Over half of those over 65 years old have age-related hearing loss, and the primary communication challenge reported by older adults is difficulty understanding speech in noisy conditions, such as a crowded restaurant. Age-related speech processing deficits can occur even with completely normal audiometric hearing, and are instead associated with temporal processing deficits in central structures such as auditory cortex. The mechanisms underlying temporal processing in auditory cortex are not well understood. Our broad goal is to elucidate these mechanisms. We will use a well-established measure of temporal processing in both humans and animals: the ability to detect a brief gap in background noise. The circuitry underlying gap detection in cortex remains unknown.
In Aim 1 we seek to elucidate this circuitry by combining neuronal recording and optogenetics in awake mice performing a gap detection task.
In Aim 2 we seek to understand how gap detection is enhanced when fear conditioning confers emotional significance to the gap. We propose to use fear potentiation of gap detection in mice as a model for how associative learning in auditory cortex assigns meaning to temporally structured sounds such as speech. We will use neuronal recording and optogenetics before, during, and after fear conditioning to determine the cortical circuit mechanisms underlying the associative learning of temporal structure. In both aims, our hypotheses are expressed as a candidate neural circuit model which makes specific predictions. In each Aim we will test these predictions, using the results to refine the model. Our broad goal is to understand which cortical neurons and circuits are necessary for gap detection and fear potentiation of gap detection, and how the dynamics of these circuits mediate these processes. Achieving this goal will provide fundamental new insights into the mechanisms underlying temporal processing, and how alterations of these mechanisms could contribute to age-related deficits in speech comprehension.

Public Health Relevance

Over half of those over 65 years old have age-related hearing loss, and the primary communication challenge reported by older adults is difficulty understanding speech in noisy conditions, such as a crowded restaurant. The proposed studies seek to elucidate the mechanisms underlying temporal processing in auditory cortex, and will provide insight into how alterations of these mechanisms could contribute to age-related deficits in speech comprehension.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
1R01DC015828-01
Application #
9220010
Study Section
Auditory System Study Section (AUD)
Program Officer
Poremba, Amy
Project Start
2016-12-01
Project End
2021-11-30
Budget Start
2016-12-01
Budget End
2017-11-30
Support Year
1
Fiscal Year
2017
Total Cost
Indirect Cost
Name
University of Oregon
Department
Psychology
Type
Schools of Arts and Sciences
DUNS #
City
Eugene
State
OR
Country
United States
Zip Code
97403
Keller, Clifford H; Kaylegian, Katherine; Wehr, Michael (2018) Gap encoding by parvalbumin-expressing interneurons in auditory cortex. J Neurophysiol 120:105-114
Moore, Alexandra K; Weible, Aldis P; Balmer, Timothy S et al. (2018) Rapid Rebalancing of Excitation and Inhibition by Cortical Circuitry. Neuron 97:1341-1355.e6