Fig. 5. Lack of effect of neuron #2 on the stretch-activated response. (A) Injection of depolarizing currents into neuron #2 produced regenerative action potentials (asterisks). (B) Such activation of neuron #2 had no effect on the stretch-activated response of TSR-4, where single and double asterisks indicate impulses conducted along the connective from depolarized neuron #2. If neuron #2 was an inhibitory accessory neuron, the stretch-activated response in B would be suppressed. Both the conducted impulses and the stretch-activated response were recorded through an en passant electrode at N3. Double arrows indicate stretch-activated impulses of TSR-4 derived from a rapidly adapting stretch receptor. The upward deflection below the trace shows a stretch stimulus at an amplitude of 1.5 mm.