  We present results from our recent lattice QCD study of $N\pi$ scattering in
the positive-parity nucleon channel, where the puzzling Roper resonance
$N^*(1440)$ resides in experiment. Using a variety of hadron operators, that
include $qqq$-like, $N\pi$ in $p$-wave and $N\sigma$ in $s$-wave, we
systematically extract the excited lattice spectrum in the nucleon channel up
to 1.65 GeV. Our lattice results indicate that N$\pi$ scattering in the elastic
approximation alone does not describe a low-lying Roper. Coupled channel
effects between $N\pi$ and $N\pi\pi$ seem to be crucial to render a low-lying
Roper in experiment, reinforcing the notion that this state could be a
dynamically generated resonance. After giving a brief motivation for studying
the Roper channel and the relevant technical details to this study, we will
discuss the results and the conclusions based on our lattice investigation and
in comparison with other lattice calculations.
