Our laboratory is trying to understand how single neurons and populations of neurons encode the information needed to plan and execute limb movements. Our goal is to decipher how the brain represents different movement parameters and then uses this information to control movements. We are investigating both kinematic and dynamic movement parameters, recording the activity of neurons in the cerebellum in primates during motor behaviors. A variety of movements are studied, including reaching to targets in space, tracking moving targets, the learning of new visuomotor relations, and hand movements. Using analytical and statistical techniques, we sort out how information about movement parameters is embedded in the neuronal discharge.
We are also interested in how information in the brain is represented spatially and temporally in populations of neurons. In the cerebellum we are using flavoprotein fluorescence and Ca 2+ dyes to visualize neural activity. We also use optogenetics to perturb the cerebellar circuit. We are able to construct detailed spatial and temporal maps of the neuronal activity in the cerebellar cortex, investigating how the cerebellar circuit functions and how synaptic plasticity modifies circuit properties. In addition, we are using these techniques to examine abnormalities in the cerebellar cortex in the spinocerebellar and episodic ataxias.
(For a comprehensive list of recent publications, refer to PubMed, a service provided by the National Library of Medicine.)
Popa LS, Streng ML, Hewitt AL, Ebner TJ. The Errors of Our Ways: Understanding Error Representations in Cerebellar-Dependent Motor Learning. Cerebellum. 2015 Jun 26.
Cramer SW, Popa LS, Carter RE, Chen G, Ebner TJ. Abnormal excitability and episodic low-frequency oscillations in the cerebral cortex of the tottering mouse. J Neurosci. 2015 Apr 8;35(14):5664-79.
Popa LS, Hewitt AL, Ebner TJ. The cerebellum for jocks and nerds alike. Front Syst Neurosci. 2014 Jun 17;8:113. doi: 10.3389/fnsys.2014.00113. eCollection 2014. Review.
Hewitt AL, Popa LS, Ebner TJ. Changes in Purkinje Cell Simple Spike Encoding of Reach Kinematics during Adaption to a Mechanical Perturbation. J Neurosci. 2015 Jan 21;35(3):1106-24.
Prosise JF, Hendrix CM, Ebner TJ. Joint angles and angular velocities and relevance of eigenvectors during prehension in the monkey. Exp Brain Res. 2014 Oct 18;.
Armbrust KR, Wang X, Hathorn TJ, Cramer SW, Chen G, Zu T, Kangas T, Zink AN, Öz G, Ebner TJ, Ranum LP. Mutant β-III spectrin causes mGluR1α mislocalization and functional deficits in a mouse model of spinocerebellar ataxia type 5. J Neurosci. 2014 Jul 23;34(30):9891-904.
Cramer SW, Gao W, Chen G, Ebner TJ. Reevaluation of the beam and radial hypotheses of parallel fiber action in the cerebellar cortex. J Neurosci. 2013 Jul 10;33(28):11412-24.
Popa, L.S., Hewitt, A.L., and Ebner, T.J. Predictive and feedback performance errors are signaled in the simple spike discharge of individual Purkinje cells. J Neurosci, in press, 2012.
Barnes, J.A., Ebner, B.A., Duvick, L.A., Gao, W., Chen, G., Orr, H.T., and Ebner, T.J. Abnormalities in the climbing fiber-Purkinje cell circuitry contribute to neuronal dysfunction in ATXN2[82Q] mice. J Neurosci, 31(36):12778-89, 2011.
Hewitt A., Popa L., Pasalar S., Hendrix C., and Ebner T. Representation of limb kinematics in Purkinje cell simple spike discharge is conserved across multiple tasks. J Neurophysiol 106(5):2232-47, 2011.
Wang, X., Chen, G., Gao, W. and Ebner, T.J. Parasagittally aligned, mGluR1-dependent patches are evoked at long latencies by parallel fiber stimulation in the mouse cerebellar cortex in vivo. J Neurophysiol 105:1732-1746, 2011.
Moseley, M.L., Zu, T., Ikeda, Y., Gao, W., Mosemiller, A.K., Daughters, R.S., Chen, G., Weatherspoon, M.R., Clark, H.B., Ebner, T.J., Day, J.W., and Ranum, L.P. Bidirectional expression of CUG and CAG expansion transcripts and intranuclear polyglutamine inclusions in spinocerebellar ataxia type 8. Nat Genet 38(7):758-769, 2006.
Pasalar, S., Roitman, A.V., Durfee, W.K. and Ebner, T.J. Force field effects on cerebellar Purkinje cell discharge: implications for internal models. Nat Neurosci 9(11):1404-1411, 2006.
Current Graduate Students:
Laurentiu Popa (Biomedical Engineering, University of Minnesota).
Jodi Prosise (Biomedical Engineering, University of Minnesota).
Martha Streng (Neuroscience, University of Minnesota).
Former Graduate Students:
Justin Barnes (Ph.D. 2011, Neuroscience, University of Minnesota).
Samuel Cramer (Ph.D. 2014, Neuroscience, University of Minnesota).
Robert L. Dunbar (Ph.D. M.A., 2002, Neuroscience, University of Minnesota).
Jose Gomez (Ph.D. 2000, Neuroscience, University of Minnesota).
Charles Hanson (Ph.D. 2S001, Neuroscience, University of Minnesota).
Angela Hewitt (Ph.D. 2013, Neuroscience, University of Minnesota).
Catherine Ojakangas (Ph.D. 1992, Neuroscience, University of Minnesota).
Kenneth Reinert (Ph.D. 2006, Neuroscience, University of Minnesota).
Sharad J. Shanbhag (Ph.D. 1999, Neuroscience, University of Minnesota).
Stephen Helms Tillery (Ph.D. 1994, Neuroscience, University of Minnesota).