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Scientists Learn About Other Forms of Brain Plasticity from People with Mixed Senses
Some people see colors when they hear music. Others taste strange flavors when they look at letters of the alphabet. And still others visualize numbers as if the digits are floating in space in front of them. Collectively referred to as synesthesia, these seemingly bizarre experiences—in which one sensory event is automatically coupled to another—aren't as rare as one might think: As many as one out of every 200 people is thought to have the condition. And by studying synesthesia, scientists can learn a lot about the way our brains are wired. The condition "provides us with a test case for theories of visual perception and other issues in brain function," says Noam Sagiv, a psychologist at Brunel University in England.
Synesthesia may sound odd to those who don't have it, but we all harbor implicit associations between sensory details like sound and color, says Julia Simner, a psychologist at the University of Edinburgh in Scotland. "Ask yourself whether the highest note on a piano is deep dark purple or light yellow—you'll say the latter," she explains. "Synesthetes agree, but they happen to see the color as a perceptual experience." In one study, Simner asked 400 people without synesthesia to pick which colors best went with certain letters. Although some of the subjects first hesitated, saying that they had no such preferences, they ended up choosing similar colors (for example, they thought of A’s as being red).
Most scientists believe that synesthesia is caused by cross-wiring in the brain due to abnormal connections between different brain regions. These connections could be more plentiful or more highly activated than normal, or it could be that the standard "pruning" of extraneous brain connections during childhood is abnormal in people with the condition. A study published in June in the journal Nature Neuroscience used brain imaging to show that synesthetes have increased connectivity within the fusiform gyrus, the brain region responsible for word and color processing. Researchers asked synesthetic subjects to rate the intensity of their synesthetic experiences and found that as intensity increased, so did the associated brain signal in that region.
Studies have implicated two other brain regions in synesthesia, too—the intraparietal sulcus and the frontal cortex, areas involved in consciousness and binding. Binding describes our ability to process a set of individual features about something and later bring these together to perceive a unitary object. "Synesthesia is an example of abnormal binding, and the study of this aspect of synesthesia could help us understand how features are bound together by our brain," says Avishai Henik, a psychologist at Ben-Gurion University of the Negev in Israel.
Synesthesia can also teach scientists about how we master skills. Learning to ride a bicycle is at first difficult, but with practice, we don't even have to think about it, Henik explains. "Riding becomes automatized," he says, meaning that it becomes effortless and involuntary, in the sense that it requires no conscious volition. Scientists have long wondered whether automatic processes become "encapsulated" within the brain, separated from other processes "so that other mechanisms cannot affect it," Henik says. But since synesthesia is considered automatic yet requires connections between different brain structures, some scientists now believe that automatic processes do not rely on encapsulation.
Why might some people experience synesthesia while others don't? It's likely to be caused by both genetic and environmental factors. The condition more often occurs in people who have a relative with the condition. But "there are clearly certain aspects that are learned, like the connection to digits or letters, which are symbolic systems that we learn in kindergarten or school," Henik explains.
And some individuals can trace their synesthetic associations back to childhood objects, says Edward Hubbard, a cognitive neuroscientist at the Institut National de la Santé et de la Recherche Médicale in France. "Whether or not someone is a synesthete is probably by and large genetic, but which associations someone ends up with depends on a complex interaction between environment, learning, and some initial randomness in the neural connections that we all have at birth," he says.
Synesthesia may have evolved for a reason, too, Hubbard says. "The gene or genes for synesthesia probably evolved for some other purpose, and synesthesia is a sort of by-product of such evolutionary pressures," he says. As our brains grew larger during evolution, we could no longer connect all brain regions to one another, because the number of required connections grew faster than the size of the brain. (If humans had fully connected brains, they "would not fit inside our heads," Hubbard explains.) Instead, some brain regions grew into separate modules, and we developed ways of translating this separated information from one sensory dimension to another. Synesthesia may be an artifact of this ability, he says.
There may also be a link between synesthesia and creativity. Individuals with synesthesia perform better on creative tasks than other individuals, Hubbard says, and are also more likely to be artists. "Creativity seems, at its root, to be a combination of ideas from different domains to create a new, useful idea," Hubbard explains. It could be that the increased connectivity involved in synesthesia allows individuals to better combine ideas. "Perhaps the extra connections just make that conceptual linking easier, in the same way that such connections lead to additional sensory experiences," he says.
While there are still a number of unanswered questions about synesthesia and its causes, by studying it, scientists have already learned a great deal about the way the brain is put together and how it works. "Many of the things that we see in synesthesia are present in all of us," Hubbard says. "But in synesthetes, these effects are stronger, and we can therefore more clearly see how everybody's brain works by studying the principles of how synesthesia arises."
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12.19.07 12:04 PM PST
Paul
I can easily remember the words to songs, but have lost other types of recallable memory to a moderate degree as I have aged. Does this mean that I have synesthesia between music and word memory? If so, can I use this to improve other types of memory?
12.19.07 5:30 PM PST
Jay
I'm watching the show now and this is an amazing story! Keep up the good work.
12.19.07 5:49 PM PST
Patrick Badstibner
Due to Meniere's disease, I have lost a business, built from scratch, my balance nerves are shot, hearing gone, and have had to go on social security. I am in advanced stages of disease, not much left for it to attack. After seeing your show this evening and seeing the lady you were able to help, that had vestibular nerve disease, I was challenged to write. The disease is so bad that when I applied for social security, I got it on first try in less than two months. I have been to the University of Miami, Have been a case study at Mayo, and have seen one of the top Doctor's in the field, associated with Duke.
Is there potential hope for me, before this disease I was an agressive athlete, now I am just a cripple.
Please respond back, but I understand if you don't, most run when they hear of my situation. Hopefully I will hear from you. Either way, Thank you for showing that one day there may be hope for others. Please keep up the Good work.
12.19.07 6:36 PM PST
Tina
I am a synthesthete- i see colors with numbers. it has helped me to have an incredible memory for long numbers- i just remember the color combinations, like bouquets. Other than that i guess i am "normal"- it really hasn't affected my other senses and it doesn't happen with letters, just numbers. This was a very interesting article and i wish i would have seen the show!!!
12.19.07 7:29 PM PST
Kathleen
I have had two pieces of short term memory removed do to seizures, which were dangerous to those within reach. Delayed memory recall has been very frustrating. At times it may take just a minute, other times it may take a day or more. Under stress memory recall can be extremely delayed. Is it possible to increase the speed of memory recall?
12.19.07 7:37 PM PST
Eric
Is synesthesia related to any form of autism? Some symptoms seem similiar. Has any of the findings or theories of Bach-y-Rita been applied to autism?
12.19.07 8:39 PM PST
David Barker
while working and seeing implanting a thought to anothere person and making them move something or do a small task of sorts
12.19.07 8:40 PM PST
Brian
Like patrick I'm interested to know if this works for Meniere's disease. My father has advanced Meniere's disease and this would help a formerly very active person. Please point the way to more information on this subject.
Thank you.
12.19.07 8:53 PM PST
suzanne
I have ataxia from an ependymoma brain tumor of the fourth ventricle. surgery and radiation have left me with with a staggered gait and a vestibular problem. the program was very interesting and gave me hope that maybe I will be able to overcome my defecits. any information would be wonderful.thank you. (unfortunately I only saw the last 3 minutes of the show)
12.19.07 9:11 PM PST
A. Nonymouse
I have had Meniere's Disease with an autoimmune component since late Nov./early Dec. 2003. I am also intrigued by the device that helped a woman with vestibular nerve disease. However, I would like to give hope to people who have the disease now hope NOW, immediately, and tell them not to be discouraged.
I was already on disabilites for an entirely different reason, and am seeking full time employment with government assistance. Earlier in my life, I sustained a traumatic brain injury. Do to that experience, I am already familiar with the brain's capabilities to re-route information and even possibly bulid new networks.
I am no longer able to dance, see a movie in a theatre, (due to pain not deafness) etc. But even though my life has changed, I have not allowed my condition to defeat me. I accept the challenges of a changed life. I do not have perfect balance or perfect hearing. Doctors cannot predict how Meniere's Disease will affect the patient in the future; some get worse, some improve slightly (especially women after menopause), some remain the same.
Here are things that specifically helped me. I cannot take steroids due to allergies, but these have helped with my balance, and hearing: 1) a low sodium diet. 2) physical therapy for 2-3 months to work with balance, 2x a week in session and by myself at home for the rest of the week 3) a low impact aerobic walking video/dvd that does not involve quick head re-positioning. It even has a small section dedicated to balance 4) and of course, now I have a hearing aid and regular check-ups
I thank god for the fact that my hearing loss remains stable and that I have met the challenge imposed on me.
My heart goes out to fellow sufferers and I hope this information is useful. I loved the program Wired and intend to watch more of it.
12.19.07 9:23 PM PST
Sue
My mother's vestibular system was destroyed by an overdose of the antibiotic gentamiacyin. She has no balance and is constantly dizzy. Where can I get information to see if my mother can benefit from the device shown on the segment tonight? Is there an experimental program available or any kind of related therapy?
12.19.07 9:43 PM PST
Jeri Messmore
My husband suffers from Cervical Dystonia. We understand that this disease is related to Parkinson's. It started with eseccential tremors, which started pulled his neck back as the muscles tremored. He now is on alot of pain medicine and takes Botox shots to his neck muscles every three months. He is up to 300mg, which we are told is the maxium. If there is anything out there that will help please let us know. He is only 52 years old, and has suffered now for about a year and half. His nerologist is the one the gives the shots. If there are any studies that you know of in this area, he would be most interested. Thank you, his wife, Jeri
12.19.07 10:43 PM PST
Danielle
My daughter has a visual spatial disorder. Can this work on that?
12.20.07 5:37 AM PST
roland
I am 47.I have been a mechanic/welder /fabricator since 13.I have also got into nutrition and bodybuilding.Had a fitnes center.Have been a cook etc..I am extremely intrested in science and the brain.If I could Id go back to school.I had an uncle years ago who had M.S..I watch my father do everythine he could for him,special this and that and even snake venom injections.Is there anyway as not so educated in the Topic right now I could be part of the team.Pauls Ideas are great to say at least and its fact not fiction about the brain minipulating and or becoming a camealeon when things go awry.Like nature over years and animals adapting etc..I'd love to contribute in my way,the coming up with Ideas and application and making the equipment.I know it might sound funny but with such a broad workfeild,there must something I can do to help.We have all seen 2-3 people in a specific feild trying to solve a problem and some dummy just walk by and immediately figure it out,because he is'nt in the same box.Thanxp.s. put me on a team for Patrick Badstimner
12.20.07 7:25 AM PST
Noel Tipton
How do I order the Wired Science shown on channel 2 Wed. Dec. 19? Has any experimentation been done with the techniques shown on this program and aphasia?
12.20.07 10:00 AM PST
Beth
I am a Physical Therapist who does alot of work with Vestibular patients. What I saw on your show last night was fascinating. Can you tell me where this is being done and where trials are held. I would love to find out more about it.
Thank You
12.20.07 10:59 AM PST
Dr. Jim Holt
I work for the PA Human Relations Commission and our organization hosts a Disabilitites Stakeholders Taskforce on behalf of the citizens of the Comonwealth of Pennsylvania. I would like to learn more about this effort to possiblly bring this information forward to the benefit of our citizens. Keep up the good work.
12.20.07 11:16 AM PST
Sue
This program sounds very interesting. Can you tell me when it will be shown again?
Thanks,
Sue
12.20.07 7:24 PM PST
Larry Merken
Is there any trial programs available for a person who has had brain surgery and now has diabetic retinopathy in the Southern California area
I would appreciate information
Thank you,
Larry Merken
12.20.07 8:21 PM PST
Tim
I just watched the show, from the 19. You see, I record the show (love the show, by the way) on my TiVo. My grandmother has vertigo, called vestibular-something,and I was wondering if it would be worth it, to drag her up the stairs to aee it. Is it going to be worth it-woth the trouble, to see it.
12.21.07 1:09 PM PST
Cindy
My sister has a vestibular imbalance problem due to taking the antibiotic "minocycline" for years. How can I get more information about the device that helped the woman on the show that aired Dec. 19, 2007.
12.22.07 2:20 PM PST
Arthur Sledziewski
55 years ago I was given Streptomycin for TB and it destroyed my equilibrium nerves. At first my balance was very bad, but now it is very much improved, my eyes and soles of my feet are my means of balance. Seeing the device working on your show seems very interesting.
12.24.07 10:44 PM PST
Maria G. Castillo
I have been suffering from vertigo and this has greatly diminished my quality of life, but just seeing the last minutes of the show gave me hope for myself and many others who like me suffer from dizziness. Only someone that is or has gone through this can know how horrible it is to live all day every day dizzy. When will this show air again? Thank you
12.27.07 10:23 AM PST
Janice Oberle
As in the episode last night[12-26-07 in NC] I too suffer from vestibular damage, and have balance and dizziness constantly...is there any where I can find out more about this device??
1.2.08 6:32 AM PST
Sylvia Jeansonne
I developed a balanced problem and had surgery on my 8th cranial nerve ta remove a 2cm neuroma. My balance is improved but I have residual bouts of dizziness. I have learned to give myself a few moments of time when arising from a sitting or prone position in order to assure that I am balanced. Accoustic Neuroma has been an interesting problem to deal with. Any information on new treatments?
1.9.08 11:11 AM PST
richard napolitano
I was mesmerized by your wired science program.I also suffer from a vestibular/balance problem as a result of IV ANTIBIOTIC THERAPY.Where can I get more information on how to secure helmet help like the one on your program?
1.9.08 4:17 PM PST
Mary Anglemyer
My friend has been confined to a wheel chair for 45 years due to a fall down a bluff which killed off part of her brain which affects balance. Where can I find more information on this study and will it help someone who has actualy lost life in that part of the brain? Her lack of balance has gotten progressively worse. It would be great just to see her have the ability to stand on her own, if not walk.
1.12.08 5:28 AM PST
teddie
Where can I find out more about brain re-training device used to restore a sense of balance?
I have Meniere's in both ears and non-diabetic peripheral neuropathy. Consequently, I must depend mostly on my eyes for balance. I would like to tell my P.T. about the brain re-training device. What is it called, is anyone using it for the general public, etc.
Thank you.
1.14.08 11:10 AM PST
richard napolitano
I've seen all the questions but no answers.What do I have to do to get information on the RETRAINING THE BRAIN PROGRAM?
5.4.08 11:13 PM PDT
Sarah
I have synesthesia! I was only recently notified that it was an actual, named condition. I had always thought everyone personified or gender coded numbers or color coded letters.
6.3.08 8:14 PM PDT
Yvette
I have had synesthesia for as long as I can remember. I've only just realized 2 years ago that not everyone was experiencing what I was. I mean I had an idea that some people just didn't get what I was trying to explain, but I never realized it was just me. Sometimes I taste my friends personalities in my food. When I was little I had a doll named Molly. I named her molly because she smelled purple, so I had to give her a purple name. (Molly is a purple name). Sometimes I describe my food in odd ways. For example I might say, this gum tastes like a combination of tar and sharp cold frost forming in my mouth. Or something weird like that.
I have a question. Do people with synesthesia have really good imagintions. For example more people with synesthesia having imaginary friends. I had an experience involving something like that once, and I just would really like to know if someone could answer that for me. Thanks! :)
1.1.09 10:27 AM PST
Christine Piejak
I sympathize with Patrick B.and Jeri M. I don't have those conditions, but am suffering from a spinal cord injury (broken neck during an epileptic seizure), leaving me a semi-quad with severe nerve pain, tremors and muscle spasticity. I have trouble with balance as well and must use a wheelchair, or, with therapy, 2 canes now! Fortunately, I'm a lawyer and can work, but must I take hydromorphone. I have found marijuana to be better than morphine at controlling my symptoms, as well as the chronic pain. I've joined NORMAL asking that medical marijuana be legalized. I hope this information helps.
2.23.09 7:04 PM PST
Tracy
My son started having problems with dizziness when he was around 12. He is now almost 14 and is still dizzy most days. The neuro Dr. put him on Zinc supplements because his Zinc was only 53 when it was tested. My son had some strange need to repetitively look to the side and look again uncontrollably. I recently discovered that he thinks of letters, days of the week etc. as colors. Could his dizziness be linked to the apparent synesthesia that he must have?
2.23.09 7:05 PM PST
Tracy
My son started having problems with dizziness when he was around 12. He is now almost 14 and is still dizzy most days. The neuro Dr. put him on Zinc supplements because his Zinc was only 53 when it was tested. My son had some strange need to repetitively look to the side and look again uncontrollably. I recently discovered that he thinks of letters, days of the week etc. as colors. Could his dizziness be linked to the apparent synesthesia that he must have?
11.9.09 6:43 PM PST
Tyler
I hardcorehave synesthesia: I can see colors with music. It's really adds more to the listening experience, and since I play guitar and sing, it's ALOT easier to write music.
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