Fig. 6. 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 3770, 1660 and 103 µm. In still water, the unit responded to the vibrating sphere with an increase in discharge rate. Ongoing discharge rate was comparable in still and running water. Consequently, the response to the vibrating sphere was not masked.