Cellular mechanisms for learning and memory and their role in auditory processing.
Mechanisms of synaptic plasticity have traditionally been ascribed to higher-order sensory processing areas such as the cortex, whereas early sensory processing centers have been considered largely hard-wired. However, recent results from our lab and human studies have revealed remarkable evidence for cellular and behavioral mechanisms for learning and memory in early stages of sensory processing. We are investigating the cellular mechanisms underlying synaptic and intrinsic plasticity in sensory systems and in their role for normal and pathological sensory processing.
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, such as tinnitus. Our goal is to understand the maladaptive plasticity mechanisms underlying the development and the establishment of tinnitus.
Thanos Tzounopoulos and his associates employ electrophysiological, imaging and behavioral approaches to answer these questions.
Middleton, J.W., Kiritani, T., Pedersen, C., Turner, J., Shepherd, G.M.G. and Tzounopoulos, T. Mice with Behavioral Evidence of Tinnitus Exhibit Dorsal Cochlear Nucleus Hyperactivity Due to Decreased GABAergic Inhibition. Proc Natl Acad Sci U S A (2011, In Press)
Zhao, Y. and Tzounopoulos, T. Physiological Activation of Cholinergic Inputs Controls Associative Synaptic Plasticity via Modulation of Endocannabinoid Signaling. J. of Neuroscience Mar 2;31(9): 3158-68, 2011.
Tzounopoulos, T. and Kraus, N. Learning to Encode Timing: Mechanisms of Plasticity in the Auditory Brainstem. Neuron, May 28; 62(4): 463-9, 2009.
Zhao, Y., Rubio, M. and Tzounopoulos, T. Distinct Functional and Anatomical Architecture of Endocannabinoid System in the Auditory Brainstem. J Neurophysiol 101: 2434-2446, 2009
Tzounopoulos, T., Rubio, M., Keen, J. and 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. and Trussell, L. Cell-specific, Spike Timing Dependent Plasticities in the Dorsal Cochlear Nucleus. Nature Neuroscience, 7, 719-725, 2004.