We examine the relationship between social interaction, simulated predator injury, and neurogenesis in the weakly electric fish, Apteronotus leptorhynchus. Social interactions are known for affecting the brain and behavior of various animal species, including humans. Grouping behavior among animals, for instance, often provides protection from environmental threats. In many species, social interaction also promotes the production of new neurons (neurogenesis). While many researchers have investigated the social factors that regulate adult neurogenesis, there has been virtually no examination of the positive effects of social interaction on the neurogenic response to body injury.
We are particularly interested in examining a phenomenon called “social buffering,” which refers to the amelioration of an individual’s behavioral or neural responses to a perceived threat when surrounded by conspecifics. We have shown that experimental tail amputation decreases brain cell proliferation in the forebrain of A. leptorhynchus in a fashion that resembles the effect of predator-induced tail injury in free-living electric fish. However, fish living with a social partner following tail amputation showed less reduction in forebrain cell proliferation than those living in isolation. This neurogenic response was specific to the forebrain and did not occur in the midbrain. This agrees with studies of other species showing that social interaction can buffer against decreases in neurogenesis caused by non-social stressors such as fearful stimuli and predator odor. We are currently examining whether the timing of social interactions relative to injury influences this social buffering of neurogenesis.
To summarize, brain cell proliferation is often enhanced in enriched social conditions or inhibited by environmental stressors like predator-induced body injury. However, because living with conspecifics could either be a release from stress for some animals or a stressor itself for others, it is critical to assess the effects of social buffering within a species-specific context. We thereby investigate the influence of social buffering on brain regions that are likely associated with social interaction and the behavioral response to predatory stimuli in A. leptorhynchus.
Margarita Vergara, July 2018