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Advisor(s)
Abstract(s)
The role of odors in the long-distance navigation of birds has elicited intense debate for more
than half a century. Failure to resolve many of the issues fueling this debate is due at least in part
to the absence of controls for a variety of non-specific effects that odors have on the navigational
process. The present experiments were carried out to investigate whether the olfactory inputs are
involved only in “activation” of neuronal circuitry involved in navigation or are also playing a
role in providing directional information. Experienced adult pigeons were exposed to controlled
olfactory stimuli during different segments of the journey (release site vs. displacement + release
site). Protein levels of IEGs (immediate early genes used to mark synaptic activity) were analyzed
in areas within the olfactory/navigation avian circuitry. The results indicate that 1) exposure to
natural odors at the release site (and not before) elicit greater activation across brain regions
than exposure to filtered air, artificial odors, and natural odors along the entire outward journey
(from home to the release site, inclusive); 2) activation of the piriform cortex in terms of odor
discrimination is lateralized; 3) activation of the navigation circuitry is achieved by means of
lateralized activation of piriform cortex neurons. Altogether, the findings provide the first direct
evidence that activation of the avian navigation circuitry is mediated by asymmetrical processing
of olfactory input occurring in the right piriform cortex.
Description
Keywords
Brain circuitries Neuronal activation Olfaction Piriform cortex Vertebrates
Citation
Chemical Senses, 0, 1-11. doi: 10.1093/chemse/bjw084
Publisher
Oxford University Press