Biomaterial Database

Two-tone rate suppression boundaries of cochlear ganglion neurons in chickens following acoustic trauma. 1997

L Chen, and P G Trautwein, and N Powers, and R J Salvi

Department of Communicative Disorders and Sciences, State University of New York at Buffalo 14214, USA.

The purpose of the present study was to examine the effects of acoustic trauma and hair cell loss and regeneration on the two-tone rate suppression (TTRS) boundaries of cochlear ganglion neurons in chickens. Chickens were exposed for 48 hours to a 525-Hz, 120-dB SPL tone which destroyed the hair cells and tectorial membrane in a crescent-shaped patch along the abneural side of the basilar papilla. Afterwards, TTRS boundaries were recorded from cochlear ganglion neurons at 0-1, 5, 14, and 28 days postexposure. Acoustic trauma reduced the percentage of neurons with TTRS boundaries below CF (TTRSb) (52.6% to 8.2%) and above CF (TTRSa) (88.4% to 46.6%). In addition, the exposure reduced TTRS boundary slopes, elevated best suppression threshold (BST), and increased the frequency separation between the tips of the TTRS boundaries and CF. All the TTRS measures started to recover by 5 days postexposure and by 14 days and 28 days postexposure, most measures had recovered to normal levels. However, the BST, TTRS slopes, and the frequency separation of TTRSb boundaries from CF were still slightly abnormal near the exposure frequency. In addition, the percentage of neurons with TTRS below CF was reduced significantly. The partial recovery of TTRS boundaries is presumably due to the regeneration of hair cells and the lower honeycomb layer of the tectorial membrane. The residual TTRS deficits observed 28 days postexposure were most closely associated with the missing upper fibrous layer of the tectorial membrane.

UI	MeSH Term	Description	Entries
D009474	Neurons	The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.	Nerve Cells,Cell, Nerve,Cells, Nerve,Nerve Cell,Neuron
D002645	Chickens	Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.	Gallus gallus,Gallus domesticus,Gallus gallus domesticus,Chicken
D003051	Cochlea	The part of the inner ear (LABYRINTH) that is concerned with hearing. It forms the anterior part of the labyrinth, as a snail-like structure that is situated almost horizontally anterior to the VESTIBULAR LABYRINTH.	Cochleas
D006198	Hair Cells, Auditory	Sensory cells in the organ of Corti, characterized by their apical stereocilia (hair-like projections). The inner and outer hair cells, as defined by their proximity to the core of spongy bone (the modiolus), change morphologically along the COCHLEA. Towards the cochlear apex, the length of hair cell bodies and their apical STEREOCILIA increase, allowing differential responses to various frequencies of sound.	Auditory Hair Cells,Cochlear Hair Cells,Auditory Hair Cell,Cell, Cochlear Hair,Cells, Cochlear Hair,Cochlear Hair Cell,Hair Cell, Auditory,Hair Cell, Cochlear,Hair Cells, Cochlear
D006317	Hearing Loss, Noise-Induced	Hearing loss due to exposure to explosive loud noise or chronic exposure to sound level greater than 85 dB. The hearing loss is often in the frequency range 4000-6000 hertz.	Acoustic Trauma,Hearing Loss, Noise Induced,Noise-Induced Hearing Loss
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001309	Auditory Threshold	The audibility limit of discriminating sound intensity and pitch.	Auditory Thresholds,Threshold, Auditory,Thresholds, Auditory
D013136	Spiral Ganglion	The sensory ganglion of the COCHLEAR NERVE. The cells of the spiral ganglion send fibers peripherally to the cochlear hair cells and centrally to the COCHLEAR NUCLEI of the BRAIN STEM.	Ganglion of Corti,Auditory Ganglion,Spiral Ganglia,Auditory Ganglions,Ganglia, Spiral,Ganglion, Auditory,Ganglion, Spiral,Ganglions, Auditory
D015834	Cochlear Diseases	Pathological processes of the snail-like structure (COCHLEA) of the inner ear (LABYRINTH) which can involve its nervous tissue, blood vessels, or fluid (ENDOLYMPH).	Cochlear Disease,Disease, Cochlear,Diseases, Cochlear