title: Odor-taste convergence in the nucleus of the solitary tract of the awake freely licking rat.
abstract: Flavor is produced by the integration of taste, olfaction, texture, and temperature, currently thought to occur in the cortex. However, previous work has shown that brainstem taste-related nuclei also respond to multisensory inputs. Here, we test the hypothesis that taste and olfaction interact in the nucleus of the solitary tract (NTS; the first neural relay in the central gustatory pathway) in awake, freely licking rats. Electrophysiological recordings of taste and taste + odor responses were conducted in an experimental chamber following surgical electrode implantation and recovery. Tastants (0.1 m NaCl, 0.1 m sucrose, 0.01 m citric acid, and 0.0001 m quinine) were delivered for five consecutive licks interspersed with five licks of artificial saliva rinse delivered on a VR5 schedule. Odorants were n-amyl acetate (banana), acetic acid (vinegar), octanoic acid (rancid), and phenylethyl alcohol (floral). For each cell, metric space analyses were used to quantify the information conveyed by spike count, by the rate envelope, and by individual spike timing. Results revealed diverse effects of odorants on taste-response magnitude and latency across cells. Importantly, NTS cells were more competent at discriminating taste + odor stimuli versus tastants presented alone for all taste qualities using both rate and temporal coding. The strong interaction of odorants and tastants at the NTS underscores its role as the initial node in the neural circuit that controls food identification and ingestion.
authors.affiliation: Department of Psychology, Box 6000, Binghamton University, Binghamton, New York 13902-6000 and.
authors.forename: Olga D
authors.initials: OD
authors.lastname: Escanilla
authors.affiliation: Brain and Mind Research Institute, Weill Cornell Medical College, New York, New York 10065.
authors.forename: Jonathan D
authors.identifier: http://orcid.org/0000-0002-9293-0111
authors.initials: JD
authors.lastname: Victor
authors.affiliation: Department of Psychology, Box 6000, Binghamton University, Binghamton, New York 13902-6000 and diloren@binghamton.edu.
authors.forename: Patricia M
authors.initials: PM
authors.lastname: Di Lorenzo
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D008297:Male; D009474:Neurons / Q000502:physiology; D055696:Olfactory Perception / Q000502:physiology*; D051381:Rats; D017552:Solitary Nucleus / Q000166:cytology / Q000502:physiology*; D055697:Taste Perception / Q000502:physiology*; D014851:Wakefulness
keywords: electrophysiology; neural coding; olfaction; rat; taste; temporal coding