Rights statement: This is the author’s version of a work that was accepted for publication in Hearing Research. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Hearing Research, 341, 2016 DOI: 10.1016/j.heares.2016.09.003
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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - Time course and frequency specificity of sub-cortical plasticity in adults following acute unilateral deprivation
AU - Brotherton, Hannah
AU - Plack, Christopher John
AU - Schaette, Roland
AU - Munro, Kevin
N1 - This is the author’s version of a work that was accepted for publication in Hearing Research. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Hearing Research, 341, 2016 DOI: 10.1016/j.heares.2016.09.003
PY - 2016/11
Y1 - 2016/11
N2 - Auditory deprivation and stimulation can change the threshold of the acoustic reflex, but the mechanisms underlying these changes remain largely unknown. In order to elucidate the mechanism, we sought to characterize the time-course as well as the frequency specificity of changes in acoustic reflex thresholds (ARTs). In addition, we compared ipsilateral and contralateral measurements because the pattern of findings may shed light on the anatomical location of the change in neural gain. Twenty-four normal-hearing adults wore an earplug continuously in one ear for six days. We measured ipsilateral and contralateral ARTs in both ears on six occasions (baseline, after 2, 4 and 6 days of earplug use, and 4 and 24 hours after earplug removal), using pure tones at 0.5, 1, 2 and 4 kHz and a broadband noise stimulus, and an experimenter-blinded design. We found that ipsi-as well as contralateral ARTs were obtained at a lower sound pressure level after earplug use, but only when the reflex was elicited by stimulating the treatment ear. Changes in contralateral ARTs were not the same as changes in ipsilateral ARTs when the stimulus was presented to the control ear. Changes in ARTs were present after 2 days of earplug use, and reached statistical significance after 4 days, when the ipsilateral and contralateral ARTs were measured in the treatment ear. The greatest changes in ARTs occurred at 2 and 4 kHz, the frequencies most attenuated by the earplug. After removal of the earplug, ARTs started to return to baseline relatively quickly, and were not significantly different from baseline by 4-24 hours. There was a trend for the recovery to occur quicker than the onset. The changes in ARTs are consistent with a frequency-specific gain control mechanism operating around the level of the ventral cochlear nucleus in the treatment ear, on a time scale of hours to days. These findings, specifically the time course of change, could be applicable to other sensory systems, which have also shown evidence of a neural gain control mechanism.
AB - Auditory deprivation and stimulation can change the threshold of the acoustic reflex, but the mechanisms underlying these changes remain largely unknown. In order to elucidate the mechanism, we sought to characterize the time-course as well as the frequency specificity of changes in acoustic reflex thresholds (ARTs). In addition, we compared ipsilateral and contralateral measurements because the pattern of findings may shed light on the anatomical location of the change in neural gain. Twenty-four normal-hearing adults wore an earplug continuously in one ear for six days. We measured ipsilateral and contralateral ARTs in both ears on six occasions (baseline, after 2, 4 and 6 days of earplug use, and 4 and 24 hours after earplug removal), using pure tones at 0.5, 1, 2 and 4 kHz and a broadband noise stimulus, and an experimenter-blinded design. We found that ipsi-as well as contralateral ARTs were obtained at a lower sound pressure level after earplug use, but only when the reflex was elicited by stimulating the treatment ear. Changes in contralateral ARTs were not the same as changes in ipsilateral ARTs when the stimulus was presented to the control ear. Changes in ARTs were present after 2 days of earplug use, and reached statistical significance after 4 days, when the ipsilateral and contralateral ARTs were measured in the treatment ear. The greatest changes in ARTs occurred at 2 and 4 kHz, the frequencies most attenuated by the earplug. After removal of the earplug, ARTs started to return to baseline relatively quickly, and were not significantly different from baseline by 4-24 hours. There was a trend for the recovery to occur quicker than the onset. The changes in ARTs are consistent with a frequency-specific gain control mechanism operating around the level of the ventral cochlear nucleus in the treatment ear, on a time scale of hours to days. These findings, specifically the time course of change, could be applicable to other sensory systems, which have also shown evidence of a neural gain control mechanism.
KW - unilateral deprivation
KW - neural gain
KW - subcortical plasticity
U2 - 10.1016/j.heares.2016.09.003
DO - 10.1016/j.heares.2016.09.003
M3 - Journal article
VL - 341
SP - 210
EP - 219
JO - Hearing Research
JF - Hearing Research
SN - 0378-5955
ER -