One of the fundamental goals of neuroscience research is to understand how the brain integrates the multitude of sensory cues arising from a constantly changing environment to generate appropriate behavioral responses and ultimately form memories. Our laboratory aims to investigate these processes in the context of social behaviors.
Social behavior encompasses a wide range of interactions among conspecifics, from simple aggregations to more complex interactions such as courtship, parental care, and competitive encounters over territory and mates. These behaviors are inherently complex and arise from the interplay between innate and learned components, shaped by evolutionary pressures that influence reproductive fitness.
Aggression is a conserved behavioral strategy across the animal kingdom, used to compete for resources, gain access to mates, defend territory, and ensure self- and kin-protection. The outcome of aggressive interactions often depends on the ability to adopt effective fighting strategies, which are shaped by prior experience and the assessment of an opponent’s strength. Notably, phenomena known as “winner” and “loser” effects, where previous victories increase the likelihood of future wins, while defeats reduce it, have been documented across numerous species, including humans. These experience-dependent processes contribute to the establishment and stabilization of social hierarchies and are thought to influence male reproductive fitness by modulating both physiological states and female receptivity.”
Drosophila melanogaster as a model system
To address these questions, our laboratory uses the fruit fly, Drosophila melanogaster, as a model system. Drosophila is a powerful genetic model that has provided key insights into numerous biological processes of medical relevance, including aging, memory, sleep regulation, and addiction-related behaviors. It offers exceptional genetic tractability and a relatively simple nervous system compared to vertebrates, containing approximately 1,000-10,000 times fewer neurons. Importantly, it has also emerged as a highly relevant model for investigating the neural and molecular mechanisms underlying aggression.
During competition for food, mates, and territory, male flies exhibit a series of stereotyped behavioral patterns. Encounters typically begin with mutual approach, followed by the display of visual threats, and can escalate into physical interactions such as lunging. As the contest progresses, individuals adapt their fighting strategies: one animal may increasingly chase and attack while displaying territorial dominance, whereas the other retreats to avoid further confrontation. These interactions ultimately lead to the establishment of stable dominance relationships between dominant and subordinate individuals.
Although aggression is an innate behavior, it is also highly plastic and subject to experience-dependent modulation. Our work has demonstrated that learning and memory play critical roles in shaping aggressive behavior. Following a single fighting encounter, both dominant and subordinate flies develop internal “winner” and “loser” states that correspond to short-term memory. These states decay over several hours, with their persistence influenced by the familiarity of the opponent. In contrast, repeated defeats induce long-lasting behavioral changes associated with the formation of a protein synthesis-dependent long-term “loser” memory, whereas repeated victories do not produce a comparable long-term “winner” effect. Such winner and loser effects are widely conserved across animal species, including humans, and are thought to represent adaptive evolutionary mechanisms, potentially by modulating reproductive fitness.
Photo credit: "Atlas of Drosophila morphology, wild type and classical mutants, 2013"
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Behavioral assays
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Genetics
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Spectrometry techniques
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Immunohistochemistry
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Functional imaging
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Machine-learning behavioral scoring (in progress)