Does the brain compensate for the loss of a sense?
August 20, 2010 10:17 AM   Subscribe

Is there any science behind the myth that if an individual loses one sense, the brain compensates by increasing the accuracy of the others?
posted by modernnomad to Grab Bag (15 answers total) 2 users marked this as a favorite
Neuroplasticity is the term brain scientists use to describe the ability of the brain to be malleable. I'm not sure if this directly applies to your question, though.
posted by dfriedman at 10:24 AM on August 20, 2010

I believe that this is an illusion (and although I am not missing any senses, I know some people who are). What is actually happening is that you use the senses that you have, necessarily, so if all you have is hearing, with no vision, all your attention is concentrated on hearing. A sighted person will sometimes close his or her eyes in order to listen to something more closely. Blind people in effect are always listening more closely. But their hearing is not actually more acute.
posted by grizzled at 10:26 AM on August 20, 2010

As someone who spent four years studying neuroscience, I can say that neuroplasticity ("adaptive" changes in the structure/function of nervous tissue in response to injuries to the nervous system or alterations in patterns of their use/disuse) is a real phenomenon.

However, any specific language you use here is going to be problematic. "Increasing the accuracy" is not the correct way to talk about it. Talking about "attention" as grizzled does, is also misleading. "Increasing accuracy" has no meaning in the kinds of mechanisms you're talking about. "Attention" has no meaning in very low level neural systems like the spinal cord.

Scientists have observed the brain changing itself in ways that seem to compensate for losses in different sensory modalities. If you do a literature search on "neuroplasticity" or even read about it generally, you will see how people familiar with the phenomenon try to talk about it coherently.
posted by fake at 10:33 AM on August 20, 2010 [6 favorites]

Here's a relevant article from Nature.
posted by limon at 10:38 AM on August 20, 2010 [1 favorite]

I have a blind friend who says in her opinion, she doesn't say, have "super" hearing at this point, compared to sighted folks. More like what grizzled said. I'm not saying there's no neuroplasticitiness occurring here, but that's what she tells me.

It's too bad, I was kinda hoping she become more Daredevil-ish after she lost her sight.
posted by bitterkitten at 11:13 AM on August 20, 2010

Can't speak to accuracy, per se, but a related and well-established phenomenon occurs when parts of the brain normally dedicated to one sensory modality, in the prolonged absence of input, get co-opted by other sensory functions. For example, blind people use parts of the visual cortex to process tactile stimuli. There are many stories of people who have lost limbs/appendages that start feeling sensations from one part of the body in the area where the missing limb used to be. In Phantoms of the Brain, VS Ramachandran tells a story about a patient who began feeling orgasms in the place where his amputated foot used to be. It is perhaps unwarranted to assume that having extra brain matter dedicated to a sense necessarily makes that sense sharper, but that is certainly a very tempting conclusion.
posted by dephlogisticated at 11:27 AM on August 20, 2010 [2 favorites]

Response by poster: Apologies for the incoherence of the question, Fake!

That Nature article is really interesting stuff.
posted by modernnomad at 11:45 AM on August 20, 2010

There's James Holman.

Also, Ben Underwood was able to use echolocation to do many things. Unfortunately he died due to cancer in 2009. Here's the link to his website.
posted by MrMulan at 12:24 PM on August 20, 2010

What I immediately thought of was an episode of Scientific American Frontiers I saw where an investigator imposed blindness on a woman for 5 days, and tested her ability to read Braille over that time. Both she and a man who had blind since birth were tested on their Braille skills, and then the visual area of the brain was "knocked out." When they were retested, they did significantly worse, indicating that in both the short- and long-term the brain "took over" the visual portion of the brain to perform tactile tasks. If you're interested, the transcript is online, and it looks like you can watch the episode, as well.

Also, I definitely second the recommendation for Phantoms of the Brain.
posted by dormouse at 12:26 PM on August 20, 2010

I am legally blind and my hearing has not improved.

I have lost my vision over the past 12 years and my hearing has stayed constant. However I have learnt to be more aware of sound and use it as a tool. Any questions fell free to ask.
posted by moochoo at 12:40 PM on August 20, 2010

You might be interested in reading The Brain that Changes Itself by Norman Doidge as it contains lengthy discussion of this topic.

If a person who has recently lost a sense (say balance, or sight) is given a tactile prosthesis (think, in the case of blindness, of a video camera that stimulates a skin patch with a pressure-pixel map of what the camera sees), the human brain will radically re-allocate neural resources to process the information coming in through that patch of skin.

The patch of skin itself isn't changing, but the brain's resources are shifted towards processing finer detail from the input received from that patch of skin. To the point that the blind subject can recognize people and "see" objects in the room via the input they're receiving through this stimulation of the skin.

That example's around 40 years old and discussed in the first chapter or so of the book. It gets better.
posted by richyoung at 12:51 PM on August 20, 2010 [1 favorite]

I think what you're looking for is the work of Paul Bach-y-Rita. Actually, I first read about him in the book mentioned just above--The Brain That Changes Itself.
posted by sunnichka at 12:55 PM on August 20, 2010

The Brain? Blindness might not necessarily/naturally/neurologically make hearing better, but one would pay more attention to audio data. A matter of priorities, focus.
posted by ovvl at 3:08 PM on August 20, 2010 [1 favorite]

I really don't think it'd take scientific data to back up the idea that if you lose one sense, you pay more attention to the other senses. And with that in mind, you learn to use them more efficiently by focusing on them, much like learning a new skill.
posted by samsara at 3:37 PM on August 20, 2010

This is not particularly formal but there's a book called Crashing Through about a man named Mike May, who has been blind since age 3 and done all kinds of amazing things with his life.

SPOILER When his vision was restored they found that while he could still sense colors and shapes he really couldn't make sense of the images because all the parts of your brain that go to recognizing objects and faces, had gone off to do something else. The last quarter of the book or so goes into some scientific depth, I imagine tracking down those researchers would be a good way to go in answering this question.

It's also an amazing read, I HIGHLY recommend it.
posted by ista at 9:36 AM on August 21, 2010

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