Auditory Neurophysiology Laboratory - Biomedical Engineering, Charles River Campus
Auditory Neuroscience Laboratory - Biomedical Engineering, Charles River Campus
Biomimetic Systems Laboratory - Biomedical Engineering, Charles River Campus
Binaural Hearing Laboratory - Biomedical Engineering, Charles River Campus
Biological Information Transmission Laboratory - Electrical, Computer and Systems Engineering/Biomedical Engineering, Charles River Campus
CNS Psychoacoustics Laboratory - Biomedical Engineering, Charles River Campus
Cochlear Biophysics Laboratory - Biomedical Engineering, Charles River Campus
Knowledge-Based Signal Processing Group - Electrical and Computer Engineering, Charles River Campus
Laboratory of Cellular and Molecular Hearing Research - Anatomy and Neurobiology, Medical Campus
Psychoacoustics Laboratory - Communication Disorders, Charles River Campus
Speech Perception Laboratory - Communication Disorders, Charles River Campus
Vestibular Laboratory - Otolaryngology, Medical Campus
Biomedical Engineering Dept. 44 Cummington Street Boston, MA 02215
The primary focus of this group is on understanding the neuronal circuitry of the cochlear nucleus, particularly the dorsal cochlear nucleus (DCN). There are two experimental thrusts - 1) studies of functional interactions of neurons by observing correlated activities of simultaneous-recorded pairs of units in both anesthetized and unanesthetized preparations, and 2) extracellular and intracellular recording and marking studies of neurons in cochlear nucleus. This experimental work provides the "reality checks" for the computational modeling effort within the group. They have been modeling an isofrequency patch of DCN and are beginning to explore cross-frequency interaction issues.
This laboratory contains an IAC sound-attenuation chamber that is fully instrumented to conduct both intracellular electrophysiological recording experiments of the auditory system in experimental animal. Experiments involving single and pair recordings are feasible under computer control. Dr. Voigt also has a fully functional histology laboratory for standard tissue staining and HRP histochemistry. An electrode room and a shared computer modeling and simulation laboratory are also available.
Biomedical Engineering Dept. 44 Cummington Street Boston, MA 02215
Research in this lab focuses on questions related to the neural
encoding and processing of the information in complex sounds. Several
different strategies are being applied to this problem, including:
- Extracellular recording from single neurons in the auditory nerve,
brainstem, and midbrain of anesthetized animals.
- Extracellular recording from single neurons in awake-and-behaving animals.
- Computational modelling of physiological responses of singe neurons and
populations of neurons.
- Computational modelling of behavioral performance, based on physiological
models.
The physiological analyses and modelling are focussed on the precise timing of neural discharges in response to complex sounds, and how the discharge patterns of single neurons or populations of neurons encode information. Because the times of neural discharges of auditory nerve fibers are influenced by nonlinearities in the inner ear, we have focussed considerable energy on characterizing the nonlinear tuning properties of auditory nerve fibers. The implications of these nonlinearities for processing of information by the auditory nervous system are also of interest, as well as their potential for explaining deficits associated with hearing impairment, which often includes a loss of nonlinear properties in the inner ear.
Biomedical Engineering 44 Cummington Street Boston, MA 02215
The goal of this laboratory is to develop large-scale biophysically-based models of the auditory periphery and subcortical auditory pathways. The purpose of these models is to aid the interpretation of and the design of physiological and psychophysical experiments as well as to study auditory models for their usefulness as preprocessors for automated recognition of acoustic signals. This laboratory is also engaged in the study of natural acoustic signal sources and acoustic environments. The purpose of this second effort is to develop a better understanding of the evolutionary pressures which have shaped the auditory pathway as well as to develop computer simulations of natural environments for use as input to the auditory models. Other current projects include the use of auditory models for the acoustic transients and development of models for processing temporal sequences.
The laboratory is equipped with two UNIX workstations, two Macintosh computers and a color printer.
Click here to link to the Biomemetic Systems Laboratory page
Biomedical Engineering 44 Cummington Street Boston, MA 02215
The Binaural Hearing Laboratory is focused on studies of binaural interaction, including phenomena such as sound localization for which monaural processing also plays a major role. The goal of these studies is an integrated understanding of binaural interaction and its role in human sound perception including the interpretation of acoustic cues in complex sound environments (e.g., multiple sources in reverberant spaces). Specific projects range from signal processing models of physiological activity to empirical measurements of the hearing abilities of listeners with hearing losses and/or neurological lesions. In the neural modeling area, we are evaluating the abilities of simple neural models to generate firing patterns equivalent to those seen in binaural cells in brainstem nuclei such as the MSO, LSO, and IC. In psychophysical studies of normal listeners, current interests include interaural discrimination and binaural detection, especially detection with reproducible noise maskers. In studies of listeners with hearing impairments, we are trying to relate listeners' abilities on a variety of binaural tests to a primary set of psychophysical measures. In studies of sound localization and recognition, we are studying and simulating the cues that lead to externalization, localization, and separation of sources.
Electrical and Computer Engineering/Biomedical Engineering 44 Cummington Street Boston, MA 02215
The Biological Information Transmission Laboratory is devoted to the computer analysis of sensory data, and to carrying out simulations and analytical calculations for biological models using engineering principles. Information processing mechanisms involving nonlinear dynamical models, and fractal characteristics, are of particular interest to members of the Laboratory. Special software has been developed to facilitate the dynamical display of theoretical results and processed data.
Cognitive and Neural Systems 677 Beacon Street Boston, MA 02215
Research in the Psychoacoustics Laboratory focuses on studies of spatial hearing, learning and plasticity in spatial perception, and quantitative analysis and modeling of human perception and performance. One current project is focused on sound localization when sources are very close to the listener by measuring and analyzing the physical cues that occur for near field sound sources, and analysis of the effects of room acoustics on the acoustic signals reaching a listener, perception, and performance, for near-field sounds. In other work, we are investigating the relationship between different measures of human spatial auditory perception in order to develop quantitative models of performance. We also are investigating the degree to which spatial perception is affected by learning and training with unusual spatial cues. All of this work is aimed at the development of computational models capable of predicting how the physical cues available to a listener are integrated to form spatial percepts, and how these percepts govern responses on specific tasks.
The laboratory is equipped with special-purpose hardware for the generation and presentation of acoustic stimuli, personal computers, tracking devices to monitor subject positions, and a sound proof booth.
This laboratory is focusing on two areas. The first is to identify, quantify, and model the mechanisms responsible for the mechanical sensitivity and frequency selectivity of the mammalian cochlea. The goal is to bridge the gap between those investigators who are principally interested in haircell biophysics and other investigators who are primarily interested in hearing mechanisms. The experimental approaches currently in use range from the direct measurement of acoustically and electrically-evoked basilar membrane motion and the direct measurement of the mechanical properties of the organ of Corti to the measurement of acoustically and electrically-evoked otacoustic emissions.
The second focus is on the measurement and interpretation of electric fields produced by electrically excitable tissues with the major focus being the auditory system. The goal is to develop methods of studying populations of cells both in vivo and in vitro. The measurement techniques under study range from conventional scalp-recorded evoked potentials to the use of electrode arrays fabricated using integrated-circuit technology. One current project involves testing the ability of planar electrode arrays to image current sources in vitro and in vivo. Another project focuses on the use of the envelope-following response for assessment of low-frequency hearing in marine mammals. Additional projects involve the use of single and multi-unit recording techniques to study processing of complex signals by the auditory brain-stem.
Laboratory facilities include a vibration-isolated sound attenuating booth with associated computer controlled instrumentation and two setups for video microscopy with associated computer equipment for stimulus control, data collection and image processing. Special purpose instrumentation includes a fiber-optic displacement probe capable of resolving motion at the angstrom level and a force-probe system capable of measuring forces at the nanonewton level.
Click here to link to the Cochlear Biophysics Laboratory page
Electrical and Computer Engineering 44 Cummington Street Boston, MA 02215
This group is concerned with the integration of signal processing and signal understanding technologies and their application to robotic hearing and assisting devices for the hearing impaired. This research utilizes electrical engineering principles for signal processing and computer science principles for signal understanding.
Laboratory facilities include workstations, A/D and D/A conversion, and special-purpose DSP hardware and software.
BUMC Anatomy and Neurobiology 80 E. Concord Street Boston, MA 02215
This laboratory is working on developmental factors which regulate the growth of hair cells in the cochlea during normal embryonic development and in regeneration following noise-induced trauma. They are primarily concerned with the structural development of the stereocilia: specialized microvilli which project from the apical surface of the hair cells. They have been studying the embryonic development of stereocilia and have searched for factors which regulate the establishment of morphological gradients in the sterociliary bundles. Also, they have examined structural changes in hair cells caused by acoustic overstimulation and have shown that the bird ear is able to completely regenerate the sensory epithelium during recovery from noise damage. Of interest to them is the fact that the regenerating hair cells go through a developmental sequence which is identical to that exhibited by hair cells in the embryonic cochlea. Thus, the regulatory mechanisms which are employed during embryogenesis are probably activated once again for hair cell regeneration. Recently, they have been examining events associated with regulating cell cycle events in the precursor cells during regeneration. This includes the expression of early response genes during the transition from G0 to G1 and timing of DNA synthesis during S phase of the cell cycle. The techniques utilized for these studies include scanning and transmission electron microscopy, confocal laser scanning microscopy, reverse transcription PCR amplification, fluorescence in situ DNA hybridization, and video- enhanced differential-interference-contrast (DIC) light microscopy.
The facilities in this laboratory include: video-enhanced DIC light microscopy, epifluorescence light microscopy, laser scanning microscopy, molecular biology facilities for RT-PCR, gene sequencing, in situ hybridization, photographic darkroom for color and black and white slide and paper processing and printing, dedicated computer digital darkroom, and image processing work station.
Click here to visit lab web site
Communication Disorders 635 Commonwealth Avenue Boston, MA 02215
The type of work done in this laboratory is human auditory perception, both experimental and theoretical. The empirical work consists of studies of auditory perception of listeners with normal hearing and listeners with sensorineural hearing loss. The theoretical work consists of evaluating decision theory based models in accounting for the empirical findings.
The Psychoacoustics Laboratory covers approximately 850 square feet. In addition, it has a shared 350 square foot shop/instrumentation room immediately adjacent. There are two sets of 3-room sound attenuating booths located in the lab. Associated with the booths are several microcomputers and racks of audiofrequency electronic equipment. The computers and electronic equipment are used to generate, control and measure stimuli used in psychophysical experiments and are wired to communicate with subject terminals located inside the booths. There is a local network for sharing peripheral devices for communication among laboratory computers, and for communication with the campus network. Also available within the department are a variety of audiometric instruments, including audiometers, evoked-potential units, and otoacoustics immitance and emission measurement devices.
Communication Disorders 635 Commonwealth Avenue Boston, MA 02215
This laboratory is concerned with testing the perception of a wide range of speech stimuli. Work includes quantifying the changes of the speech of persons who have lost their hearing through Neurofibromatosis II. The work in this lab also includes analyzing the speech of subjects who were previously deafened and have received cochlear implants which allows them to improve their speech. Basic properties of speech produced by normal-hearing speakers under a variety of rate and clarity conditions is being studied.
This laboratory covers roughly 400 square feet and includes a double-walled sound booth (10' x 10) for speech perception studies. The laboratory contains the necessary instrumentation to generate and present speech stimuli, collect subject responses and analyze the data. Specific hardware includes a microcomputer, insert earphones, speakers, D/A, A/D, programmable attenuators and appropriate software.
BUMC Otolaryngology 720 Harrison Avenue Boston, MA 02215