Disparity between sensory nerve activity and psychophysical responses for air-puff stimulation of the index finger and palm in man.

Air-puff stimuli were delivered to five successive sites over the index finger and palm to obtain psychophysical responses and to record sensory nerve action potentials (SNAPs) from the median nerve at the wrist for elucidating psychoneural correlations across different locations of the glabrous hand. Magnitude estimations at each location evoked uniform subjective magnitudes for all stimulus locations. The time-integral of all SNAP components was the largest at the finger tip and the smallest at the most proximal site over the palm in agreement with the reported receptor density gradient across the finger and palm. Thus, the constant magnitude estimations with different quantities of peripheral afferent inputs across areas imply that the central nervous system plays a major role in shaping subjective magnitude estimation across different locations.