1. In a medical imaging apparatus comprising scanning means for scanning a portion of the central nervous system to produce signals corresponding to the tissue of various regions of the scanned system to be imaged, and imaging means coupled to the scanning means for generating an image representing the scanned tissue of various regions of the central nervous system, the improvement comprising: memory means for storing and generating signals representing a predetermined electrophysiological condition of the central nervous system at various regions thereof including the spectrum of components in an electroencephalographic signal; detector means for detecting signals representing the actual electrophysiological condition of the central nervous system at various regions thereof including means for spectrally analyzing the components of the detected electroencephalographic signal for the various regions; comparison means coupled to said memory means and said director means for comparing the directed signals with the stored signals for said various regions of said central nervous system and for generating signals representing the deviation of the detected signals in one of the regions from said stored signals for said one of the regions; and display means coupled to said comparison means and the imaging means for visually indicating said one of the regions representing said deviation on said image.