Functional Magnetic Resonance Imaging (fMRI) Introduction Structural imaging reveals the static physical characteristics of the brain. It makes it useful in diagnosing disease. Functional imaging reveals dynamic changes in brain physiology that might correlate with cognitive functioning, for example. Neural activity consumes oxygen from the blood. This triggers an increase in blood flow to that region and a change for deoxyhemoglobin in that region. As the brain is always physiologically active, functional imaging needs to measure relative changes in physiological activity. The most basic experimental design in functional imaging research is to subtract the activity in each part of the brain whilst doing one task away from the activity in each part of the brain whilst doing a slightly unfamiliar task.  We call this cognitive subtraction . Other methods, including parametric and factorial designs, can minimize many of the problems associated with cognitive subtraction. There is no foolp

Electroencephalography (EEG) Electroencephalography (EEG) is a non-invasive electrophysiological method to measure the electrical activity of the brain. We can compare it with echocardiography of the heart that measures the electrical activity of the heart. EEG measures voltage fluctuations resulting from ionic current within the neurons of the brain. Clinically, it refers to the recording of the brain's spontaneous electrical activity over a period, as recorded from multiple electrodes placed on the scalp. Diagnostic features Event-related potentials: These investigate potential fluctuations time-locked to an event, such as 'stimulus onset' or 'button press'. Spectral content: This analyses the type of neural oscillations (popularly called "brain waves") that can be observed in EEG signals in the frequency domain.   Uses Most often we use EEG to diagnose epilepsy. It is also used to diagnose 1.        Sleep disorders 2.       Depth o