Behavioral neuroscientist Dr. Tara Perrot wants to know what we can do in early life – and even before birth – to ensure a healthy, well-regulated stress response throughout life.

Dr. Tara Perrot, Austin Korgan and Janeske Vonkeman discuss how the enhanced cage environment helps reduce mother rats’ stress levels and improve the care they provide to their pups.Dr. Tara Perrot, Austin Korgan and Janeske Vonkeman discuss how the enhanced cage environment (on the left) helps reduce mother rats’ stress levels and improve the care they provide to their pups.

“The stress response is essential, we need it to survive, but an overactive stress response has serious negative effects on our bodies and brains,” says Dr. Perrot, a professor in the departments of Psychology & Neuroscience and Medical Neuroscience at Dalhousie University in Halifax, Nova Scotia, and a member of the Brain Repair Centre’s executive committee.

The stress response is the cascade of physiological and hormonal reactions that occurs in our bodies and brains in response to real and perceived threats. The heart races, adrenalin and cortisol flood the bloodstream, and we feel that sense of conflicted panic known as the “fight or flight” response.

“If the stress response is over-activated – especially if this happens too often or during certain vulnerable times in life such as before birth, in early childhood or in adolescence – it can lead to a chronic state of anxiety or depression,” says Dr. Perrot. “It can also impair the brain’s ability to generate new neurons, making a person more vulnerable to neurodegenerative conditions later in life.”

Dr. Perrot and her team of graduate and undergraduate students are currently investigating how a mother’s stress levels affect the stress response and general health of her offspring, by examining hormonal shifts and behavioral changes in rats raised in a variety of conditions.

“We’ve created an enhanced cage with a burrow that allows the mother to safely hide her pups while she leaves them to forage for food,” explains Dr. Perrot. “This simulates the natural environment and reduces her level of stress.”

Rats are naturally good mothers, explains Dr. Perrot, but when they’re exposed to excessive stress, they don’t spend as much time grooming or nursing their offspring and show other signs of lack of attachment, which in turn stresses their pups. In one experiment, she found that pregnant rats exposed to a cat later gave birth to pups with lower-than-average birth weights and elevated stress responses.

“We want to know if prenatal and early-life stress predisposes these rats to exhibiting stress in adolescence and adulthood,” explains Dr. Perrot. “Conversely, we want to know if reducing stress during pregnancy and/or while raising pups has a positive effect on the stress response in their offspring.”

Dr. Perrot has been studying how gender, age, reproductive status and the environment affect stress responses in rats for years. Now, as a member of the Brain Repair Centre, she is moving toward collaborative projects examining stress-response issues in humans.

“I’m interested in learning how we can foster resilience and reduce vulnerability in the face of the inevitable stresses we will face in our lives,” she says. “Our work is highlighting just how important it is to avoid over-activating the stress response early in life, to set the stage for a healthier stress response and better mental health for life.”  



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