Non-invasive functional monitoring of prefrontal cortex by electroencephalogaphy and near infrared spectroscopy

Abstract

The human brain is one of the most complex systems that mankind has ever known. Neuronal disorders in the brain, when present, affect the quality of life of the person concerned; a variety of neuronal problems related to attention, emotion, behavior, etc. have been reported. In such disorders, the brain is normally probed with sophisticated neurotechnologies to diagnose the type of disorder and plan further treatment. Hemodynamic and electrical signals are the two types of physiological signals that can be obtained from the brain. Electroencephalography (EEG) is the established standard to record the electrical activity of the cortex. EEG alone has been successfully used in the treatment of many neuronal disorders. On the other hand, the hemodynamic parameters can be obtained by either functional Magnetic Resonance Imaging (fMRI) or Near Infrared Spectroscopy (NIRS). NIRS has some advantages over fMRI - it is cheaper, has better portability thereby allowing bedside usage and is safer to be used on people of all ages and medical conditions. By extracting both the hemodynamic and electrical signals simultaneously, the medical condition of the concerned patient can be understood better. The objective behind this project was to study how the hemodynamic and electrical signals of a normal person vary, using simultaneous NIRS and EEG, when subjected to a working memory task.