Abstract
We reviewed recent animal studies of neurovascular coupling with in vivo two-photon excitation laser
scanning fluorescence microscopy (two-photon microscopy). Two-photon microscopy was introduced
into the field of biomedical imaging by Denk et al. in 1990. Since then, the technique has enabled us to
directly observe the cell-to-cell interactions involved in neurovascular coupling in in vivo animal brains.
Recent studies have shown that neurovascular coupling is accompanied by two microvascular events, (i)
an increase of red blood cell speed in brain capillaries at the region of evoked neural activity, and (ii)
vasodilation of the upstream pre-capillary and penetrating arterioles. However, the physiological
mechanism regulating these microvascular responses and their consequences for central nervous system
function remain incompletely understood. Future studies with in vivo two-photon imaging must address
these issues with multiple live cell imaging approach. A deeper understanding of neurovascular coupling
mechanism will have broad implications for the study of neurodegenerative disorders and brain aging.
