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Behavioral and neural responses to gustatory stimuli delivered non-contingently through intra-oral cannulas.

Publication ,  Journal Article
Soares, ES; Stapleton, JR; Rodriguez, A; Fitzsimmons, N; Oliveira, L; Nicolelis, MAL; Simon, SA
Published in: Physiol Behav
November 23, 2007

The act of eating requires a decision by an animal to place food in its mouth. The reasons to eat are varied and include hunger as well as the food's expected reward value. Previous studies of tastant processing in the rat primary gustatory cortex (GC) have used either anesthetized or awake behaving preparations that yield somewhat different results. Here we have developed a new preparation in which we explore the influences of intra-oral and non-contingent tastant delivery on rats' behavior and on their GC neural responses. We recorded single-unit activity in the rat GC during two sequences of tastant deliveries, PRE and POST, which were separated by a waiting period. Six tastants ranging in hedonic value from sucrose to quinine were delivered in the first two protocols called 4TW and L-S. In the third one, the App L-S protocol, only hedonically positive tastants were used. In the 4TW protocol, tastants were delivered in blocks whereas in the two L-S protocols tastants were randomly interleaved. In the 4TW and L-S protocols the probability of ingesting tastants in the PRE sequence decreased exponentially with the trial number. Moreover, in both protocols this decrease was greater in the POST than in the PRE sequence likely because the subjects learned that unpleasant tastants were to be delivered. In the App L-S protocol the decrease in ingestion was markedly slower than in the other protocols, thus supporting the hypothesis that the decrease in appetitive behavior arises from the non-contingent intra-oral delivery of hedonically negative tastants like quinine. Although neuronal responses in the three protocols displayed similar variability levels, significant differences existed between the protocols in the way the variability was partitioned between chemosensory and non-chemosensory neurons. While in the 4TW and L-S protocols the former population displayed more changes than the latter, in the App L-S protocol variability was homogeneously distributed between the two populations. We posit that these tuning changes arise, at least in part, from compounds released upon ingestion, and also from differences in areas of the oral cavity that are bathed as the animals ingest or reject the tastants.

Duke Scholars

Published In

Physiol Behav

DOI

ISSN

0031-9384

Publication Date

November 23, 2007

Volume

92

Issue

4

Start / End Page

629 / 642

Location

United States

Related Subject Headings

  • Taste Buds
  • Taste
  • Sensory Receptor Cells
  • Rats, Long-Evans
  • Rats
  • Random Allocation
  • Neurons
  • Models, Neurological
  • Flavoring Agents
  • Evoked Potentials
 

Citation

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ICMJE
MLA
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Soares, E. S., Stapleton, J. R., Rodriguez, A., Fitzsimmons, N., Oliveira, L., Nicolelis, M. A. L., & Simon, S. A. (2007). Behavioral and neural responses to gustatory stimuli delivered non-contingently through intra-oral cannulas. Physiol Behav, 92(4), 629–642. https://doi.org/10.1016/j.physbeh.2007.05.038
Soares, Ernesto S., Jennifer R. Stapleton, Abel Rodriguez, Nathan Fitzsimmons, Laura Oliveira, Miguel A. L. Nicolelis, and Sidney A. Simon. “Behavioral and neural responses to gustatory stimuli delivered non-contingently through intra-oral cannulas.Physiol Behav 92, no. 4 (November 23, 2007): 629–42. https://doi.org/10.1016/j.physbeh.2007.05.038.
Soares ES, Stapleton JR, Rodriguez A, Fitzsimmons N, Oliveira L, Nicolelis MAL, et al. Behavioral and neural responses to gustatory stimuli delivered non-contingently through intra-oral cannulas. Physiol Behav. 2007 Nov 23;92(4):629–42.
Soares, Ernesto S., et al. “Behavioral and neural responses to gustatory stimuli delivered non-contingently through intra-oral cannulas.Physiol Behav, vol. 92, no. 4, Nov. 2007, pp. 629–42. Pubmed, doi:10.1016/j.physbeh.2007.05.038.
Soares ES, Stapleton JR, Rodriguez A, Fitzsimmons N, Oliveira L, Nicolelis MAL, Simon SA. Behavioral and neural responses to gustatory stimuli delivered non-contingently through intra-oral cannulas. Physiol Behav. 2007 Nov 23;92(4):629–642.
Journal cover image

Published In

Physiol Behav

DOI

ISSN

0031-9384

Publication Date

November 23, 2007

Volume

92

Issue

4

Start / End Page

629 / 642

Location

United States

Related Subject Headings

  • Taste Buds
  • Taste
  • Sensory Receptor Cells
  • Rats, Long-Evans
  • Rats
  • Random Allocation
  • Neurons
  • Models, Neurological
  • Flavoring Agents
  • Evoked Potentials