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Pattern discrimination and visuomotor behaviour after monocular visual deprivation in cats
EBBS ABSTRACTS
359
should play a secondary role. In the first set of experiments the spatial factor was examined by modifying the position of Sz relative to $1. We found that the inhibitory effect was present when $2 was positioned above, below, to the right or to the left of the receptive field stimulated by $1. When $2 was positioned along a given meridian of the visual field at progressively greater distances from the unit receptive field the intensity of the effect remained constant. In the second set of experiments the temporal factor was examined by introducing $2 either simultaneously with or at a variety of intervals before the entrance of $1 into the unit receptive field. $2 was repetitively moved at a uniform speed along a fixed position of the visual field until $1 crossed the unit receptive field. We found the inhibitory effect to be strongest when $2 was presented simultaneously with entrance of $1 into the unit receptive field and to progressively decay in strength as the interval between the two stimuli increased. When the interval was 3 sec or greater, the inhibitory effect was no longer present. These findings are consistent with the idea that the inhibitory effect may play a role in the selection between two visual stimuli.
1 CAMARDA,R., GRUPP, L. A., PISA, M., AND RIZZOLATTI, G., Response properties of superior colliculus unit: effect of extra-receptive field stimuli, Brain Research,49 (1972) 504.
Pattern discrimination and visuomotor behaviour after monocular visual deprivation in cats J. VAN HOF-VAN DUIN - - D e p a r t m e n t of Physiology, Erasmus University Rotterdam,
Rotterdam (The Netherlands) Visuomotor behaviour and pattern discrimination were studied in 13 cats in which the lids of one eye were sutured after birth. At the age of 8-10 months the visually naive eye was opened and the non-deprived eye sutured. Visuomotor tests (optokinetic nystagmus, tracking, visual placing responses, visual cliff, jumping behaviour) were made before and after reversed closure. Twelve months after reversed closure visuomotor defects were still present, although behaviour in several tests improved in the course of time. In a perimetry test for instance the size of the visual field was found to expand considerably. The slow and partial recovery of visuomotor behaviour was in marked contrast with the ability to discriminate patterns in a training box which required no sophisticated visuomotor coordination. In several animals it was found that as soon as 6 weeks after reverse closure discrimination of striated patterns was normal, both in accuracy and rate of learning. In other words: the behavioural disturbances after monocular deprivations are due to insufficiencies of visuomotor behaviour rather than to pattern identification.
359
should play a secondary role. In the first set of experiments the spatial factor was examined by modifying the position of Sz relative to $1. We found that the inhibitory effect was present when $2 was positioned above, below, to the right or to the left of the receptive field stimulated by $1. When $2 was positioned along a given meridian of the visual field at progressively greater distances from the unit receptive field the intensity of the effect remained constant. In the second set of experiments the temporal factor was examined by introducing $2 either simultaneously with or at a variety of intervals before the entrance of $1 into the unit receptive field. $2 was repetitively moved at a uniform speed along a fixed position of the visual field until $1 crossed the unit receptive field. We found the inhibitory effect to be strongest when $2 was presented simultaneously with entrance of $1 into the unit receptive field and to progressively decay in strength as the interval between the two stimuli increased. When the interval was 3 sec or greater, the inhibitory effect was no longer present. These findings are consistent with the idea that the inhibitory effect may play a role in the selection between two visual stimuli.
1 CAMARDA,R., GRUPP, L. A., PISA, M., AND RIZZOLATTI, G., Response properties of superior colliculus unit: effect of extra-receptive field stimuli, Brain Research,49 (1972) 504.
Pattern discrimination and visuomotor behaviour after monocular visual deprivation in cats J. VAN HOF-VAN DUIN - - D e p a r t m e n t of Physiology, Erasmus University Rotterdam,
Rotterdam (The Netherlands) Visuomotor behaviour and pattern discrimination were studied in 13 cats in which the lids of one eye were sutured after birth. At the age of 8-10 months the visually naive eye was opened and the non-deprived eye sutured. Visuomotor tests (optokinetic nystagmus, tracking, visual placing responses, visual cliff, jumping behaviour) were made before and after reversed closure. Twelve months after reversed closure visuomotor defects were still present, although behaviour in several tests improved in the course of time. In a perimetry test for instance the size of the visual field was found to expand considerably. The slow and partial recovery of visuomotor behaviour was in marked contrast with the ability to discriminate patterns in a training box which required no sophisticated visuomotor coordination. In several animals it was found that as soon as 6 weeks after reverse closure discrimination of striated patterns was normal, both in accuracy and rate of learning. In other words: the behavioural disturbances after monocular deprivations are due to insufficiencies of visuomotor behaviour rather than to pattern identification.