Spinal interneurons specialized for flexion reflex:

 
Some spinal interneurons (example at right) are activated at short latency during fictive flexion reflex (limb withdrawal; A), but inhibited during fictive scratching (B) and fictive swimming (C). These interneurons (colored and black circles) were all found in the dorsal horn (D), in contrast to most T neurons (white circles) and most other scratch-activated interneurons (gray circles). (Int, interneuron; HF and KE, hip flexor and knee extensor motor nerves, respectively; Stim., stimulation.)

(Adapted from Berkowitz, J. Neurosci. 27:4634-4641, 2007.)