失败者效应 z-bo 2020-11-04 373

　　Past social experiences can affect the mental state of humans and the functional state of animals’ brains, causing individuals to make completely opposite behavioral choices in the same scene or facing the same stimuli. A typical case is the impact of a failed fight on an individual. During the fight, the individual participating in the fight can always distinguish between winners and losers; once an individual with high morale is defeated, he will run away and avoid future fights. This phenomenon is called the "loser effect". However, scientists do not yet know the molecular neural mechanism of the loser effect and the means to reverse the loser effect.

　　Recently, the research group of Zhu Yan, a researcher at the Institute of Biophysics, Chinese Academy of Sciences, published a research paper titled Serotonin signals overcome loser mentality in Drosophila on iScience. Studies have found that serotonin (5-HT), serotonin receptors and their neural circuits play an important role in reversing the loser effect.

　　Through a large-scale behavioral screening based on optogenetics, the researchers found that activating 5-HT neurons in the central brain of Drosophila can significantly up-regulate the attack level of the loser in the previous round of fighting, reducing the latency of the attack; through activation About 1/3 of the losers of these 5-HT neurons can reverse the established win-lose relationship and become a winner; if two losers meet, these 5-HT neurons can be activated again to form a new win-lose relationship ; Activating serotonin neurons can in turn reconstruct the level of aggression for multiple losers.

　　Further research found that only activating a pair of 5-HT neurons can reverse the fruit fly loser effect. In addition, at the level of neural circuits, serotonin neurons, upstream P1 neurons, and downstream 5-HT1B receptor neurons form a P1/5-HT/5-HT1B axis. The researchers were able to re-establish the aggressiveness of the loser flies by up-regulating the activity of neurons on this axis. Other neurons known to be involved in the regulation of the level of Drosophila attack (such as TK neurons, PLP neurons, etc.) do not participate in the reconstruction of the aggressiveness of the loser Drosophila. At the molecular level, serotonin and its receptor 5-HT1B molecules are important signaling molecules to reverse the loser effect.

　　More importantly, with a single failure, the individual loser will exhibit behavioral defects (abnormal) in other behaviors (such as domain behavior, intimidation behavior, courtship behavior, etc.) besides aggressive behavior, but by regulating the serotonin pathway, Rescue these abnormal behaviors. In view of the loser effect and the widespread existence of the serotonin pathway in the animal kingdom, this research is expected to provide new perspectives and experiments for understanding the psychological problems caused by negative social experiences, and the mechanisms of post-traumatic stress disorder (PTSD) caused by experiences such as disasters and wars. in accordance with.