China News Service, Beijing, December 22 (Reporter Sun Zifa) The internationally renowned academic journal "Nature" recently published a neuroscience research paper stating that researchers have clarified the neural mechanism that restores hearing to cochlear implants through a rat study.
This research provides avenues to help improve the performance of these widely used medical devices.
Cochlear implants can help restore hearing to people who are totally deaf, but responses vary widely, according to the paper.
Some implanted patients can understand conversations within hours of implant activation, but others do not improve much even after months.
To understand why, co-corresponding author Robert Froemke of New York University School of Medicine and colleagues custom-made cochlear implants in 16 deaf rats to study patterns of brain activity associated with auditory restoration.
Like humans, rats respond widely to implants: in this study, activation of the rat locus coeruleus, a brainstem region implicated in learning, predicted a positive response.
When the same brain region was artificially activated, the observed differences between animals disappeared, and all rats stimulated in this way showed a response to the sound within days of implantation.
The authors conclude that neurons in the locus coeruleus manufacture and release the neuromodulatory substance norepinephrine, which in turn affects the structure and function of multiple neural networks.
This brain "rewiring" is a key feature of learning; when cochlear implants are unsuccessful, it may be that the brain fails to rewire itself due to insufficient involvement of the locus coeruleus.
Strategies to help engage this targeted area, they suggest, could help optimize how neural implants work.
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