Fig. 1.

Effects on auditory spatial acuity of depriving ferrets of patterned visual cues during development. a Testing arena used to measure the spatial acuity of adult animals at the midline. The ferrets were also tested in the lateral sound field with the loudspeakers placed symmetrically around 45° to one side. A trial was initiated when a ferret stood on the central start platform, placed its head through the head grid and made contact with the center spout. This triggered the presentation of a noise burst, which was selected at random from one of the two loudspeakers. In response, the ferret had to approach and lick the response spout positioned closest to the loudspeaker. b, c Logistic curves fitted to the psychometric functions in the lateral sound field for 4 visually-deprived ferrets. The shaded region represents the range of data from a normal-sighted control group. The stimuli were either 100 ms (b) or 40 ms (c) in duration. The performance of the visually-deprived animals was less variable than that of the sighted ferrets and their psychometric functions fell either just above or in the upper range for the control group. No difference was found, however, at the midline. Adapted, with permission, from King and Parsons (1999)