Fig. 12. Internal object motion does not affect the initial response or habituation
of DCMDs to repeated looming stimuli. (Ai) Sample raster plots of sequences of
15 approaches (4 s intervals) of a `bird' from 0° azimuth (top rasters) or
of a `bird' from 0° azimuth with an additional roll component (bottom
rasters). The subtense angle of the `bird' wing (Bw) and
`bird' body (Bb) during an approach (Aii, top) are the
same for both stimulus types. The roll angle about the `bird's longitudinal
axis during an approach is shown in (Aii, bottom). Note that the spike trains
for each approach number were similar for each type of stimulus and that spike
trains did not phase-lock to the roll angle. (Bi) The peak spike rate, (Bii)
the spike rate 200 ms before collision and (Biii) the number of spikes of the
pooled right and left DCMDs during approaches 1 and 15 were compared between
the different stimulus types. There were no significant differences
(Kruskal–Wallis ANOVA on ranks; see text) in any of the measured
parameters compared during approach 1 or during approach 15. Data plotted are
the mean ± S.D. (N=11; significant differences as
in Fig. 6).