Independence of Echo-Threshold and Echo-Delay in the Barn Owl
(A) Responses evoked during the lead-alone (open, blue, squares) and lag-alone (closed, red, squares) segments. Each data point represents the median number of spikes, normalized to the average response evoked, in each cell, by 30 ms sounds (>50 repetitions) presented from the center of its SRF . Vertical lines indicate the first and third quartiles of each response. The upper row of numbers along the abscissa represents the onset-delay and the bottom row represents the length of each segment. (B) Responses evoked during the superposed segments when the target led (open, blue, squares) or lagged (closed, red, squares). Responses evoked by two, simultaneous, uncorrelated, noise-bursts from the target and masker loci are indicated by black diamonds (A,B). Note that the ordinate axis in panel B is expanded relative to that of panel A.