Researchers are for the first time undertaking a large-scale study to try and map out exactly how our brains are wired. Matthew Knight learns how the Human Connectome Project hopes to help scientists further understand various neurodisorders, including autism and Alzheimer's disease
The human brain is a bewilderingly complex place made up of billions of nerve cells controlling our every thought and deed.
While scientists know much about its basic anatomy, little is understood about how the brain’s constituent parts communicate with one another.
But a new pioneering venture in the United States called the Human Connectome Project hopes to change all that by creating a detailed map of the brain’s functional and structural connectivity.
The hope is that building a “connectome” will lead to better understanding of the brain and its disorders like autism, schizophrenia and Alzheimer’s disease.
“Knowing the brain’s building plan is crucial to understanding how the brain works and how the brain adapts to change, including growth, development and reaction to injury and disease,” says Professor Van Wedeen, director of Connectomics at the Martinos Center for Biomedical Imaging at Massachusetts General Hospital (MGH).
Wedeen is co-leading one of two consortiums awarded funds of US$40m in September 2010 by the US National Institutes of Health.
With the help of German tech group Siemens, MGH has built a powerful new diffusion Magnetic Resonance Imaging (MRI) scanner 10 times more sensitive than conventional ones which tracks the three-dimensional motion of water molecules along the brain’s fibre networks.
“It’s already proving to be a brilliant instrument beyond our expectations,” Wedeen says.
Reporting in the American journal Science earlier this year, Wedeen et al revealed the most detailed images yet of the brain’s structure.
It confounded the traditional notion of brain connections being organised like a bowl of spaghetti with wires going from one place to another.
Instead, what the connectome scanner found was a far more organised, grid-like structure, Wedeen says, with the brain’s pathways tracking along a three-dimensional grid resembling the warp and weft of cloth.
“As a strategy for analysing and describing the brain, having a natural longitude and latitude coordinates system is a huge step up,” Wedeen explains.
The scanner is currently being brought up to its full operating capacity ahead of its main task of examining the brains of 1,200 healthy subjects later this year.
“By having a map and a model, we hope that this will be instrumental in making progress into connectivity and the mental health consequences of connectivity,” he says.
Mental health has lacked objective standards for assessing the condition of the brain and its functions, Wedeen says.
“In the heart we have echoes (echocardiogram), for cholesterol we have blood tests, in the brain we have interviews,” he adds.
“A quantitative, objective marker which can be used by clinicians would have some calculable benefits for mental health.”
Taleb Altel, Associate Professor of organic medicinal chemistry at the UAE’s University of Sharjah, thinks it could help with assessing the effectiveness of drug therapies before and after treatment.
Altel is spearheading efforts at the university to develop new treatments for Alzheimer’s disease – a deadly form of dementia where a build up of “plaques” and “tangles” on neurons disrupt communications between brain cells.
The disease affects around 6 million people in North America and a similar number in Europe.
Altel and colleagues recently published the results of a three-year study investigating the use of chemical compounds to target the proteins and enzymes which cause the disease to progress.
“We are making a huge effort at the University of Sharjah to find the right molecules. We have found three or four which have the potential to inhibit the enzymes effectively,” says Altel.
“These molecules might be a potential drug candidate that leads to a reverse of the progression of Alzheimer’s disease. This primary research is very, very promising,” Altel says, though he cautions that a potential drug treatment is still several years away.
Visit www.humanconnectomeproject.org for more information on the research project