|Top panel: social transmission of fear|
Bottom panel: olfactory transmission of fear in the
absence of mother
When the baby rats were in the presence of their mother and no stimulus, they were calm. Only when the mother smelled peppermint and expressed fear did the pups get stressed. To take this one step further, the researchers exposed pups to either the smell of peppermint and their mother, or the smell of peppermint and the smell of their frightened mother. They found that cortisol levels in the pups (an indicator of stress level) was significantly higher in the baby rats that smelled their frightened mother. Observations of amygdalae - an area of the brain that processes emotions - in these pups also showed elevated activity.
This type of phenomenon is also seen in humans: often, mothers with strong phobias or PTSD can transmit these fears to their children. Dr. Jacek Debiec, who led the research, treats mothers and children with anxiety, and hopes that this research will help in his work by exploring the roots of fear in infancy and how maternal trauma can affect subsequent generations. He hopes that this research will inform the development of better preventative and therapeutic methods.