Does whisker stimulation induce c‐Fos expression in the rat ipsilateral deafferented cerebral cortex?

Recent study has shown that whisker stimulation of intact whiskers causes c-Fos expression in contralateral barrel layers. However, as few reports have investigated what kind of effect whisker stimuli has on c-Fos expression in the ipsilateral cerebral cortex, we researched the effect of such whisker stimuli. One side of the whisker pad was deafferented on adult rats, so that the deafferented barrel no longer received direct external stimuli and only one side of the barrel-whisker system remained. Whiskers on the intact side were then stimulated and the effects of these stimuli on the ipsilateral deafferented barrel cortex were investigated by observing levels of c-Fos expression, which is known as an excellent marker for functionally excited neurons. Whisker stimulation caused significantly increased c-Fos expression on the layers II/III, IV of the ipsilateral deafferented cerebral cortex (P < 0.05, P < 0.01). In conclusion, whisker stimulation caused c-Fos expression not only in the contralateral cerebral cortex, but also in the ipsilateral cerebral cortex.