Fig. 9. Experiment 2B network performing the variable-speed path integration task. Plot shows link weights (y-axis; see Fig. 8) over the whole trial (x-axis; see Fig. 7). B_1,2,3 show the approximate time of arrival at each beacon (the nest is reached at the very end of the trial). From 2 time units into the trial until 3 time units, a large change in the values of w_L3/R3 reflects noise applied to the forward motor output, as detected by the speed sensor. The second abrupt change in these values reflects the period of enforced captivity of the agent at the last beacon before homing begins.