The theoretic as well as the practical advantages of considering the electrical activity of the cortex in terms of a spectrum has been emphasized in earlier papers.1 The most important of these advantages is that a spectrum reduces to an orderly arrangement a tremendous volume of data and thereby makes it comprehensible. A continuous spectrum, however, is necessary unless one is willing to discard a large part of the data.
Even before a technic was available for making this transformation, attempts were made to represent the electroencephalogram as a distribution of energy over a range of frequencies. Travis and Knott2 plotted the mean amplitude of waves of a given duration against the frequency. Gibbs, Gibbs and Lennox3 expressed their results in terms of energy distribution on a scale of frequency, relying for evidence as to whether the energy distribution was predominantly fast or slow on wave counts
GIBBS FA, LENNOX WG, GIBBS EL. THE CORTICAL FREQUENCY SPECTRUM IN EPILEPSY. Arch NeurPsych. 1941;46(4):613–620. doi:10.1001/archneurpsyc.1941.02280220046003
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