Neural mechanisms underlying sensitivity to reverse-phi motion in the fly
Fig 5
Motion-sensitive tangential cells show selectively inverted responses upon reverse-phi stimulation.
a-b Average membrane potential of lobula plate tangential cells (N = 23, pooled across 8 horizontal and 15 vertical system cells, with accordingly oriented direction of movement) in wild-type flies. Responses were recorded at 2 kHz and down-sampled to 50 Hz for presentation. Gray shaded area indicates stimulation period (λ = 45°, v = 128° s-1, step width = 6°). Shading around traces shows bootstrapped 95% confidence intervals. a Phi stimulation. Cells depolarize for motion in preferred direction (PD) and hyperpolarize weakly for motion in the opposite null direction (ND). b Reverse-phi stimulation. The PD response is abolished, whereas the ND response inverts. c Summary statistics (averaged across initial 2 s post-onset). Note that whiskers show the full sample range. See Materials and Methods for details on electrophysiology experiments.