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


CONCLUSIONS
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.
Maekawa
Fumihiko
F
Laboratory of Molecular Neuroscience, School of Biomedical Science and Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 113-8519, Japan. fmaekawa@ms2.jichi.ac.jp <fmaekawa@ms2.jichi.ac.jp>
Komine
Okiru
O
Sato
Katsushige
K
Kanamatsu
Tomoyuki
T
Uchimura
Motoaki
M
Tanaka
Kohichi
K
Ohki-Hamazaki
Hiroko
H
D000818:Animals; D000831:Animals, Newborn; D001522:Behavior, Animal / Q000502:physiology; D001931:Brain Mapping; D002642:Chick Embryo; D002645:Chickens; D003118:Color Perception / Q000502:physiology*; D004558:Electric Stimulation / Q000379:methods; D007173:Imprinting, Psychological / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology; D010775:Photic Stimulation / Q000379:methods; D014793:Visual Cortex / Q000293:injuries / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology*