Brain Mapping with Windows 95

This paper presents the design of a Windows brain mapping application named brainmap Brain mapping is a technique that presents the spatial distribution of the electrical brain activ ity which is generated at the cortex and subsequently recorded on the scalp The brain map is constructed by interpolation of the measured scalp potentials at the electrode locations brainmap combines the e orts of Giele and Margarita into an all embracing brain mapping program for neurophysiological research on the functioning of the human brain brainmap s main design goals are to display scalp potential maps as well as scalp current density maps for a user speci ed time instance Moreover the program must generate high quality images for inclusion in articles or conference posters brainmap incorporates a variety of functions e g for displaying the brain maps in full color or in grey colors These functions can best be presented to the user with the Windows environment where the user can select menu items or compare di erent brain maps by clicking with a mouse between various windows The key to a functional and valuable user interface is rapid prototyping where the user is involved in the program design at an early stage It is a process of continually evaluating and re ning prototypes in cooperation with a representative group of future users brainmap s program code is written with Microsoft s Visual c in conjunction with the Microsoft Foundation Class library mfc Visual c together with mfc helps to de ne the structure of the application When the programmer adapts his or her needs to this prede ned structure mfc provides numerous functions which dramatically reduce the amount of code the programmer must otherwise write to create an acceptable program The spherical spline interpolation method forms the pillar of the generated brain maps This interpolation method provides a simple mathematical derivation of the scalp current density which enables the user to identify scalp current sources and sinks brainmap uses fast al gorithms to compute the spherical spline The algorithms provide accurate potential and scalp current density maps while keeping a very short computation time brainmap is still a prototype An intensive evaluation of the correctness of brainmap s al gorithms and the usability of it s user interface must point out the program s strong and weak aspects brainmap can serve as a basic platform for new functionality to be added in the future It s structure garanties an easy interpretation of the required extensions This paper aims to present an overview of brainmap s Windows design issues as well as the program s main algorithms to compute the brain map Moreover this paper provides a valuable background on brainmap s operation for the user