Pii: 0014-4886(76)90152-7

The purpose of this investigation was to examine the phase relations of action potentials of single cells in CA1 to the rhythmical slow waves induced by eserine in the rabbit. All animals had an intercollicular decerebration so only structures rostra1 to the cut contributed to the results obtained. Spikeslow wave phase patterns were compared with a random model using the x3 test. Nonrandom patterns (P < 0.01) characterized 22 of 47 cells tested. With use of digital filters, consistent phase patterns were observed even if the slow wave duration varied by as much as 100 msec. Comparing unit firings with nonconcurrent slow wave cycles showed the patterns were phase related, not occurring by chance or coincidence. Apparently clusters of CA1 pyramidal cells fire phase-related spikes.