was verified twice a week, and on a separate day the acuity measurements were carried out using sinusoidal gratings.
Results: :
In control cats the retinal lesions resulted in an initial decrease in motion performance, followed by a period of significant improvement at 5 weeks post-lesion. The binocularly deprived cats displayed a permanently impaired motion performance independent of the retinal lesioning. In controls spatial frequency thresholds remained constant whereas in binocular deprived cats spatial frequency thresholds increased by a factor 4 in the 3 months post-lesion.
Conclusions: :
Thus, central retinal lesions in binocularly deprived cats may trigger the peripheral retina to recruit the visual system for stationary fine detail analysis.
Keywords: plasticity • visual development • retina