Fig. 3.

Neural output of the jump motor network. The nine flexor motor neurons were stimulated to fire (A) during the cocking phase, which increased tension in the flexor muscle (F) and rotated the tibia into a fully flexed position (H). The extensor motor neuron FETi (B) began firing to produce co-contraction and increase flexor frequency through the central excitatory synaptic connection from FETi to FLTi. The inhibitory interneurons M (C) and flexor inhibitor (FI) (D) then began firing once the extensor had reached the desired tension level (E). This caused the tension in the flexor (F) to fall below the tendon lock threshold (G), which disabled the tendon spring. The unopposed tension produced a rapid extension of the tibia (H). Each chart corresponds to the output from a labeled element from Fig. 2.