Fig. 2

Spatiotemporal changes in regional cerebral blood flow following olfactory nerve stimulation. a Schema showing the area of blood flow recorded using a laser speckle contrast imager. b–d Sample recording of regional cerebral blood flow in one rat. b, c Averaged signal over selected periods of 1 s. d Differential signal changes obtained from b and c when subtracting the baseline (b −1 to 0 s) signal from the subsequent image (c 5–6 s). e Percentage signal changes in the ipsilateral and contralateral olfactory bulb and frontal cortex in response to olfactory nerve stimulation (data extracted from the region of interest indicated by the black circle in a) and mean arterial pressure averaged every 1 s. Changes in each parameter are expressed as the percentages of corresponding basal values (mean value for 10 s before time zero). Each point and vertical bar represent the mean ± SEM (n = 6). *p < 0.05, **p < 0.01: significantly different from the pre-stimulus basal values (−1 to 0 s) using one-way repeated-measures ANOVA followed by Dunnett’s multiple comparison test