  We investigate the fluctuation dynamics of a probe around a deterministic
motion induced by interactions with driven particles. The latter constitute the
nonequilibrium medium in which the probe is immersed and is modelled as
overdamped Langevin particle dynamics driven by nonconservative forces. The
expansion that yields the friction and noise expressions for the reduced probe
dynamics is based on linear response around a time dependent nonequilibrium
condition of the medium. The result contains an extension of the second
fluctuation dissipation relation between friction and noise for probe motion in
a nonequilibrium fluid
