Fig. 5
Disrupted coordination of rhythmic 4 Hz firing patterns in the VTA of D2R-OE mice. a Spikes of two simultaneously recorded VTA neurons, (red and black), during performance of the WM task. Each row corresponds to a single sample or choice run, aligned to run onset. Note the presence of coordinated rhythmic firing patterns in the two neurons. Scale bar: 250 ms. b Autocorrelograms of the two neurons in (a) (top, middle) and their cross-correlogram (bottom). Thin line indicates the sinusoidal function that best fit the correlograms and which was used to determine the presence of rhythmic firing and its frequency (inset; see Methods). c Distribution of frequencies at which rhythmic firing was observed in VTA DA and GABA neurons. Note the prevalence of firing patterns between 3 and 6 Hz, referred to here as “4 Hz” firing. d The percentage of VTA DA (Control: n = 113; D2R-OE: n = 103) and GABA neurons (Control: n = 124; D2R-OE: n = 104) displaying rhythmic firing in the 4 Hz range. The proportion of neurons was the same in both genotypes for both VTA DA (p = 1.00, Fisher’s exact test) and GABA neurons (p = 0.1). e Distribution of frequencies at which VTA neuron pairs displayed rhythmic coordinated firing. f Proportion of DA-DA (Control: n = 358; D2R-OE: n = 352), GABA-GABA (Control: n = 376; D2R-OE: n = 296), and DA-GABA (Control: n = 780; D2R-OE: n = 696) cell pairs showing coordinated 4 Hz firing. The proportion of cell pairs showing rhythmic coordinated 4 Hz firing was lower in D2R-OE mice (**p < .01, ****p < .0001, Fisher’s exact test)
