MAP: a Macintosh program for generating categorical maps applied to cortical mapping

Abstract

One technique for studying the cortex entails mapping the distribution of neuronal response properties across a cortical zone. In sensory cortex, ‘receptive fields’ are arranged in an orderly way such that they form a topographical representation, or ‘map’, of the sensory surface on the cortex. Detailed maps can be constructed by making many microelectrode penetrations across the cortex and measuring the receptive field at each site. A computer program called MAP was designed to aid in the efficient generation of these maps. MAP allows the user to mark penetration sites on digitized images of the cortical surface and to draw receptive fields on digitized images of the skin surface being studied. Penetration sites are then automatically assigned a category based on the location of the receptive field. MAP has significantly increased the speed of this experimental process. MAP contains a number of mechanisms designed to facilitate analysis. For example, it can automatically generate cortical maps based on receptive field locations. It can also show recorded neurophysiological data at each penetration site allowing the experimenter to visualize activity across the cortical zone. These features along with several others make MAP an effective tool for cortical mapping.