  In the standard seesaw model, finite corrections to the neutrino mass matrix
arise from one-loop self-energy diagrams mediated by heavy neutrinos. We
discuss the impact that these corrections may have on the different entries of
the tree-level effective neutrino mass matrix, paying special attention to
their dependence with the seesaw model parameters. We also briefly comment on
the implications these corrections might have on low-energy neutrino
observables.
