Transcranial flavoprotein fluorescence imaging of mouse cortical activity and plasticity

Endogenous fluorescence signals derived from mitochondria reflect activity-dependent changes in brain metabolism and may be exploited in functional brain imaging. Endogenous flavoprotein fluorescence imaging in mice is especially important because many genetically manipulated strains of mice are available and the transparent skull of mice allows transcranial fluorescence imaging of cortical activities. In the primary sensory areas of mice, cortical activities and experience-dependent plasticity have been investigated using transcranial fluorescence imaging. Furthermore, differential imaging, based on stimulus specificity of cortical areas, distinguished activities in higher visual areas around the primary visual cortex from those in primary visual cortex. The combination of transcranial fluorescence imaging with the suppression of cortical activities using photobleaching of flavoproteins is expected to aid in elucidating the roles of sensory cortices including higher areas in mice.