Magnetic Resonance Imaging ( MRI )

Felix Bloch of Stanford University and Edward Purcell of Harvard University get the credit for discovering nuclear magnetic resonance (NMR). It is based on the fact that certain atoms behave like tiny spinning magnets. These images are mostly obtained from the resonance of hydrogen atoms. These atoms gather with respect to the magnetic force when placed in a magnetic field. Although the asymmetry of these atoms make them spin and wobble, the difference of atomic weight make the nuclei of different elements wobble at different frequencies. When radio waves are beamed across the atoms at right angle to the magnetic field, the spinning nuclei wobble synchronously. When the radio waves are turned off the synchrony induces a voltage (magnetic resonance) in the magnetic field. The different wobbling atoms are then located and analyzed by a computer to reconstruct image of the brain. MRI provides opportunity of structurally mapping the brain. Unlike CT scan, these images show the makeup and surroundings of cells.

Psychologists have also shown interest in the study of multiple sclerosis. In multiple sclerosis the immune system malfunctioning attacks the protective myelin cover leading to hard scar in the affected areas. This scar distorts normal conduction of nerve impulses along the axons. Ciccarelli et al (2000) used the MRI images for diagnosing multiple sclerosis and found isolated lesions around the lateral ventricles and in the white matter. Pyhtinen et al. (2006) have highlighted importance of MRI as a diagnostic tool for multiple sclerosis.

Although MRI does not provide information about the functioning of the brain, it does allow one to examine brain structure without exposing the client/ participant to radiation. However, the make-up of the machine is usually uncomfortable to claustrophobics.