Fig. 2. Sensitivity of medial octavolateralis nucleus (MON) units to running water. Change in discharge rate is plotted as a function of flow velocity. A rate change of zero indicates that discharge rates in still and running water were identical. (A) Data from flow-sensitive units that responded with increasing ongoing discharge rates to increasing flow velocities. Broken lines represent data from units in which discharge rates decreased at flow velocities above approx. 10 cm s^-1. (B) Data from flow-sensitive units that responded with decreasing discharge rates to increasing flow velocities. (C) Data from flow-insensitive units. In these units, ongoing discharge rate in still water was not different from the ongoing rates measured at any of the tested flow velocities.