Depth perception in cats after cerebral hemispherectomy: comparisons between neonatal- and adult-lesioned animals.
Depth perception was studied in adult cats following removal of the left cerebral hemisphere as a neonate or as an adult. Both monocular and binocular thresholds were determined using a visual cliff. Although both age-at-lesion groups showed depth perception deficits, the neonatal-lesioned animals performed much worse under binocular conditions on the visual cliff than either adult-lesioned or intact animals. This was primarily due to the lack of a binocular advantage in the neonatal-lesioned cats since their monocular thresholds were similar to that of adult-lesioned animals. Both lesioned groups showed higher monocular thresholds compared to intact animals but this effect reached significance only for the right eye. In addition, the neonatal-lesioned cats showed ocular misalignment which may have contributed to their lack of binocular depth perception. Regardless of these deficits neonatal-lesioned cats were more like intact controls regarding the types of errors made on the visual cliff. Neonatal-lesioned animals and intact controls made random errors, whereas adult-lesioned animals made most of their errors when the shallow shelf was presented on the animals' right side. This may indicate that the adult-lesioned animals have greater motor and/or visual field biases than do neonatal-lesioned cats.
Hovda
D A
DA
Department of Psychiatry, UCLA School of Medicine 90024-1759.
Villablanca
J R
JR
D000375:Aging / Q000502:physiology*; D000818:Animals; D000831:Animals, Newborn; D001931:Brain Mapping; D002415:Cats; D002540:Cerebral Cortex / Q000502:physiology*; D003290:Convergence, Ocular; D003867:Depth Perception / Q000502:physiology*; D004292:Dominance, Cerebral / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology