 Functional Neurophysiological Assessment FNPA. Research participants will lie supine on a mat with legs in an extended position. They will be asked to perform a series of eight exercises. 1 Relaxation for 5 minutes. 2 Reinforcement maneuvers. 3 Voluntary motor tasks. 4 Passive movements. 5 Tendon taps.. 6 Manual clonus elicitation. 7 Tonic vibratory response. 8 Withdrawal suppression. The plantar surface of the foot will be stimulated as is done to elicit the Babinski sign. The stimulus will be delivered with a rod. For the initial three trials subjects will be instructed to relax and allow the leg to jump should it do so. For the subsequent three trials subjects will be instructed to relax and prevent the leg from jumping. 