RESUMO
Although aggression is more prevalent in males, females also express aggressive behaviors and in specific ecological contexts females can be more aggressive than males. The aim of this work is to assess sex differences in aggression and to characterize the patterns of neuronal activation of the social-decision making network (SDMN) in response to intra-sexual aggression in both male and female zebrafish. Adult fish were exposed to social interaction with a same-sex opponent and all behavioral displays, latency, and time of resolution were quantified. After conflict resolution, brains were sampled and sex differences on functional connectivity throughout the SDMN were assessed by immunofluorescence of the neuronal activation marker pS6. Results suggest that both sexes share a similar level of motivation for aggression, but female encounters show shorter conflict resolution and a preferential use of antiparallel displays instead of overt aggression, showing a reduction of putative maladaptive effects. Although there are no sex differences in the neuronal activation in any individual brain area from the SDMN, agonistic interactions increased neuronal activity in most brain areas in both sexes. Functional connectivity was assessed using bootstrapped adjacency matrices that capture the co-activation of the SDMN nodes. Male winners increased the overall excitation and showed no changes in inhibition across the SDMN, whereas female winners and both male and female losers showed a decrease in both excitation and inhibition of the SDMN in comparison to non-interacting control fish. Moreover, network centrality analysis revealed both shared hubs, as well as sex-specific hubs, between the sexes for each social condition in the SDMN. In summary, a distinct neural activation pattern associated with social experience during fights was found for each sex, suggesting a sex-specific differential activation of the social brain as a consequence of social experience. Overall, our study adds insights into sex differences in agonistic behavior and on the neuronal architecture of intrasexual aggression in zebrafish.
RESUMO
El objetivo de esta investigación fue analizar de manera experimental el efecto de la disponibilidad de recursos económicos sobre funciones cognitivas y preferencias sociales en estudiantes universitarios. Se condujo un estudio con diseño experimental inter-sujetos en el que participaron 60 estudiantes universitarios. Se comparó el desempeño de participantes expuestos a condiciones de altos y bajos recursos económicos en tareas de desempeño cognitivo (inteligencia fluida y control inhibitorio) y de preferencias sociales (Juego del Ultimátum, con ofertas de distinto grado de justicia). En general, los resultados indicaron que no hubo diferencias significativas entre los participantes de las condiciones de bajos y altos recursos económicos en las funciones cognitivas y preferencias sociales. En cambio, hubo diferencias según sexo en el dominio cognitivo. Se discuten los resultados a la luz de investigaciones previas y se reconocen las principales limitaciones.
O objetivo desta pesquisa foi analisar de maneira experimental o efeito da disponibilidade de recursos econômicos sobre as funções cognitivas e preferências sociais de estudantes universitários. Foi realizado um estudo com desenho experimental intra-sujeitos, no qual participaram 60 estudantes universitários. Comparou-se o desempenho dos participantes expostos a condições de altos e baixos recursos econômicos em tarefas de desempenho cognitivo (inteligência fluida e controle inibitório) e de preferências sociais (Jogo do Ultimato, com ofertas de diferentes graus de justiça). Em geral, os resultados não indicaram diferenças significativas entre os participantes de condições de baixa e alta renda nas funções cognitivas e preferências sociais. Por outro lado, houve diferenças segundo o sexo no domínio cognitivo. Se discutem os resultados à luz de investigações anteriores e se reconhecem as principais limitações.
The objective of this research was to analyze experimentally the effect of the availability of economic resources on cognitive functions and social preferences in university students. A study with inter-subject experimental design was conducted. 60 university students participated. The performance of participants exposed to conditions of high and low economic resources was compared in tasks of cognitive performance (fluid intelligence and inhibitory control) and social preferences (Ultimatum Game, with offers of different degrees of justice). In general, the results showed that there were no significant differences between the participants of the conditions of low and high economic resources in cognitive functions and social preferences. In contrast, there were differences according to sex in the cognitive domain. The results are discussed in light of previous research and the main limitations are recognized.
RESUMO
Recursive social decision-making requires the use of flexible, context-sensitive long-term strategies for negotiation. To succeed in social bargaining, participants' own perspectives must be dynamically integrated with those of interactors to maximize self-benefits and adapt to the other's preferences, respectively. This is a prerequisite to develop a successful long-term self-other integration strategy. While such form of strategic interaction is critical to social decision-making, little is known about its neurocognitive correlates. To bridge this gap, we analysed social bargaining behaviour in relation to its structural neural correlates, ongoing brain dynamics (oscillations and related source space), and functional connectivity signatures in healthy subjects and patients offering contrastive lesion models of neurodegeneration and focal stroke: behavioural variant frontotemporal dementia, Alzheimer's disease, and frontal lesions. All groups showed preserved basic bargaining indexes. However, impaired self-other integration strategy was found in patients with behavioural variant frontotemporal dementia and frontal lesions, suggesting that social bargaining critically depends on the integrity of prefrontal regions. Also, associations between behavioural performance and data from voxel-based morphometry and voxel-based lesion-symptom mapping revealed a critical role of prefrontal regions in value integration and strategic decisions for self-other integration strategy. Furthermore, as shown by measures of brain dynamics and related sources during the task, the self-other integration strategy was predicted by brain anticipatory activity (alpha/beta oscillations with sources in frontotemporal regions) associated with expectations about others' decisions. This pattern was reduced in all clinical groups, with greater impairments in behavioural variant frontotemporal dementia and frontal lesions than Alzheimer's disease. Finally, connectivity analysis from functional magnetic resonance imaging evidenced a fronto-temporo-parietal network involved in successful self-other integration strategy, with selective compromise of long-distance connections in frontal disorders. In sum, this work provides unprecedented evidence of convergent behavioural and neurocognitive signatures of strategic social bargaining in different lesion models. Our findings offer new insights into the critical roles of prefrontal hubs and associated temporo-parietal networks for strategic social negotiation.