Fig. 2

Intrinsic optical signal (IOS) imaging of spreading depolarizations. a Representative, background subtracted IOS image sequences demonstrate SD evolution across the experimental groups. Increased IOS intensity indicates SD. White arrowheads show the position of the KCl filled microcapillary or the stimulating electrode (ES) in the aCSF condition. Red dotted lines in “Area covered” delineate the maximal cortical area invaded by the SD. b The cortical area covered by SD relative to the total surface of the cortex. c The rate of SD propagation. d The localization of all SD foci observed in the cerebral cortex (Ctx) and the striatum (Str) in a schematic drawing. Some of the cortical SDs (n = 3) invaded the striatum at the ventral tip of the cortex, which is shown by the arrow. e The latency of spontaneous SDs with respect to HM or OGD exposure. ES bipolar electric field stimulation, KCl microinjection of 1 M KCl solution, HM hypo-osmotic medium, OGD oxygen–glucose deprivation, Str striatum, Ctx cerebral cortex. Data are given as mean ± stdev. Sample size (i.e. number of SD events analyzed) is indicated in each bar. A one-way analysis of variance (ANOVA) followed by a Holm–Sidak post hoc test (b, c) or a two-tailed T-test (e) was used for statistical analysis. The level of significance is given as p < 0.001*** vs. KCl; p < 0.01^## and p < 0.001^### vs. ES; p < 0.05^$, p < 0.01^$$ and p < 0.001^$$$ vs. HM