ECE WEB

Education:
B.S., Electrical Engineering, Florida International University, 1993
M.S., Electrical Engineering: Signal Processing and Stochastic Modeling, Columbia University, 1995
Ph. D., Bioengineering, University of California at Berkeley and San Francisco, 2000

Research Interests:
The overall goal of my research is to understand how the central nervous system processes complex sounds in their environment, such as speech, back-ground noise and animal vocalizations. It is very easy for animals (including humans) to detect and discriminate vocalizations in the midst of high background noise and yet it is still not clear how this process is achieved within the central nervous system. Artificial systems for voice recognition and hearing aids fail miserably at this simple task. Currently I am using a number of techniques to gain insight into this basic process.

The bulk of my work deals with performing neurophysiologic recordings of single neuron activity in response to complex synthetic stimuli. I use techniques derived from signal processing, systems identification, control systems, and information theory in order to characterize how auditory neurons process spectral and temporal acoustic information. Most of this work is performed in three distinct brain regions: the inferior colliculus (ICC), the auditory thalamus (MGBv) and the primary auditory cortex (AI). Presently I am interested in how 1) acoustic signals are encoded by single neuron activity in the central auditory system, 2) how the activity of single neurons gives rise to spatially distributed representations or "sensory maps" for acoustic signal attributes, 3) how these representations are transformed from one auditory station to the other, and 4) how this functional organization relates to the anatomical substrate.

I am also attempting to link physiologic results with psychoacoustic findings in humans. I use complex spectro-temporal sound sequences to gain insight into the ability of humans to discriminate and detect temporal and spectral acoustic information. This is important since pertinent sound, such as speech, are largely composed of both spectral and temporal acoustic features. I am using the knowledge gained from these studies to design computational algorhithms for pre-processing sounds in artificial hearing devices.

Recent Publications
Active Research Projects
Professional Activities

Recent Publications:
Archival Technical Journal Publications:

"Spectrotemporal Receptive Fields in the Lemniscal Auditory Thalamus and Cortex," (with L.M. Miller, H.L. Read and C.E. Schreiner), Journal of Neurophysiology, Vol. 87, No. 1, pp. 516-527, 2002.

"Nonlinear Spectrotemporal Sound Analysis by Neurons in the Auditory Midbrain," (with C.E. Schreiner), Journal of Neuroscience, Vol. 22, No. 10, pp. 4114-4131, 2002.

"Functional Convergence of Response Properties in the Auditory Thalamocortical System," (with L.M. Miller, H.L. Read and C.E. Schreiner), Neuron, Vol. 32, No. 1, pp. 151-160, 2001.

"Feature Selectivity and Interneuronal Cooperation in the Thalamocortical System," (with L.M. Miller and C.E. Schreiner), Journal of Neuroscience, Vol. 21, No. 20, pp. 8136-8144, 2001.

Books, Book Chapters, Book Sections & Edited Volumes:

" Biosignal Analysis, " (J. D. Enderle, S. M. Blanchard and J. Bronzino, eds.), Introduction to Biomedical Engineering, Academic Press, San Diego, CA, 2005.

Conference Proceedings & Other Publications:

"Dichotic Presentation of Spectro-Temporally Correlated Noise Create Illusory Moving Ripples," (with R. Nassiri and L.M. Miller), Abstracts of the 25th Midwinter Meeting, Association for Research in Otolaryngology, Vol. 25, p. 181, St. Petersburg Beach, FL, January 2002.

"Modeling Spectrotemporal Integration in the Central Nucleus of the Inferior Colliculus," (with A. Qui), Abstracts of the 25th Annual Midwinter Meeting, Association for Research in Otolaryngology, Vol. 25, p. 39, St. Petersburg Beach, FL, January 2002.

Active Research Projects:

" Supplement – Neural Mechanism for Sound Source Separation in the Central Auditory System, " UCRF Faculty Research Account, June 1, 2002-June 30, 2005.

" Animal Models for Developmental Learning Disabilities IV," (PI: H. L. Read, Co-PI: M. A. Escabi), National Institutes of Health, August 1, 2003-July 31, 2005.

" Organization of Spectro-Temporal and Binaural Response Properties in the Inferior Colliculus, " (PI: M. A. Escabi, Co-PI: H. L. Read), PHS/National Institutes of Health/National INS on Deafness & Communications, July 15, 2004-May 31, 2006.

Professional Activities:

" Spectro-Temporal Processing in the Auditory Cortex of a Microgyric Rat Model, " (with N. C. Higgins and H. L. Read), Association in Research for Otolaryngology Abs., No. 1395, February, 2005.

" Altered Intrinsic Optical Responses in Auditory Cortex with Early Induction of Cortical Micrygyri, " (with H. L. Read and N. C. Higgins), Association in Research for Otolaryngology Abs., No. 1282, February, 2005.

" The What and Where of Sound Bandwidth Representation in Mammalian Cortex, " (with H. L. Read), Auditory Processing: Localization and Separation, COSYNE 2005.