FIGURE 7: Coordination of LFP activity across AC and pStr during sound-triggered reward time prediction.

A. Left: Illustration of electrode implanted in right AC and pStr. Right: Histological verification of electrode positions in AC (left) and pStr (right). The brain slice acquired from an example animal is overlaid with the corresponding coronal section from the Allen Mouse Brain Atlas (see Methods). The electrode tracks are indicated by the green dotted line on the brain slices and the markers in the middle indicate the depth at which the electrode was implanted in the right hemisphere. Scale bar: 500μm.

B. Normalized average pStr LFP (solid line denotes mean, shaded area represents SEM across no-lick trials) recorded in response to the sound onset from an example animal trained on the four different sound-reward intervals (represented by the different colors). The shaded pink region represents the period from sound onset.

C. Average pStr onset response magnitude computed across animals (N = 8) for each of the sound-reward intervals. Error bars represent mean ± SEM across animals. Comparison across sound-reward intervals yields ***p = 8.96×10⁻⁶ (Kruskal-Wallis test).

D. Scatter plot of the trial-wise correlation between AC and pStr onset response magnitudes for each of the sound-reward intervals for an example animal. Filled circles of different colors represent the trial-wise onset response magnitudes and the solid lines represent the linear fits for each of the sound-reward intervals. Pearson correlation coefficients for each of the sound-reward intervals was positive and significant: 0.5s interval (red): r = 0.582, p<0.001; 1.5s interval (orange): r = 0.673, p<0.001; 2.5s interval (purple): r = 0.673, p<0.001; 5s interval (green): r = 0.561, p<0.001.

E. The average correlation coefficients across animals across sound-reward intervals are not significantly different (p = 0.99, Kruskal-Wallis test)

F. Heat map representing the trial-wise cross-correlation of AC and pStr sound-evoked LFP responses for an example animal trained on an 0.5s sound-reward interval behavioral session. Time axis is set such that it denotes AC leading on the positive side and pStr leading on the negative side. Color bar indicates the cross-correlation coefficients.

G. Average cross correlation of AC and pStr sound evoked LFP responses across trials for the behavioral session shown above is indicated in black. The dotted red line shows the average of the shuffled cross correlation computed from randomized AC and pStr sound evoked LFP responses from the session.

H. The solid black line shows the difference trace between the real and shuffled average cross correlation in panel G. This cross-correlation difference trace has a peak at 0.03s as indicated by the dotted black line.

I. The average of the peak times of the cross-correlation difference traces computed across all animals and across all sound-reward intervals is significantly greater than 0s (**p= 0.0084, Wilcoxon signed rank test).

J. Average peak times of the cross-correlation difference traces across all animals was not significantly different across sound-reward intervals (p = 0.94, Kruskal-Wallis test).