Equine-assisted activities and the impact on perceived social support, self-esteem and self-efficacy among adolescents - an intervention study.

In this project, we examined the effect of a 4-month intervention with horses on perceived social support, self-esteem and general self-efficacy among Norwegian adolescents aged 12-15 years. The intervention took place at farm-based stables and included work with the horses and riding. A waiting-list crossover design was used and the participants answered questionnaires at three time periods.

Frustrative reward omission increases aggressive behaviour of inferior fighters.

Animals use aggressive behaviour to gain access to resources, and individuals adjust their behaviour relative to resource value and own resource holding potential (RHP). Normally, smaller individuals have inferior fighting abilities compared with larger conspecifics. Affective and cognitive processes can alter contest dynamics, but the interaction between such effects and that of differing RHPs has not been adjudged.

Coping with unpredictability: dopaminergic and neurotrophic responses to omission of expected reward in Atlantic salmon (Salmo salar L.).

Comparative studies are imperative for understanding the evolution of adaptive neurobiological processes such as neural plasticity, cognition, and emotion. Previously we have reported that prolonged omission of expected rewards (OER, or 'frustrative nonreward') causes increased aggression in Atlantic salmon (Salmo salar). Here we report changes in brain monoaminergic activity and relative abundance of brain derived neurotrophic factor (BDNF) and dopamine receptor mRNA transcripts in the same paradigm.

Omission of expected reward agitates Atlantic salmon (Salmo salar).

The evolutionary background for cognition and awareness is currently under ardent scrutiny. Poikilothermic vertebrates such as teleost fishes are capable of classical conditioning and have long-term memories, but it remains unknown to what degree such capabilities are associated with affective states. Here, we investigate whether the concept of frustration may apply to Atlantic salmon.

Pigments, parasites and personalitiy: towards a unifying role for steroid hormones?

A surging interest in the evolution of consistent trait correlations has inspired research on pigment patterns as a correlate of behavioural syndromes, or "animal personalities". Associations between pigmentation, physiology and health status are less investigated as potentially conserved trait clusters. In the current study, lice counts performed on farmed Atlantic salmon Salmo salar naturally infected with ectoparasitic sea lice Lepeophtheirus salmonis showed that individual fish with high incidence of black melanin-based skin spots harboured fewer female sea lice carrying egg sacs, compared to less pigmented fish.