“Critical role of the novel neural circuit in the cerebrum in filial imprinting of newly hatched domestic chicks”

Filial imprinting in precocial birds is a useful model for studying early learning, as it is characterized by a well-defined sensitive or critical period. We recently showed that the thyroid hormone 3,5,3′-triiodothyronine (T₃) determines the onset of the sensitive period. Moreover, exogenous injection of T₃ into the intermediate medial mesopallium (IMM) region (analogous to the associative cortex in mammals) enables imprinting even on post-hatch day 4 or 6 when the sensitive period has been terminated. In our research project, we will reveal the functional significance of the intermediate hyperpallium apicale (IMHA) region in T₃ action. Our data showed that the bilateral excitotoxic ablation of the IMHA prevented imprinting. In addition, the ablation suppressed the recovery of the sensitive period by the localized intra-IMM injection of T₃ in day-4 chicks. These results suggest that the IMHA is critical for memory acquisition following T₃ action in the IMM and that it retains the received information from the IMM. We also detected the neural connections from the IMM to the IMHA. From our research, we will reveal the hierarchical process from the primary area (IMM) to the secondary area (IMHA) which is critical for imprinting.

 
Recent Publications
1. Yamaguchi S, Aoki N, Kitajima T, Iikubo E, Katagiri S, Matsushima T, Homma K J (2012) Thyroid hormone determines the start of the sensitive period of imprinting and primes later learning. Nat Commun 3:1081.doi:10.1038/ncomms2088.
2. Kurokawa T, Takasuga, S, Sakata, S, Yamaguchi S, Horie S, Homma K J, Sasaki T, Okamura Y (2012) 3’ phosphatase activity toward PI(3,4)P2 by voltage-sensing hosphatase,VSP. Proc Natl Acad Sci USA 109: 10089-10094.
3. Yamaguchi S, Kurokawa T, Taira I, Aoki N, Sakata S, Okamura Y, Homma, K J (2014) Potential role of voltage-sensing phosphatases in regulation of cell structure through the production of PI(3,4)P₂. J Cell Physiol 229: 422-433.

Posted:2016/03/10