Mapping the growing brain

Mapping the growing brain

SYLVAIN COMEAU | Researchers at the Montreal Neurological Institute are launching a world first: a massive project to map the development of the human brain. The data will come from Magnetic Resonance Imaging (MRI) scans of children, from infancy to the age of 18, who show no signs of neurological impairment.

Dr. Alan Evans, left, and Dr. Bruce Pike PHOTO: NORMAND BLOUIN/MNI

"We're trying to build a data base on the anatomy of the developing brain," says principal investigator and project coordinator Alan Evans, "and the behavioural profiles of the kids (in the study) as they develop. As brains grow and mature, various functional capabilities such as planning, memory and linguistic tasks get better. We want to understand how the developing brain correlates with the improved performance."

Evans, a biomedical engineering professor and the coordinator for the MNI's McConnell Brain Imaging Centre, says that the data will be the most definitive to date, given the limitations of this kind of study.

"We will use a sample of hundreds of kids, to have good statistics on what is important in brain growth, and what it means in terms of improved cognitive abilities. The ideal would be to start with 500 infants and scan them every year for 18 years, but that's not feasible. So we have to look at a cross section of kids at different ages and try to come up with a profile of what is important in the brain."

The data will be collected in collaboration with seven American research centres. The result, at the end of the six-year project, will be the first pediatric neuroanatomy atlas, available to researchers on the web. The data will give researchers a point of comparison between normal brains and those of patients with neurological disorders.

"If you want to study any particular patient group, to find out what it is about that group that is abnormal, the very first problem is that we really don't know what normal is. So we are building the definitive data base on the normal brain, which can be used as a point of reference for these kinds of studies — for example, studies on autistic children or children with child-onset schizophrenia."

The database may also be used in studies looking at social/environmental factors involved in the onset of neurological disorders.

"Abnormalities in the brain can predispose someone to develop neurological diseases like schizophrenia, but environmental factors can be a trigger which sets it off. Twins with the same predisposition might not both become ill, if they grow up in different environments," says Evans.

Building this kind of database has only become technically possible in recent years.

"We don't have this kind of information because the technology has not existed in the past to allow us to nail down what is normal, structurally and behaviorally. Until recently, we didn't have magnetic resonance imaging, nor did we have the computer power to analyze the data and represent it with 3-D images on the web."

But perhaps the most innovative aspect of the project is that it is concerned with studying normal, healthy brains, unlike most neurological studies.

"For example, a study on autism will look at thirty autistic kids, compared to thirty normal kids, and try to determine the difference between the two.

"Typically, you find that that number of subjects in each group is not enough to give you definitive answers.

"The thrust of our project is that, once and for all, the pediatric research community needs one data set which helps any given group of researchers to make confident statements about the pathology of the disease that they study."

Financing permitting, the project may be extended to include adulthood, and possibly even old age, which would provide insight into diseases such as Alzheimer's.

Other McGill researchers who will play a leading role in the study include MNI neuroscientists Bruce Pike and Tomas Paus. The total budget for the project is $22 million, nine million of which is earmarked for the MNI-based portion of the study. Funding is being provided by the U.S. National Institutes of Health.