Document Detail

Inhibitory neurotransmission, plasticity and aging in the mammalian central auditory system.
MedLine Citation:
PMID:  18490394     Owner:  NLM     Status:  MEDLINE    
Aging and acoustic trauma may result in partial peripheral deafferentation in the central auditory pathway of the mammalian brain. In accord with homeostatic plasticity, loss of sensory input results in a change in pre- and postsynaptic GABAergic and glycinergic inhibitory neurotransmission. As seen in development, age-related changes may be activity dependent. Age-related presynaptic changes in the cochlear nucleus include reduced glycine levels, while in the auditory midbrain and cortex, GABA synthesis and release are altered. Presumably, in response to age-related decreases in presynaptic release of inhibitory neurotransmitters, there are age-related postsynaptic subunit changes in the composition of the glycine (GlyR) and GABA(A) (GABA(A)R) receptors. Age-related changes in the subunit makeup of inhibitory pentameric receptor constructs result in altered pharmacological and physiological responses consistent with a net down-regulation of functional inhibition. Age-related functional changes associated with glycine neurotransmission in dorsal cochlear nucleus (DCN) include altered intensity and temporal coding by DCN projection neurons. Loss of synaptic inhibition in the superior olivary complex (SOC) and the inferior colliculus (IC) likely affect the ability of aged animals to localize sounds in their natural environment. Age-related postsynaptic GABA(A)R changes in IC and primary auditory cortex (A1) involve changes in the subunit makeup of GABA(A)Rs. In turn, these changes cause age-related changes in the pharmacology and response properties of neurons in IC and A1 circuits, which collectively may affect temporal processing and response reliability. Findings of age-related inhibitory changes within mammalian auditory circuits are similar to age and deafferentation plasticity changes observed in other sensory systems. Although few studies have examined sensory aging in the wild, these age-related changes would likely compromise an animal's ability to avoid predation or to be a successful predator in their natural environment.
Donald M Caspary; Lynne Ling; Jeremy G Turner; Larry F Hughes
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Review    
Journal Detail:
Title:  The Journal of experimental biology     Volume:  211     ISSN:  0022-0949     ISO Abbreviation:  J. Exp. Biol.     Publication Date:  2008 Jun 
Date Detail:
Created Date:  2008-05-20     Completed Date:  2008-09-10     Revised Date:  2014-09-13    
Medline Journal Info:
Nlm Unique ID:  0243705     Medline TA:  J Exp Biol     Country:  England    
Other Details:
Languages:  eng     Pagination:  1781-91     Citation Subset:  IM    
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MeSH Terms
Age Factors
Aging / physiology*
Auditory Perception*
Brain / anatomy & histology,  physiology*
Brain Chemistry
Neuronal Plasticity*
Synaptic Transmission*
Grant Support

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