In the face of social disruption, rats created fewer brain cells in the hippocampus and showed a preference for familiar rats, researchers at Princeton University have found.
"Adult-born neurons are thought to have a role in responding to novelty, and the hippocampus participates in resolving conflicts between different goals for use in decision-making," first author Maya Opendak, PhD, now at the New York University School of Medicine, said in a Princeton press release. "Data from this study suggest that the reward of social novelty may be altered... Indeed, sticking with a known partner rather than approaching a stranger may be beneficial in some circumstances."
The study appeared in The Journal of Neuroscience.
The researchers placed rats into several separate groups and, after social hierarchies had been established, they swapped the alpha rats.
In these disturbed groups, the scientists found that rats preferred familiar rats over strangers. This behavioral change was coupled with a decrease in neurogenesis, or the production and incorporation of neurons in the hippocampus, a brain structure that plays a vital role in memory and stress responses. The rate of neurogenesis dropped by 50 percent. And when researchers chemically increased adult neurogenesis in the rats to normal levels, the animals' preference for familiarity decreased.
From the release:
'These results show that the reduction in new neurons is directly responsible for social behavior, something that hasn't been shown before,' said Elizabeth Gould, PhD, professor and chair of psychology. The exact mechanism behind how lower neuron growth led to the behavior change is not yet clear, she said.
The researchers suggest the study could have implications for understanding adaptation and resilience:
'For people who are exposed to social disruption frequently, our animal model suggests that these life events may be accompanied by long-term changes in brain function and social behavior,' Opendak said. 'Although we hope that our findings may guide research on the mechanisms of resilience in humans, it is important as always to exercise caution when extrapolating these data across species.'
Previously: Daedalus or Icarus? A small set of nerve cells in the brain determines risk-preference settings and Brain radio: Switching nerve circuit's firing frequency radio ally alters alertness levels in animal models
Image by Caroline