Fig. 4. Regional variation in excitatory postsynaptic potential amplitudes in the opener muscles in the lobster walking leg (left) and claw (right). The excitatory motor neuron was stimulated at either 30 Hz/10-pulse train (walking leg) or 50 Hz/20-pulse (claw) train. The largest potentials were measured in proximal fibres, with smaller potentials in distal fibres; the smallest potentials occurred in central fibres.