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Potential fields of seizure waves in the rabbit's cortex were mapped by means of a computer and the relationships between their behaviour and the graphoelements were studied. Elementary seizure waves are due to circular potential fields moving in the 10−1 m/sec range over the cortex. More complex graphoelements are due to the superimposition of potential fields of different characteristics. Usually, regular repetitive seizure waves are due to potential fields moving in the same direction. At cytoarchitectonic borderlines the potential fields become distorted and fade out or elicit other potential fields to arise in the contiguous area. Transverse vertical incisions in the cortex prevent the potential fields not only from transgressing the incision but also from spreading along it. The polarity of the potential field that moves corresponds to the polarity of the more “peaked” phase (the steeper phase) of the grapho-element. In most cases the positive fields are the moving ones. The consequences of these observations for the nature of the EEG are discussed.

A computer program is presented which transforms simultaneous recordings of multiple electrodes into graphical approximate representations of isopotential lines.