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Faculty
 Marion
Frank
Professor of Oral Health and Diagnostic Sciences
Director, Center for Neurosciences
mfrank@nso2.uchc.edu
Areas of interest:
To reveal chemosensory stimulus coding strategies, we study odor and
taste identification in humans, and gustatory neurophysiology and
behavior in hamsters. The broad goal of our research is to develop
fundamental understanding of the functioning of mammalian gustatory and
olfactory systems.
In the ever-changing mix of real-world compounds, taste and smell likely
evolved to identify stimulus quality at low concentrations. The high
concentrations of chemicals used in studies to establish specificity
often elicit multiple sensations and may act as reagents, bypassing
specific transduction mechanisms. Also, in nature, stimuli are embedded
in complex mixtures, but most studies have employed single-component
stimuli for ease of study design and data interpretation. Our work on
golden hamsters (Mesocricetus auratus), uses behavioral assays
(conditioned taste aversion (CTA), intake) and peripheral nerve
recordings [chorda tympani (CT), glossopharyngeal (GL)] to challenge
candidate peripheral labeled line codes with single, binary and ternary
stimuli in the sweet and bitter domains. Our work on humans challenges
the human capacity to identify gustatory and olfactory quality with
dynamic, complex stimuli at concentrations encountered in natural
settings.
Lab Rotation Projects:
Neuroscience projects
Students who wish to formulate their own novel questions about the
effects of selective adaptation on human odor perception or
behavioral/neural analysis of mixture stimuli by hamsters are welcome.
In addition the following projects are available:
#1 – Short description of a project and what will be involved in the
research: Hamsters are repelled by cycloheximide, a protein
synthesis inhibitor. Its aversive potency at concentrations of less than
1 M increases dramatically after a single exposure. Yet it is not
known whether cycloheximide is a taste stimulus for hamsters. Humans can
hardly detect the compound by taste. A rotation project would involve
electrophysiological recording from the CT in 2 groups of hamsters,
those that had been exposed to cycloheximide and those that had not been
exposed to cycloheximide. This project may lead to a thesis project on
“induction” of taste receptors for dangerous compounds.
#2 – Short description of a project and important methods that will
be learned: Electrophysiological recordings of chorda tympani nerve
responses to binary mixtures in hamsters show specific inhibition of
sucrose responses by quinine and quinine responses by NaCl. No one has
looked at responses to ternary mixtures of NaCl + sucrose + quinine. A
lab rotation would involve learning micro-neurosurgical techniques to
isolate the chorda tympani nerve, electrophysiological techniques to
obtain recordings, computerized analysis techniques to quantify the
data, and statistical analysis to evaluate the significance of the data.
#3– Short description of a project and important methods that will be
learned: In binary mixtures, identification of a component’s
characteristic quality is difficult, and in quaternary mixtures,
identification is impossible. This is called mixture suppression.
Presenting stimuli in pairs, each stimulus for a few seconds, can rescue
an extra component in the second stimulus from mixture suppression. This
selective adaptation has been shown for one water-soluble stimulus
(label) quartet. No one has looked at other odorous compounds like
benzaldehyde (almond), maltol (caramel), methyl
anthranilate (grape) and 2-methoxy-3-isobutylpyrazine (green
bell pepper). A lab rotation would provide training in testing
hypotheses about chemosensory systems by using the human response as the
dependent variable. It also requires learning methods of data analysis
and statistical evaluation of results.
Publications
Selected Publications:
Grover R, Frank ME. (2008) Regional specificity of chlorhexidine
effects on taste perception. Chem Senses. Feb 7 [Epub ahead of print].
Goyert HF, Frank ME, Gent JF, Hettinger TP. (2007) Characteristic
component odors emerge from mixtures after selective adaptation. Brain
Res Bull 72: 1-9.
Hettinger TP, Formaker BK, Frank ME. (2007) Cycloheximide: no
ordinary bitter stimulus. Behav Brain Res 180: 4-17.
Frank ME, Formaker BK, Hettinger TP. (2005) Peripheral gustatory
processing of sweet stimuli by hamsters. Brain Res Bull 66: 70-84.
Frank ME, Wada Y, Makino J, Mizutani M, Umezawa H, Katsuie Y,
Hettinger TP, Blizard DA. (2004) Variation in intake of sweet and bitter
solutions by inbred strains of golden hamsters. Behav Genet.
Jul;34(4):465-76.
Frank ME, Bouverat BP, MacKinnon BI, Hettinger TP. (2004) The
distinctiveness of ionic and nonionic bitter stimuli. Physiol Behav.
Jan;80(4):421-31.
Gent JF, Shafer DM, Frank ME. (2003) The effect of orthognathic
surgery on taste function on the palate and tongue. J Oral Maxillofac
Surg. Jul;61(7):766-73.
Frank ME, Formaker BK, Hettinger TP. (2003) Taste responses to
mixtures: analytic processing of quality. Behav Neurosci.
Apr;117(2):228-35.
Frank, M.E. (2002) Effects of chlorhexidine on human taste
perception. Physiol. Behav. 74: 85-99.
Gent, J.F., Frank, M.E., and Hettinger, T.P. (2002) Taste confusions
following chlorhexidine treatment. Chem. Senses 27: 73-80.
Formaker, B.K., Frank, M.E. (2000) Taste function in people with oral
burning.Chem. Senses 25: 575-581.
Frank, M.E. (2000) Neuron types, receptors, behavior, and taste
quality.Physiol. Behav. 69: 53-62. rev.
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