  The two-point discrimination threshold(2PDT) serves as a critical indicator
in the study of tactile acuity, representing the minimal distance at which an
individual can differentiate two distinct points of contact on the skin. This
measurement is instrumental in exploring the neural mechanisms underlying
tactile perception. On the other hand, tactile acuity can be modulated by
global stimulation. Prior research indicates that experimental inflammation
induced by an application of capsaicin cream increases2PDT. In our study, we
applied chemicals(oregano, menthol, and Sichuan pepper) to selectively activate
receptors that usually respond to mild physical stimuli to investigate their
influence on2PDT without inducing inflammation. The results unveiled a
pronounced augmentation of2PDT following any form of global stimulation.
Intriguingly, the cumulative effect of the chemical mix on2PDT appeared to be
additive. These observations suggest that Wide Dynamic Range(WDR) neurons,
functioning as relay nuclei with projections for touch, warmth, and cold
sensations, play a pivotal role in this process. In lateral connection
structures parallel to afferent nerve transmission pathways with WDR neurons as
relay nuclei, global stimulation amplifies excitatory connections over
inhibitory ones, thereby elevating the two-point discrimination threshold.
