Sensory interaction theory: revision of the craniofacial region

Purpose
The objective of this study was to review the literature to find scientific evidence about the mechanisms involved in orofacial sensory interaction, including trigeminal and special sensory modalities.

Views
Conscious sensory perception depends on peripheral external and internal stimuli, which are integrated and processed in central neural centres in order to promote the sensory experience through learning and memory. In the orofacial region, besides somatosensory inputs, there are special sensory modalities (gustation, olfaction, vision and audition) that interact with trigeminal ascendant inputs in a way that makes this area of the body unique. Moreover, the trigeminal nerve may have an important role due to the complex functions of this region, including breathing, feeding and detecting threats. In recent decades the development of equipment accurate enough to detect sensory thresholds has produced a wide range of evidence about orofacial interaction, which allows for the possible development of a unified underlying theory on this issue.

Conclusions
The trigeminal system seems to mediate olfactory and gustative sensations in cortical associative centres, and sensory peripheral neural inputs are modulated by physiological and pathological conditions. Future experimental studies should seek to clarify the mechanisms involved in this interaction, and the role of pathological states in abnormalities of sensory thresholds and perception.