Coding of Electric Pulse Trains Presented through Cochlear Implants in the Auditory Midbrain of Awake Rabbit: Comparison with Anesthetized Preparations
Cochlear implant (CI) listeners show limits at high frequencies in tasks involving temporal processing such as rate pitch and interaural time difference discrimination. Similar limits have been observed in neural responses to electric stimulation in animals with CI; however, the upper limit of tempo...
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| Format: | Article |
| Language: | en_US |
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Society for Neuroscience
2014
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| Online Access: | http://hdl.handle.net/1721.1/91535 https://orcid.org/0000-0003-1349-9608 |
| _version_ | 1826216095739019264 |
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| author | Delgutte, Bertrand Chung, Yoojin Hancock, Kenneth E. Nam, Sung-Il |
| author2 | Massachusetts Institute of Technology. Research Laboratory of Electronics |
| author_facet | Massachusetts Institute of Technology. Research Laboratory of Electronics Delgutte, Bertrand Chung, Yoojin Hancock, Kenneth E. Nam, Sung-Il |
| author_sort | Delgutte, Bertrand |
| collection | MIT |
| description | Cochlear implant (CI) listeners show limits at high frequencies in tasks involving temporal processing such as rate pitch and interaural time difference discrimination. Similar limits have been observed in neural responses to electric stimulation in animals with CI; however, the upper limit of temporal coding of electric pulse train stimuli in the inferior colliculus (IC) of anesthetized animals is lower than the perceptual limit. We hypothesize that the upper limit of temporal neural coding has been underestimated in previous studies due to the confound of anesthesia. To test this hypothesis, we developed a chronic, awake rabbit preparation for single-unit studies of IC neurons with electric stimulation through CI. Stimuli were periodic trains of biphasic pulses with rates varying from 20 to 1280 pulses per second. We found that IC neurons in awake rabbits showed higher spontaneous activity and greater sustained responses, both excitatory and suppressive, at high pulse rates. Maximum pulse rates that elicited synchronized responses were approximately two times higher in awake rabbits than in earlier studies with anesthetized animals. Here, we demonstrate directly that anesthesia is a major factor underlying these differences by monitoring the responses of single units in one rabbit before and after injection of an ultra-short-acting barbiturate. In general, the physiological rate limits of IC neurons in the awake rabbit are more consistent with the psychophysical limits in human CI subjects compared with limits from anesthetized animals. |
| first_indexed | 2024-09-23T16:41:56Z |
| format | Article |
| id | mit-1721.1/91535 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T16:41:56Z |
| publishDate | 2014 |
| publisher | Society for Neuroscience |
| record_format | dspace |
| spelling | mit-1721.1/915352022-09-29T20:51:01Z Coding of Electric Pulse Trains Presented through Cochlear Implants in the Auditory Midbrain of Awake Rabbit: Comparison with Anesthetized Preparations Delgutte, Bertrand Chung, Yoojin Hancock, Kenneth E. Nam, Sung-Il Massachusetts Institute of Technology. Research Laboratory of Electronics Delgutte, Bertrand Cochlear implant (CI) listeners show limits at high frequencies in tasks involving temporal processing such as rate pitch and interaural time difference discrimination. Similar limits have been observed in neural responses to electric stimulation in animals with CI; however, the upper limit of temporal coding of electric pulse train stimuli in the inferior colliculus (IC) of anesthetized animals is lower than the perceptual limit. We hypothesize that the upper limit of temporal neural coding has been underestimated in previous studies due to the confound of anesthesia. To test this hypothesis, we developed a chronic, awake rabbit preparation for single-unit studies of IC neurons with electric stimulation through CI. Stimuli were periodic trains of biphasic pulses with rates varying from 20 to 1280 pulses per second. We found that IC neurons in awake rabbits showed higher spontaneous activity and greater sustained responses, both excitatory and suppressive, at high pulse rates. Maximum pulse rates that elicited synchronized responses were approximately two times higher in awake rabbits than in earlier studies with anesthetized animals. Here, we demonstrate directly that anesthesia is a major factor underlying these differences by monitoring the responses of single units in one rabbit before and after injection of an ultra-short-acting barbiturate. In general, the physiological rate limits of IC neurons in the awake rabbit are more consistent with the psychophysical limits in human CI subjects compared with limits from anesthetized animals. National Institutes of Health (U.S.) (Grant R01 DC005775) National Institutes of Health (U.S.) (Grant P30 DC005209) Massachusetts Eye and Ear Infirmary (Curing Kids Fund) 2014-11-12T14:20:02Z 2014-11-12T14:20:02Z 2013-12 2013-10 Article http://purl.org/eprint/type/JournalArticle 0270-6474 1529-2401 http://hdl.handle.net/1721.1/91535 Chung, Y., K. E. Hancock, S.-I. Nam, and B. Delgutte. “Coding of Electric Pulse Trains Presented through Cochlear Implants in the Auditory Midbrain of Awake Rabbit: Comparison with Anesthetized Preparations.” Journal of Neuroscience 34, no. 1 (December 31, 2013): 218–231. https://orcid.org/0000-0003-1349-9608 en_US http://dx.doi.org/10.1523/jneurosci.2084-13.2014 Journal of Neuroscience Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf Society for Neuroscience Society for Neuroscience |
| spellingShingle | Delgutte, Bertrand Chung, Yoojin Hancock, Kenneth E. Nam, Sung-Il Coding of Electric Pulse Trains Presented through Cochlear Implants in the Auditory Midbrain of Awake Rabbit: Comparison with Anesthetized Preparations |
| title | Coding of Electric Pulse Trains Presented through Cochlear Implants in the Auditory Midbrain of Awake Rabbit: Comparison with Anesthetized Preparations |
| title_full | Coding of Electric Pulse Trains Presented through Cochlear Implants in the Auditory Midbrain of Awake Rabbit: Comparison with Anesthetized Preparations |
| title_fullStr | Coding of Electric Pulse Trains Presented through Cochlear Implants in the Auditory Midbrain of Awake Rabbit: Comparison with Anesthetized Preparations |
| title_full_unstemmed | Coding of Electric Pulse Trains Presented through Cochlear Implants in the Auditory Midbrain of Awake Rabbit: Comparison with Anesthetized Preparations |
| title_short | Coding of Electric Pulse Trains Presented through Cochlear Implants in the Auditory Midbrain of Awake Rabbit: Comparison with Anesthetized Preparations |
| title_sort | coding of electric pulse trains presented through cochlear implants in the auditory midbrain of awake rabbit comparison with anesthetized preparations |
| url | http://hdl.handle.net/1721.1/91535 https://orcid.org/0000-0003-1349-9608 |
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