Chronic intracochlear electrical stimulation in the neonatally deafened cat. II: Temporal properties of neurons in the inferior colliculus

Snyder, Russell L.; Rebscher, Stephen J.; Leake, Patricia A.; Kelly, Kevin E.; Cao, Keli

doi:10.1016/0378-5955(91)90175-9

Cited by 76 publications

(47 citation statements)

References 26 publications

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“…Previous results from control animals and neonatally deafened animals that received chronic electrical stimulation during development have shown characteristic differences in the temporal resolution of electrical signals between neurons in the ICX and ICC Snyder et al 1991;Vollmer et al 1999). Specifically, neurons in the ICC had significantly higher temporal resolution (i.e., higher F max and shorter latencies) than those in the ICX.…”

Section: External Nucleus Of the Ic (Icx)mentioning

confidence: 84%

Degradation of Temporal Resolution in the Auditory Midbrain After Prolonged Deafness Is Reversed by Electrical Stimulation of the Cochlea

Vollmer¹,

Leake²,

Beitel³

et al. 2005

Journal of Neurophysiology

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In an animal model of prelingual deafness, we examined the anatomical and physiological effects of prolonged deafness and chronic electrical stimulation on temporal resolution in the adult central auditory system. Maximum following frequencies (F max ) and first spike latencies of single neurons responding to electrical pulse trains were evaluated in the inferior colliculus of two groups of neonatally deafened cats after prolonged periods of deafness (Ͼ2.5 yr): the first group was implanted with an intracochlear electrode and studied acutely (long-deafened unstimulated, LDU); the second group (LDS) received a chronic implant and several weeks of electrical stimulation (pulse rates Ն300 pps). Acutely deafened and implanted adult cats served as controls. Spiral ganglion cell density in all long-deafened animals was markedly reduced (mean Ͻ5.8% of normal). Both long-term deafness and chronic electrical stimulation altered temporal resolution of neurons in the central nucleus (ICC) but not in the external nucleus. Specifically, LDU animals exhibited significantly poorer temporal resolution of ICC neurons (lower F max , longer response latencies) as compared with control animals. In contrast, chronic stimulation in LDS animals led to a significant increase in temporal resolution. Changes in temporal resolution after long-term deafness and chronic stimulation occurred broadly across the entire ICC and were not correlated with its tonotopic gradient. These results indicate that chronic electrical stimulation can reverse the degradation in temporal resolution in the auditory midbrain after long-term deafness and suggest the importance of factors other than peripheral pathology on plastic changes in the temporal processing capabilities of the central auditory system.

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Section: External Nucleus Of the Ic (Icx)mentioning

confidence: 84%

Degradation of Temporal Resolution in the Auditory Midbrain After Prolonged Deafness Is Reversed by Electrical Stimulation of the Cochlea

Vollmer¹,

Leake²,

Beitel³

et al. 2005

Journal of Neurophysiology

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“…7, 8 A, B) as responses became mostly limited to the onset of the pulse train. A similar inability of IC neurons to give sustained responses at frequencies above 100 -300 Hz has been reported with monolateral electric stimulation with pulse trains and sinusoids in anesthetized animals (Snyder et al, 1991(Snyder et al, , 1995 but is not consistently observed for stimulation with pure tones in nomalhearing animals, in which about half of high-CF neurons show sustained responses even at tens of kilohertz (Le Beau et al, 1996;Nuding et al, 1999). Sustained responses are also observed in the auditory nerve for high-frequency electric stimulation, although some fibers show pronounced adaptation (Moxon, 1967;van den Honert and Stypulkowski, 1987;Parkins, 1989;Litvak et al, 2003).…”

Section: Effect Of Pulse Rate On Ic Responsesmentioning

confidence: 94%

Sensitivity to Interaural Time Differences in the Inferior Colliculus with Bilateral Cochlear Implants

Smith

Delgutte²

2007

Journal of Neuroscience

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Bilateral cochlear implantation attempts to increase performance over a monaural prosthesis by harnessing the binaural processing of the auditory system. Although many bilaterally implanted human subjects discriminate interaural time differences (ITDs), a major cue for sound localization and signal detection in noise, their performance is typically poorer than that of normal-hearing listeners. We developed an animal model of bilateral cochlear implantation to study neural ITD sensitivity for trains of electric current pulses delivered via bilaterally implanted intracochlear electrodes. We found that a majority of single units in the inferior colliculus of acutely deafened, anesthetized cats are sensitive to ITD and that electric ITD tuning is as sharp as found for acoustic stimulation with broadband noise in normal-hearing animals. However, the sharpness and shape of ITD tuning often depended strongly on stimulus intensity; some neurons had dynamic ranges of ITD sensitivity as low as 1 dB. We also found that neural ITD sensitivity was best at pulse rates below 100 Hz and decreased with increasing pulse rate. This rate limitation parallels behavioral ITD discrimination in bilaterally implanted individuals. The sharp neural ITD sensitivity found with electric stimulation at the appropriate intensity is encouraging for the prospect of restoring the functional benefits of binaural hearing in bilaterally implanted human subjects and suggests that neural plasticity resulting from previous deafness and deprivation of binaural experience may play a role in the poor ITD discrimination with current bilateral implants.

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“…Our earlier studies have reported that chronic electric stimulation delivered on a single channel of a CI leads to an expansion of the STC width in animals that were deafened neonatally or as adults and chronically stimulated thereafter (e.g., Leake and Rebscher 2004;Leake et al 2000;Moore et al 2002;Snyder et al 1991). However, due to the longer durations of deafness, the longdeafened animals reported in the present study demonstrated an even more pronounced degradation in spatial selectivity than that reported in any of those previous studies.…”

Section: Spatial Selectivitymentioning

confidence: 99%

Spatial Selectivity to Intracochlear Electrical Stimulation in the Inferior Colliculus is Degraded After Long-Term Deafness in Cats

Vollmer¹,

Beitel²,

Snyder³

et al. 2007

Journal of Neurophysiology

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Vollmer M, Beitel RE, Snyder RL, Leake PA. Spatial selectivity to intracochlear electrical stimulation in the inferior colliculus is degraded after long-term deafness in cats. J Neurophysiol 98: 2588 -2603, 2007. First published September 12, 2007 doi:10.1152/jn.00011.2007. In an animal model of electrical hearing in prelingually deaf adults, this study examined the effects of deafness duration on response thresholds and spatial selectivity (i.e., cochleotopic organization, spatial tuning and dynamic range) in the central auditory system to intracochlear electrical stimulation. Electrically evoked auditory brain stem response (EABR) thresholds and neural response thresholds in the external (ICX) and central (ICC) nuclei of the inferior colliculus were estimated in cats after varying durations of neonatally induced deafness: in animals deafened Ͻ1.5 yr (short-deafened unstimulated, SDU cats) with a mean spiral ganglion cell (SGC) density of ϳ45% of normal and in animals deafened Ͼ2.5 yr (long-deafened, LD cats) with severe cochlear pathology (mean SGC density Ͻ7% of normal). LD animals were subdivided into unstimulated cats and those that received chronic intracochlear electrical stimulation via a feline cochlear implant. Acutely deafened, implanted adult cats served as controls. Independent of their stimulation history, LD animals had significantly higher EABR and ICC thresholds than SDU and control animals. Moreover, the spread of electrical excitation was significantly broader and the dynamic range significantly reduced in LD animals. Despite the prolonged durations of deafness the fundamental cochleotopic organization was maintained in both the ICX and the ICC of LD animals. There was no difference between SDU and control cats in any of the response properties tested. These findings suggest that long-term auditory deprivation results in a significant and possibly irreversible degradation of response thresholds and spatial selectivity to intracochlear electrical stimulation in the auditory midbrain.

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Chronic intracochlear electrical stimulation in the neonatally deafened cat. II: Temporal properties of neurons in the inferior colliculus

Cited by 76 publications

References 26 publications

Degradation of Temporal Resolution in the Auditory Midbrain After Prolonged Deafness Is Reversed by Electrical Stimulation of the Cochlea

Degradation of Temporal Resolution in the Auditory Midbrain After Prolonged Deafness Is Reversed by Electrical Stimulation of the Cochlea

Sensitivity to Interaural Time Differences in the Inferior Colliculus with Bilateral Cochlear Implants

Spatial Selectivity to Intracochlear Electrical Stimulation in the Inferior Colliculus is Degraded After Long-Term Deafness in Cats

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