He studies the brain. She focuses on the heart and body. But Tomas Paus and his wife Zdenka Pausova have joined forces to understand how the brain and body influence each other in the development of depression, cardiovascular disease and other disorders.
The couple recently returned to Canada from England to launch an ambitious, multigenerational study of families from different ethnic groups in Toronto.
Their goal is to learn more about the genetic and environmental factors that shape our brains and our metabolisms and can lead to such problems as addiction, obesity and hypertension, also known as high blood pressure.
Does how reactive someone is to stress affect whether they become obese? Are there structural differences in the brain that mean people prefer fatty diets or that they are not easily satiated when they eat? Does adversity in early childhood affect weight gain or drug use in adolescence?
These are some of the questions they hope to answer by doing detailed brain and body scans of thousands of volunteers. Participants will also provide blood samples and answer questions about what they eat and how they live.
Ideally, Dr. Paus and Dr. Pausova would like to follow individuals from childhood through to old age, but they say that is extremely difficult. The next best thing is to recruit multigenerational families – children, parents and grandparents – to study the interplay between genes and the environment.
One of their goals is to find new ways to tell whether an adolescent is susceptible to a particular disease.
“We want to look at early risk factors and subclinical signs in adolescence that diseases are already starting before the symptoms are apparent,” says Dr. Pausova, 47. She studies cardiovascular health in adolescence and has taken a position at Toronto's Hospital for Sick Children.
Dr. Paus, 48, a neuroscientist and one of the world's leading experts on the adolescent brain, has joined Baycrest's Rotman Research Institute.
They are both from the Czech Republic, but moved to Montreal in 1990 and stayed for 15 years. They became Canadian citizens and raised their daughter there, but left five years ago for the University of Nottingham and an opportunity to work together on how the brain influences the body, and vice versa.
They came back to Canada in part because the Rotman Research Institute committed to raise the $10-million needed for the new Toronto Trans-generational Brain and Body Centre.
It's their dream project, a more ambitious version of a study they began in the Saguenay region of Quebec five years before they left Canada. It involved nearly 600 adolescents between the ages of 12 and 18.
They applied for grants separately, but studied the same group. Dr. Paus found, for example, that exposure to cigarette smoke in the womb appears to affect brain development and behaviour in adolescence. A part of the brain known as the orbital frontal cortex was thinner in the children whose mothers had smoked during pregnancy. Those children were also more likely to have experimented with drugs.
In lab animals, exposure to nicotine in the womb influences the reward circuitry in the brain and how they respond to psychoactive drugs later in life.
Dr. Pausova found that girls exposed to nicotine in the womb were more likely to put on weight late in adolescence.
The Saguenay study also yielded intriguing insights into differences in how the male and female brain develop in adolescence. In the boys, the volume of white matter in the brain increased by 25 per cent between the ages of 12 and 18. White matter connects different parts of the brain together and the rapid growth appears to be mediated by testosterone. In girls, the changes were less dramatic, about a 5-per-cent increase in white matter.
