Figure 2.

Subthreshold Mismatch Responses Are Widespread in L2/3, and Responses Correlate with Locomotion Speed

(A) Top: heatmap of average V_m responses to mismatch for 32 neurons, sorted by average response. Neurons classified as dMM and hMM are marked by orange and turquoise shading, respectively. Asterisks indicate examples shown in Figure 1. Bottom: average V_m response to mismatch across 17 dMM neurons (orange), 6 hMM neurons (turquoise), and 9 unclassified neurons (gray). Shading indicates SEM over neurons.

(B) Histogram of average mismatch responses. In dark gray are counts of neurons with a significant response (p < 0.05, paired t test between pre- and post-mismatch average V_m). Turquoise and orange lines indicate hMM and dMM thresholds, respectively. Shown above the histogram are mismatch responses colored according to their p value. ^∗p < 0.05, ^∗∗p < 0.01, ^∗∗∗p < 0.001.

(C) Top: heatmap of the average spiking rate during mismatch. Color coding and sorting are as in (A). Bottom: average mismatch-induced change in the spiking rate for the same groups of neurons as in (A). Shading indicates SEM over neurons.

(D) Boxplots comparing spiking rate responses to mismatch for dMM neurons (orange, n = 17), unclassified neurons (gray, n = 9), and hMM neurons (turquoise, n = 6). One-way ANOVA: p < 0.01, F-statistic = 12.5; dMM versus hMM: p < 0.01, dMM versus unclassified: p = 0.43, hMM versus unclassified: p < 0.02, rank-sum test. Boxplots show median, quartiles, and range-excluding outliers (see the Statistics section in STAR Methods for details).

(E) Top: average V_m response for the 10 mismatch events with the highest (black) and lowest (gray) locomotion speeds for an example dMM neuron. Shading indicates SEM over trials. Values in gray bold italics indicate the mean pre-stimulus voltage. Bottom: scatterplot between average locomotion speed and mismatch response for 45 trials. The dashed gray line shows linear regression.

(F) As in (E), but for an example hMM neuron. Average V_m responses were calculated from five trials with the lowest (gray) and highest (black) locomotion speeds.

(G) Histogram of correlation coefficients between locomotion speed and mismatch response. In dark gray are counts of neurons with a significant correlation (p < 0.05). Boxplot compares values for dMM neurons (orange, n = 15), hMM neurons (turquoise, n = 5), and unclassified neurons (gray, n = 7), with significant correlations shown as dark data points. One-way ANOVA on ranks: p < 0.02, chi-square = 8; dMM versus hMM: p < 0.02, dMM versus unclassified: p = 0.07, hMM versus unclassified: p = 0.34, rank-sum test. Boxplots show median, quartiles, and range-excluding outliers.

See Table S1 for inclusion criteria.