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Persistent effects of early augmented acoustic environment on the auditory brainstem
D L Oliver1, M A Izquierdo, M S Malmierca
1Department of Neuroscience, University of Connecticut Health Center, Farmington, CT 06030-3401, USA.
Neuroscience
|April 19, 2011
Summary
An augmented acoustic environment (AAE) during a critical developmental period in rats altered auditory brainstem responses. This early acoustic exposure caused lasting changes in the auditory system, impacting neural activity and organization.
Area of Science:
- Neuroscience
- Auditory System Development
- Sensory Plasticity
Background:
- Postnatal "critical periods" are crucial for auditory system development.
- Acoustic experiences shape the auditory cortex's functional organization.
- The impact of altered acoustic environments on the developing brainstem is not fully understood.
Purpose of the Study:
- To investigate the effects of a non-traumatic augmented acoustic environment (AAE) on the central nucleus of the inferior colliculus (ICC) and lower brainstem nuclei in rats during a critical developmental period.
- To understand the long-lasting changes in auditory processing following early-life altered acoustic exposure.
Main Methods:
- Rats were exposed to an AAE between postnatal days 9 and 28.
- Evoked auditory brainstem responses (ABRs) were measured.
- Neural activity and frequency response areas in the ICC were analyzed.
Main Results:
- AAE exposure led to persistent changes in ABRs, including decreased latency and increased amplitude at and above the stimulus frequency.
- Increased numbers of responsive sites in the ICC were observed for the AAE frequency, with higher thresholds.
- Neurons with best frequencies higher than the AAE stimulus showed decreased activity at low sound levels and, less often, increased activity at high sound levels.
Conclusions:
- Early-life exposure to an altered auditory environment can induce multifaceted, persistent changes in the developing auditory brainstem.
- These findings highlight interactions between activity-dependent plasticity, homeostasis, and neural development in the auditory system.
- Altered acoustic environments during critical periods can lead to long-lasting network-wide changes in the auditory system.
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