Figure 6.

HGA on the CE correlated more with co-firing than the CE spike rate did. a, Single trial examples comparing the first co-firing pattern (dark blue) to HGA (turquoise) and spike rate (magenta) on the CE (time relative to reward onset). b, Correlation (R) of multivariate linear regression (MLR) fit of the first co-firing pattern to spike rate (magenta), or to HGA (turquoise), averaged over all the CEs (dashed lines, individual CEs, N=9; bars, mean ± s.d., ***p=0.004, two-sided Wilcoxon signed rank test). c, R of MLR fit using an increasing number of factors to either spike rate (magenta) or HGA (magenta). We fitted a factor analysis model for each number of factors separately. Thick trace and colored shades: mean, s.d. over CEs. d, Absolute values of the co-firing weights of two example monkey-CEs. CEs outlined in red. e, Mean values of the absolute co-firing weights on the electrodes adjacent to the CE (red), as well as the mean (±s.d.) of average value of the absolute co-firing weights on the electrodes adjacent to 20 randomly selected electrodes (gray) of two example monkeys. These R values were not significantly different (p>0.4, one-sided permutation test).