title: Improved auditory spatial acuity in visually deprived ferrets.
abstract: We have examined the effects on auditory spatial acuity in the horizontal plane of depriving ferrets of patterned visual cues by binocular eyelid suture in infancy or for a comparable period in adulthood. Minimum audible angles (MAAs) were measured for 500-, 100- and 40-ms broadband noise bursts at the midline and at 45 degrees to one side. A logistic regression analysis revealed no consistent difference between the midline MAAs of normal and infant lid-sutured ferrets. However, the lateral field MAAs of the infant-deprived group were significantly smaller and showed less inter-subject variability than those of normal-sighted ferrets. The animals deprived in adulthood were tested in the lateral field only, firstly 6 months after binocular eyelid suture and again after a further 10 months. For the first test, the MAAs achieved by these animals with 500- and 100-ms noise bursts were significantly smaller than the normal values and no different from those of the infant-deprived group. A significant improvement in performance at the two shortest stimulus durations (100 and 40 ms) was observed when the adult-deprived animals were re-tested. Their second-test MAAs did not differ from those of the infant-deprived group at any of the three stimulus durations used, and both groups achieved significantly better scores than the normal-sighted control animals. These results show that prolonged visual deprivation in both juvenile and adult ferrets can lead to a significant improvement in auditory spatial acuity in the lateral sound field. This is consistent with reports that congenitally blind humans can localize peripheral sounds more accurately than normal controls.
authors.affiliation: University Laboratory of Physiology, Parks Road, Oxford OX1 3PT, UK. andrew.king@physiol.ox.ac.uk
authors.forename: A J
authors.initials: AJ
authors.lastname: King
authors.forename: C H
authors.initials: CH
authors.lastname: Parsons
mesh_terms: D000161:Acoustic Stimulation; D000818:Animals; D001309:Auditory Threshold / Q000502:physiology*; D003463:Cues; D005289:Ferrets; D019416:Head Movements; D007858:Learning; D011930:Reaction Time; D012044:Regression Analysis; D012683:Sensory Deprivation; D013017:Sound Localization / Q000502:physiology*; D014796:Visual Perception