I present some recent experimental methods for determining the phase-resetting curves for neurons in noisy environments. I show that the shape of the PRC determines how well neurons synchronize to noisy correlated inputs. In particular, PRCs which have negative and positive regions synchronize much better than strictly positive PRCs.  The former arise near subcritical Hopf bifurcations (HB) while the latter near saddle-node on a limit cycle bifurcations (SNIC). I derive equations for the invariant density of phases in noisy maps and provide some approximate solutions.  I also describe patterns in arrays of oscillators using the experimentally determined maps.