Filial imprinting of domestic chicks is a useful model for early learning. In imprinting, the chick follows a moving object and then memorizes it after a series of the training, even it is inanimate. Imprinting has clear sensitive period which is from hatching to day 3. Our recent study showed thyroid hormone 3,5,3'-triiodothyronine (T₃) plays critical roles for the start of the sensitive period. Even after the sensitive period closed, intravenous T₃ injection enables the chick acquire imprinting. Furthermore, direct injection of T₃ into an associative area IMM (intermediate medial mesopallium) which is necessary for imprinting recovers the sensitive period. The IMM has been intensively studied as a central neural mechanism for the imprinting. However, brain regions which are important as downstreams from IMM for imprinting is not known. In this study, we show IMHA (Intermediate hyperpallium apicaleplay), a dorsal posterior part of visual Wulst which is homologous to the primary visual cortex in mammals, plays important roles as a downstream from IMM. Bilateral ablation of IMHA prevented the acquisition of imprinting and the recovery of sensitive period induced by T₃. But direct injection of T₃ into IMHA could not enable the chick acquire imprinting, suggesting that IMHA alone is not sufficient for imprinting acquisition. On the other hand, IMHA-ablated chicks which were injected with T₃ into IMM were not imprinted. Futhermore, by using an anterograde tracer WGA (wheat-germ agglutinin) which can transfer transsynaptically, the neural connections from IMM to IMHA were detected. These results suggest the IMHA receives T₃ signaling from IMM and modulates it to acquire imprinting.