EEG responses to visual landmarks in flying pigeons.
BACKGROUND
GPS analysis of flight trajectories of pigeons can reveal that topographic features influence their flight paths. Recording electrical brain activity that reflects attentional processing could indicate objects of interest that do not cause changes in the flight path. Therefore, we investigated whether crossing particular visual landmarks when homing from a familiar release site is associated with changes in EEG.


RESULTS
Birds carried both data-loggers for recording GPS position and EEG during flight. First, we classified characteristic EEG frequencies of caged birds and found five main bands: A: 0-3, B: 3-12, C: 12-60, D: 60-130, and E: 130-200 Hz. We analyzed changes in these activity bands when pigeons were released over sea (a featureless environment) and over land. Passing over the coastline and other prominent landmarks produced a pattern of EEG alterations consisting of two phases: activation of EEG in the high-frequency bands (D and/or E), followed by activation of C. Overlaying the EEG activity with GPS tracks allowed us to identify topographical features of interest for the pigeons that were not recognizable by distinct changes of their flight path.


CONCLUSIONS
We provide evidence that EEG analysis can identify landmarks and objects of interest during homing. Middle-frequency activity (C) reflects visual perception of prominent landmarks, whereas activation of higher frequencies (D and E) is linked with information processing at a higher level. Activation of E bands is likely to reflect an initial process of orientation and is not necessarily linked with processing of visual information.
Vyssotski
Alexei L
AL
Institute of Anatomy, University of Zurich, Winterthurerstr. 190, 8057 Zurich, Switzerland. alexei@ini.phys.ethz.ch
Dell'Omo
Giacomo
G
Dell'Ariccia
Gaia
G
Abramchuk
Andrei N
AN
Serkov
Andrei N
AN
Latanov
Alexander V
AV
Loizzo
Alberto
A
Wolfer
David P
DP
Lipp
Hans-Peter
HP
D000818:Animals; D001288:Attention; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D010856:Columbidae / Q000502:physiology*; D003463:Cues; D004569:Electroencephalography; D005426:Flight, Animal / Q000502:physiology*; D040362:Geographic Information Systems; D006702:Homing Behavior / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*