Siniscalchi, M., Sasso, R., Pepe, A. M., Dimatteo, S., Vallortigara, G., & Quaranta, A. (). Sniffing with the right nostril: lateralization of response to odour stimuli by dogs. Anim. Behav., In Press, Corrected Proof.
Abstract: Lateralization in dogs, Canis familiaris, has been reported for paw usage and response to visual and acoustic stimuli. Surprisingly, however, no investigation of possible lateralization for the most relevant sensory domain of dogs, namely olfaction, has been carried out. Here we investigated left and right nostril use in dogs freely sniffing different emotive stimuli in unrestrained conditions. When sniffing novel nonaversive stimuli (food, lemon, vaginal secretion and cotton swab odours), dogs showed initial preferential use of the right nostril and then a shift towards use of the left nostril with repeated stimulus presentation. When sniffing arousal stimuli such as adrenaline and veterinary sweat odorants, dogs showed a consistent right nostril bias all over the series of stimulus presentations. Results suggest initial involvement of the right hemisphere in processing of novel stimuli followed by the left hemisphere taking charge of control of routine behaviour. Sustained right nostril response to arousal stimuli appears to be consistent with the idea that the sympathetic hypothalamic-pituitary-adrenal axis is mainly under the control of the right hemisphere. The implications of these findings for animal welfare are discussed.
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Siniscalchi, M., Sasso, R., Pepe, A. M., Vallortigara, G., & Quaranta, A. (2010). Dogs turn left to emotional stimuli. Behav. Brain. Res., 208(2), 516–521.
Abstract: During feeding behaviour, dogs were suddenly presented with 2D stimuli depicting the silhouette of a dog, a cat or a snake simultaneously into the left and right visual hemifields. A bias to turn the head towards the left rather than the right side was observed with the cat and snake stimulus but not with the dog stimulus. Latencies to react following stimulus presentation were lower for left than for right head turning, whereas times needed to resume feeding behaviour were higher after left rather than after right head turning. When stimuli were presented only to the left or right visual hemifields, dogs proved to be more responsive to left side presentation, irrespective of the type of stimulus. However, cat and snake stimuli produced shorter latencies to react and longer times to resume feeding following left rather than right monocular visual hemifield presentation. Results demonstrate striking lateralization in dogs, with the right side of the brain more responsive to threatening and alarming stimuli. Possible implications for animal welfare are discussed.
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Siniscalchi, M., Sasso, R., Pepe, A. M., Dimatteo, S., Vallortigara, G., & Quaranta, A. (2010). Catecholamine plasma levels following immune stimulation with rabies vaccine in dogs selected for their paw preferences. Neuroscience Letters, 476(3), 142–145.
Abstract: Epinephrine and norepinephrine plasma levels were assessed in dogs in relation to paw preference following an immune challenge with rabies vaccine. The results showed that both catecholamines increased after the vaccine administration, confirming the main role of the sympathetic nervous system in the modulation activity between the brain and the immune system. Moreover, ambidextrous dogs showed a significantly higher increase of epinephrine levels 8 days after immunization with respect to right- and left-pawed dogs, suggesting that the biological activity of this molecule could be key for a different immune response with regard to laterality.
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