Research article

Imprinting modulates processing of visual information in the visual wulst of chicks

Fumihiko Maekawa^1,2,3 , Okiru Komine¹ , Katsushige Sato⁴ , Tomoyuki Kanamatsu⁵ , Motoaki Uchimura¹ , Kohichi Tanaka¹ and Hiroko Ohki-Hamazaki^1,6

¹  Laboratory of Molecular Neuroscience, School of Biomedical Science and Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 113-8519, Japan

²  Japan Society for the Promotion of Science, Chiyoda-ku, Tokyo 102-8471, Japan

³  Department of Physiology, Division of Integrative Physiology, Jichi Medical University, Shimotsuke, Tochigi 329-0498, Japan

⁴  Department of Physiology and Cell Biology, Tokyo Medical and Dental University Graduate School and Faculty of Medicine, Bunkyo-ku, Tokyo 113-8519, Japan

⁵  Department of Environmental Engineering for Symbiosis, Faculty of Engineering, Soka University, Hachioji, Tokyo 192-8577, Japan

⁶  "Recognition and Formation", Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan

author email corresponding author email

BMC Neuroscience 2006, 7:75doi:10.1186/1471-2202-7-75

Published:	14 November 2006

Abstract

Background

Imprinting behavior is one form of learning and memory in precocial birds. With the aim of elucidating of the neural basis for visual imprinting, we focused on visual information processing.

Results

A lesion in the visual wulst, which is similar functionally to the mammalian visual cortex, caused anterograde amnesia in visual imprinting behavior. Since the color of an object was one of the important cues for imprinting, we investigated color information processing in the visual wulst. Intrinsic optical signals from the visual wulst were detected in the early posthatch period and the peak regions of responses to red, green, and blue were spatially organized from the caudal to the nasal regions in dark-reared chicks. This spatial representation of color recognition showed plastic changes, and the response pattern along the antero-posterior axis of the visual wulst altered according to the color the chick was imprinted to.

Conclusion

These results indicate that the thalamofugal pathway is critical for learning the imprinting stimulus and that the visual wulst shows learning-related plasticity and may relay processed visual information to indicate the color of the imprint stimulus to the memory storage region, e.g., the intermediate medial mesopallium.