A T5 cell and its direction-selective responses to unidirectional grating motion. The intracellular recording (A) shows excitatory responses to upward progressive motion, and inhibitory responses to downward regressive motion (see Douglass and Strausfeld, 1995 for additional information). The recorded neuron (B) was filled with Lucifer yellow and reconstructed from confocal projections. The dendrites of T5 reside exclusively within the outermost stratum (below dotted line) of the lobula (Lo). Output terminals of T5 cells in the lobula plate (LoP) tend to be restricted to one of four layers that are sensitive to upward, downward, progressive and regressive motion directions. The cell body (not shown) lies proximal to the lobula plate, and is connected to the base of the dendritic tree via the cell body fiber (arrows). Ch, chiasma. Scale bar: 25 µm. For additional information, see Douglass and Strausfeld (1995).