Fig. 10

The effect of aging and chronic neuroinflammation on the excitability profile of cholinergic neurons in the MS. A Sample voltage traces recorded after step current injections from 10 pA to 300 pA representing the firing frequency–current relationship (F–I curve). B, C Graphs of the F–I curves for all the groups describing the relationship between the current injected into cholinergic neurons and the firing frequency associated with the stimulus. The upward shift of the F–I curve in the young and adult group of IL6-control is indicative of increased excitability. D Box plot depicting the average gain of the F–I curves in all groups tested. E Sample voltage traces recorded following sinusoidal chirp stimulation (0.1–100 Hz) at different intensities (from bottom to top: 30 pA, 60 pA, 125 pA, 250 pA). F, G Graphs of the SFC curves for all the groups describing the relationship between the oscillation intensity and the maximal frequency at which the cell is still excitable. Note the upward shift in the maximal oscillation frequency in adult GFAP-IL6 mice, indicative of increased responsiveness compared to the age-matched control group. H Box plot depicting the average gain of the SFC curves in all groups tested. Data are shown as box plot, the box upper and lower limits are the 25th and 75th quartiles, respectively. The whiskers depict the lowest and highest data points, the horizontal line through the box is the median and the + sign represents the mean, two-way ANOVA, with Tukey’s post hoc test. Post hoc indicated by asterisks (*p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001)