239Imaging Membrane Potential with SHG
experimental evidence about forward propagation of voltage signals upon synaptic input onto dendritic
spines. Eorts have been made to elucidate the membrane potential changes upon synaptic stimulation
using dierent techniques [25,38], but SHG recordings will be the ideal tools to answer this question.
With regard to axons, changes in axonal electrical information processing have drawn much attention
[39], but the direct observation of such processes needs to follow. Here again, membrane potential imag-
ing by SHG will be a powerful tool that can be employed to meet these needs. With the improvement of
this technique, we expect that SHG imaging will become a precious tool to complement other existing ...