Scientists at the University of Illinois developed a non-invasive diagnostic tool that can study changes occuring at the surface of the brain dur to the brain activity.This technique is based uopn near-infrared spectroscopy and is simpler to use and less expensive thatn other methods such as functional magnetic resonance imaging and postition emission tonography.
According to Enrico Gratton, a UI professor of Physics, whenever the region of the brain is activated, it uses more oxygen. This method works by measuring the blood flow and oxygen consumption in the brain.
Firstly, light emitted by near infrared laser diodes is cariied through optical fibres to a person's head. The light penetrates the skull where it assesses the brain's oxygen level and blood volume.The scattered light is then collected by optical fibers, sent to detectors and analysed by a computer.By examining how much is absorbed, Gratton and his colleagues in the University's laboratory for Flourescence Dynamics can map portions of the brain and extract information about brain activity.
By measuring the scattering , we can determine where the neurons are firing. By this way one can simultaneously detect both blood profusion and neural activity and this technique can be used in many diagnostic, prognostic and clinical applications.
Gratton said, that it could be used to monitor recovering stroke patients on a daily, or even hourly basis. To validate the technique, Gratton and Vladislav Toronov, a postdoctoral research associate at the University's Beckman Institute for Advanced Science and Technology, compared haemoglobin oxygen concentrations in the brain obtained simultaneously by infra-red spectroscopy and by functional MRI-the gurrent "Gold Standard" in brain studies.
Both methods were used to generate functional maps of the brain's motor cortex during a periodic sequence of stimulation by finger motion and rest. The researchers demonstrated spatial congruence between the haemoglobin signal and the MRI signal in the motor cortex related to finger movement. They also demonstrated collocation between haemoglobin oxygen levels and changes in scattering due to brain activities.