title: Breadth of tuning in taste afferent neurons varies with stimulus strength.
abstract: Gustatory stimuli are detected by taste buds and transmitted to the hindbrain via sensory afferent neurons. Whether each taste quality (sweet, bitter and so on) is encoded by separate neurons ('labelled lines') remains controversial. We used mice expressing GCaMP3 in geniculate ganglion sensory neurons to investigate taste-evoked activity. Using confocal calcium imaging, we recorded responses to oral stimulation with prototypic taste stimuli. Up to 69% of neurons respond to multiple tastants. Moreover, neurons tuned to a single taste quality at low concentration become more broadly tuned when stimuli are presented at higher concentration. Responses to sucrose and monosodium glutamate are most related. Although mice prefer dilute NaCl solutions and avoid concentrated NaCl, we found no evidence for two separate populations of sensory neurons that encode this distinction. Altogether, our data suggest that taste is encoded by activity in patterns of peripheral sensory neurons and challenge the notion of strict labelled line coding.
authors.affiliation: Graduate Program in Neurosciences, Miller School of Medicine, University of Miami, Miami, Florida 33136, USA.
authors.forename: An
authors.initials: A
authors.lastname: Wu
authors.affiliation: Department of Physiology and Biophysics Miller School of Medicine, University of Miami, Miami, Florida 33136, USA.
authors.forename: Gennady
authors.initials: G
authors.lastname: Dvoryanchikov
authors.affiliation: Department of Physiology and Biophysics Miller School of Medicine, University of Miami, Miami, Florida 33136, USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Pereira
authors.affiliation: Graduate Program in Neurosciences, Miller School of Medicine, University of Miami, Miami, Florida 33136, USA.|Department of Physiology and Biophysics Miller School of Medicine, University of Miami, Miami, Florida 33136, USA.
authors.forename: Nirupa
authors.initials: N
authors.lastname: Chaudhari
authors.affiliation: Graduate Program in Neurosciences, Miller School of Medicine, University of Miami, Miami, Florida 33136, USA.|Department of Physiology and Biophysics Miller School of Medicine, University of Miami, Miami, Florida 33136, USA.
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Roper
mesh_terms: D000818:Animals; D020013:Calcium Signaling / Q000502:physiology; D005071:Evoked Potentials / Q000502:physiology*; D005830:Geniculate Ganglion / Q000502:physiology*; D049452:Green Fluorescent Proteins; D051379:Mice; D008822:Mice, Transgenic; D018613:Microscopy, Confocal; D009475:Neurons, Afferent / Q000502:physiology; D061848:Optical Imaging; D010812:Physical Stimulation; D011984:Sensory Receptor Cells / Q000502:physiology; D012965:Sodium Chloride; D013649:Taste / Q000502:physiology*; D013650:Taste Buds / Q000502:physiology*
chemical_list: D049452:Green Fluorescent Proteins; D012965:Sodium Chloride