The role of serotonergic action in amygdala in rodent prosocial behavior

• Applicant: Professor Tobias Kalenscher, Ph.D.
• Subject Area: General, Cognitive and Mathematical Psychology
• Term: from 2013 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 237274537

Prosocial choice, the preference for outcomes that produce benefits for other individuals, is ubiquitous in human interactions. However, despite recent advances in both humans and animals, the behavioral and neural bases of prosocial behavior remain unclear. In a first funding period supported by DFG, we have developed a task to assess prosocial choice behavior in rats. We found that rats revealed preference for outcomes that produced benefits for other rats; their behavior hence qualified as prosocial. There was a substantial degree of heterogeneity in the prosocial tendencies between animals, with some rats showing very strong prosocial preferences, while other rats being indifferent to the production of reward to their conspecifics. Moreover, we obtained preliminary evidence showing that the rodent lateral orbitofrontal cortex (lOFC) was important for disambiguating social from non-social contexts, suggesting that lOFC was ultimately involved in determining whom to help and whom not. However, it is unclear which other brain structures support prosocial behavior in concert with lOFC, and the underlying psychopharmacology is entirely elusive. We hypothesize, based on evidence from research on social cognition, goal-directed behavior and reinforcement learning, that basolateral amygdala (BLA) is a central hub for managing social behavior, and that this function is supported by serotonin (5-HT) action in BLA. To test this prediction, rats will be trained in an automated version of our prosocial choice task. In this task, two rats, an actor and a partner rat, interact in a double T-maze. Actor rats are always first movers and choose between two choice compartments yielding either just a reward for them, delivered in their compartment (own reward; OR), or own reward plus an additional reward for the partner rat placed in an adjacent compartment (both reward; BR). In a first experiment, we plan to apply lesions to BLA and compare the prosocial tendencies of the lesioned rats (% BR choices) to the tendencies of control rats with sham lesions. In two subsequent experiments, we will examine the effects of local microinjections of serotonin 5-HT1A receptor agonists (8-OH-DPAT) and antagonists (WAY-100,635) into bilateral BLA on prosocial behavior. Our results are of high relevance for a societally pertinent problem: psychopathy. Psychopathy is characterized by amygdala dysfunction as well as dysregulated serotonergic homeostasis. Our studies will therefore provide an important step in furthering our understanding of disorders characterized by psychopathy and antisocial behavior.

• DFG Programme: Research Grants
• Major Instrumentation: 2 x Doppelte T-Mazes
• Instrumentation Group: 3440 Elektrophysiologische Meßsysteme (außer 300-309 und 340-343)
• Co-Investigator: Dr. Sandra Schäble