Fig. 5. Responses of a type I medial octavolateralis nucleus (MON) unit to a 50 Hz vibrating sphere stimulus in still (left) and running (15.5 cm s^-1; right) water. Raster plots and level-response functions are as in Fig. 4. Displacement amplitudes were 2720, 305 and 60 µm. In still water, the unit responded to the vibrating sphere with a decrease in discharge rate. In running water, the unit's ongoing discharge rate was decreased (sphere displacements <60 µm were not tested). As a consequence, the response to the vibrating sphere was masked in terms of spike rate. Phase-coupling was comparable in still and running water.