In a new JNeurosci paper, a Boston College research team led by John Christianson explored how a pathway between two areas of the brain—the insular cortex and prefrontal cortex—supports social decisions in male rats. Why did the researchers choose to assess the insular cortex and prefrontal cortex of rats? Says Christianson, "For rodents and humans alike, the insular cortex is a brain region where contextual information about the environment and the self are bound together. The insular cortex sends this information to the prefrontal cortex, which is one of the final brain areas involved in making decisions. Because our internal states can shape our decisions, we hypothesized that connections between the insula and prefrontal cortex would be necessary for social responses to others in distress."
In a task where rats were exposed to either stressed pups or adult peers, rats tended to approach juveniles while avoiding adults. The ability to make these social decisions required both the prefrontal cortex and insula, as well as intact signaling between these areas. The researchers theorize this signaling may mean that rats find the presence of a distressed pup a more urgent social situation requiring less evaluative effort and quicker action than a situation involving a distressed adult peer, whose reason for being distressed may be more unclear to the rats.
Addressing remaining unknowns, says Christianson, "We know that when you take the pathway away, it affects behavior. But we can't tell exactly what information is relayed from the insula to the prefrontal cortex. We plan to record neural activity in these regions seeking to decode which aspects of social encounters are processed in this circuit. Is it stress? Age? Threat? Or all of the above?" This work may ultimately help with developing treatment strategies for psychiatric conditions characterized by social anxiety or trauma, according to the authors.
