Introduction

Abstract

Advances in computer technology and software have made it possible for medical imaging techniques to be developed in the past 10 years that permit the visualization of structures and functional processes of the human brain (Freeman and Maurer 1989 b). The term “neuroimaging” refers to any of a number of procedures for visualizing features of the central nervous system. Imaging procedures that depict structures are computed tomography (CI) and magnetic resonance imaging (MRI), while procedures demonstrating functions include positron emission tomography (PET), cerebral blood flow analysis (CBF, also measured by single photon emission computed tomography, SPECT), magnetoencephalography (MEG), and computerized electroencephalographic topography (CET). The last-named procedure is generally called mapping or brain mapping. It is noninvasive, permitting follow-up examinations to be performed as often as needed, and has extremely short analysis times (in the range of milliseconds). Electroencephalographic (EEG) and evoked potential (EP) mapping do not portray anatomic structures but the constantly varying spatial distribution of the electrical fields generated by the brain.