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Stereotactically-guided Ablation of the Rat Auditory Cortex, and Localization of the Lesion in the Brain
Published on: October 11, 2017
Affects of aging on receptive fields in rat primary auditory cortex layer V neurons
Jeremy G Turner1, Larry F Hughes, Donald M Caspary
1Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, 62794-9629, USA. jturner@siumed.edu
Journal of Neurophysiology
|July 8, 2005
Summary
Aging impairs auditory processing in the brain. Studies show changes in primary auditory cortex (AI) neurons in older rats, suggesting reduced signal clarity and potential neurotransmitter imbalances.
Area of Science:
- Neuroscience
- Auditory Neuroscience
- Aging Research
Background:
- Advanced age leads to hearing loss (presbycusis) due to cochlear and central auditory system changes.
- Primary auditory cortex (AI) layer V neurons are crucial for auditory information processing and output.
Purpose of the Study:
- To investigate the central neural changes in presbycusis using the Fischer Brown Norway rat model.
- To characterize the response properties of primary auditory cortex (AI) layer V neurons in aged versus young rats.
Main Methods:
- In vivo single-unit extracellular recordings were performed on 114 neurons in aged rats (29-33 mo) and 105 in young rats (4-6 mo).
- Pure-tone receptive field mapping was used to analyze neuronal response properties.
- Neuronal responses were assessed across three consecutive stimulus repetitions to evaluate reliability.
Main Results:
- Aged rats showed fewer classic V/U-shaped receptive fields and more complex receptive fields compared to young rats.
- Neuronal receptive fields in aged rats were less reliable across stimulus repetitions.
- Aging altered neuronal firing patterns: decreased firing in V/U-shaped neurons and increased firing in complex neurons, which were inhibited in young rats.
Conclusions:
- Age-related changes in AI layer V neurons suggest diminished signal-to-noise ratio in auditory processing.
- Findings are consistent with compromised GABAergic neurotransmission in the aging auditory cortex.
