Does Adding Painful Information to Tactile Stimuli Improve the Accuracy of Perceived Locations?

This study investigated whether localization accuracy could be improved by combining painful and tactile stimuli, exploring that this would provide insight into the mechanisms responsible for the accuracy of tactile information processing. Pain stimulation devices with small pin sizes delivered tactile and painful stimuli by pressing against the left palm. Ten college students participated in the experiment and reported the intensity of the pain sensation and perceived locations. The intensity of the pain sensation increased significantly with smaller pin sizes but did not vary by stimulated locations. Length of constant error (CE), the distance between the stimulated and perceived locations, did not seem to change with pin sizes, implying that the CE length did not change with the intensity of the pain sensation. These results indicated that it is difficult to simply integrate nociceptive and tactile signals in the brain, which were thought to contribute to the accuracy of perceived locations.