Artikel
Auditory Midbrain Implant: effects of multi-site stimulation along the isofrequency laminae of the inferior colliculus central nucleus on auditory cortical activity
Suche in Medline nach
Autoren
Veröffentlicht: | 22. April 2008 |
---|
Gliederung
Text
Introduction: The auditory midbrain implant (AMI), designed for electrical stimulation of the inferior colliculus central nucleus (ICC) for hearing restoration, is now in clinical trials. All four implanted patients obtain hearing improvements on a daily basis with our single shank array and simple stimulation strategies. Since the ICC is a complex 3-D structure, we investigated in an animal model if further improvements may be achieved by stimulating across multiple regions throughout the ICC.
Methods: Two single shank multi-site arrays were inserted along the tonotopic gradient of the ICC in ketamine-anesthetized guinea pigs. We then recorded cortical responses to electrical stimulation (with single pulses, cathodic-leading, biphasic, 205 µs/phase) of two ICC sites within the same frequency lamina and with varying inter-site delays.
Results: Superposition of activity for two stimulated sites depends strongly on the inter-site delay and can exhibit nonlinear activation properties. Furthermore, there exists a crucial time window in which one stimulated site can elicit the maximum effect on a proceeding stimulated site that depends on stimulation location.
Conclusion: These findings have important implications as to how multiple regions within the ICC can be stimulated to elicit nonlinear and enhanced neural activation within higher auditory centers. Potential behavioral correlates of these electrophysiological findings will be discussed in terms of future AMI stimulation strategies.
Unterstützt durch: Funding provided by Cochlear Ltd. and SFB 599