Thyroid Hormone Sensitizes the Imprinting-Associated Induction of Biological Motion Preference in Domestic Chicks.

ABSTRACT: Filial imprinting is associated with induction of predisposed preference to animations that bear visual features of Johansson's biological motion (BM), and the induction is limited to a few days after hatching. As thyroid hormone (3,5,3'-triiodothyronine, T₃) plays a critical role in determining the sensitive period of imprinting, we examined if exogenously applied T₃ (or iopanoic acid, IOP; a selective inhibitor for converting enzymes) could also sensitize (or desensitize) the BM induction. Chicks were trained by using a non-BM stimulus (rotating red toy) according to a conventional imprinting procedure. Trained chicks were tested for preference to a point-light BM animation (walking chick) over a non-BM animation (linear motion), and for the preference for the familiarized stimulus (red toy) over an unfamiliar one (yellow toy). In 1-day chicks, those injected with IOP showed significantly lower scores than controls on both BM and imprinting tests. In 4-days chicks, those injected with T₃ showed higher scores than control, but the difference in BM score was not significant. Imprinting and the accompanying T₃ surge may be necessary for the predisposed BM preference to appear in 1-day chicks. Even after the conventional sensitive period is over, exogenous T₃ can partly re-sensitize the BM preference as it does imprinting.

SUBMITTER: Miura M 

PROVIDER: S-EPMC6305540 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature