Reciprocal relationship between the major EEG rhythms and latencies of evoked potential intermediate components. A tentative explanation.

We recently demonstrated that there is a reciprocal relationship between the known brain wave rhythms (delta, 3.3 c/sec, 5 c/sec, theta, alpha, spindle, and beta) on the one hand, and the averaged evoked potential mid component latencies, on the other. In other words, the latter are closely related to the periods of the known brain wave frequencies. In this paper we offer a hypothetical explanation of this puzzling relationship, by assuming the following: 1) Whenever the fastest component of a sensory signal reaches the cortex it depresses EEG except for those waves of different frequencies which at that very instant exhibit a high amplitude peak of a preferential polarity. One half period later, different in real time for each brain wave frequency, high amplitude peaks will emerge from the record with opposite polarity to that which was preferential at the time of the signals' arrival. These segmental peaks are the same as those that express evoked potential components of mid latencies. For the somatosensory evoked potentials the time of occurrence of these peaks are defined by the following expression: (Formula; see text) where N is equal to successive numbers between 1 and 12, as well as to the fractions of 1; 20 msec is the moment of arrival of the fastest signal to the cortex. Some of the latencies correspond to the arrival of the delayed components of the somatosensory signals. Some correspond to the time of arrival of the auditory and visual signals, in an apparent expectation of multi-sensory signals.(ABSTRACT TRUNCATED AT 250 WORDS)