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Publication
Regulação do mate-choice copying por neurónios apetitivos ou neurónios aversivos de dopamina em Drosophila melanogaster
Advisor(s)
Abstract(s)
O presente estudo descreve o papel de neurónios específicos de dopamina na regulação da aprendizagem social, em contexto sexual, em Drosophila melanogaster.
A dopamina (DA) é um neuro-modulador que controla a formação de memórias associativas, com valência positiva (memórias apetitivas) ou negativa (memórias aversivas) durante o processo de aprendizagem associal, e a nossa pergunta é se o mesmo mecanismo também ocorre na aprendizagem social.
Como paradigma de aprendizagem social, utilizámos o mate-choice copying (MCC), que é uma forma de aprendizagem social por observação das interações sexuais entre conspecíficos, e que se sabe ser regulado pela dopamina. Como controlo, utilizámos o teste de independent mate choice (IMC), que avalia a preferência inata das fêmeas por machos com fenótipos distintos, neste caso fenótipos artificiais de cor azul e rosa.
Replicámos estes dois paradigmas comportamentais num grupo controlo (uma linha heterozigótica, a Canton-Special, ou CS), e em duas linhas transgénicas com neurónios dopaminérgicos desativados: a linha PAM para os neurónios apetitivos, e a linha PPL1 para os neurónios aversivos. Os resultados mostram que a linha CS faz MCC, a linha PAM não faz e a PPL1 parece fazer, mas este último resultado não é conclusivo, provavelmente porque o tamanho da amostra é pequeno. Sabendo que as memórias apetitivas são importantes nos processos motivacionais, incluindo a motivação para o acasalamento, a formação de memórias apetitivas durante o MCC é certamente um mecanismo adaptativo. Por essa razão, poderá haver um menor contributo das memórias aversivas, contudo, o nosso estudo deixa essa hipótese ainda em aberto.
The present study describes the role of dopamine-specific neurons in regulating social learning in a sexual context, in Drosophila melanogaster. Dopamine (AD) is a neuro-modulator that controls the formation associative memories, with positive (appetitive) or negative (aversive) valence during the asocial learning process, and our question is whether the same mechanism also occurs in social learning. As paradigm of social learning, we used mate-choice copying (MCC), which is a form of social learning by observing conspecific sexual interactions, and that is known to be regulated by dopamine. As a control, we used the independent mate choice (IMC) test, which assesses female innate preference for males with distinct phenotypes, in this case the artificial blue and pink phenotypes. We replicated these two behavioural paradigms in a control group (a heterozygous line, Canton-Special, or CS), and in two transgenic lines with dopaminergic deactivated neurons: the PAM line for appetitive neurons and the PPL1 line for aversive neurons. The results show that the CS line does MCC, the PAM line does not, and the PPL1 line seems to do, but the latter result is not conclusive, probably because the sample size is small. Knowing that appetitive memories are important in motivational processes, including mating motivation, the formation of appetitive memories during MCC is certainly an adaptive mechanism. For this reason, there may be a minor contribut
The present study describes the role of dopamine-specific neurons in regulating social learning in a sexual context, in Drosophila melanogaster. Dopamine (AD) is a neuro-modulator that controls the formation associative memories, with positive (appetitive) or negative (aversive) valence during the asocial learning process, and our question is whether the same mechanism also occurs in social learning. As paradigm of social learning, we used mate-choice copying (MCC), which is a form of social learning by observing conspecific sexual interactions, and that is known to be regulated by dopamine. As a control, we used the independent mate choice (IMC) test, which assesses female innate preference for males with distinct phenotypes, in this case the artificial blue and pink phenotypes. We replicated these two behavioural paradigms in a control group (a heterozygous line, Canton-Special, or CS), and in two transgenic lines with dopaminergic deactivated neurons: the PAM line for appetitive neurons and the PPL1 line for aversive neurons. The results show that the CS line does MCC, the PAM line does not, and the PPL1 line seems to do, but the latter result is not conclusive, probably because the sample size is small. Knowing that appetitive memories are important in motivational processes, including mating motivation, the formation of appetitive memories during MCC is certainly an adaptive mechanism. For this reason, there may be a minor contribut
Description
Dissertação de Mestradoapresentada no ISPA – Instituto Universitário para obtenção de grau de Mestre na especialidade de Neurociências Cognitivas e Comportamentais.
Keywords
Mate-choice copy (MCC) Aprendizagem social Preferências sexuais inatas Neurónios de dopamina (DA) Memórias apetitivas (cluster PAM) Memórias aversivas (cluster PPL1) Social learning Innate mate preferences Dopamine (DA) neurons Appetitive memories (PAM cluster) Aversive memories (cluster PPL1).