Top-down signals from the forebrain gaze fields modulate sensory responses in the barn owl OTm. A) Experimental set-up. The AGF was microstimulated (7 μA; 25 ms; 200 Hz) while responses of an OTm unit to simultaneously presented auditory stimuli were recorded in the OTm. B) The effect of AGF microstimulation on auditory spatial tuning when the centers of the receptive fields (RF) in the AGF and OTm were aligned. Dashed lines: widths at half-max response without (black) and with (red) AGF microstimulation; black arrowhead: RF center for the OTm unit; red arrowhead: RF center for the AGF site; asterisks: P< 0.02 (paired t-test). C) Same as in B, but for an AGF microstimulation site that was not aligned with the RF of the OTm unit. Black arrowhead: RF center for the OTm unit; blue arrowhead: RF center for the AGF site. Modified from Winkowski and Knudsen, 2006.