Inhibition of scratch-specialized cells during swimming:

 
This spinal interneuron was rhythmically activated during fictive scratching (A&B) but received hyperpolarizing inhibition during fictive forward swimming (C&D). Its morphology was distinct from T neurons (E). Its firing rate was strongly rhythmically modulated during scratching (F). It displayed large membrane potential oscillations during fictive scratching and smaller oscillations during fictive swimming. (Int 5 is a scratch-specialized interneuron; KE, HF, and HE are knee extensor, hip flexor, and hip extensor motor nerves, respectively; Stim., stimulation.)

(Adapted from Berkowitz, J. Neurophysiol. 99:2887-2901, 2008.)