Experimental evidence for a role of dopamine on avian personality traits

Abstract

There is increasing interest in the genetic and physiological bases of behavioural differences among individuals, namely animal personality. One particular dopamine (DA) receptor gene (the dopamine receptor D4 gene) has been used as candidate gene to explain personality differences, but with mixed results. Here, we used an alternative approach, exogenously manipulating the dopaminergic system and testing for effects on personality assays in a social bird species, the common waxbill (Estrilda astrild). We treated birds with agonists and antagonists for DA receptors of both D1 and D2 receptor pathways (the latter includes the D4 receptor) and found that short-term manipulation of DA signalling had an immediate effect on personalityrelated behaviours. In an assay of social responses (mirror test), manipulation of D2 receptor pathways reduced time spent looking at the social stimulus (mirror image). Blocking D2 receptors reduced motor activity in this social assay, while treatment with a D2 receptor agonist augmented activity in this social assay but reduced activity in a nonsocial behavioural assay. Also, in the non-social assay, treatment with the D1 receptor antagonist markedly increased time spent at the feeder. These results show distinct and context-specific effects of the dopaminergic pathways on waxbill personality traits. Our results also suggest that experimental manipulation of DA signalling can disrupt a behavioural correlation (more active individuals being less attentive to mirror image) that is habitually observed as part of a behavioural syndrome in waxbills. We discuss our results in the context of animal personality, and the role of the DA system in reward and social behaviour.

Constitutive gene expression differs in three brain regions important for cognition in neophobic and non-neophobic house sparrows (Passer domesticus)

“…Although genes with the highest fold change do not necessarily have the highest biological significance, these receptors are strong candidates for future work. Dopamine receptor 2 specifically has already been linked to personality traits such as boldness and novelty seeking in other species [88][89][90]. Surprisingly, neophobic birds in our study showed no evidence for differential expression of the dopamine receptor 4 (DRD4) gene in any of the four brain regions we examined.…”

Association of Personal Anxiety with Dopamine Receptor D4 (DRD4), DAT Genes Polymorphism

“…Lack of dopamine results in depletion of the nervous system, and its increased level causes bipolar disorders [4,27]. It has been shown that in people with the long form of the DRD4 gene (the number of repeats is six or more), the affinity of dopamine for the receptor is reduced and the number of receptors is reduced.…”

“…These brain structures play a vital part in the implementation of psychomotor, cognitive, neuroendocrine functions [3]. Relationship between 'novelty seeking' and dopamine system has been found: an association of temperament with genetic polymorphism encoding the fourth type dopamine receptor (DRD4) was established [4].…”

Casting the Net Widely for Change in Animal Welfare: The Plight of Birds in Zoos, Ex Situ Conservation, and Conservation Fieldwork

“…The second is that individual birds even of the same species may react very differently to the world and will do so according to individual personality traits [ 81 , 82 ]. There is now plenty of evidence that personality or temperament has a good deal to do with a bird’s reproductive success and overall health [ 60 , 61 , 83 , 84 ]. They can suffer ‘mental’ health issues of varying degrees of severity—the worst of which, in cockatoos (family Cacatuidae), are stages of catatonic immobility and swaying while not attending to any external stimuli [ 27 ].…”