The Fungiform Papilla Is a Complex, Multimodal, Oral Sensory Organ

Curr Opin Physiol. 2021 Apr;20:165-173. doi: 10.1016/j.cophys.2021.01.012. Epub 2021 Jan 21.

Abstract

When solid or liquid stimuli contact the tongue tip during eating, the sensations of taste, touch and temperature are immediately evoked, and tongue function relies on these simultaneous multimodal responses. We focus on the fungiform papilla of the anterior tongue as a complex organ for taste, tactile and thermal modalities, all via chorda tympani nerve innervation from the geniculate ganglion. Rather than a review, our aim is to revise the classic archetype of the fungiform as predominantly a taste bud residence only and instead emphasize an amended concept of the papilla as a multimodal organ. Neurophysiological maps of fungiform papillae in functional receptive fields demonstrate responses to chemical, stroking and cold lingual stimuli. Roles are predicted for elaborate extragemmal nerve endings in tactile and temperature sensations, and potential functions for keratinocytes in noncanonical sensory signaling. The fungiform papilla is presented as a polymodal lingual organ, not solely a gustatory papilla.

Keywords: chemosensory; chorda tympani; geniculate ganglion; receptive field; somatosensory; taste; trigeminal ganglion.