Animal Behaviour

Research Interests

The main research aim of our group is the understanding of the interrelationship between neuroendocrine mechanisms and social behaviour, using an integrative approach (i.e. by integrating ecological/evolutionary analysis with physiological analysis of behavior). With our studies we hope to contribute to the understanding of how complex social environmental processes interact with biological systems. I have been developing two main research lines: (1) to understand how the social environment modulates hormones and the expression of hormone-dependent behaviors; and (2) the study of the neuroendocrine mechanisms underlying sexual plasticity. Both research lines have been mainly focused in teleost fish as study models but I have also expanded my research to other vertebrate groups, including humans. For example, I have recently started joint projects in collaboration with the Departments of Health Psychology and Developmental Psychology at ISPA, on the variation of salivary steroid levels in humans according to psychosocial stimuli (e.g. variation of androgens and prolactin in prospective fathers; response of sex steroids to social challenges; hormone changes related to social interactions and to the quality of inter-personal relationships). In these research lines we combine neuroendocrinology and molecular biology techniques with behavioural observations (and the use of psychological methodologies in humans) and we conduct studies both in the lab and in free-living subjects.

Group Members

Leonor Galhardo	Postdoc
	Tel: 21 446 4688
José Miguel Simões	External Ph.D. Student
	Tel: 21 446 4688
Magda Teles	External Ph.D. Student
	Tel: 21 446 4531
Rodrigo Abreu	2007 PGCN PhD Student
	Tel: 21 446 6531

Research Project

Winners and losers: social modulation of hormones, brain and behaviour

The nature vs. nurture debate has been ubiquitous in the history of the Behavioural Sciences, and the approaches of the social and the biological sciences to the study of behaviour have been seen as almost mutually exclusive. However, more recently, a growing body of literature has documented social influences on genetic constitution and gene expression, functioning of the endocrine and nervous systems, and immune activity. These results suggest that the effects of social factors on the expression of behaviour must have underlying biological processes. Therefore, a major challenge in current psychobiology is to understand how psychosocial factors can modulate biological mechanisms. In social species individuals must fine-tune the expression of their social behaviour according to the social environment in which they live. Theoretically, the cellular, molecular and physiological basis of motivational changes underlying this behavioural plasticity can be explained either by structural reorganization or by biochemical switching of the neural networks underlying social behaviour, depending on the effects of social context on behaviour being long-lasting and slow or rapid and reversible, respectively. These potential neural mechanisms underlying phenotypic plasticity have a parallel in hormonal mechanisms: structural organization of neural circuits can be influenced by organizational effects of hormones, while biochemical switches can be driven by activational effects of hormones on central pathways underlying behaviour. The major endocrine candidates to play a mediator role in the control of behavioural plasticity are androgens and glucocorticoids, since both classes of steroid hormones respond to social interactions and have effects on the expression of social behaviour. Therefore, the social context in which an individual lives influences their circulating steroid levels which in turn may influence the behaviour that the individual expresses in that particular context. Thus, steroid hormones may be viewed as moderators of agonistic and sexual motivation according to the social environment that they are facing, helping the individual to fine-tune its behaviour according to social context. This rationale implies 3 causal steps: a) social modulation of steroid levels; b) steroid hormones acting on the neural mechanisms underlying social behaviour, at an activational (functional) or an organizational (structural) level; and (c) changes in the activity/structure of these neural mechanisms adjust the expression of subsequent behaviour according to the social context. So far in our lab we have been focusing mainly on the social influences on circulating androgen levels (see references). With the current project we aim to test the hypothesis that the endocrine responsiveness to the social environment mediates behavioural plasticity, by acting on an activational or organizational fashion, depending on the duration of the social experience. Thus, we predict that short-term social interactions will activate neuromodulatory mechanisms, while long-term experiences will have structural reorganization effects. Moreover, we also hypothesize that structural changes induced by long-term social experiences might be flexible according to social context. Neurogenesis assessed by cell proliferation markers (BrdU) together with neuronal markers (HuD and NeuN), will be used as an indicator of structural reorganization. Changes in the gene/protein expression of neuromodulatory systems (arginine-vasotocin and isotocin) and in steroid receptors (AR, ER, GR) and steroid metabolizing enzymes (aromatase and 11-beta-HSD) will be used as indicators of biochemical switching. The proposed study requires a model species with a complex social system that can be easily manipulated in the lab, and whose individuals could be analyzed at the physiological, cellular and molecular level. The cichlid fish, Oreochromis mossambicus provides one such model system. The following questions will be adressed: 1) What brain areas are activated by social interactions, and if winning and losing experiences activate different brain areas (using the expression of the immediate early genes)? 2) How animals integrate multiple social experiences (winning/losing sequential social interactions), happening at different time-scales, and how it affects steroid circulating levels, neurogenesis and neuromodulation, and the subsequent expression of behaviour? 3) If long-term induced changes in structural reorganization and biochemical switching mechanisms can be manipulated by induced reversals on social status? Together, these three questions will allow a better understanding of how the social environment affects the adult brain and modulates behavioural flexibility. (Note: The neurogenesis work included in this project will be run in collaboration with Prof. Günther Zupanc from Jacob University, Bremen, Germany)

Funding

PTDC/PSI/71811/2006

Collaborators

Jacobs University Bremen, Germany
Günther Zupanc
http://www.jacobs-university.de/directory/02940/

Publications

Gonçalves, D.M., J. Alpedrinha, M. Teles & Oliveira, R.F. (2007). Endocrine control of sexual behavior in sneaker males of the peacock blenny Salaria pavo: effects of castration, aromatase inhibition, testosterone and estradiol. Hormones and Behavior 51 :534-541

Ros, A.F.H., Oliveira, R.F., N. Bouton & R.S. Santos (2006). Alternative male reproductive tactics and the immunocompetence handicap in the Azorean rock pool blenny, Parablennius parvicornis. Proceedings of the Royal Society of London B 273 :901-909

Hirschenhauser, K. & Oliveira, R.F. (2006). Social modulation of androgen levels in male vertebrates: a meta-analysis of the challenge hypothesis. Animal Behaviour 71 :265-277

Oliveira, R.F., L.A. Carneiro & A.V.M. Canário (2005). No hormonal response in tied fights. Nature 437 :207-208

Oliveira, R.F. (2004). Social modulation of androgens in vertebrates: mechanisms and function. Advances in the Study of Behaviour 34 :165-239

K. Hirschenhauser, M. Taborsky, T. Oliveira, A.V.M. Canario & Oliveira, R.F. (2004). A test of the ‘challenge hypothesis’ in cichlid fish: simulated partner and territory intruder experiments. Animal Behaviour 68 :741-750

Ros, A.F.H., R. Bruintjes, R.S. Santos, A.V.M. Canario & Oliveira, R.F. (2004). The role of androgens in the trade-off between territorial and parental behavior in the Azorean rock-pool blenny, Parablennius parvicornis. Hormones and Behavior 46 :491-497

Miranda, J.A., Oliveira, R.F., L.A. Carneiro, R.S. Santos & M.S. Grober (2003). Neurochemical correlates of male polymorphism and alternative reproductive tactics in the Azorean rock-pool blenny, Parablennius parvicornis. General and Comparative Endocrinology 132 :183-189

M.S. Grober, A.A. George, K.K. Watkins, L.A. Carneiro & Oliveira, R.F. (2002). Forebrain AVT and courtship in a fish with alternative reproductive tactics. Brain Research Bulletin 57 :23-25

Oliveira, R.F., L.A. Carneiro, D.M. Gonçalves, A.V.M. Canário & M.S. Grober (2001). Effects of 11-Ketotestosterone in sneaker males of the peacock blenny, a species with male alternative mating tactics. Brain, Behavior and Evolution. 58 :28-37

Oliveira, R.F., M. Lopes, L.A. Carneiro & A.V.M. Canário. (2001). Watching fights raises fish hormone levels. Nature 409 :475