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, ME (2002) Effects of chlorhexidine on human taste
perception. Physiol. Behav. 74: 85-99.
Gent, JF, Frank, ME, and Hettinger, TP (2002) Taste
confusions following chlorhexidine treatment. Chem. Senses 27:
73-80.
Formaker, BK, Frank, ME (2000) Taste function in people with
oral burning. Chem. Senses 25: 575-581.
Frank, ME (2000) Neuron types, receptors, behavior, and taste
quality. Physiol. Behav. 69: 53-62.
 View more publications, see
Pubmed listing.
Revised April, 2008. |
