NEUROENDOCRINOLOGY OF REPRODUCTIVE BEHAVIOUR IN THE AFRICAN CICHLID OREOCHROMIS MOSSAMBICUS: REGULATORY MECHANISMS AND SOCIAL MODULATION OF REPRODUCTION

Funder

Organizational Unit

Publications

Social interactions elicit rapid shifts in functional connectivity in the social decision-making network of zebrafish

Publication . Teles, Magda; Almeida, Olinda; Lopes, João Sollari; Oliveira, Rui Filipe

According to the social decision-making (SDM) network hypothesis, SDM is encoded in a network of forebrain and midbrain structures in a distributed and dynamic fashion, such that the expression of a given social behaviour is better reflected by the overall profile of activation across the different loci rather than by the activity of a single node. This proposal has the implicit assumption that SDM relies on integration across brain regions, rather than on regional specialization. Here we tested the occurrence of functional localization and of functional connectivity in the SDM network. For this purpose we used zebrafish to map different social behaviour states into patterns of neuronal activity, as indicated by the expression of the immediate early genes c-fos and egr-1, across the SDM network. The results did not support functional localization, as some loci had similar patterns of activity associated with different social behaviour states, and showed socially driven changes in functional connectivity. Thus, this study provides functional support to the SDM network hypothesis and suggests that the neural context in which a given node of the network is operating (i.e. the state of its interconnected areas) is central to its functional relevance.

2015Journal article

Restricted access

Castration affects reproductive but not aggressive behavior in a cichlid fish

Publication . Almeida, Olinda; Canário, Adelino V. M.; Oliveira, Rui Filipe

Gonads are the main source of sex steroids, which have been implicated in the regulation of sexually differentiated behavior, such as reproductive and aggressive displays. In the Mozambique tilapia (Oreochromis mossambicus) territorial males have higher androgen levels than non-territorials, express reproductive behavior and use a urine-borne pheromone to signal their social status towards conspecifics. Here we investigated the effects of gonadectomy on the circulating levels of androgens and cortisol, and on the expression of aggressive and reproductive behavior (nest building, courtship behavior, and nuptial coloration). Males were either castrated, urine bladder damaged, or sham-operated and visually exposed to a group of females during 8 consecutive days and subsequently to a male on day 9. The urine bladder damaged treatment was included in the experimental design because a full castration procedure in this species causes quite often damage to the urine bladder. Gonadectomy lowers dramatically the circulating levels of androgens measured at 4 and 8 days post-castration and abolishes the expression of nest building, courtship behavior and nuptial coloration, but has no effect on the expression of aggressive behavior. These results confirm the gonads as the main source of androgens in this species and show that androgens are necessary for the expression of reproductive behaviors. However, the expression of aggressive behavior seems to be decoupled from gonadal steroids, namely androgens, suggesting the action of independent central mechanisms.

2014Journal article

Restricted access

Interaction between vasotocin and gonadal hormones in the regulation of reproductive behavior in a cichlid fish

Publication . Almeida, Olinda; Félix, Ana Sofia; Oliveira, Rui F.

Vasotocin (VT) has been associated with the regulation of diferent aspects of social behavior (e.g., mating and aggression). Given the fact that androgens are also known to regulate reproductive behavior, we hypothesized that VT and androgens could be interacting, rather than acting independently, in the regulation of reproductive behavior. In the present study, we aimed to understand the efect of VT and its interaction with gonadal hormones (putatively androgens) on diferent aspects of reproductive behavior of a polygynous and territorial cichlid fsh, the Mozambique tilapia (Oreochromis mossambicus). Using a within-subject design, we treated territorial males, that were previously castrated or sham-operated, with diferent dosages of VT as well as with a V1A receptor antagonist (Manning compound) and subsequently analyzed their behavior towards females and towards an intruder male. Our results showed that VT afected the behavior of territorial males towards females but not towards males. Specifcally, VT-treated males interacted less with females (i.e., spent less time touching the transparent partition that allowed visual contact with females) and were less aggressive towards females than salinetreated males. Moreover, in sham-operated males, blocking V1A receptors increased the frequency of bites towards females in comparison to saline-treated males, but not in castrated males. This result suggests that VT down-regulates aggressiveness towards females through the action of V1A receptors in the gonads (putatively decreasing androgen secretion), and that androgens up-regulate this behavior. In summary, our results suggest that VT may modulate social behavior, through an interaction with gonadal hormones.

2022Journal article

Open access

How to Improve the YLS/CMI? Exploring a Particularly Predictive Combination of Items

Publication . Villanueva, Lidón; Pereira, Miguel Basto; Cuervo, Keren

Recidivism risk assessment is central to addressing criminogenic needs among youth offenders. To accomplish this, the Youth Level of Service/Case Management Inventory (YLS/CMI) is worldwide used, but it is long and has limited predictive validity for minority populations. This study presents a particularly predictive combination of seven items that overcomes these limitations. A sample of 430 Spanish youth offenders participated in this study. The YLS/CMI long version was filled out and reconvictions were collected over a 2-year period. Results show that this combination of seven items reduced more than 80% of the inventory and improved the predictive validity, globally and for minorities. The items that were included were related to psychopathic traits and the lack of protective role models. Therefore, this specific combination of YLS/CMI items has considerable higher predictive validity across gender and culture, and may be useful to practitioners in this field.

2019Journal article

Open access