Figure 11.

Rest activity in the GPi after strong DA depletion (D = 20%). A, Top, The population activity (averaged over 20 neurons) in the GPi displays oscillations with a frequency ∼11 Hz. Bottom, Raster plots for the spike trains of the 20 units in the top figure. B, Correlation matrix of the spike trains of three units in GPi. Diagonal, Autocorrelations. Off-diagonal, Cross-correlations (see Materials and Methods). C, The distribution of the average firing rates of GPi neurons for D = 20%. Despite the dramatic change in the pattern of neuronal activity, the time average distribution does not change greatly after DA depletion [compare with the distribution in the normal situation (Fig. 6A)].