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Free keywords:
behavioral molecular mapping; bird orientation; cognition; magnetic
sense; ZENK (zif268, Egr-1, NGF-1A, and Krox-24)
Abstract:
Twice each year, millions of night-migratory songbirds migrate
thousands of kilometers. To find their way, they must process and
integrate spatiotemporal information from a variety of cues including
the Earth’s magnetic field and the night-time starry sky. By
using sensory-driven gene expression, we discovered that nightmigratory
songbirds possess a tight cluster of brain regions highly
active only during night vision. This cluster, here named ‘‘cluster
N,’’ is located at the dorsal surface of the brain and is adjacent to
a known visual pathway. In contrast, neuronal activation of cluster
N was not increased in nonmigratory birds during the night, and it
disappeared in migrants when both eyes were covered. We suggest
that in night-migratory songbirds cluster N is involved in
enhanced night vision, and that it could be integrating visionmediated
magnetic andor star compass information for nighttime
navigation. Our findings thus represent an anatomical and
functional demonstration of a specific night-vision brain area.
