SINGLE UNIT AND ENSEMBLE RESPONSE PROPERTIES OF THE GUSTATORY CORTEX IN THE AWAKE RAT
Abstract
Most studies of gustatory coding have been performed in either anesthetized or awake,
passively stimulated rats. In this dissertation the influences of behavioral state
on gustatory processing in awake rats are described. In the first set of experiments,
the effects of non-contingent tastant delivery on the chemical tuning of single neurons
were explored. Tastants were delivered non-contingently through intra-oral cannulas
to restrained, non water-deprived rats while single unit responses were recorded from
the gustatory cortex (GC). As the subjects' behavior progressed from acceptance to
rejection of the tastants, the chemical tuning of the neurons changed as well. This
suggests that the subjects' behavioral state powerfully influences gustatory processing.
In the second set of experiments, rats were trained to lick for fluid reinforcement
on an FR5 schedule while single unit activity was recorded from GC. In this case,
the chemical tuning was much more stable. Under this paradigm, chemosensory responses
were rapid (~ 150 ms) and broadly tuned. In the third study, it was found that ensembles
of GC neurons could discriminate between tastants and their concentrations on a single
trial basis, and such discrimination was accomplished with a combination of rate and
temporal coding. Ensembles of GC neurons also anticipated the identity of the upcoming
stimulus when the tastant delivery was predictable. Finally, it was found that ensembles
of GC neurons could discriminate between the bitter stimuli nicotine and quinine.
Nicotine is both a bitter tastant and a trigeminal stimulant, and when the acetylcholine
receptors in the lingual epithelium were blocked with mecamylamine, the ensembles
failed to discriminate nicotine from quinine.
Type
DissertationDepartment
NeurobiologySubject
Biology, Neurosciencegustatory cortex
taste
generalized linear model
multi-unit electrophysiology
ensembles
fixed ratio schedule
Permalink
https://hdl.handle.net/10161/404Citation
Stapleton, Jennifer Rebecca (2007). SINGLE UNIT AND ENSEMBLE RESPONSE PROPERTIES OF THE GUSTATORY CORTEX IN THE AWAKE
RAT. Dissertation, Duke University. Retrieved from https://hdl.handle.net/10161/404.Collections
More Info
Show full item record
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 United States License.
Rights for Collection: Duke Dissertations
Works are deposited here by their authors, and represent their research and opinions, not that of Duke University. Some materials and descriptions may include offensive content. More info