The objective of this research is to better understand across-channel processing in the auditory system.
The aim of the present research plan is to study two auditory phenomena in which sounds presented outside of the immediate spectral vicinity of an audio signal influence the ability to detect the signal: auditory enhancement and psychophysical suppression. Auditory enhancement refers to a set of effects in which a component of the stimulus is enhanced by delaying its onset. All of the enhancement effects appear to depend upon frequency components presented above about 1.2 times the signal frequency (f/s). Psychophysical suppression denotes a phenomenon in which adding an appropriately chosen sound to a frequency region slightly above the signal (around 1.1-1.2f/s) can make a masked signal easier to detect. The primary goal is to determine the relationship between auditory enhancement and psychophysical suppression. In the experimental paradigm, a tonal signal is presented either during or after various masking sounds. The subject is required to indicate in which of two observation intervals the signal was presented. The connection between enhancement and suppression will be established by comparing the results across conditions in which maskers are presented only in the frequency region which produces suppression, only in the frequency region which produces enhancement, or in both regions. The general hypotheses to be tested are that (1) Stimulating the suppression region simultaneously with the enhancement region can reduce the amount of enhancement, and (2) Stimulating the enhancement region prior to stimulating the suppression region can reduce the amount of psychophysical suppression. Enhancement and suppression both show temporal changes in frequency resolution which may strongly influence the perception of real- world sounds such as speech. Finally, a deeper understanding of enhancement and suppression in normal-hearing listeners may aid in the diagnosis and treatment of hearing disorders, because both effects are much smaller in hearing-impaired listeners.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
1R29DC002997-01
Application #
2128499
Study Section
Hearing Research Study Section (HAR)
Project Start
1995-08-01
Project End
2000-07-31
Budget Start
1995-08-01
Budget End
1996-07-31
Support Year
1
Fiscal Year
1995
Total Cost
Indirect Cost
Name
University of California San Francisco
Department
Otolaryngology
Type
Schools of Medicine
DUNS #
073133571
City
San Francisco
State
CA
Country
United States
Zip Code
94143
Fitzgerald, Matthew B; Wright, Beverly A (2005) A perceptual learning investigation of the pitch elicited by amplitude-modulated noise. J Acoust Soc Am 118:3794-803
Wright, Beverly A; Fitzgerald, Matthew B (2004) The time course of attention in a simple auditory detection task. Percept Psychophys 66:508-16
Wright, B A (2001) Why and how we study human learning on basic auditory tasks. Audiol Neurootol 6:207-10
Wright, B A; Fitzgerald, M B (2001) Different patterns of human discrimination learning for two interaural cues to sound-source location. Proc Natl Acad Sci U S A 98:12307-12
Wright, B A; Bowen, R W; Zecker, S G (2000) Nonlinguistic perceptual deficits associated with reading and language disorders. Curr Opin Neurobiol 10:482-6
Wright, B A; Saberi, K (1999) Strategies used to detect auditory signals in small sets of random maskers. J Acoust Soc Am 105:1765-75
Dai, H; Wright, B A (1999) Predicting the detectability of tones with unexpected durations. J Acoust Soc Am 105:2043-6
Nagarajan, S S; Blake, D T; Wright, B A et al. (1998) Practice-related improvements in somatosensory interval discrimination are temporally specific but generalize across skin location, hemisphere, and modality. J Neurosci 18:1559-70
Wright, B A; Dai, H (1998) Detection of sinusoidal amplitude modulation at unexpected rates. J Acoust Soc Am 104:2991-6
Wright, B A (1997) Detectability of simultaneously masked signals as a function of masker bandwidth and configuration for different signal delays. J Acoust Soc Am 101:420-9

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