Associate Professor of Biological Sciences
PhD, 1997 University of Notre Dame
Mechanisms of learning and memory in fruit fly
Research descriptionWe study the molecular / cellular, systems, and behavioral control of learning using Drosophila. These learning mechanisms are examined in three interdependent approaches. We identify new gene function in neural systems to support learning in behavioral paradigms that we define.
Molecular / cellular mechanisms of learning. Because of the commonality of some gene function in resistance to ethanol effects on behavior and learning, we characterized the memory phenotypes of several novel ethanol sensitive mutants. We found three new genes that have learning functions in operant place learning and classical olfactory conditioning. These genes implicate novel and different processes in memory formation. We continue to characterize these mutant flies.
Neural system mechanisms of learning. Using genetic and pharmacological approaches, we found that the serotonergic system is necessary for memory formation. Indeed, we find that altering excitability of these neurons leads to memory performance levels of different strengths. Furthermore, we discovered that the serotonergic system is critical for a process that enhances memory performance after experience with unpredicted experience with negative reinforcement. We are determining the role of the serotonergic system in olfactory memory and developing tools for manipulating subsets of the serotonergic nervous system.
Behavioral analysis. We examined the role of reinforcement pre-exposure on subsequent memory acquisition. This manipulation leads to either enhancement or decrement in later memory formation in many animal models. It was an open question how reinforcement pre-exposure would alter learning in Drosophila. We found that reinforcement pre-exposure increases associative memory performance, the first example of this sort in an invertebrate animal. Furthermore, yoking experiments show that it is the lack of an accurate predictor that is important for acquisition of this effect.
Kahsai, L., T. Zars (2013) Visual working memory: Now you see it, now you don’t. Current Biology 23, R843-845.
Masoner, V., R. Das, L. Pence, A. Gaurav, H. LaFerriere S. Goode, T. Zars, S. Bouyain, L. Dobens (2013). The kinase domain of Drosophila tribbles is required for turnover of fly C/EBP protein during cell migration. Developmental Biology. Developmental Biology, 375, 33-44
Ostrowski, D., and T. Zars. Place memory. in Handbook of Behavior Genetics of Drosophila melanogaster: Behavioral Phenotypes and Models of Neurobehavioral Disorders. J. Dubnau, ed. Cambridge, UK. Cambridge University Press. in press
Zars, T. (2012) She said no, pass me a beer. Science 335, 1309-1310.
Sitaraman, D.*, H. LaFerriere*, and T. Zars (2012) Serotonin is critical for rewarded olfactory short-term memory in Drosophila. J. Neurogenetics, 26, 238-244.
Chen, A., E.F. Kramer, L. Purpura, J.L. Krill, T. Zars, K. Dawson-Scully (2011) The influence of natural variation at the foraging gene on thermotolerance in adult Drosophila in a narrow temperature range. J. Comp. Physiol. A, 197, 1113-1118.
Kahsai, L., and T. Zars. (2011) Learning and memory in Drosophila: behavior, genetics, and neural systems. Int. Rev. Neurobiol. 99, 139-167.
Zars, T. (2011) Flies race to a safe place. Nature 474, 169-170.
LaFerriere H., K. Speichinger, A. Stromhaug, and T. Zars. (2011) The radish gene reveals a memory component with variable temporal properties PLoS ONE, 6 (9) e24557.
LaFerriere, H., D. Ostrowski, D.J. Guarnieri, and T. Zars (2011) The arouser EPS8L3 gene is critical for normal memory in Drosophila. PLoS ONE 6 (7) e22867.
Zars, T. (2010) Visualizing PKA dynamics in a learning center. Neuron 65, 442-444.
Zars, T. (2010) Short-term memories in Drosophila are governed by general and specific genetic systems. Learning and Memory 17, 246-251
Sitaraman, D., M. Zars, and T. Zars. (2010) Place memory formation in Drosophila is independent of proper octopamine signaling. J. Comp. Physiol. A 196, 299-305.
Sitaraman, D. and T. Zars. (2010) Lack of prediction for high-temperature exposures enhances Drosophila place learning. J. Exp. Biol. 213, 4018-4022