Fig. 13.
Correlation between field activity and population discharge of neurons. A, A short segment of theta activity (theta) and summed activity of 3int(p) and 16 pyr. Note the similarity between theta field and summed interneuron activity. B, The square of the mean correlation coefficients between unit activity and theta plotted as a function of the number of simultaneously recorded neurons. Note that interneurons (int) showed a more reliable relationship with theta than did pyramidal cells.Asterisk, Three of the six interneurons recorded from the alveus and st. oriens. C, The square of the mean correlation coefficients between unit activity and ripple cycles plotted as a function of the number of simultaneously recorded neurons during ripple. Note that pyramidal cell ensembles predict ripples more reliably than theta, but the reverse is true for interneurons.