Statistical structure of speech sound classes is congruent with cochlear nucleus response properties

2014 ◽  
Author(s):  
Christian E. Stilp ◽  
Michael S. Lewicki
Keyword(s):  
Cochlear Nucleus ◽  
Speech Sound ◽  
Statistical Structure ◽  
Response Properties

An in vivo investigation of inferior colliculus single neuron responses to cochlear nucleus pulse train stimulation

2012 ◽  
Vol 108 (11) ◽  
pp. 2999-3008 ◽  
Author(s):  
Stefan J. Mauger ◽  
Mohit N. Shivdasani ◽  
Graeme D. Rathbone ◽  
Antonio G. Paolini
Keyword(s):  
Speech Perception ◽  
Brain Stem ◽  
Inferior Colliculus ◽  
Cochlear Nucleus ◽  
Acoustic Stimulation ◽  
Neural Firing ◽  
Response Properties ◽  
Stimulus Rate ◽  
Auditory Brain Stem

The auditory brain stem implant (ABI) is being used clinically to restore hearing to patients unable to benefit from a cochlear implant (CI). Speech perception outcomes for ABI users are typically poor compared with most CI users. The ABI is implanted either on the surface of or penetrating through the cochlear nucleus in the auditory brain stem and uses stimulation strategies developed for auditory nerve stimulation with a CI. Although the stimulus rate may affect speech perception outcomes with current stimulation strategies, no studies have systematically investigated the effect of stimulus rate electrophysiologically or clinically. We therefore investigated rate response properties and temporal response properties of single inferior colliculus (IC) neurons from penetrating ABI stimulation using stimulus rates ranging from 100 to 1,600 pulses/s in the rat. We found that the stimulus rate affected the proportion of response types, thresholds, and dynamic ranges of IC activation. The stimulus rate was also found to affect the temporal properties of IC responses, with higher rates providing more temporally similar responses to acoustic stimulation. Suppression of neural firing and inhibition in IC neurons was also found, with response properties varying with the stimulus rate. This study demonstrated that changes in the ABI stimulus rate results in significant differences in IC neuron response properties. Due to electrophysiological differences, the stimulus rate may also change perceptual properties. We suggest that clinical evaluation of the ABI stimulus rate should be performed.

scholarly journals Nonlinear temporal receptive fields of neurons in the dorsal cochlear nucleus

2013 ◽  
Vol 110 (10) ◽  
pp. 2414-2425 ◽  
Author(s):  
Sharba Bandyopadhyay ◽  
Eric D. Young
Keyword(s):  
Cochlear Nucleus ◽  
Receptive Fields ◽  
Sound Level ◽  
Second Order ◽  
Dorsal Cochlear Nucleus ◽  
Spectral Processing ◽  
Low Contrast ◽  
Response Properties ◽  
First Order ◽  
Order Components

Studies of the dorsal cochlear nucleus (DCN) have focused on spectral processing because of the complex spectral receptive fields of the DCN. However, temporal fluctuations in natural signals convey important information, including information about moving sound sources or movements of the external ear in animals like cats. Here, we investigate the temporal filtering properties of DCN principal neurons through the use of temporal weighting functions that allow flexible analysis of nonlinearities and time variation in temporal response properties. First-order temporal receptive fields derived from the neurons are sufficient to characterize their response properties to low-contrast (3-dB standard deviation) stimuli. Larger contrasts require the second-order terms. Allowing temporal variation of the parameters of the first-order model or adding a component representing refractoriness improves predictions by the model by relatively small amounts. The importance of second-order components of the model is shown through simulations of nonlinear envelope synchronization behavior across sound level. The temporal model can be combined with a spectral model to predict tuning to the speed and direction of moving sounds.

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