Faculty & Staff
Dr. Chin-Parker began teaching at Denison in the fall of 2004. He teaches Introduction to Psychology, Research Methods, Cognitive Psychology, Research in Cognitive Psychology, and a seminar titled “Creativity and Cognition”. When he is not in the classroom (or his lab), Dr. Chin-Parker enjoys spending time with his family, running on the trails of the Denison Biological Reserve, and attempting to play the guitar.
My research program focuses on the interplay between conceptual knowledge and experience: Conceptual knowledge plays a critical role in shaping the interactions we have with the world, and it is correspondingly shaped by those interactions. Reflecting this interplay, I have adopted two perspectives that frame my research:
- Access to relevant conceptual knowledge can change the processing associated with a given behavior, and so cognitive functions (e.g. category learning and explanation) that tap into conceptual knowledge should be studied in situations where relevant knowledge is available.
- The acquisition of conceptual knowledge, or category learning, should be studied in context. People learn about categories of items as they complete other tasks – the processing associated with these tasks, as well as the goals of the individual, affect what is learned about the categories to which the items belong.
By taking this stance, I am able to examine several important issues that have been overlooked by much of the research in the area. Because there is a tendency in experimental work to isolate cognitive functioning in order to get a “cleaner” view of the processes involved, we sometimes inadvertently change the nature of the processing by removing it from the context in which it typically occurs. This is especially a concern when studying cognitive processes that link up with conceptual knowledge.
Ultimately, my research interests stem from a desire to better appreciate what it means to “understand”. I consider our behaviors, especially cognitive processes, to be largely dedicated to meaning making – seen in the constant questions of a three year old and extending to the way that we reflect on our world and ourselves through art, literature, science. I have selected to study the cognitive processes and structures that underlie the acquisition and use of conceptual knowledge because they are so intimately tied to how we make sense of the world.
Student Research Collaborations
- Avraham Baranes, Summer 2010, Anderson Summer Research Assistantship
Title: Working memory and decision making: A look at the somatic marker hypothesis
- Amy Milewski, Summer 2010, Denison University Research Funded Assistantship
Title: The effects of use-relevant information and diagnosticity on conceptual organization
- Elizabeth Cummings, Summer 2008, Anderson Summer Research Assistantship
Title: Coherence effects in naturally occurring knowledge
- Julie Tucker, Summer 2008, Anderson Summer Research Assistantship
Title: Coherence in real world categories in natural groups
- Jessie Birdwhistell, Summer 2007 and Spring 2008, Anderson Summer Research Assistantship
Title: Beyond the solution: Learning about categories during problem solving
- Amber Hill, Summer 2006, Hughes Summer Research Assistantship
Title: The interaction of knowledge and learning with cross-classified items
- Robert Horn, Summer 2006, Denison University Research Funded Assistantship
Title: Constraints on explanations: Empirically testing philosophical theories of explanation
- Catherine Mehta, Summer 2006, Anderson Summer Research Assistantship
Title: Structural alignment across category learning paradigms
- Olivia Hernandez, Summer 2005, Hughes Summer Research Assistantship
Title: A process model of explanation-based learning
- Murray Matens, Summer 2005, Anderson Summer Research Assistantship
Title: A comparative study of category learning through classification and explanation
- Chin-Parker, S., & Bradner, A. (2010). Background shifts affect explanatory style: How a pragmatic theory of explanation accounts for background effects in the generation of explanations. Cognitive Processing, 11, 227-249.
- Chin-Parker, S. (2010). (Category) Learning by Doing: How Goal Directed Tasks Constrain Conceptual Acquisition. In S. Ohlsson & R. Catrambone (Eds.), Proceedings of the 32nd Annual Conference of the Cognitive Science Society. Mahwah, NJ: Erlbaum.
- Patalano, A. L., Chin-Parker, S., & Ross, B. H. (2006). The importance of being coherent: The role of category coherence in reasoning about cross-classified entities. Journal of Memory and Language, 54, 407-424.
- Chin-Parker, S., Hernandez, O., & Matens, M. (2006). Explanation in Category Learning. In R. Sun & N. Miyake (Eds.), Proceedings of the 28th Annual Conference of the Cognitive Science Society. Mahwah, NJ: Erlbaum.
- Ross, B. H., Chin-Parker, S., & Diaz, M. (2005). Beyond classification learning: A broader view of category learning and category use. In W. Ahn, R. L. Goldstone, B. C. Love, A. B. Markman, & P. Wolff (Eds.), Categorization inside and outside the lab: Festschrift in honor of Douglas L. Medin. Washington, DC: APA.
- Erickson, J., Chin-Parker, S., & Ross, B. H. (2005). Inference and classification learning of abstract coherent categories. Journal of Experimental Psychology: Learning, Memory and Cognition, 31, 86-99.
- Chin-Parker, S., & Ross, B. H. (2004). Diagnosticity and prototypicality in category learning: A comparison of inference learning and classification learning. Journal of Experimental Psychology: Learning, Memory and Cognition, 30, 216-226.
- Chin-Parker, S., & Ross, B. H. (2002). The effect of category learning on sensitivity to within-category correlations. Memory & Cognition, 30, 353-362.
- Anderson, A. L., Ross, B. H., & Chin-Parker, S. (2002). A further investigation of category learning by inference. Memory & Cognition, 30, 119-128.
- Chin-Parker, S. (July 2011). What Varying the Category Structure and Learning Task Reveal About Inference Learning. Poster presented at the 33rd Annual Conference of the Cognitive Science Society, Boston, MA.
- Chin-Parker, S. (August 2010). (Category) Learning by Doing: How Goal Directed Tasks Constrain Conceptual Acquisition. Poster presented at the 32nd Annual Conference of the Cognitive Science Society, Portland, OR.
- Chin-Parker, S. (May 2010). Use-Relevant Features Constrain Category Learning. Paper presented at the 80th Annual Meeting of the Midwest Psychological Association, Chicago, IL.
- Chin-Parker, S. & Bradner, A. (September 2009). A Philosopher and a Psychologist Walk Into a Lab…: An Interdisciplinary Study of Explanation. Talk presented to the Denison Scientific Association. Granville, OH.
- Birdwhistell, J. & Chin-Parker, S. (November 2008). Beyond the Solution: Problem Solving as Category Learning. Poster presented at the 49th Annual Meeting of the Psychonomics Society. Chicago, IL.
- Chin-Parker, S. & Bradner, A. (August 2008). The Pragmatics of Explanation. Paper presented at the 30th Annual Conference of the Cognitive Science Society, Washington, D.C.
- Bradner, A. & Chin-Parker, S. (July 2008). An Empirical Constraint on the Pragmatic Theory of Explanation. Poster presented at the 34th Annual Meeting of the Society for Philosophy and Psychology, Philadelphia, PA.
- Chin-Parker, S., Hernandez, O., & Matens, M. (November 2006). Explanation as Category Learning. Poster presented at the 47th Annual Meeting of the Psychonomics Society. Houston, TX.
- Chin-Parker, S., Hernandez, O., & Matens, M. (August 2006). Explanation in Category Learning. Poster presented at the 28th Annual Conference of the Cognitive Science Society, Vancouver, B.C., Canada.
- Chin-Parker, S. (October 2005). An Explanation (and Exploration) of Category Learning. Denison University Department of Psychology Colloquium. Granville, OH.
- Chin-Parker, S., & Ross, B. H. (May 2005). Category Learning (Not) Made Simple: The Effect of Learning Two Category Sets on Classification Performance. Paper presented at the 77th Annual Meeting of the Midwest Psychological Association, Chicago, IL.
- Effland, K. J., Lancaster, K., Polovick, M. A., Welker, K. G., & Chin-Parker, S. (May 2005). The Effect of Abstract Knowledge on a Category Construction Task. Paper presented at the 77th Annual Meeting of the Midwest Psychological Association, Chicago, IL.
Barbara Fultner, Professor of Philosophy and Women's Studies, joined the faculty at Denison in 1995. She earned a B.A. from Simon Fraser University, an M.A. from McGill University and a Ph.D. from Northwestern University. She teaches courses in philosophy of language, the history of modern philosophy, philosophy of mind, and philosophy of feminism among others. She served as chair of the department from 2004-2008 and is currently the Director of the Women’s Studies Program.
Dr. Fultner was the recipient of a 2008-2009 University of Connecticut Humanities Institute Fellowship, as well as Denison University's R.C. Good Fellowship for 2008-2009. In 2000, she received Denison's Feminist Teaching Award. Most recently, she has been awarded a “New Directions Initiative” grant by the GLCA to pursue yoga teacher training as part of her research on embodiment, practice, and intersubjectivity.
Dr. Fultner's research interests lie at the cross-roads of analytic and continental philosophy, with a focus on theories of meaning and social practice. She is interested in the nature of normativity and its relationship to the social aspects of language. In her recent work, she has been examining the connections between semantic normativity and the development of inter-subjectivity in early childhood as well as the relationship between convention and creativity in dialogue. She also has strong interests in feminist philosophy. Her articles have appeared in journals including Philosophical Studies, Philosophy and Social Criticism, and The International Journal of Philosophical Studies and in several edited collections. She is translator of Jürgen Habermas Truth and Justification (MIT Press 2003) and his On the Pragmatics of Social Interaction (MIT Press 2000). She is the editor of Habermas: Key Concepts (Acumen 2011).
Dr. Hassebrock came to Denison in 1983 and teaches courses in Cognitive Psychology, Adult Development and Aging, Research Methods in Psychology, and Introduction to Psychology and seminars on The Seven Sins of Memory: The Psychology of Remembering and Forgetting, and Autobiographical Memory and the Remembering Self.
In 2011, Dr. Hassebrock was named as a Teagle Pedagogy Fellow by the Great Lakes College Association. Teagle Pedagogy Fellow have key roles in the development of a new consortial program, called the GLCA Lattice for Pedagogical Research and Practice, created with funding from the Teagle Foundation. These Fellows engage with interested faculty members on their own campuses and at other GLCA colleges, helping to generate heightened interest and momentum in exploring different modes of pedagogy to enhance student learning and achievement.
At Denison’s Honors Convocation in April 2013, Dr. Hassebrock received the Charles and Nancy Brickman Distinguished Service Chair, 2013-2016.
Dr. Hassebrock was selected in 2013 to be Denison’s first Faculty Fellow for Learning and Teaching. In this role, he collaborates with Denison’s faculty members, at all career stages, on teaching-related issues in order to:
(a) provide individual support and consultation,
(b) develop opportunities and provide information for the exploration of innovative pedagogies and new initiatives,
(c) promote access to scholarship and research on learning and teaching,
(d) coordinate relevant activities, programs, and resources across campus, and
(e) support a shared culture of discussion, reflection, and experimentation about learning and teaching activities.
My recent research projects have explored the cognitive psychology of autobiographical memory including age and gender differences in remembering meaningful personal experiences and significant life events. Another direction of this research has compared the different types of memory functions (e.g., self, social, emotional, and motivational) that guide how adults of different ages recall autobiographical memories associated with consumer objects versus keepsake objects including mementos and souvenirs.
Selected Publications and Conference Presentations
- Volk, S., Cunningham, K., Hassebrock, F., Knupsky, A., Thompson, C. (2014). Towards a consortial teaching and learning commons: Collaborating across campuses to address faculty needs. Symposium to be presented at the Annual Meeting of the Association of American Colleges and Universities, Washington, D.C.
- Kennedy, S., & Hassebrock, F. (2012). Developing a team-taught capstone course in neuroscience. The Journal of Undergraduate Neuroscience Education, 11(1), A12-A16.
- Hassebrock, F., & Boyle, B. (2009). Memory and narrative: Reading ‘The Things They Carried’ for psyche and persona. Across the Disciplines: Interdisciplinary Perspectives on Language, Learning, and Academic Writing. Click to download.
- Hassebrock, F., & Snyder, R. (1997). Applications of a computer algebra system for teaching bivariate relationships in statistics courses. Behavior Research Methods, Instruments, & Computers, 29, 246-249.
- Hassebrock, F. (1995). Memory of patients past: Contextual and temporal characteristics. J. Stewman (Ed.), Proceedings of the 8th Florida AI Research Symposium (p. 102-106).
- Hassebrock, F. (1995). Tracing the cognitive revolution through a literature search. In M. Ware & D. Johnson (Eds.), Handbook of Demonstrations and Activities in Teaching of Psychology. Mahwah, NJ: Erlbaum.
- Hassebrock, F., Johnson, P. E., Bullemer, P., Fox, P., & Moller, J. (1993). When less is more: Representation and selective memory in expert problem solving. American Journal of Psychology, 106, 155-189.
- Hassebrock, F., & Prietula, M. (1992). A protocol-based coding scheme for the analysis of medical reasoning. International Journal of Man/Machine Studies, 37, 613-652.
Selected Student Research Collaborations
- Hassebrock, F., & Shelton, O. (2014). Age Differences in Future Episodic Thinking About Keepsakes and Consumer Objects. Research poster accepted, Annual meeting of the Association for the Psychological Science, San Francisco.
- Hassebrock, F., & Gaines, M. (2012). Functions of autobiographical memories cued by keepsakes and consumer objects. Research poster, Annual meeting of the Midwestern Psychological Association, Chicago.
- Hassebrock, F., & Fox, M. (2010). Emotional priming effects on retrieving autobiographical memories. Research poster, Annual meeting of the Midwestern Psychological Association, Chicago.
- Hassebrock, F., Goans, C., & Bassett, L. (2009) Perceptual modality and emotional valence of autobiographical memory retrieval cues. Research poster, Annual meeting of the Association of Psychological Science, San Francisco.
- Fox, C., & Hassebrock, F. (2009). The effect of positive and negative emotional pictures on the autobiographical memory of younger and older adults. Research poster, Annual meeting of the Eastern Psychological Association, Pittsburgh.
- Goans, C., & Hassebrock, F. (2009). Autobiographical memory retrieval following auditory, pictorial, and word cues. Research poster, Annual meeting of the Eastern Psychological Association, Pittsburgh.
- Nowell, M., & Hassebrock, F. (2009). The effect of emotional auditory cues on autobiographical memory retrieval. Research poster, Annual meeting of the Eastern Psychological Association, Pittsburgh.
- Moellenberg, S., & Hassebrock, F. (2008). Specificity of autobiographical memory for positive and negative academic experiences in college students with learning disabilities. Research Poster, Annual Meeting of the Midwestern Psychological Association, Chicago.
- Saffell, T., & Hassebrock, F. (2007). Misinformation effects produced by life memories and time delay. Research Poster, Annual Meeting of the Midwestern Psychological Association, Chicago.
- Moellenberg, S., & Hassebrock, F. (2006). Perceived stress, political participation, and autobiographical memory in relation to the 2004 presidential election. Research poster, Annual Meeting of the Midwestern Psychological Association, Chicago.
- Yeager, L., & Hassebrock, F. (2005). The effects of recall mode and cognitive interview mnemonics on eyewitness memory. Research poster. Annual Meeting of the Midwestern Psychological Association, Chicago.
Dr. Kennedy joined the faculty at Denison in 1992 following completion of a four-year post-doctoral fellowship in behavioral immunology at Ohio State's College of Medicine. Dr. Kennedy teaches Physiological Psychology, Psychopharmacology, and Introductory Psychology, and is co-advisor to Denison's newly-formed Neuroscience Concentration.
My research interests are focused in two general areas of behavioral neuroscience and psychopharmacology. The first area is concerned with how animals' behavioral responses to stimulant drugs such as amphetamine might abe modified by previous drug experience. This work has implications for models of “addiction,” which maintain that early experiences (such as stress) may make an organism “at risk” for later stimulant addiction. Secondly, I am interested in the historical and cultural contributions to current drug policy, and the role of science versus popular culture in defining public policy regarding licit and illicit drugs.
Student Research and Collaborations
- Perlman, J. & Kennedy, S. Sensitization to amphetamine in the developing rat pup. (submitted for presentation at the Midwestern Psychological Association Meeting, April, 1999)
- Hersman, M.N., Freeman, J.E. & Kennedy, S. (May, 1997) Short-term chronic fluoxetine treatment increases wheel-running of rats in the activity-stress paradigm. Midwestern Psychological Association Meeting, Chicago, IL.
- Perry, L. & Kennedy, S. (November, 1996) Endocrine responses to a metabolic stressor in the developing rat: Role of litter and maternal influences. International Society for Neuroimmunomodulation, Bethesda, MD.
- Kennedy, S., Collier, A.C., Bilio, D. & Perry, L. (April, 1996) Comparative effects of social and metabolic stressors during development: Role of age and maternal influences following reunion. Psychoneuroimmunology Research Society Meeting, Santa Monica, CA.
- Kennedy, S. Williams, J., Geiman, E. & Leccese, A.P. ( November, 1995). Modulation of amphetamine-induced stereotypy in preweanling rat pups by 2-deoxy-D-glucose. Society for Neuroscience Annual Meeting, San Diego, CA.
- Molnar, S.A. & Kennedy, S. 2-deoxy-D-glucose modulation of hypothalamic norepinephrine in the developing rat pup. (November, 1994). Psychoneuroimmunology Research Society, Key Biscayne, FL.
- Agha, S., Brooks, D. C., & Kennedy, S. (in preparation). College students' perceptions (and misperceptions) about alcohol and marijuana.
- Kennedy, S. (in preparation). Psychopharmacology: An introduction to drugs and behavior. Wadsworth, Thomson Learning.
- Kennedy, S. (in press). The psychoneuroimmunology of AIDS: Stress, personality factors and coping, interpersonal relationships and health outcomes. In The Management of Stress and Anxiety in Medical Disorders (Mostovsky, D. & Barlow, D., Eds).
- Kennedy, S. (1996). Herpesvirus infections and psychoneuroimmunology. In H. Friedman, et. al (Eds). Psychoneuroimmunology, Stress and Infection. Boca Raton, FL: CRC Press.
- Kennedy, S. & Collier, A.C. (1994). Stress-induced modulation of the immune response in the developing rat pup. Physiology and Behavior, 56, 825-828.
- Glaser, R., Kiecolt-Glaser, J.K., Bonneau, R.H., Malarkey, W., Kennedy, S. & Hughes, J. (1992). Stress-induced modulation of the immune response to recombinant hepatitis B vaccine. Psychosomatic Medicine, 54, 22-29.
- Glaser, R., Pearson, G.R., Jones, J.F., Hillhouse, J., Kennedy, S., Mao, H. & Kiecolt-glaser, J.K. (1991). Stress-related activation of Epstein-Barr Virus. Brain, Behavior and Immunity, 5, 219-232.
- Kennedy, S., Glaser, R. &Kiecolt-Glaser, J.K. (1990). Human psychoneuroimmunology. In J.T. Caccioppo & R.E. Petty (Eds). Principles of Psychophysiology: Physical, social and Inferential Elements. New York: Cambridge University Press.
- Kennedy, S., Kiecolt-Glaser, J.K. & Glaser, R. (1990). Social Support, stress, and the immune system. In B.R. Sarason, I.G. Sarason & G.R. Pierce (Eds). Social Support: An Interactional View. New York: Wiley.
- Tomei, L.D., Kiecolt-Glaser, J.K., Kennedy, S. & Glaser, R. (1990). Psychological-stress and phorbol ester inhibition of radiation-induced apoptosis in human peripheral blood leukocytes. Psychiatry Research, 33, 59-71.
- Glaser, R., Kennedy, S., Lafuse, W.P., Bonneau, R.H., Speicher, C.E. & Kiecolt-Glaser, J.K. (1990). Psychological stress-induced modulation of IL-2 receptor gene expression and IL-2 production in peripheral blood leukocytes. Archives of General Psychiatry, 47, 707-712.
- Kennedy, S., Kiecolt-Glaser, J.K. & Glaser, R. (1989). Neuroimmunology of normal human behavior. In E.J. Goetzl (Ed). Neuroimmune Networks: Physiology and Diseases. New York: Alan Liss.
- Kiecolt-Glaser, J.K., Kennedy, S., Malkoff, S., Speicher, C.E. & Glaser, R. (1988) Marital discord and immunity in males. Psychosomatic Medicine, 50, 213-229.
- Kennedy, S., Kiecolt-Glaser, J.K. & Glaser, R. (1988). Immunological consequences of acute and chronic stressors: Mediating role of interpersonal relationships. British Journal of Medical Psychology, 61, 77-85.
- Pellis, S.M., O?Brien, D.P., Pellis, V.C., Teitelbaum, P., Wolgin, D.L. & Kennedy, S. (1988). Escalation of feline predation along a gradient from avoidance through “play” to “killing.” Behavioral Neuroscience, 102, 760-777.
- Alander, D.H., Servidio, S., Schallert, T. & Teitelbaum, P. (1983). Possible vestibular involvement in behaviors induced by d-amphetamine. Federation Proceedings, 1159.
- Kennedy, S. Teaching brain-behavior relationships to undergraduates. (March, 1994). Midwest Institute for Teaching of Psychology, Chicago, IL
- Collier, A.C., Kennedy, S., Glaser, R. & Hennessy, M.B. (July, 1990). Developmental effects of mother-infant separation on immune functioning in rats. International Society for Developmental Psychobiology Annual Meeting, London, England.
- Glaser, R., Griffin, A., Bucci, D., Hillhouse, J., Kennedy, S., Kotur, M. & Kiecolt-Glaser, J.K. (November, 1989). Psychological stress down-regulates IL-1 production in human macrophage/monocytes. Society for Neuroscience Annual Meeting, Phoenix, AZ.
- Kiecolt-Glaser, J.K., Dura, J.R., Kennedy, S., Speicher, C.E. & Glaser, R. (April, 1989). Stress and immunity: Alzheimer family caregivers. American Psychiatric Association Annual Meeting, San Francisco, CA.
- Kennedy, S., Malarkey, W.B., Shaut, D. & Glaser, R. (November, 1988). Enhanced blasteogenesis of human lymphocytes by prolactin. Society for Neuroscience Annual Meeting, Toronto, Canada.
- Glaser, R., Tomei L.D., Kennedy, S. & Kiecolt-Glaser, J.K. (April 1988). Cellular and molecular consequences of psychological stress. Molecular Biology of Stress, Keystone, CO.
- Kennedy, S., Kiecolt-Glaser, J.K., Malkoff, S., Fisher, L., Speicher, C.E. & Glaser, R. (November, 1987). Changes in herpesvirus latency in a stressed population: Implications for psychological mediation of immune responses. Society for Neuroscience and Annual Meeting, New Orleans, LA.
After graduating from Penn State with a degree in Computer Engineering and a minor in Philosophy, Dr. Kretchmar worked as a software engineer at IBM to develop their first data warehousing project. In his graduate programs at Rensselaer and Colorado State, Dr. Kretchmar focused on a variety of artificial intelligence and machine learning techniques. His Ph.D. dissertation analyzed a robust (fault tolerant) reinforcement learning controller for a large HVAC system. Dr. Kretchmar teaches a wide range of courses across the computer science curriculum as well as introductory liberal arts mathematics courses. Dr. Kretchmar's classes often experiment with non-traditional pedagogies including a portfolio based system in his Sophomore Data Structures class, and a research paper based Artificial Intelligence seminar. He is also very interested in writing pedagogy and in first year student experiences; he served as Denison's Dean of First Year Students from 2007 to 2012.
Selected Student Research Projects:
- Text Message Authorship Classification Using Support Vector Machines, Yifu Zhou, 2013.
- A Reinforcement Learning Robotic Arm Controller, Taylor Kessler Faulkner, 2013.
- An Analysis of Ballot Ordering for Final Tribal Councils in the Television Series Survivor, Nat Kell. 2010.
- Kernel Methods for Image Processing, Dan Bucatanschi, 2006.
My research area is machine learning techniques. I concentrate in Reinforcement Learning, especially in building controllers for various dynamic systems. Additionally I work in the area of classification techniques including Kernel Machines and Support Vector Machines. I also dabble in games and game theory, and in discrete and combinatorial mathematics.
- Suspense at the Ballot Box. (with Nat Kell) The College Mathematics Journal, Vol 44, No 1. 2013.
- Tree Traversals and Permutations. (with Todd Feil and Kevin Hutson) Congressus Numerantium, Vol 172. 2005.
- Improved Automatic Discovery of Subgoals for Options in Hierarchical Reinforcement Learning. (with Todd Feil and Rohit Bansal) Journal of Computer Science and Technology. October, 2003.
- A Neighborhood Search Technique for the Freeze Tag Problem. (with Dan Bucatanschi, Blaine Hoffman and Kevin Hutson) Extending the Gap: Advances in Computing, Optimization, and Decision Technologies. 2007.
Field of Interest:
I think of myself as something of an intellectual vampire -- I feed off of the different aspects of my job. My research feeds my intellectual curiosity and helps keep my scientific knowledge current and well grounded in experience. Teaching is my passion, a real source of emotional energy. On this page, I've tried to give you an overview of both my teaching and research interests. I encourage you to look elsewhere on my web pages to find out more, and to email me or stop by to talk about anything here that intrigues you.
Broadly, my research interests lie in the area of Molecular Evolution. Specifically, I'm interested in the rates at which biological macromolecules evolve and the forces, both at the level of molecule and of organism, which constrain the rate of evolution of individual molecules.
The past decade has seen a true revolution in the technology of biomolecular sequence determination, and a corresponding explosion in the magnitude of sequence information available for analysis. This wealth of information has given us an increasingly clear picture of how and why biological macromolecules change over time. But it also highlights our ignorance. For example, virtually every large scale molecular evolutionary tree shows one or more groups of organisms with aberrant rates of evolution -- which shows up as unusually long or short branches. Yet no one is able to predict these rate hiccups, or even to explain them post-facto, and that intrigues me. But rather than simply looking for these cases of bizarre evolutionary rate, my interest is with the forces involved; I seek to explicitly test hypotheses about causal events that can drive rate abnormalities.
The goal of my research program is therefore to explore cases of altered evolutionary rate and to generate biochemical systems for testing hypotheses about the consequences of the rate acceleration. My focus for the last several years has been on one such case study: describing and exploring the accelerated evolution of the genes encoding the subunits of the RNA polymerase in chloroplasts of plants in the genus Pelargonium. To learn more about my research interests, and the projects that students have pursued in my lab, please see my research page.
- P. Kuhlman, H.L. Duff*, and A. Galant*. 2004. A fluorescence-based assay for multi-subunit DNA-dependent RNA polymerases. Analytical Biochemistry. v. 324 p. 183-190
- C. K. Brown, P. L. Kuhlman, S. Mattingly, K. Slates, P. J. Calie, and W. W. Farrar. 1998. A model of the quaternary structure of enolases, based on structural and evolutionary analysis of the octameric enolase from Bacillus subtilis. J. Prot. Chem.. v. 17 p. 855-866
- Y. Cho, Y.-L. Qiu, P. Kuhlman, and J. D. Palmer . 1998. Explosive invasion of plant mitochondria by a group I intron.. Proc. Natl. Acad. Sci USA. v. 95 p. 14244-14249
- J.C. Vaughn, M. T. Mason, G. L. Sper-Whitis, P. Kuhlman, and J. D. Palmer. 1995. Fungal origin by horizontal transfer of a plant mitochondrial group I intron in the chimeric coxI gene of Peperomia. J. Mol. Evol.. v. 41 p. 563-572
- P. Kuhlman and J. D. Palmer. 1995. Isolation, expression, and evolution of the gene encoding mitochondrial elongation factor Tu in Arabidopsis thaliana. Plant Mol. Biol.. v. 29 p. 1057-1070
- P. Kuhlman, V. T. Moy, B. A. Lollo, and A. A. Brian. 1991. The accessory function of murine ICAM-1 in T lymphocyte activation: Contributions of adhesion and activation. J. Immunol. v. 146 p. 1773-1782
[* denotes an undergraduate student working under my guidance]
- S. Stefanović, P. Kuhlman, P. Calie, and J. Palmer. 2007. Rapid evolution of plastid RNA polymerases in three unrelated flowering plant lineages. Platform talk at the joint annual meetings of the Botanical Society of America and the American Society for Plant Biologists.
- P. Kuhlman and P. Calie. 2006. Accelerated sequence evolution of the four proteins comprising the core complex of the bacterial-derived DNA-dependant RNA polymerase in the plant family Geraniaceae. Poster presentation at the National IDeA Symposium of Biomedical Research Excellence.
- S. Hoskins, J. Hogan, D. Bautista, P. Kuhlman and P. Calie. 2004. Modeling studies suggest that the accelerated sequence evolution in the a-subunit of the Geraniaceae DNA-dependant RNA polymerase is accompanied by a high level of conservation of secondary structure. Poster presentation at the annual meeting of the American Society of Plant Biologists.
- P. Kuhlman and H.L. Duff*. 2003. A fluorescence-based assay for RNA Polymerase activity. Poster presentation at Experimental Biology 2003, the combined annual meeting of several national societies for experimental biologists, including the American Society for Biochemistry and Molecular Biology.
- C. N. Gorman*, H. L. Duff*, and P. Kuhlman . 2000. Investigations into the function of the rapidly evolving RNA Polymerase in Pelargonium chloroplasts. Poster presentation at the annual meeting of the (international) Protein Society.
- H. Duff*, T. Wine*, and P. Kuhlman . 1999. Investigation of the rapidly evolving plastid RNA polymerase in Pelargonium. Poster presentation at the International Botanical Congress.
- P. Kuhlman, P. J. Calie, J. M. Logsdon, A. Z. Wang*, G. Vora*, B. Thomason*, and J. D. Palmer . 1998. Accelerated evolution of the chloroplast-encoded RNA polymerase driven by positive Darwinian selection. Talk given at the 1998 international meeting of the Society for Molecular Biology and Evolution.
Academic Positions Professor
Professor, Department of Biology at Denison University, 2007 to present
Chair, Department of Biology at Denison University, 2002 to 2007
Associate Professor, Department of Biology at Denison University, 2000 to 2007
Grant Reviewer, Developmental Neurobiology at National Science Foundation, 2001 and 2004
External Reviewer for faculty promotions, ex. Department of Political Science at Pomona College (2007), Kalamazoo College (2001)
Ad Hoc Manuscript Reviewer, ex. Department of Political Science at Genetics, Oncogene
Student-Teacher Referee, Department of Education at Denison University, 2001
Assistant Professor, Department of Biology at Denison University, 1994 - 2000
Teaching Assistant, Department of Molecular and Cell Biology at University of CA-Berkeley
- Smith, JA and Liebl, EC. 2006. Identification of the Molecular Lesions in Alleles of the Drosophila Abelson Tyrosine Kinase. Drosophila Information Service. v. 88 p. 20-23
- Forsthoefel, DJ, Liebl, EC, Kolodziej, PA, Seeger, MA. 2005. The Abelson tyrosine kinase, the Trio GEF, and Enabled interact with the Netrin receptor Frazzled in Drosophila. Development. v. 132 p. 1983-1994
- Liebl EC, Rowe RG, Forsthoefel DJ, Stammler AL, Schmidt ER, Turski M, Seeger MA. 2003. Interactions between the secreted protein Amalgam, Amalgam's transmembrane receptor Neurotactin and the Abelson tyrosine kinase affect axon pathfinding. Development. v. 130 no. 14 p. 3217-3226
- Liebl EC, DJ Forsthoefel, LS Franco, SH Sample, JE Hess, JA Cowger, MP Chandler, AM Shupert and MA Seeger. 2000. Dosage-sensitive, reciprocal genetic interactions between the Abl tyrosine kinase and the putative GEF trio reveal trio's role in axon pathfinding. Neuron. v. 26 p. 107-118
- Liebl EC. 1999. Molecular Characterization of the Insertion Site in Eight P-Insertion Lines from the Kiss Collection. Drosophila Information Service. v. 82 p. 79-81
- Liebl, EC, DJ Forsthofel, ER Schmidt, M Turski, KB Markham and MA Seeger. Mutational analysis of amalgam provides insights into Abl-dependent, Neurotactin-mediated adhesion and axon pathfinding in Drosophila. Genetics.
- Hu, W-L, G Minihan, GR Buckles, H Hayter, EC Liebl, M-C Ramel and FN Katz. 2002. Dachs encodes an unconventional myosin that is required for segmentation and morphogenesis during limb development in Drosophila. Developmental Biology.
- Liebl EC, DJ Forsthoefel, LS Franco, SH Sample, JE Hess, JA Cowger, MP Chandler, AM Shupert and MA Seeger. 2000. Dosage-sensitive, reciprocal genetic interactions between the Abl tyrosine kinase and the putative GEF trio reveal trio's role in axon pathfinding. Neuron. v. 26 p. 107-118
- Liebl EC. 1999. Molecular Characterization of the Insertion Site in Eight P-Insertion Lines from the Kiss Collection. Drosophila Information Service. v. 82 p. 79-81
- Liebl EC. 1998. Testing for mutagens using fruit flies. The American Biology Teacher. v. 60 p. 1-5
- Comer AR, EC Liebl and FM Hoffmann. 1995. Can clues to the molecular defects in chronic myelogenous leukemia come from genetic studies on the Abelson tyrosine kinase in fruit flies?. The Journal of Laboratory and Clinical Medicine. v. 125 p. 686-691
- Gertler FB, AR Comer, JL Juang, SM Ahern, MJ Clark, EC Liebl and FM Hoffmann. 1995. enabled, a dosage-sensitive suppresser of mutations in the Drosophila Abl tyrosine kinase, encodes an Abl substrate with SH3-domain binding properties. Genes and Development. v. 9 p. 521-533
- Liebl EC and FM Hoffmann. 1994. Growth factors and signal transduction in Drosophila. M. Nilsen-Hamilton, ed., Growth Factors and Signal Transduction in Development. p. 165-174
- Liebl EC, LJ England and GS Martin. 1993. Reactivation of host-dependent src kinase activity by coexpression with a heterologous tyrosine kinase. Virology. v. 195 p. 265-267
- Liebl EC, LJ England, JE DeClue and GS Martin. 1992. Host range mutants of v-src: Alterations in kinase activity and substrate interactions. J. Virol. v. 66 p. 4315-4324
- Liebl EC and GS Martin. 1992. Intracellular targeting of pp60src expression: Localization to adhesion plaques is sufficient to transform chicken embryo fibroblasts. Oncogene. v. 7 p. 2417-2428
- Young JC, EC Liebl and GS Martin. 1998. A host-dependent temperature sensitive mutant of Rous sarcoma virus: Evidence for host factors affecting transformation. Virology. v. 166 p. 561-572
- Pai JK, EC Liebl, CS Tettenborn, FI Ikegwuonu and GC Mueller. 1987. 12-O-tetradecanoylphorbol-13-acetate activates the synthesis of phosphatidylethanol in animal cells exposed to ethanol. Carcinogenesis. v. 8 p. 173-178
- Liebl EC, CL Baldyga, LL Bickle, A Bishop, KE Dean, M Kopeke, RR Manohar, JR McCall, J McCroskey, JA Smith, MA Seeger. 2007. A screen for dominant enhancers of a trio mutant phenotype. 48th Annual Drosophila Research Conference. Philadelphia, PA
- Liebl EC, CL Baldyga, LL Bickle, M Kopeke, RR Manohar, JR McCall, JA Smith, MA Seeger. 2005. A screen for dominant enhancers of a trio mutant phenotype. Cold Spring Harbor Meeting on Neurobiology of Drosophila. Cold Spring Harbor, NY
- Liebl, EC, RG Roew, DJ Forsthoefel, AM Stammler, MA Seeger. 2003. Identification of neurotactin as a dominant enchancer of the Abelson tyrosine kinase mutant phenotype. 44th Annual Drosophila Research Conference. Chicago, IL
- Liebl, EC. 2003. Amalgam functions as a dominant enhancer of the Abl mutant phenotype . Science Lecture Series. Ohio Wesleyan University, OH
- Liebl, EC., ER Schmidt, DJ Forsthoefel, SC Howard, MA Seeger. 2001. Identification of amalgam as a dominant enhancer of the Abelson tyrosine kinase phenotype. 42nd Annual Drosophila Research Conference. Washington, DC
- Liebl EC. 2001. Gaining insights into axonal pathfinding: combining genetics and cell biology nto an interesting amalgam. Kenyon College Biology Lecture Series. Gambier, OH
- Forsthoefel DJ, ER Schmidt, S Howard, MA Seeger, EC Liebl. 2000. Trio, a cytoplasmic GEF, and Amalgam, a secreted member of the immunoglobulin superfamily, exhibit dosage-sensitive genetic interactions with the Abelson tyrosine kinase and function in Drosophila axon guidance pathways. Axon Guidance & Neural Plasticity Meeting. Cold Spring Harbor, NY
- Liebl EC. 1999. Signal transduction in the developing CNS: Reciprocal genetic interactions between the Abl tyrosine kinase and a guanine-nucleotide-exchange factor. Ohio State Molecular, Cellular and Developmental Biology Seminar Series. Columbus, OH
- Korn JM* and EC Liebl. 1999. Isolating Dominant Enhancers of the two-thirds-trio Mutant Phenotype. Genetics Society of America's Midwest Drosophila Conference. Allerton Park, IL
- Schmidt E, SC Howard R Perala, EC Liebl. 1999. Fine Mapping of the M109 Gene. Genetics Society of America's Midwest Drosophila Conference. Allerton Park, IL
- Liebl EC, DJ Forsthoefel, SH Sample, LS Franco, JE Hess, MP Chandler, JA Cowger, AM Jackson, MA Seeger. 1999. Dosage-Sensitive Interactions Between two-thirds-trio, a Putative Guanine-Nucleotide-Exchange Factor, the Abl Tyrosine Kinase, enabled and failed-axon-connections. Cold Spring Harbor Meeting on Neurobiology of Drosophila. Cold Spring Harbor, NY
- Liebl EC, SH Sample, LS Franco, JE Hess, JA Cowger, AM Jackson, DJ Forsthoefel, MA Seeger. 1999. Dosage-Sensitive, Reciprocal Genetic Interactions Between a Putative Guanine-Nucleotide-Exchange Factor and the Abl Tyrosine Kinase. Fifteenth Annual Meeting on Oncogenes and Tumor Supressors: Signal Transduction and Cell Cycle Regulation in Cancer. Fredrick, MD
- Liebl EC. 1998. These Nobels Were Dynamite: Using the Genius of Morgan, McClintock and Mullis to Clone a Gene. Biology Symposium. The College of Wooster, OH
- Liebl EC. 1998. The Last of the Positional Cloners. I-71 Cellular and Molecular. Kenyon College, OH
- Liebl EC, JE Hess, FM Hoffmann. 1997. haracterization of M89: A Gene Redundant to the Abl Tyrosine Kinase. netics Society of America's Midwest Drosophila Conference. Allerton Park, IL
- Liebl EC and T Schuh. 1996. Using Xenopus and Drosophila in Your Developmental Biology Lab - A Practical Guide. 55th Annual Society for Developmental Biology Symposium. Nashville, TN
- Liebl EC. Tubby Flies. 1995. CNS Axons and Leukemia: Using Genetics to Unravel a Biological Problem. Denison Scientific Association. Granville, OH
- FB, AR Comer, J-L Juang, SM Ahern, MJ Clark, EC Liebl, FM Hoffmann. 1995. enabled, a Suppresser of Mutations in the Drosophila Abl Tyrosine Kinase, Encodes an Abl Substrate with SH3-domain Binding Properties. 54th Annual Society for Developmental Biology Symposium. San Diego, CA
- Liebl EC, FB Gertler, FM Hoffmann. 1994. Interactions with dachs May Link Abl Tyrosine Kinase-Mediated Signal Transduction with Cellular Adhesion. 53rd Annual Society for Developmental Biology Symposium. Madison, WI
- Liebl EC, FB Gertler, FM Hoffmann. 1994. Genetic Interactions with dachs May Serve to Link Abl Tyrosine Kinase-Mediated Signal Transduction with Cellular Adhesion. 35th Annual Drosphila Research Conference. Chicago, IL
- Liebl EC, FB Gertler, KK Hill, FM Hoffmann. 1993. Genetic Modifiers of the abl Mutant Phenotype. 9th Annual Meeting on Oncogenes. Fredrick, MD
- Liebl EC, KK Hill, FB Gertler, FM Hoffmann. 1993. Second Site Suppressors of the abl Mutant Phenotype. 34th Annual Drosophila Research Conference. San Diego, CA
- Liebl EC, KK Hill, FB Gertler, MJ Clark, M Visalli, FM Hoffmann. 1992. Identification of Second Site Modifiers of the abl Mutant Phenotype. 33rd Annual Drosophila Research Conference. Philadelphia, PA
- Liebl EC, LJ England, GS Martin. 1990. Insertion/Deletion Mutagenesis of v-src: Effects on Intracellular Location and Protein-Tyrosine Phosphorylation. Sixth Annual Meeting on Oncogenes. Fredrick, MD
- Liebl EC, LJ England, JE DeClue, GS Martin. 1989. Intracellular Localization of v-src: Effects on Fibroblast Transformation.. Fifth Annual Meeting on Oncogenes. Fredrick, MD
- Liebl EC and J Pai. 1986. Phorbol Esters Induce the Synthesis of Phosphatidyl Alcohols, a Unique Class of Phospholipids. McArdle Chemical Carcinogenesis Seminar. Madison, WI
- Liebl EC, K.E. Dean, A.R. Fields, M. J Geer, E.C. King, B. T. Lynch, K.C. Palozola, E.M. Steenkiste, Y. Zhang. 2012. Characterizing M9.17, a strong dominant enhancer of the trio mutant phenotype. . Given at the 71st Annual Meeting of the Society for Developmental Biology. Montreal, Canada,
- Liebl EC, A.R. Fields, M. J Geer, L.J. Korbel, B. T. Lynch, K.C. Palozola. 2011. Characterizing M9.17, a strong dominant enhancer of the trio and abl mutant phenotypes.. Given at the 53rd Annual Drosophila Research Conference. San Diego , CA
- Liebl EC, M. J Geer, B. T. Lynch, K.C. Palozola. 2010. Characterizing dominant enhancers of a trio mutant phenotype.. Given at the 52nd Annual Drosophila Research Conference. Washington , DC
- Palozola KC, O. Uguru, K.E. Dean, R.R. Manohar, J.R. McCall, J.A. Smith and E.C. Liebl . 2008. Dissecting signal transduction networks involving the Abl tyrosine kinase and the Trio guanine nucleotide exchange factor.. Given at the first annual McArdle Laboratory Research Symposium. Madison , WI
- Liebl EC. 2008. Dosage-sensitive genetic interaction affecting axon guidance.. Given to the University of Toledo Biology Department. Toledo , OH
Honors and Awards
- Richard Lucier Endowed Professorship in recognition of outstanding teaching and scholarship. August 2007 - present
- National Institutes of Health Academic Research Enhancement Award (AREA) Grant, "Understanding Trio and Abl in Drosophila Axon Guidance Through Genetic Modifiers" (PI; 1R15HD059924-01); $196,312; 8/2009 to 8/2012.
- Denison University Research Foundation Award, “A Systematic Search for Genetic Interactions Affecting Nervous System Development Involving the Abl Kinase and the Trio Guanine-Nucleotide-Exchange Factor”, $10,967, 2008-2009
- Participant in the Faculty Summer Institute on the Ethical, Legal and Social Implications of the Human Genonome Project sponsored by the Dartmouth College Institute for the Study of Applied and Professional Ethics. June, 2004 at Howard University, Washington D.C.
- National Science Foundation Grant, "Investigation of the integrated roles of Abl, Trio, and Neurotactin in axon outgrowth" (co-PI; NSF 0344053); $240,000; 2004-2007
- R. C. Good Fellowship, Denison University, 2001
- National Science Foundation Grant, "Genetic and Cell Biological Characterization of Trio and Amalgam: Two New Enhancers of Abl" (co-PI); $341,752; 2001-2004
- Andrew W. Mellon Foundation, Collaboration with Technology Grant (PI); $21,216 2000-2001
- Faculty Professional Development Award, Denison University, 2000
- Denison University Research Foundation Award, "Fine Mapping and Cloning of the Fruit Fly M109 Gene", $3,534, 1999-2000
- Faculty Professional Development Award, Denison University, 1999
- Junior Faculty Fellowship, Denison University, 1998
- National Institutes of Health Academic Research Enhancement Award (AREA) Grant, "Probing Drosophila Abelson Tyrosine Kinase with Genetics" (PI); $98,182; 1996-2000.
- Faculty Professional Development Award, Denison University, 1995
- Damon Runyon-Walter Winchell Cancer Research Postdoctoral Fellowship, 1991-1994
- Outstanding Graduate Student Instructor, University of California, 1988
- National Science Foundation Graduate Fellowship Honorable Mention, 1987
- Regents Fellowship, University of California, 1986
- Honors Degree in Molecular Biology, University of Wisconsin, 1985
- Trewartha Honors Undergraduate Research Grant, University of Wisconsin, 1984
Senior Thesis Advised
- Localizing dominant enhancers of the trio mutant phenotype and structure/function assays of Neurotactin. Kathryn Elizabeth Dean, 2007*
- Tyrosine phosphorylation of Trio by Abelson tyrosine kinase. Andrew Justin Bishop, 2007*
- An investigation of axon pathfinding in the central nervous system of Drosophila through the molecular and genetic characterization of dominant enhancers of the trio mutant phenotype. Jenna Susanne McCroskey, 2007*
- Investigating Neurotactin and localizing the dominant enhancers of the trio mutant phenotype. Rohan Raoul Manohar, 2006*
- Study on Neurotactin and dominant enhancers of the trio mutant phenotype. Lindsay Lee Bickel, 2006*
- Identification of protein:protein interactions of the intracellular domain of Neurotactin by biopanning of a phage display cDNA library. Timothy Ryan Heacock, 2004*
- Axon pathfinding in the central nervous system of D. melanogaster: Determining enhancers of the trio mutantphenotype from a random mutagenesis screen. Morgan Rebecca Koepke, 2004*
- Interactions with Nrt: A yeast two-hybrid assay. Brant Lloyd Eutzy, 2003*
- Amalgam and neurotactin are dosage-sensitive genetic modifiers of the Abl tyrosine kinase mutant phenotype. R. Grant Rowe, 2003*
- The development of the central nervous system of Drosophila melanogaster: Potential interactions with Trio and Neurotactin. Kara Beth Markham, 2001*
- Localization and characterization of the M109 mutation: A new allele of the Drosophila amalgam gene. Erica R. Schmidt, 2000*
- Isolation of enhancers of the trio mutant phenotype. Jay Korn, 2000
- Testing the effectiveness of two cryoprotectants (glycerol and ethylene glycol) and two freezing methods (dry ice block freezing and controlled rate freezing) in the cryopreservation of domestic felid spermatozoa. Katherine A. Beltaire, 1999*
- M89: Transposon mutagenesis and recombination with fax. Lara S. Franco, 1999
- Mycobacteriophage L5: Investigation of the integration complex and further characterization of the mIHF binding site. J. Michelle Kahlenberg, 1998*
- Generation and characterization of gamma-ray generated M89 alleles. Matthew P. Chandler, 1998
- Fine localization and characterization of the M89 gene in Drosophila melanogaster. Jon E. Hess, 1998*
- Deficiency and meiotic recombinant mapping of the Drosophila Abl interacting gene M109. N. Reid Perala, 1998*
- Genetic experiments exploring the Abl:Disabled genetic interaction. James Pavelka, 1997.
- The search for a suppressor of the enabled mutant phenotype. Jason A. Hoppe, 1997.
- The mapping and characterization of the M89 mutation in the genome of Drosophila melanogaster. Jennifer A. Cowger, 1997*
- Using Drosophila genetics to study signal transduction by the Abl tyrosine kinase. Susan C. Howard, 1996*
- The mapping and characterization of the M89 mutation in Drosophila. Angela M. Jackson, 1996*
- Detection of a polymorphic microsatellite in the 21-hydroxylase gene region of the horse. Jennifer J. Carlisle, 1995*
* Denotes an honors thesis
Dr. Matthews joined the faculty at Denison in 2001 after completing a four-year post-doctoral fellowship in the Center for Neurobiology & Behavior at Columbia University. He teaches Sensation & Perception, Statistics for the Behavioral Sciences, Research Methods, and Introduction to Psychology. Seminars he has offered include “Perceptual Learning and Brain Plasticity”, “The Cognitive Neuroscience of Music”, “Ruining Humor with Science”, “Neuroscience and the Liberal Arts”, and “NERDs Without Borders”. His research addresses issues in human vision and audition, with an emphasis on how these sensory systems improve with training.
Peer Reviewed Journal Articles With Denison Student Co-Authors
9. Matthews N, Welch, L., Festa, E.K., & Clement, A. (2013). Remapping Time Across Space. Journal of Vision. 13(8):2, 1-15. [PubMed]
8. Matthews N, Vawter, M, & Kelly, J, 2012. Right Hemifield Deficits in Judging Simultaneity: A Perceptual Learning Study. Journal of Vision. 12(2):1, 1-14. [PubMed]
7. Kelly J, & Matthews N, 2011. Attentional Oblique Effect When Judging Simultaneity. Journal of Vision. 11(6):10, 1-15. [PubMed]
6. Reardon K, Kelly J, & Matthews N, 2009. Bilateral Attentional Advantage on Elementary Visual Tasks. Vision Research. 49(7), 692-702. [PubMed]
5. Strong K, Kurosawa K, & Matthews N, 2006. Hastening Orientation Sensitivity. Journal of Vision. 6(5), 661-670. [PubMed]
4. Matthews N, Rojewski A, & Cox J, 2006. The time course of the oblique effect in orientation judgments. Journal of Vision. 5(3), 202-214. [PubMed]
3. Matthews N, & Allen J, 2005. The role of speed lines in subtle direction judgments. Vision Research. 45(12), 1629-1640. [PubMed]
2. Saffell T, & Matthews N, 2003. Task-specific perceptual learning on speed and direction discrimination. Vision Research. 43(12), 1365-1374. [PubMed]
1. Stanley R, & Matthews N, 2003. Invalid cues impair auditory motion sensitivity. Perception. 32(6), 731-740. [PubMed]
Assistant Professor, Department of Biology at Denison University, January 2008 to present
Postdoctoral fellow, Department of Biology at Boston University, 2004-2007
Grass Fellow, Neuroscience at Marine Biological Laboritories at Woods Hole, 2006
Postdoctoral researcher, Department of Neurobiology at Duke University, 2004
I am interested in understanding how neural circuits produce perceptions and behaviors. In my current research I study the vocal circuit of the African clawed frog (Xenopus laevis). Xenopus produce rhythmic vocal patterns using a type of neural circuit called a central pattern generator (CPG). CPGs are neural circuits that are capable of generating a rhythmic output without any rhythmic input; they are essentially pacemakers. They are used to control a wide variety of rhythmic behaviors in other animals, such as walking, swimming, and breathing. CPG circuits can take many forms and we don't yet understand the structure or function of the Xenopus vocal CPG, but that's one of the goals of my research.
The CPG in the Xenopus vocal system is cool in a couple of ways. First, we can activate it in an isolated brain preparation to evoke rhythmic neural activity patterns called fictive vocalizations (like vocalizations without a voice). Being able to reproduce the neural patterns associated with vocalizations in an isolated brain allows us to physically and pharmacologically manipulate the neural circuit and see how it affects vocal production.
Second, the Xenopus vocal circuit is altered by hormones. Male and female frogs produce different calls, and by changing hormone exposure you can change the types of vocal rhythms the brain produces. For example, giving a female testosterone will cause her to produce male-like vocal patterns. I'd like to know more about how hormones alter the neural circuits to produce these effects.
I am also interested in understanding what cues naturally activate the vocal CPG to cause the animals to start calling. What external stimuli or internal hormonal cues trigger vocal behavior and how?
The techniques I use in my lab include electrophysiology (recording the electrical potentials produced by one or more active neurons in brain tissue), histology (examining anatomical features of neurons), immunocytochemistry (using antibodies find the locations of neurotransmitters and other chemicals in the brain), and behavioral studies (using automated underwater microphones to monitor frog vocal behavior).
If you are interested in my research, read the publications listed below and also look up papers by Ayako Yamaguchi (my former mentor) and Darcy Kelley both of whom also study the Xenopus vocal system.
Rhodes, H.J., Yu, H.J., Yamaguchi, A.. 2007. Xenopus vocalizations are controlled by a sexually differentiated hindbrain central pattern generator. J Neurosci. v. 27 no. 6 p. 1485-1497 View online.