  Models involving large extra spatial dimension(s) have interesting
predictions on lepton flavor violating processes. We consider some 5D models
which are related to neutrino mass generation or address the fermion masses
hierarchy problem.
  We study the signatures in low energy experiments that can discriminate the
different models. The focus is on muon-electron conversion in nuclei, $\mu\ra e
\gamma$ and $\mu\ra 3e$ processes and their $\tau$ counterparts. Their links
with the active neutrino mass matrix are investigated. We show that in the
models we discussed the branching ratio of $\mu\ra e \gamma$ like rare process
is much smaller than the ones of $\mu\ra 3e$ like processes. This is in sharp
contrast to most of the traditional wisdom based on four dimensional gauge
models. Moreover, some rare tau decays are more promising than the rare muon
decays.
