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Research Project
NEURONAL PATHWAYS INVOLVED IN OLFACTORY ACTIVATION OF NAVIGATIONAL SYSTEMS
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Home sweet home: evidence for nest-fidelity in the rocky intertidal fish, the shanny Lipophrys pholis
Publication . Martins, Joana; Almada, Frederico José Oliveira de; Gonçalves, Ana Sofia Ribeiro; Coelho, Pedro Duarte; Jorge, Paulo
The ability to be faithful to a particular area or site was analysed in the shanny Lipophrys pholis. Using passive integrated transponders, adults from a population of L. pholis at Cabo Raso, Portugal, were followed over a period of 3 years. The findings showed that site fidelity is a consistent behaviour during the breeding season with specific breeding males being found only in particular sectors within the area, and in specific nests throughout the years. The fact that, in general, L. pholis individuals were absent from the study area during the non-breeding season and breeding males were recorded returning to the same nests and sectors for consecutive breeding seasons suggests that they have developed excellent homing abilities. Translocation data corroborate this idea showing that breeding males successfully returned to their nests after a displacement of >100 m. Altogether, these findings highlight the relevance of life-history traits (e.g. nesting) in the conditioning of site fidelity and homing for this species of rocky intertidal fish, and more importantly, provide evidence for the need of a well-developed navigational system.
Asymmetrical processing of olfactory input in the piriform cortex mediates "activation" of the avian navigation circuitry
Publication . Jorge, Paulo; Marques, Paulo A. M.; Pinto, Belmiro V.; Phillips, John B.
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.
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Funding agency
Fundação para a Ciência e a Tecnologia
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Funding Award Number
SFRH/BPD/64087/2009