Monocular sleep following passive avoidance learning in chicks.

Monocular sleep following passive avoidance learning was investigated in young chicks. One group of animals (Experimental Group) was presented with a bead coated with an aversive substance; a second group (Control Group 1) underwent bead presentations as in the Experimental Group but with the bead coated with water rather than with the aversive substance, and a third group (Control Group 2) did not undergo to any bead presentation. Binocular and monocular sleep was recorded during the 8 h subsequent the learning (or the control) event. The main results were that (1) the percentage of time spent in binocular sleep and the percentage of episodes of binocular sleep were lower in the Experimental Group that in the Control Groups; (2) the times spent in monocular sleep was higher in the Experimental Group and progressively lower in Control Group 1 and Control Group 2; (3) chicks slept predominantly with their left eye closed, but there was no evidence of specific changes in the opening of t...