Fig. 6.

Bursting activity in VTA DA cells.a, HRs exhibited a higher percentage of spikes emitted in bursts compared with LRs (t₁₀₄ = −2.79; p < 0.01). Each vertical bar represents the mean ± SEM of each group.b, The scatter plot illustrates the relationship between firing rate and bursting activity. There was a similar positive correlation between these two variables in both groups of animals (for LRs, r = 0.66; p < 0.001; for HRs, r = 0.75; p < 0.001; comparison of the regression slopes between the two groups,p > 0.4). Each point represents an individual cell. Empty circles depict cells from LRs;filled circles are cells from HRs. c, Representative traces of a nonbursting or bursting DA cell are shown.