Abstract
Loudness recruitment, an abnormally rapid growth of perceived loudness with sound level, is a common symptom of sensorineural hearing loss. Following acoustic trauma, auditory-nerve rate responses are reduced, and rate grows more slowly with sound level, which seems inconsistent with recruitment (Heinz et al., J. Assoc. Res. Otolaryngol. 6:91-105, 2005). However, rate-level functions (RLFs) in the central nervous system may increase in either slope or saturation value following trauma (e.g., Salvi et al., Hear. Res. 147:261-274, 2000), suggesting that recruitment may arise from central changes. In this paper, we studied RLFs of neurons in ventral cochlear nucleus (VCN) of the cat after acoustic trauma. Trauma did not change the general properties of VCN neurons, and the usual VCN functional classifications remained valid (chopper, primary-like, onset, etc.). After trauma, non-primary-like neurons, most noticeably choppers, exhibited elevated maximum discharge rates and steeper RLFs for frequencies at and near best frequency (BF). Primary-like neurons showed the opposite changes. To relate the neurons' responses to recruitment, rate-balance functions were computed; these show the sound level required to give equal rates in a normal and a traumatized ear and are analogous to loudness balance functions that show the sound levels giving equal perceptual loudness in the two ears of a monaurally hearing-impaired person. The rate-balance functions showed recruitment-like steepening of their slopes in non-primary-like neurons in all conditions. However, primary-like neurons showed recruitment-like behavior only when rates were summated across neurons of all BFs. These results suggest that the non-primary-like, especially chopper, neurons may be the most peripheral site of the physiological changes in the brain that underlie recruitment.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 5-22 |
| Number of pages | 18 |
| Journal | JARO - Journal of the Association for Research in Otolaryngology |
| Volume | 10 |
| Issue number | 1 |
| DOIs | |
| State | Published - Mar 2009 |
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Keywords
- Acoustic trauma
- Auditory nerve
- Bushy cell
- Hyperacusis
- Loudness recruitment
- Neural encoding
- Neuroplasticity
- Primary-like units
- Rate-level function
- Sensorineural hearing loss
- Sound intensity
- Sound level
- Stellate cell
- Ventral cochlear nucleus
ASJC Scopus subject areas
- Otorhinolaryngology
- Sensory Systems
Cite this
Encoding intensity in ventral cochlear nucleus following acoustic trauma : Implications for loudness recruitment. / Cai, Shanqing; Ma, Wei Li D; Young, Eric D.
In: JARO - Journal of the Association for Research in Otolaryngology, Vol. 10, No. 1, 03.2009, p. 5-22.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Encoding intensity in ventral cochlear nucleus following acoustic trauma
T2 - Implications for loudness recruitment
AU - Cai, Shanqing
AU - Ma, Wei Li D
AU - Young, Eric D.
PY - 2009/3
Y1 - 2009/3
N2 - Loudness recruitment, an abnormally rapid growth of perceived loudness with sound level, is a common symptom of sensorineural hearing loss. Following acoustic trauma, auditory-nerve rate responses are reduced, and rate grows more slowly with sound level, which seems inconsistent with recruitment (Heinz et al., J. Assoc. Res. Otolaryngol. 6:91-105, 2005). However, rate-level functions (RLFs) in the central nervous system may increase in either slope or saturation value following trauma (e.g., Salvi et al., Hear. Res. 147:261-274, 2000), suggesting that recruitment may arise from central changes. In this paper, we studied RLFs of neurons in ventral cochlear nucleus (VCN) of the cat after acoustic trauma. Trauma did not change the general properties of VCN neurons, and the usual VCN functional classifications remained valid (chopper, primary-like, onset, etc.). After trauma, non-primary-like neurons, most noticeably choppers, exhibited elevated maximum discharge rates and steeper RLFs for frequencies at and near best frequency (BF). Primary-like neurons showed the opposite changes. To relate the neurons' responses to recruitment, rate-balance functions were computed; these show the sound level required to give equal rates in a normal and a traumatized ear and are analogous to loudness balance functions that show the sound levels giving equal perceptual loudness in the two ears of a monaurally hearing-impaired person. The rate-balance functions showed recruitment-like steepening of their slopes in non-primary-like neurons in all conditions. However, primary-like neurons showed recruitment-like behavior only when rates were summated across neurons of all BFs. These results suggest that the non-primary-like, especially chopper, neurons may be the most peripheral site of the physiological changes in the brain that underlie recruitment.
AB - Loudness recruitment, an abnormally rapid growth of perceived loudness with sound level, is a common symptom of sensorineural hearing loss. Following acoustic trauma, auditory-nerve rate responses are reduced, and rate grows more slowly with sound level, which seems inconsistent with recruitment (Heinz et al., J. Assoc. Res. Otolaryngol. 6:91-105, 2005). However, rate-level functions (RLFs) in the central nervous system may increase in either slope or saturation value following trauma (e.g., Salvi et al., Hear. Res. 147:261-274, 2000), suggesting that recruitment may arise from central changes. In this paper, we studied RLFs of neurons in ventral cochlear nucleus (VCN) of the cat after acoustic trauma. Trauma did not change the general properties of VCN neurons, and the usual VCN functional classifications remained valid (chopper, primary-like, onset, etc.). After trauma, non-primary-like neurons, most noticeably choppers, exhibited elevated maximum discharge rates and steeper RLFs for frequencies at and near best frequency (BF). Primary-like neurons showed the opposite changes. To relate the neurons' responses to recruitment, rate-balance functions were computed; these show the sound level required to give equal rates in a normal and a traumatized ear and are analogous to loudness balance functions that show the sound levels giving equal perceptual loudness in the two ears of a monaurally hearing-impaired person. The rate-balance functions showed recruitment-like steepening of their slopes in non-primary-like neurons in all conditions. However, primary-like neurons showed recruitment-like behavior only when rates were summated across neurons of all BFs. These results suggest that the non-primary-like, especially chopper, neurons may be the most peripheral site of the physiological changes in the brain that underlie recruitment.
KW - Acoustic trauma
KW - Auditory nerve
KW - Bushy cell
KW - Hyperacusis
KW - Loudness recruitment
KW - Neural encoding
KW - Neuroplasticity
KW - Primary-like units
KW - Rate-level function
KW - Sensorineural hearing loss
KW - Sound intensity
KW - Sound level
KW - Stellate cell
KW - Ventral cochlear nucleus
UR - http://www.scopus.com/inward/record.url?scp=67349231958&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=67349231958&partnerID=8YFLogxK
U2 - 10.1007/s10162-008-0142-y
DO - 10.1007/s10162-008-0142-y
M3 - Article
C2 - 18855070
AN - SCOPUS:67349231958
VL - 10
SP - 5
EP - 22
JO - JARO - Journal of the Association for Research in Otolaryngology
JF - JARO - Journal of the Association for Research in Otolaryngology
SN - 1525-3961
IS - 1
ER -