Nature: Stimulation of the blue plakia nucleus in the brain is expected to improve the efficiency of cochlear implant users in restoring hearing

In a new study of deaf rats, researchers from New York University School of Medicine found that restarting the brain's natural ability to adapt to a new environment (i.
e.
, neuroplasticity) can improve the efficiency
of cochlear implants in restoring hearing loss.
They note that the study may help explain the extreme differences
in hearing improvements experienced by cochlear implant implanters.
The results of the study were published online in Nature on December 21, 2022, under the title "Locus coeruleus activity improves cochlear implant performance.
"

Unlike hearing aids, which amplify, balance, and sharpen incoming sound, cochlear implants send electrical signals
that represent sound directly to the brain.
Unfortunately, experts say, it can take time
to understand the meaning of these signals.
Past studies have shown that while some cochlear implanters can understand some speech within hours of receiving their cochlear implant, others take months or years to do so
.
However, the mechanisms that determine how quickly the brain adapts to implants have been unclear
.

In the new study, the authors conducted a new study in rats to evaluate whether stimulating the locus coeruleus, the main site of neuroplasticity located deep in the mammalian brainstem--- increases ---the speed at
which they learn to use their cochlear implants.
The results showed that rats who received additional stimulation within just three days of receiving a cochlear implant were able to effectively perform tasks
that required accurate hearing.
In contrast, those rats that were not additionally stimulated took up to 16 days to do so
.

Lead author Dr.
Erin Glennon of New York University School of Medicine said, "Our findings suggest that differences in neuroplasticity, particularly in certain parts of the brain, such as the blue spot, may help explain why some cochlear implant users improve hearing
faster than others.
" ”

In earlier studies, scientists have found that electrical stimulation of the blue spot nucleus of rodents increases neuroplasticity and changes the way
the brain's auditory system behaves to sound.
However, the new study is the first to confirm that stimulating this brain region accelerates hearing improvement
in cochlear implant users.

In the new study, the authors trained hearing rats to press a button after hearing a specific sound and ignore the button
if they heard a different tone.
Once deaf, these rats were unable to complete the task
.
They were then implanted with cochlear implants and retrained to rely on the device to accomplish the same challenge
.

Auditory regulation
when normal hearing rats are with/without tasks.
Image from Nature, 2022, doi:10.
1038/s41586-022-05554-8
.

Among these findings, the new study shows that when these rats learned to use their cochlear implants, blue spot nucleus activity changed
significantly.
At first, this brain region is most active
when they get food after hearing a tone and pressing the correct button.
After they learn to associate button presses with receiving rewards, blue-spotted nuclear activity reaches its peak
when they simply hear a tone.
Remarkably, the faster this change occurs, the faster the rats will be consistently successful on the task
.

Dr.
Robert Froemke, a neuroscientist at New York University School of Medicine and co-corresponding author of the paper, said, "Our results suggest that improving the neuroplasticity of the blue plakia may accelerate and enhance the effectiveness of
cochlear implants.
Froemke said the team next plans to explore ways
to non-invasively stimulate this brain region in humans.

Dr.
Mario Svirsky, co-corresponding author of the paper, from New York University School of Medicine, said, "Since our goal is to activate the blue spot, we need to determine which non-invasive mechanisms can be used to trigger this large brain region
.
”

Svirsky cautions that the rats' hearing is checked using simple sounds in a simple task, while humans need to respond
to subtle language patterns in noisy environments.
Further research is needed into other brain regions
that may be involved, he said.
(Biovalley Bioon.
com)

Resources:

1.
Erin Glennon et al.
 Locus coeruleus activity improves cochlear implant performance.
Nature, 2022, doi:10.
1038/s41586-022-05554-8.

2.
Brain Flexibility Might Speed Up Hearing Improvements from Cochlear Implants

https://nyulangone.
org/news/brain-flexibility-might-speed-hearing-improvements-cochlear-implants