Figure 7. Spatially cued orientation discrimination task.

(A) The sequence of stimuli for the cued-location protocol (Methods; Movie S1) is shown as a time series from left to right; only one of the multiple, interleaved target conditions is shown. Either a valid spatial cue (red circle; top) or a neutral spatial cue (two green circles; bottom) preceded the stimulus sequence: left-right mirror symmetric locations tested on interleaved trials, with the contrast of the four distractor dots varied randomly across trials. For the illustrated condition (horizontal grating), the correct response is to the box in both cases (red arrows). The visual stimuli and locations are not drawn to scale. (B) Data for the group 2 birds (C59 and C69) tested with the cued-location protocol before the OT lesion, ≤5 weeks post-lesion, and >5 weeks post-lesion. The bars indicate the difference in percent correct measured for valid versus neutrally cued trials at the lesioned location (exptl loc) and non-lesioned location (cntrol loc). Data were combined across distractor strengths. Single asterisk: p<0.05, double asterisk: p<0.01; Fisher’s exact test. Pre-lesion, C59 exhibited a cueing benefit only for targets on the right side (exptl loc: p=0.019, n= 195 trials). Following the OT lesion, the cueing benefit was reduced dramatically ≤5 weeks post-lesion (p>0.9, n=64 trials). A benefit from cueing was marginal, but not significant, at the lesioned location (exptl loc) >5 weeks post-lesion (p>0.1, n=294 trials; weeks 6–11 post-lesion). No benefit appeared at the non-lesioned location (cntrol loc) during this period (p>0.7, n=294 trials; weeks 6–11 post-lesion). Pre-lesion, C69 exhibited improved discrimination performance on both sides with cueing (exptl loc (left): p=0.037, n= 712 trials; cntrol loc (right): p=0.028, n= 712 trials). Cueing had a detrimental effect on performance at the lesioned (exptl) location (p=0.003, n=825 trials; weeks 1–5 post-lesion), while continuing to benefit performance at the cntrol location (p=0.015, n=825 trials; weeks 1–5 post-lesion). No benefit from cueing appeared at the lesioned (exptl) location up to 12 weeks post-lesion (p>0.5, n=679 trials; weeks 6–12 post-lesion), while the benefit from cueing continued at the non-lesioned (cntrol) location throughout this period (p= 0.021, n=688 trials; weeks 6–12 post-lesion).