Assistant Professor, Otolaryngology University of Pittsburgh Phone: (412) 383-8626 Email: thanos@pitt.edu This e-mail address is being protected from spam bots, you need JavaScript enabled to view it This e-mail address is being protected from spam bots, you need JavaScript enabled to view it

Ph.D. Vollum Institute, Oregon Health and Science University 

Research Interests

Our previous studies in the dorsal cochlear nucleus (DCN), an auditory brainstem nucleus, have uncovered novel forms of synaptic plasticity that occur at the earliest levels of sensory processing. The objective of our research is to determine mechanisms and synaptic rules underlying activity-dependent changes in synaptic strength of excitatory and inhibitory inputs to the auditory brainstem. Our central hypothesis is that the concerted operation of opposing forms of long-term synaptic plasticity at synapses onto different cell types in the DCN determines activation and spike timing precision of the output cell. Understanding the mechanisms and role of activity-dependent plasticity in shaping the activity of the DCN circuitry should not only contribute to a unified understanding of the generation of neural responses, but will also have a significant impact on our understanding and cures for disorders caused by neural plasticity-like mechanisms, including tinnitus.

A second area of our research focuses on tinnitus and its underlying cellular mechanisms. The nervous system is plastic; expression of neural plasticity can lead to compensation for loss of function and adaptation to changing demands. However, plasticity-induced changes can also cause signs and symptoms of disease. Tinnitus - commonly referred to as ringing in the ears or head - is the perception of sound in the absence of an environmental acoustic stimulus. 10% of the adult population experiences some degree of tinnitus. In light of recent studies implicating changes in the balance of excitation and inhibition in specific brain regions, we hypothesize that unique plasticity mechanisms discovered in these regions can provide cellular mechanisms underlying tinnitus.

Tzounopoulos lab and colleagues employ electrophysiological, imaging and behavioral approaches to answer these questions.

Recent Publications

• Tzounopoulos T. Mechanisms of Synaptic Plasticity in the Dorsal Cochlear Nucleus: Plasticity-induced Changes that could Underlie Tinnitus. Am J Audiol 17(2): S170-5, 2008.
• Tzounopoulos T, Rubio M,  Keen J, Trussell L. Coactivation of Pre- and Postsynaptic Signaling Mechanisms Determines Cell-specific Spike Timing-Dependent Plasticity. Neuron 54: 291-301, 2007.
• Tzounopoulos T, Kim Y, Oertel D, Trussell L. Cell-specific, Spike Timing Dependent Plasticities in the Dorsal Cochlear Nucleus. Nat Neurosci 7: 719-725, 2004.
• Stackman RW, Hammond RS, Linardatos E, Gerlach A, Maylie J, Adelman JP, Tzounopoulos T. Small Conductance Ca2+-Activated K+ Channels Modulate Synaptic Plasticity and Memory Encoding.  J Neurosci 22: 10163-10171, 2002.
• Tzounopoulos T, Janz R, Sudhof TC, Nicoll RA, Malenka RC  A role for cAMP in mossy fiber long-term depression. Neuron 21: 837-845, 1998.