Fig 3. Intrinsic optical imaging reveals a decrease in sensory-evoked signals in the contralateral somatosensory cortex after ION ligation.

A: Intrinsic optical signals were recorded through the intact skull, on the right posteromedial barrel subfield of the primary omatosensory cortex (S1BF; the black dotted line designates the borders of the imaging chamber). Variation in the reflected light (at 570 nm) induced by repetitive C1 whisker deflections (1 s at 100 Hz) is shown for a sham-operated (left) and an ION-ligated mouse (right). The results obtained before surgery (Baseline: BL, upper images) or 2 and 4 weeks after the surgery (2W and 4W, respectively, lower images) are expressed as R-R₀/R₀, with R representing the averaged reflected light measured over 1 s immediately after the stimulus presentation and R₀ representing the reflected light averaged over 1 s before the stimulus presentation. B: Spatial profiles of the reflected light measured along the rostro-caudal axis, using the region of interest indicated in A by the light grey rectangle. Note the absence of signal variation for the ION-ligated mouse at 2W and 4W. C: Quantification of the evoked signals was performed by looking for the minimal values of the spatial profiles (with examples shown in B). The ION ligation resulted in a significant decrease in evoked signals that persisted from the first week after the surgery through the following weeks. *p<0.05 and **p<0.01 ***p<0.001 vs. sham mice; #p<0.05 and ##p<0.01 vs. BL (n = 6 sham, n = 6 ION). All data are expressed as means ± SEM.