ABSTRACT
Scientists have been able to use the manner in which neurons work together as a window into their function. A variety of techniques for observing activity in the brain have been developed. The four major types of brain imaging techniques are EEG, MEG, PET, and fMRI. EEG (electroencephalography) is a technique for recording electrical activity from the scalp related to cortical activity. MEG (magnetoencephalography) measures the small magnetic field gradients exiting and entering the surface of the head that are produced when neurons are active. Positron emission tomography (PET) is a measure related to blood flow in the brain that reflects cognitive processing. Functional magnetic resonance imaging (fMRI) is based on the fact that blood flow increases in active areas of the cortex.
