Brain imaging

The attempt to map functions to different parts of the brain must be one of the most fascinating areas of modern biology. Images of the brain in action can be created in a variety of ways. Some of the most exciting images arise from functional magnetic resonance imaging (fMRI), a further development of the older magnetic resonance imaging (MRI). The technique detects subtle increases in blood flow associated with activation of parts of the brain. Several web sites provide introductions to MRI and fMRI. Beginners might turn to the MRI Tutor, created by Ray Ballinger, at the Veteran's Administration Medical Center in Gainesville, Florida. The MRI Tutor offers visitors everything from an overview of the physics of magnetism to an explanation of fMRI. The web site of the Laboratory of Functional MRI at the Memorial Sloan-Kettering Cancer Center provides an introduction to fMRI to which illustrations add extra punch, for instance, one shows how touching a subject's hand triggered activity in the back of the brain. The site also gives an historical view of the technique's origins and an overview of its current role and future prospects, as well as a tour of other sites about fMRI on the web. To get a feel for the mechanics of the fMRI process, take a tour of the Neurovisualization Laboratory site at the University of Virginia, or visit the web site of the Center for Magnetic Resonance Research at the University of Minnesota, which contains some fMRI images in the form of three-dimensional overlays, with detailed descriptions of the experiment and of how the data were processed. Researchers in the field can turn to the Center for Magnetic Resonance Research's page to find fMRI software. 'Stimulate', for example, is a GUI-based (graphical user interface) software package, developed at the center, that analyzes fMRI images. Users can download the software and a complete HTML-based user's guide containing images and examples. The center's site also offers PhysioFix, a program that can be used to bring out finer details in an fMRI image. To learn more about such statistical approaches in imaging, take a look at the Statistical Parametric Mapping page at the web site of the Wellcome Department of Cognitive Neurology of University College London, which describes one technique that can be used to test hypotheses about imaging data. A software package called AFNI (Analysis of Functional NeuroImages), which was developed at the Biophysics …