Neural Mechanisms in Complex Sound Processing

Alexander Galazyuk, Ph.D.

 Assistant Professor
Department of Neurobiology

Northeastern Ohio Universities
College of Medicine
4209 St. Rt. 44, P.O. Box 95
Rootstown, Ohio 44272-0095
Phone: (330) 325-6640
Fax: (330) 325-5916
Email: agalaz@neoucom.edu
Community of Science Expertise
Department of Neurobiology

 

Education:

1992 Ph.D. A.A.Bogomoletz Institute of Physiology, Kiev, Ukraine
1982 MSc Kiev State University, Faculty of Biological Sciences, Human and Animal Physiology

Professional Experience:

2003-present Assistant Professor, Dept. of Neurobiology, Northeastern Ohio Universities College of Medicine
1998 - 2003 Research Scientist, Dept.of Molecular and Integrative Physiology , University of Illinois at Urbana-Champaign
1994 - 1998 Postdoctoral Research Associate, Dept.of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign
1986-1994 Research Fellow, Institute of Physiology, Department of Physiology of Cerebral Cortex and Subcortical Structures
Bogomoletz Institute of Ukraine Academy of Science
1973-1986 Senior Technician, Institute of Physiology, Department of Physiology of Cerebral Cortex and Subcortical Structures
Bogomoletz Institute of Ukraine Academy of Science

Research Interests:

We want to study how the timing between temporally discrete sounds in a sequence influences the fundamental response properties of central auditory neurons. Sounds produced in sequences are common to most bioacoustic signals such as the biosonar sounds used by bats and communication sounds including speech. Our recent studies in bats show that amplitude and frequency selectivity of auditory neurons progressively increases when time between sound elements of complex sound decreased. In addition, we found that the ability of human listeners to discriminate small differences in sound level improves when time between acoustic stimuli during psychophysical experiments was decreased. Therefore, understanding the mechanisms that underlie time-dependent changes in amplitude and frequency selectivity could be important not only to explain behavioral performance of echolocating bats, but it could also advance our understanding of speech processing in humans. We use a variety of techniques, including physiological (extracellular and intracellular recording from single auditory neurons in awake bats), and pharmacological (single unit recording with micro-iontophoresis).

 

 

Selected Publications:

  • Voytenko, S.V. and Galazyuk, A.V. (2005) Temporal integration of postsynaptic events by inferior colliculus neurons. (submitted)

  • Galazyuk, A.V., Lin W., Llano, D.A. and Feng, A.S. (2005) Leading inhibition to neural oscillation is important for time domain processing in the auditory midbrain. J. Neurophysiol. 94: 314-326.

  • Galazyuk, A.V. White, K.R., Feng, A.S. (2004) Temporal dynamics of amplitude-tuning in the inferior colliculus of the little brown bat. In:
    Echolocation in Bats and Dolphins, J. Thomas, C. Moss, and M. Vater, eds.
    University of Chicago Press, Chicago. pp 136-140.

  • Smalling J. M., Galazyuk, A.V., Feng, A.S (2001) Stimulation rate influences frequency tuning characteristics of inferior colliculus neurons in the little brown bat, Myotis lucifugus. NeuroReport 12: 3539-3542.

  • Galazyuk, A.V., Feng, A.S (2001) Oscillation may play a role in time domain central auditory processing. J. Neuroscience 21: RC147.

  • Galazyuk, A.V., Llano D., Feng, A.S (2000).Temporal dynamics of acoustic stimuli enhance amplitude tuning of inferior collicular neurons J. Neurophysiol. 83: 128-138.

  • Volkov I.O., Galazyuk A.V. (1998) Cochleo- and tonotopic organization of the second auditory cortical area (AII) in the cat. Neuroscience 82: 499-509

  • Galazyuk, A.V., Feng, A.S (1997) Encoding of duration of sound pulses by neurons in the auditory cortex of the little brown bat, Myotis lucifugus J. Comp. Physiol. A180: 301-311.

  • Galazyuk A.V., Volkov I.O. (1994) Reactions of cat second auditory cortex neurons to sound and nonsound stimulation.Neurophysiology 26:356 - 364.

  • Volkov I.O., Galazyuk A.V. (1992) Peculiarities of inhibition in cat auditory cortex neurons evoked by tonal stimuli of various durations. Exp. Brain Res. 91: 115-120,.

  • Volkov I.O., Galazyuk A.V. (1991) Formation of spike response to sound tones in cat auditory neurons: Interaction of excitatory and inhibitory effects. Neuroscience. 43: 307 - 321, 1991.

  • Volkov I.O., Galazyuk A.V.(1985) Responses of auditory cortex neurons in unanesthetized cats to best - frequency tones. Neurophysiology. 17: 360-367.

  • Volkov I.O., Dembnovetskii O.F., Galazyuk A.V. (1985) Response of cat auditory cortex neurons to tonal stimulation during and after nembutal anesthesia. Neurophysiology. 17: 517-524.