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Age-related changes in the response properties of cartwheel cells in rat dorsal cochlear nucleus
- Source :
-
Hearing Research . Jun2006, Vol. 216-217, p207-215. 9p. - Publication Year :
- 2006
-
Abstract
- Abstract: The fusiform cell and deep layers of the dorsal cochlear nucleus (DCN) show neurotransmitter and functional age-related changes suggestive of a downregulation of inhibitory efficacy onto DCN output neurons. Inhibitory circuits implicated in these changes include vertical and D-multipolar cells. Cartwheel cells comprise a large additional population of DCN inhibitory neurons. Cartwheel cells receive excitatory inputs from granule cell parallel fibers and provide a source of glycinergic inhibitory input onto apical dendrites of DCN fusiform cells. The present study compared the response properties from young and aged units meeting cartwheel-cell criteria in anesthetized rats. Single unit recordings from aged cartwheel cells revealed significantly higher thresholds, increased spontaneous activity and significantly altered rate-level functions characterized by hyperexcitability at higher intensities. Aged cartwheel cells showed a significant reduction in off-set suppression. Collectively, these findings suggest a loss of tonic and perhaps response inhibition onto aged DCN cartwheel neurons. These changes likely reflect a compensatory downregulation of synaptic inhibition in response to a loss of excitatory drive from auditory and non-auditory excitatory inputs via granule cells. The impact of increased excitability of cartwheel cells on DCN output neurons is likely to be complex, influenced by loss of glycinergic release and/or subunit receptor changes which would only partially off-set age-related loss of inhibition onto the somata and basal dendrites of fusiform cells. [Copyright &y& Elsevier]
- Subjects :
- *CELLS
*NEURONS
*NERVOUS system
*BRAIN stem
Subjects
Details
- Language :
- English
- ISSN :
- 03785955
- Volume :
- 216-217
- Database :
- Academic Search Index
- Journal :
- Hearing Research
- Publication Type :
- Academic Journal
- Accession number :
- 21211876
- Full Text :
- https://doi.org/10.1016/j.heares.2006.03.005