RESUMO
The brain regulates energy homeostasis in the organism. Under resource shortage, the brain takes priority over peripheral organs for energy supply. But can the brain also down-regulate its own consumption to favor survival? We show that the brain of Drosophila specifically disables the costly formation of aversive long-term memory (LTM) upon starvation, a physiological state required for appetitive LTM formation. At the neural circuit level, the slow oscillations normally triggered in two pairs of dopaminergic neurons to enable aversive LTM formation were abolished in starved flies. Transient artificial activation of these neurons during training restored LTM formation in starved flies but at the price of a reduced survival. LTM formation is thus subject to adaptive plasticity that helps survival under food shortage.
Assuntos
Neurônios Dopaminérgicos/fisiologia , Drosophila/fisiologia , Memória de Longo Prazo , Inanição , Animais , Encéfalo/metabolismo , Cálcio/metabolismo , Condicionamento Psicológico , Cicloeximida/farmacologia , Drosophila/genética , Proteínas de Drosophila/biossíntese , Metabolismo Energético , Homeostase , Memória de Longo Prazo/efeitos dos fármacos , Modelos Animais , Mutação , Inibidores da Síntese de Proteínas/farmacologiaRESUMO
Two distinct forms of consolidated associative memory are known in Drosophila: long-term memory and so-called anesthesia-resistant memory. Long-term memory is more stable, but unlike anesthesia-resistant memory, its formation requires protein synthesis. We show that flies induced to form long-term memory become more susceptible to extreme stress (such as desiccation). In contrast, induction of anesthesia-resistant memory had no detectable effect on desiccation resistance. This finding may help to explain why evolution has maintained anesthesia-resistant memory as another form of consolidated memory, distinct from long-term memory.