Maurizio Corbetta and colleagues reported their findings in the March 15, 2007 issue of the journal Neuron, published by Cell Press.
The researchers used "functional connectivity" MRI (FC MRI) to examine connections between active regions of the brain. MRI is a widely used analytical technique, in which harmless radio waves and magnetic fields are used to map oxygen levels in brain regions. By performing FC MRI in patients with spatial neglect, the authors identified regions of the brain where there was a disruption of normal functional brain circuitry.
In their experiments, the researchers used FC MRI to study the brains of 11 stroke patients with neglect, both at one month and at more than six months after their strokes. While the patients' brains were being scanned, the researchers asked them to perform a simple task to determine their ability to perceive the left and right visual fields. Specifically, the patients were asked to indicate whether they could see an asterisk presented on the right or left side of a computer screen. As a control, the researchers also conducted similar tests on healthy volunteers.
The study revealed new details about how functional connectivity within and between different regions of the "attention networks" in the parietal cortex of the brain was disrupted in the brains of the stroke patients. The study also enabled new insights into how this disruption contributes to spatial neglect.