Spending much more time in the dark could improve hearing in old age | Dana Smith

If one area of our brain is broken, other neurons will typically get above to select up the slack. Scientists have located the brain retains this ‘plasticity’ even in old age. Photograph: Alamy

In the Marvel Comic Daredevil our eponymous hero is the victim of a radioactive spill, leaving him blind but also with an extraordinary heightening of his other senses, especially hearing.

For Julie, her superhuman hearing isn’t the result of radioactivity, but is rather due to the reorganisation of neurons in her brain, enhancing her sense of hearing right after the reduction of her sight at the age of sixteen.

The cells in our brain are plastic, not static, which means they can adapt and increase in accordance to our experiences. So if 1 region of your brain is damaged, disrupting a particular approach, other neurons in neighbouring regions will frequently get more than, increasing new projections or strengthening current ones to select up the slack. This has been most significantly shown in young children who have an entire hemisphere of their brain removed, generally to deal with excessive situations of epilepsy. Miraculously, these kids develop up to perform practically entirely typically – strolling, working, talking and thinking – going through school and even on to university as if absolutely nothing have been out of the ordinary.

Co-ordinated reorganisation among our auditory and visual areas is particularly effective, and it is this type of cross-sensory plasticity that has led to tales of enhanced hearing and even extraordinary musical ability in folks who are blind (Stevie Wonder, for instance), the auditory pathway compensating for disability in the visual circuit.

Now, new analysis has shown that this cellular sensory adaptation can take place with temporary disability in outdated age, suggesting our cells are even far more malleable than previously considered, and opening the door for possible non-invasive therapies for hearing loss.

Published in Neuron this month, US scientists from Johns Hopkins University in Baltimore and the University of Maryland identified evidence of enhanced auditory capacity and cell firing in mice that had been subjected to visual sensory deprivation for a week. Very first, the researchers locked the mice in a darkened chamber for six to eight days. Following re-exposing them to light, the researchers played the mice a series of tones, evaluating their responses to these of a group of manage mice that had merely been hanging out in their cages throughout this time.

Though probably unpleasant, the time in the visual sensory deprivation chamber apparently did the mice some very good, at least as far as their hearing was concerned. Those that had been “blinded” for a week showed greater action in response to the tones in neurons in the auditory cortex that originated in the thalamus, a kind of way-station in the brain that processes sensory information and therefore may possibly support integrate responses from both our eyes and our ears.

The cells fired more strongly and quicker, demonstrating that the auditory cells in the blinded group had been much more sensitive to the noise than the same cells in the normal group. The visually deprived mice have been also greater at detecting quieter tones. In addition, these super-hearing mice have been greater at discriminating among different varieties of tones, meaning their perception of pitch was also improved.

Importantly, this analysis was carried out in adult mice, exhibiting that this sensory reorganisation can still happen in older animals. Previously, researchers considered that neural plasticity in these thalamo-cortical cells was only available while our brains have been nonetheless building. Emily Petrus, a graduate pupil at Johns Hopkins University who was first writer on the paper, informed me: “Most people considered these synapses stopped shifting soon after a crucial age, but we show that cross-modally you do nonetheless see a adjust. These findings go towards the dogma that this element of the brain is aplastic [unchanging].”

In other phrases, there is hope for translating these findings into new treatment options for ageing grownups going through hearing loss. Although locking individuals in a dark room for a week most likely isn’t a possible treatment now, shorter spells of sensory deprivation could attain the same results. In reality, past analysis suggests that getting blindfolded for only 90 minutes can lead to enhanced hearing.

For now, the advantages are only temporary – the mice returned to their regular abilities right after a week in the light. But according to Petrus the likely is there for more lengthy-term changes, notably for men and women who are struggling to understand how to use cochlear implants right after going deaf.

“You have to force the brain to do anything it does not normally do. And if you do it long enough – if you have been put in the dark long adequate and forced to use the cochlear implant – you could understand how to use it. After the brain realises it is important, it will commence to adapt.”

Spending much more time in the dark could improve hearing in old age | Dana Smith