Effect of monocular deprivation on binocular neurones in the owl's visual Wulst

Abstract

DESPITE the two hundred million years during which their evolutionary history was different from mammals, birds possess a central visual apparatus with surprising functional similarities to the striate cortex of cats and monkeys¹. The visual Wulst² of the owl contains neurones which can be binocularly activated and which show precise selectivity for the orientation, direction of movement and binocular disparity of moving straight line contours¹, all characteristic properties of single neurones recorded from the striate cortex of cats and monkeys^3,4. We were interested to determine whether binocular neurones in the owl's Wulst are also sensitive to visual experience in the neonatal period since another important characteristic of binocular neural connections in cat and monkey visuail cortex is their extreme sensitivity to monocular deprivation during the critical period^5,6. The preliminary observations we present here, on young, monocularly-deprived owls, suggest that the functional parallel between the mammalian striate cortex and the avian Wulst extends to the phenomenon of plasticity as well.