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Source: McMaster University,Mapping the Mysteries of the Mind
Professor of psychiatry and behavioral neurosciences Dr. Sandra F. Witelson's discoveries - including the fact that men's and women's brains have different physical structures and that there are anatomical differences in the brains of heterosexual and homosexual people - have captured the attention of not only the scientific community, but the popular media as well.
"People are fascinated by brain research because, after all, the brain is what we are," comments Dr. Witelson. "Human beings interpret the world the way the brain perceives the world, and so its structure, and the relationship between its structure and our behavior, is very intriguing to us. It is also crucial information for progress in human society."
Our interest in the roots of our behavior is equalled by our concern about disorders of the brain, which impose a heavy cost upon society, emotionally and economically. The brain is vulnerable to a great many disorders, many of them chronic. They range from relatively milder afflictions such as dyslexia and learning problems, which nonetheless take their toll in individuals' sense of self-esteem and in society's efforts to treat and support them, to debilitating diseases like Alzheimer and schizophrenia, which can have severe effects on the lives of the victims, their families and their communities.
It seems hard to believe, given human beings' thirst for knowledge, that almost all the information we have about the brain is very recent - 90 per cent of what we know about the brain has been discovered in the last 15 years, according to estimates made by the Society for Neuroscience. Dr. Witelson is one of those contributing to this explosion in understanding, in large part through her development of a unique resource at McMaster - a brain bank, one that allows the discovery of relationships between cognition and anatomy in the normal brain, which in turn will help understand dis-ordered cognition and behavior.
Her achievement is unique not only because there are very few such collections in existence - there are only about two dozen brain banks in the world - but also because traditional collections contain samples from individuals who suffered neuropsychiatric disorders, such as Huntington's disease or Parkinson's disease.
What's unique about the bank that Witelson has established at McMaster is that the samples are from people who were intellectually and neuro-logically normal. They died, for the most part, of cancer in other parts of the body, and agreed in advance of their deaths to take part in interviews and neuro-psychological tests that would profile their cognitive abilities for eventual comparison with the anatomy of their brains.
"My admiration for these people is profound," says Witelson. "It is a difficult and sensitive issue for patients and family members, to decide to leave a part of yourself for medical research. These were people with limited life spans who were willing to give up time for research. Their reasons for agreeing to do this differed but were important to them - they wanted to make some kind of contribution to the medical community or to leave something behind that would be useful for future generations. They often said, 'Perhaps the research will help my grandchildren.'"
She adds that she's grateful to the Hamilton hospital network and administrators, path-ologists, nurses and oncologists, such as Dr. Peter McCulloch at the Hamilton Regional Cancer Centre, whose co-operation made it possible to create a resource that never existed before.
Started in 1977 and now numbering more than 100 specimens, the brain bank has enabled Dr. Witelson to look at the normal structure of the healthy brain and to make a number of discoveries about how its anatomy is related to language, behavior and functional ability.
One of her long-standing interests, for example, has been the lateralization of language function in the brain - only one side of the brain, the left hemisphere in most people, is responsible for language ability. This interest stemmed from her earliest research, as a student and as a professor here, on developmental dyslexia, the disorder that makes it difficult for otherwise bright children to learn to read and write.
Scientists already knew from studies of people who had suffered strokes that language ability is impaired when the left side of the brain is damaged, and that even though the stroke patient's right hemisphere might be perfectly healthy it is unable to take over the language function.
However, it was also known that there are people, usually left-handed people, with bilateralization of language function - their ability to speak, read and write is mediated by both sides of their brain.
"Our hypothesis was that the corpus callosum - the fibre tract that connects the two sides of the brain like a telephone cable - might be larger in a left-handed person: more communication, more fibres, we speculated," says Dr. Witelson. "And that's what we found. The bigger the corpus callosum, the more likely it was that the person had language in both hemispheres of the brain and the more likely it was that they were left-handed. A remaining question is: how can one get the right hemisphere to take on a language function?"
Dr. Witelson's interest in dyslexia has also led her to examine the structure of male and female brains to see if they reveal differences, since dyslexia afflicts boys much more frequently than girls.
She conducted painstaking studies of the temporal lobe of the cerebral cortex, the area of the brain that perceives language, in male and female brains, and discovered that women have about 11 per cent more brain cells in cortical layers of the area than men. The variation in cell density in the brains of the two sexes has been hailed as a way to explain why men and women can show the same levels of intelligence when the male brain is on average 10 per cent larger than the female counterpart. It also may account for some of the well-known cognitive and emotional differences between men and women.
Because of the importance of the brain bank and the work she has been doing, Dr. Witelson was contacted by the doctor who removed Albert Einstein's brain at his autopsy, and a portion of the great physicist's brain was sent to McMaster for examination.
"This was an important opportunity to study an extreme example - the brain of an extraordinary intellect - which may make it easier to discover relationships between ability and anatomy," explains Witelson.
Her research over the years has won her many prestigious awards and honors, including most recently Fellowship in the Royal Society of Canada, and her work has been supported by the U.S.'s National Institutes of Health as well as Canada's Medical Research Council and foundations such as the J. P. Bickell, EJLB and Morgan Firestone.
The personal rewards of her work, she says, have been in the excitement of beginning to answer some of the questions aboutwhy human beings function as they do. "When I listen to an opera aria, watch beautiful dancing, or work with a person struggling to learn to read or to re-learn to speak after brain damage, I wonder what the neural basis is of these functions and dysfunctions," says Witelson. "Like every-one else, I wonder, 'How does this work? What's going on?'"
Professor of psychiatry and behavioral neurosciences Dr. Sandra F. Witelson's discoveries - including the fact that men's and women's brains have different physical structures and that there are anatomical differences in the brains of heterosexual and homosexual people - have captured the attention of not only the scientific community, but the popular media as well.
"People are fascinated by brain research because, after all, the brain is what we are," comments Dr. Witelson. "Human beings interpret the world the way the brain perceives the world, and so its structure, and the relationship between its structure and our behavior, is very intriguing to us. It is also crucial information for progress in human society."
Our interest in the roots of our behavior is equalled by our concern about disorders of the brain, which impose a heavy cost upon society, emotionally and economically. The brain is vulnerable to a great many disorders, many of them chronic. They range from relatively milder afflictions such as dyslexia and learning problems, which nonetheless take their toll in individuals' sense of self-esteem and in society's efforts to treat and support them, to debilitating diseases like Alzheimer and schizophrenia, which can have severe effects on the lives of the victims, their families and their communities.
It seems hard to believe, given human beings' thirst for knowledge, that almost all the information we have about the brain is very recent - 90 per cent of what we know about the brain has been discovered in the last 15 years, according to estimates made by the Society for Neuroscience. Dr. Witelson is one of those contributing to this explosion in understanding, in large part through her development of a unique resource at McMaster - a brain bank, one that allows the discovery of relationships between cognition and anatomy in the normal brain, which in turn will help understand dis-ordered cognition and behavior.
Her achievement is unique not only because there are very few such collections in existence - there are only about two dozen brain banks in the world - but also because traditional collections contain samples from individuals who suffered neuropsychiatric disorders, such as Huntington's disease or Parkinson's disease.
What's unique about the bank that Witelson has established at McMaster is that the samples are from people who were intellectually and neuro-logically normal. They died, for the most part, of cancer in other parts of the body, and agreed in advance of their deaths to take part in interviews and neuro-psychological tests that would profile their cognitive abilities for eventual comparison with the anatomy of their brains.
"My admiration for these people is profound," says Witelson. "It is a difficult and sensitive issue for patients and family members, to decide to leave a part of yourself for medical research. These were people with limited life spans who were willing to give up time for research. Their reasons for agreeing to do this differed but were important to them - they wanted to make some kind of contribution to the medical community or to leave something behind that would be useful for future generations. They often said, 'Perhaps the research will help my grandchildren.'"
She adds that she's grateful to the Hamilton hospital network and administrators, path-ologists, nurses and oncologists, such as Dr. Peter McCulloch at the Hamilton Regional Cancer Centre, whose co-operation made it possible to create a resource that never existed before.
Started in 1977 and now numbering more than 100 specimens, the brain bank has enabled Dr. Witelson to look at the normal structure of the healthy brain and to make a number of discoveries about how its anatomy is related to language, behavior and functional ability.
One of her long-standing interests, for example, has been the lateralization of language function in the brain - only one side of the brain, the left hemisphere in most people, is responsible for language ability. This interest stemmed from her earliest research, as a student and as a professor here, on developmental dyslexia, the disorder that makes it difficult for otherwise bright children to learn to read and write.
Scientists already knew from studies of people who had suffered strokes that language ability is impaired when the left side of the brain is damaged, and that even though the stroke patient's right hemisphere might be perfectly healthy it is unable to take over the language function.
However, it was also known that there are people, usually left-handed people, with bilateralization of language function - their ability to speak, read and write is mediated by both sides of their brain.
"Our hypothesis was that the corpus callosum - the fibre tract that connects the two sides of the brain like a telephone cable - might be larger in a left-handed person: more communication, more fibres, we speculated," says Dr. Witelson. "And that's what we found. The bigger the corpus callosum, the more likely it was that the person had language in both hemispheres of the brain and the more likely it was that they were left-handed. A remaining question is: how can one get the right hemisphere to take on a language function?"
Dr. Witelson's interest in dyslexia has also led her to examine the structure of male and female brains to see if they reveal differences, since dyslexia afflicts boys much more frequently than girls.
She conducted painstaking studies of the temporal lobe of the cerebral cortex, the area of the brain that perceives language, in male and female brains, and discovered that women have about 11 per cent more brain cells in cortical layers of the area than men. The variation in cell density in the brains of the two sexes has been hailed as a way to explain why men and women can show the same levels of intelligence when the male brain is on average 10 per cent larger than the female counterpart. It also may account for some of the well-known cognitive and emotional differences between men and women.
Because of the importance of the brain bank and the work she has been doing, Dr. Witelson was contacted by the doctor who removed Albert Einstein's brain at his autopsy, and a portion of the great physicist's brain was sent to McMaster for examination.
"This was an important opportunity to study an extreme example - the brain of an extraordinary intellect - which may make it easier to discover relationships between ability and anatomy," explains Witelson.
Her research over the years has won her many prestigious awards and honors, including most recently Fellowship in the Royal Society of Canada, and her work has been supported by the U.S.'s National Institutes of Health as well as Canada's Medical Research Council and foundations such as the J. P. Bickell, EJLB and Morgan Firestone.
The personal rewards of her work, she says, have been in the excitement of beginning to answer some of the questions aboutwhy human beings function as they do. "When I listen to an opera aria, watch beautiful dancing, or work with a person struggling to learn to read or to re-learn to speak after brain damage, I wonder what the neural basis is of these functions and dysfunctions," says Witelson. "Like every-one else, I wonder, 'How does this work? What's going on?'"