title: Dynamic taste responses of parabrachial pontine neurons in awake rats.
abstract: The parabrachial nuclei of the pons (PbN) receive almost direct input from taste buds on the tongue and control basic taste-driven behaviors. Thus it is reasonable to hypothesize that PbN neurons might respond to tastes in a manner similar to that of peripheral receptors, i.e., that these responses might be narrow and relatively "dynamics free." On the other hand, the majority of the input to PbN descends from forebrain regions such as gustatory cortex (GC), which processes tastes with "temporal codes" in which firing reflects first the presence, then the identity, and finally the desirability of the stimulus. Therefore a reasonable alternative hypothesis is that PbN responses might be dominated by dynamics similar to those observed in GC. Here we examined simultaneously recorded single-neuron PbN (and GC) responses in awake rats receiving exposure to basic taste stimuli. We found that pontine taste responses were almost entirely confined to canonically identified taste-PbN (t-PbN). Taste-specificity was found, furthermore, to be time varying in a larger percentage of these t-PbN responses than in responses recorded from the tissue around PbN (including non-taste-PbN). Finally, these time-varying properties were a good match for those observed in simultaneously recorded GC neurons-taste-specificity appeared after an initial nonspecific burst of action potentials, and palatability emerged several hundred milliseconds later. These results suggest that the pontine taste relay is closely allied with the dynamic taste processing performed in forebrain.
authors.affiliation: Biology Department, Brandeis University, Waltham, Massachusetts; Volen National Center for Complex Systems, Brandeis University, Waltham, Massachusetts; mabaez@brandeis.edu.
authors.forename: Madelyn A
authors.initials: MA
authors.lastname: Baez-Santiago
authors.affiliation: Psychology Department, Brandeis University, Waltham, Massachusetts;
authors.forename: Emily E
authors.initials: EE
authors.lastname: Reid
authors.affiliation: Psychology Department, Brandeis University, Waltham, Massachusetts; Volen National Center for Complex Systems, Brandeis University, Waltham, Massachusetts; Department of Neurobiology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel; and.
authors.forename: Anan
authors.initials: A
authors.lastname: Moran
authors.affiliation: Department of Neurobiology and Anatomy, Wake Forest School of Medicine, Winston-Salem, North Carolina.
authors.forename: Joost X
authors.initials: JX
authors.lastname: Maier
authors.affiliation: Psychology Department, Brandeis University, Waltham, Massachusetts;
authors.forename: Yasmin
authors.initials: Y
authors.lastname: Marrero-Garcia
authors.affiliation: Biology Department, Brandeis University, Waltham, Massachusetts; Psychology Department, Brandeis University, Waltham, Massachusetts; Volen National Center for Complex Systems, Brandeis University, Waltham, Massachusetts;
authors.forename: Donald B
authors.initials: DB
authors.lastname: Katz
mesh_terms: D000818:Animals; D005260:Female; D065823:Parabrachial Nucleus / Q000166:cytology / Q000502:physiology*; D051381:Rats; D020318:Rats, Long-Evans; D011984:Sensory Receptor Cells / Q000502:physiology*; D055697:Taste Perception; D014851:Wakefulness
keywords: gustatory cortex; parabrachial nucleus; taste processing; temporal coding