  We study the renormalization group (RG) running of the neutrino masses and
the leptonic mixing parameters in two different extra-dimensional models,
namely, the Universal Extra Dimensions (UED) model and a model, where the
Standard Model (SM) bosons probe an extra dimension and the SM fermions are
confined to a four-dimensional brane. In particular, we derive the beta
function for the neutrino mass operator in the UED model. We also rederive the
beta function for the charged-lepton Yukawa coupling, and confirm some of the
existing results in the literature. The generic features of the RG running of
the neutrino parameters within the two models are analyzed and, in particular,
we observe a power-law behavior for the running. We note that the running of
the leptonic mixing angle \theta_{12} can be sizable, while the running of
\theta_{23} and \theta_{13} is always negligible. In addition, we show that the
tri-bimaximal and the bimaximal mixing patterns at a high-energy scale are
compatible with low-energy experimental data, while a tri-small mixing pattern
is not. Finally, we perform a numerical scan over the low-energy parameter
space to infer the high-energy distribution of the parameters. Using this scan,
we also demonstrate how the high-energy \theta_{12} is correlated with the
smallest neutrino mass and the Majorana phases.
