The long-term objective of this research is to understand how synaptic processing in auditory cortex transforms the neural representation of temporally structured sounds such as music and speech. The focus in this proposal is to test specific hypotheses about how synaptic inhibition transforms the representation of sound from a temporal code into a rate code. This transformation may support multi-sensory integration, because information from sensory areas with different dynamics may need to be converted into a common rate code to be meaningfully combined. The synaptic mechanisms underlying this process remain unknown.
Aim 1 will test whether sustained rate-coded responses in auditory cortex are generated by a stimulus-specific decrease in synaptic inhibition.
Aim 2 will test whether rate-coded responses to periodic stimuli are generated by a stimulus-specific decrease in synaptic inhibition.
Aim 3 will test whether opponent processing of periodic stimuli occurs by a synaptic push-pull mechanism. To accomplish these aims, we will use whole-cell voltage clamp recordings from rat auditory cortical neurons to measure the excitation and inhibition evoked by optimal tones and periodic stimuli. These experiments will help to elucidate the synaptic mechanisms that transform how temporally structured sounds are encoded in auditory cortex. Because temporal structure provides information critical for speech perception, the synaptic processing of time-varying signals in auditory cortex is especially relevant to our understanding of the mechanisms underlying speech processing. The proposed studies will therefore contribute to our basic understanding of the cortical synaptic mechanisms involved in speech perception.

Public Health Relevance

Language-learning impaired children show profound deficits in the processing of temporally structured sound, but specific auditory training can speed up auditory processing in these children and lead to improved speech processing. The proposed studies will provide insight into how the representation of this temporal structure is transformed by synaptic processing in auditory cortex. In the long term, a greater understanding of the mechanisms that contribute to speech processing in auditory cortex will likely influence the development of improved rehabilitation strategies for language impairments.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Research Project (R01)
Project #
5R01DC011379-03
Application #
8385566
Study Section
Auditory System Study Section (AUD)
Program Officer
Miller, Roger
Project Start
2010-12-01
Project End
2015-11-30
Budget Start
2012-12-01
Budget End
2013-11-30
Support Year
3
Fiscal Year
2013
Total Cost
$337,250
Indirect Cost
$99,750
Name
University of Oregon
Department
Other Basic Sciences
Type
Organized Research Units
DUNS #
948117312
City
Eugene
State
OR
Country
United States
Zip Code
97403
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Kyweriga, Michael; Stewart, Whitney; Cahill, Carolyn et al. (2014) Synaptic mechanisms underlying interaural level difference selectivity in rat auditory cortex. J Neurophysiol 112:2561-71
Weible, Aldis P; Liu, Christine; Niell, Cristopher M et al. (2014) Auditory cortex is required for fear potentiation of gap detection. J Neurosci 34:15437-45
Weible, Aldis P; Moore, Alexandra K; Liu, Christine et al. (2014) Perceptual gap detection is mediated by gap termination responses in auditory cortex. Curr Biol 24:1447-55