Figure 1.
Experimental procedures. On the day of training (1- or 4-days post-hatch), chicks received intravenous injection of IOP (iopanoic acid), T3 (triiodo-thyronine), or respective vehicle at ca. 30 min before the training started. The chick was placed on a treadmill with one LCD monitor that displayed a rotating plastic toy for 1 h twice with a 1-h interval. At 30 min after the training, the chick was tested for BM preference (walking chick vs. linear chick) twice for 5 min each, and for imprinting (familiar vs. unfamiliar). The period in which the chick stayed in the left and right arm was recorded.