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Deborah K. Hanula has a year of Journalism training from Humber College, a Political Science degree from the University of Waterloo, and a Law degree from the University of British Columbia. In addition, she has Diplomas in Cognitive Behavioural Therapy, Child Psychology, and Psychotherapy and Counselling as well as a Family Life Educator and Coach Certificate and Certificates in Reflexology, Assertiveness Training, and Mindfulness Meditation. She is the author of five cookbooks, primarily concerned with gluten-free and dairy-free diets, although one pertains to chocolate. As an adult, in the past she worked primarily as a lawyer, but also as a university and college lecturer, a tutor, editor, writer, counsellor, researcher and piano teacher. She enjoys a multi-faceted approach when it comes to life, work and study, in order to keep things fresh and interesting. Check out her new book: A Murder of Crows & Other Poems (2023).

Thursday, March 13, 2014

Intelligence Quotient (IQ) and Thickness of the Brain's Cortex


The rate of change in the thickness of the brain’s cortex is an important factor associated with a person’s change in the intelligence quotient, more popularly known as IQ.  For decades, it was a commonly held belief that IQ remains more or less constant over time, so that your childhood IQ is pretty well what you have for life.

According to a comprehensive study by scientists at the Montreal Neurological Institute and Hospital, at McGill University, and at the McGill University Health Centre, (all of which are located in Montreal, Quebec) as well as by scientists from four other countries, IQ varies over time according to the thickness of the brain’s cortex.
The cortex is the thin, outermost layer of the brain’s nerve cell tissue.  It usually measures just a few millimetres in thickness.  It contains nerve cell bodies and is critical for cognitive functions such as perception, language, memory and consciousness.
It appears that the cortex begins to thin around the age of six or seven as part of the normal process of aging. The study in question here, led by Professor Sherif Karama of McGill University, and his colleagues, involved following 188 children and adolescents over a period of two years. Magnetic resonance imaging (MRI) of the young people was conducted at six sites across the United States. This study is the first to show the association between cortical thickness and development as it relates to full scale IQ. It found that within a relatively short period of two years:  “people with a significant increase in IQ did not have the expected cortical thinning;  people whose IQ stayed the same had the normal expected cortical thinning;  people with a significant decrease in IQ had exaggerated cortical thinning.” (1)
The reasons behind the findings remain unclear. Some of the developmental changes may be genetically pre-determined, or other factors such as nutrition and education may be at play.  The changes could also be due to a combination of these or include other unconsidered factors.

D.

(1) “Link Between IQ and Brain Cortex Confirmed By New Evidence”, http://www.redorbit.com/news/science/1113086884, March 2014.
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