Fig. 2
Impaired recruitment of 4 Hz oscillations in the VTA and PFC during working memory in D2R-OE mice. a Neural activity was compared in the center arm of the maze in the sample (blue) and choice phases (red). Overt behavior is the same in both phases but working memory is only required in the choice phase. b Example LFP trace recorded in the VTA (top) during the choice phase and its spectrogram (bottom). Note the presence of 3–6 Hz oscillations, referred to as “4 Hz” oscillations, which can also be observed in the filtered LFP trace (thick lines). Scale bar: 100 µV. c, d Average spectral power in the VTA during the sample and choice phases for control (c) and D2R-OE (d) mice. e Average strength of 4 Hz oscillations (calculated by averaging power between 3 and 6 Hz) during sample and choice phases in the two groups. Four Hertz oscillations were stronger during the choice phase in the VTA of control animals (n = 19, ***p < .001, sign-rank test) but not in D2R-OE mice (n = 17, p = 0.79, sign-rank test). f–h Four Hertz power in the PFC of control and D2R-OE mice during sample and choice phases, shown as in c–e. 4 Hz oscillations were stronger during the choice phase in the PFC of control animals (n = 19, ***p < .001, sign-rank test) but not in D2R-OE mice (n = 17, p = 0.18, sign-rank test). Shaded regions and error bars represent mean ± s.e.m over animals
