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George D Pollak
Professor Emeritus
Department of NeuroscienceHow the auditory system processes species-specific communication signals and the cues that enable association with its location in space.-
Research Summary:
My principal interests are in elucidating how circuits in the mammalian brain transform information in sensory systems and how populations of neurons then represent features of the external world.
Specifically, I study the mammalian auditory system and evaluate how the auditory system processes species-specific communication signals and the cues that enable animals to associate a sound with its location in space. The animals that I use for experimental subjects are echolocating bats. The reasons for using bats are that they are mammals and thus their auditory systems are mammalian in design, yet they rely to an inordinate degree on their sense of hearing for survival. Because of the high premium they place on hearing, their auditory systems are greatly enlarged and express features with exceptional clarity.
Like all animals, bats also have to what a sound is and where in space it came from. Projects that address what the sound is, investigate how the brain decodes and represents complex acoustic signals. We do this by recording from individual nerve cells to evaluate how nerve cells respond to complex signals and what rules the auditory system employs to create response selectivity and diversity.
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in press Pollak, G.D., Andoni, S. Bohn, K. and Gittelman, J. X . The repertoire of Communication calls emitted by bats and the way the calls are processed in the inferior colliculus. In: Animal Models of Speech and Language. S. Helekar (ed), Springer-Verlag
in press Gittelman, J.X., Wang, L., Colburn, S.S. and Pollak, G.D., Inhibition Shapes Response Selectivity by Controlling the Gain of the Transition from Postsynaptic Potentials to Spikes. , Frontiers Neuroscience2012 Pollak, G.D., Circuits for processing dynamic interaural intensity disparities in the inferior colliculus., Hearing Res 288: 47-57
2011 Andoni, S. and Pollak, G.D., ) Motion selectivity as a neural mechanism for encoding natural communication signals in the inferior colliculus, J Neurosci 31: 16529-16540.
2011 Gittelman, J.X. and Pollak, G.D., It’s about time: How input timing is used and not used to create emergent properties in the auditory system. , J Neurosci 31: 2576-2583
2011 Pollak, G.D., Xie, R., Gittelman, J.X., Andoni, S. and Li, N. , The Dominance Of Inhibition In the Inferior Colliculus. , Hearing Res 274: 27-39
2011 Pollak, G.D., Discriminating among Complex Signals: The Roles of Inhibition for Creating Response Selectivities, J Comp Physiol A 197: 625-640.
2011 Pollak, G.D., Gittelman, J.X., Li, N., and Xie, R. , Inhibitory projections from the ventral nucleus of the lateral lemniscus and superior paraolivary nucleus create directional selectivity of frequency modulations in the inferior colliculus: A comparison of bats with other mammals., Hearing Res 273: 134-144
2010 Li, N., Gittelman, J.X., and Pollak, G.D. , Intracellular recordings reveal novel features of neurons that code interaural intensity disparities in the inferior colliculus, J Neurosci 30: 573–14584.
2009 Bohn, K.M, Schmidt-French, B., Schwartz, C., Smotherman, M. and Pollak, G.D. , Versatility and Stereotypy of Free-tailed Bat Songs., PLoS ONE Vol.2, e6746: 1-10
2009 Gittelman, J., Li, Na., and Pollak, G.D. , Mechanisms Underlying Directional Selectivity for Frequency Modulated Sweeps in the Inferior Colliculus Revealed by in-vivo Whole-Cell Recordings, J Neurosci. 29: 13030-13041
2008 Xie R, Gittelman JX, Li N, Pollak GD., Whole cell recordings of intrinsic properties and sound-evoked responses from the inferior colliculus., Neurosci. 154: 245-56
2007 Xie R, Gittelman JX, Pollak GD., Rethinking tuning: in vivo whole-cell recordings of the inferior colliculus in awake bats., J Neurosci. 27: 9469-9481
2007 Andoni S, Li N, Pollak GD., Spectrotemporal receptive fields in the inferior colliculus revealing selectivity for spectral motion in conspecific vocalizations., J Neurosci 27: 4882-4893
2007 Pecka M, Zahn TP, Saunier-Rebori B, Siveke I, Felmy F, Wiegrebe L, Klug A, Pollak GD, Grothe B., Inhibiting the inhibition: a neuronal network for sound localization in reverberant environments., J Neurosci 27: 4019-4037
2005 Hurley, L.M. and Pollak, G.D., Serotonin shifts first-spike latencies in inferior colliculus neurons., J.Neurosci. 25: 7876-7886
2005 Hurley, L.M. and Pollak, G.D., Serotonin modulates responses to species specific calls , J. Comp. Physiol. 191: 535-546
2005 Xie, R., Meitzen, J and Pollak, G.D., Differing roles of inhibition in heirarchical processing of species-specific calls in auditory brainstem nuclei., J. Neurophysiol. 94: 4019-4037
2002 Hurley, L.M., Thompson, A.M., and Pollak, G.D., Serotonin in the inferior colliculus, Hearing Res. 168: 1-15
2002 Pollak, G.D., Model Hearing, Nature 417: 502-503
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