Differences between male and female brain explored
Advances in genetics as well as differences between the male and female brain were hot topics at a recent lecture organized by Weizmann Women and Science, a branch of the Canadian Society for the Weizmann Institute of Science.
From left are Francie Klein, chair of the Toronto chapter of Weizmann Women and Science; broadcaster Liza Fromer; Dr. Katherine Siminovitch, of Mount Sinai Hospital; Dr. Tali Kimchi, of Weizmann Institute and Cathy Beck, president of Weizmann Canada.
[Neil Meirovich photo]
The March 9 event was moderated by former Breakfast Television co-host and broadcast journalist Liza Fromer. It featured guest speakers Dr. Tali Kimchi of the department of neurobiology at the Weizmann Institute of Science in Rehovot, Israel, and Dr. Kathy Siminovitch of the Samuel Lunenfeld Research Institute at Mount Sinai Hospital.
Kimchi said that different genes lead to brain differences and therefore behavioural differences in males and females. However, while men and women often appear to be polar opposites, their brains are surprisingly similar, she said.
For more than half a century, scientists have believed that prototypically aggressive males and calm, nurturing females are mainly set apart by sex hormones that control genes and sexually dimorphic neuronal circuits that develop during youth. But, Kimchi said, current studies have suggested that gender-specific behaviours might have more to do with a single genetic “switch” that can be turned on and off.
Kimchi said her experiments performed at Harvard University involving mutant mice have helped her understand human genetic diseases that relate to social behaviour. She said her findings have shown that the behaviour of female mice can be radically altered when the creatures are deprived of their ability to sense pheromones, the subtle scents that animals give off and receive to communicate.
Removing the gene responsible for picking up pheromone signals from the female mice caused them to neglect their pups in the pursuit of potential mates, whom they tried to mount while emitting courtship whistles, she said. The male mice that could not smell the pheromones became less forceful and spent more time taking care of the newborn pups.
Kimchi said these results imply that the brain is capable of both male and female behaviour and that neurochemical cues initiate different actions. In the long run, her findings might improve the understanding of some disorders believed to be related to gender (males are more prone to autism, Parkinson’s disease and schizophrenia, while females are more prone to anxiety, depression and panic disorders). This will in turn aid in the development of gender-specific drug treatments, she said.
A senior investigator at the Samuel Lunenfeld Research Institute, Siminovitch is striving to provide new knowledge and technologies to enable more effective and “individualized” therapies for major diseases.
Siminovitch’s research is directed at identifying the molecular factors that regulate normal immune responses and that, when disrupted, result in immune deficiency or autoimmune diseases such as rheumatoid arthritis and inflammatory bowel disease. Such information is essential for improved therapeutic treatments yet to be created, she said.
Siminovitch’s presentation focused on the shift in science from genes to genomics. She said the shift in science through genome education will help identify biological determinants of diseases and improve health-care delivery. Genomics examines genetic information to determine biological markers predisposing an individual to disease, while genetics simply uses the information from one or two genes to explain a disease state.
Siminovitch spoke about targeted gene therapy – “the right dose of the right drug with the right indication for the right patient at the right time.” She said gene therapy is a technique for correcting defective genes responsible for disease development, and while the technology is still very new, it has been used with some success. Scientific breakthroughs continue to move gene therapy toward mainstream medicine, she said.