Fig. 3: Electric field strength in CA1 correlated with the stimulation-evoked effects during 40 Hz and 140 Hz stimulation, but not 1 kHz.

a Example fields-of-view showing max-min projected GCaMP7f fluorescence in the CA1 in a mouse with visible electrode tip during (i) 40 Hz, (ii) 140 Hz, and (iii) 1 kHz stimulation. The electrode is outlined with a white dashed rectangle, and its tip marked with a white cross. White dashed circles mark every 200 µm from the electrode tip. Every neuron is marked with a small colored circle (red = activated, blue = suppressed, gray = unchanged) outlined in white. (b) The fraction of neurons being activated (red) or suppressed (blue) within each distance bin across recordings (0–200 µm, 200–400 µm, and >400 µm) during (i) 40 Hz, (ii) 140 Hz, and (iii) 1 kHz stimulation (±95% confidence interval; Chi-squared test, statistical results in Suppl. Table 1). c The mean GCaMP7f fluorescent traces (±95% confidence interval) of activated (red) and suppressed (blue) neurons in each bin (0–200 µm = lightest shade, 200–400 µm = middle shade, and >400 µm = darkest shade) during (i) 40 Hz, (ii) 140 Hz, and (iii) 1 kHz stimulation. d Quantification of the area under the curve (AUC) during stimulation for the traces shown in c during (i) 40 Hz (ii) 140 Hz, and (iii) 1 kHz stimulation (Kruskal-Wallis with Dunn-Sidak correction, statistical results in Suppl. Table 1). Violin plots depict the kernel density overlaid with box plots showing the interquartile range (1x, 1.5x). The white lines in the boxes are the median. All tests are two-tailed. n.s., not significant, *p < 0.05, **p < 0.01, ***p < 0.005.