Distinct cortical encoding of acoustic and electrical cochlear stimulation
Ariel E Hight1,2,3, Michele N Insanally2,3,4, Julia King Scarpa2,3
1Translational Neuroscience Institute, New York University Grossman School of Medicine, New York, NY 10016.
Biorxiv : the Preprint Server for Biology
|August 6, 2025
Summary
Cochlear implants help restore hearing, but brain responses differ from natural sound. This study reveals distinct neural activity patterns between acoustic and electrical stimulation in the auditory cortex.
Area of Science:
- Biomedical Engineering
- Neuroscience
- Auditory Neuroscience
Background:
- Cochlear implants are neuroprosthetic devices aiding hearing restoration in deaf individuals.
- Understanding neural responses to cochlear implant stimulation is crucial for improving device efficacy.
- Previous research demonstrated that deafened rats could learn to recognize sounds via cochlear implants.
Purpose of the Study:
- To investigate how local cortical neuron populations represent acute cochlear implant stimuli.
- To compare neural representations of acoustic stimuli versus electrical stimulation from cochlear implants.
- To explore the spatio-temporal dynamics of auditory cortex activity during different stimulation types.
Main Methods:
- Utilized micro-electrocorticography (μECoG) with custom electrode arrays for cortical surface recordings in rats.
- Recorded neural activity in the primary auditory cortex in response to both acoustic and cochlear implant stimulation.
- Developed decoders to assess information transfer and compare response profiles between stimulation types.
Main Results:
- Found limited tonotopic organization for cochlear implant stimulation compared to acoustic stimulation in normal-hearing rats.
- Single-trial iEEG responses were more reliable for acoustic inputs than for cochlear implant stimulation.
- Decoders trained on acoustic responses showed minimal information transfer for electrical stimulation responses, indicating distinct neural dynamics.
Conclusions:
- Acute cochlear implant stimulation may activate the auditory cortex in a cochleotopic manner.
- The spatio-temporal network activity dynamics differ significantly between acoustic and electrical stimulation.
- Pitch perception derived from acoustic and electrical stimulation is likely fundamentally different due to distinct neural processing.
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