The word synesthesia comes from two Greek words, syn (together) and aisthesis (perception); so synesthesia literally means, "joined perception." (1) I became interested in synesthesia when I learned a friend of mine has this neurologically based phenomenon. She associates colors with letters of the alphebete – most known case of synesthesia to the public. Synesthesia, however, can involve any two or more senses. Current research suggest that “wires” in a person’s brain between two or more sense are crossed, therefor producing the phenomon of tasting sounds and hearing tasts or any other unique combination.I read more about this phenomenon in an autobiogrophy called Born On A Blue Day by Daniel Tammet. This is a story of the extrodinary gifts and misfurtones Daniel Tammet had faced throughout his life. He tells accounts from early childhood till adulthood of his abilities and disabilities. Daniel Tammet is titled an autistic savant. There are many types of sevants, but in general it mean a learned person, a scholar (dictionary.com). Daniel Tammet has extraordinary mental abilities. One example, he views numbers in shapes and can multiply large numbers as dipicted above (5). Daniel describes that even as a child, numbers have given him a sort of pleasure and comfort. He calles them his friends. Emotion is an imporant sideaffect that many people with synesthesia have. Unfortinatly, Daniel was not without disadvantages. He is diagnosed with Asperger Syndrome Autism; which is a very high functioning type of autism, and in his childhood epilepsy. What causes synesthesia is still unknown however cases like Daniel Tammet’s and Sherrilyn Roush’s (2) give reason to believe that synesthesia can be brought on by seizures or stroke.
New York Time article, “When the Senses Become Confused” by Sandra Blakesless, describes the case of a woman, Sherrilyn Roush, who only started experiencing the neurobiology phenomenon, synesthesia, at age 35 only after she had a stroke. After her stroke caused by a lesion the size of a lentil in a region of her midbrain, she began to feel tingling on her body in response to sounds. It is believed that synesthesia is originated in an affected left hemisphere of the brain (2). Some scientists believe that synesthesia results from crossed-wiring in the brain. They hypothesize that in people with synesthesia, neurons and synapses that are supposed to be contained within one sensory system cross to another sensory system. The cables connecting two different boxes in our analogy of the nervous system are crossed. The cause of this switching of cables is unknown, perhaps due to seizures or stoke as I mentioned before or perhaps it is genetic. Interestingly, some researchers believe that these crossed connections are present in everyone at birth, and only later are the connections refined. In some studies, infants respond to sensory stimuli in a way that researchers think may involve synesthetic perceptions. Adult synesthetes may have simply retained these crossed connections from childhood (3).
The difficulties in researching synesthesia are the difficulty of interpreting personal first person accounts in an objective third person view. A large proponent of synesthesia is that is must be durable, involuntary, and memorable. When a person with synesthesia who associated colors with letters remembers a new name and associates red and blue with the name Nelly for example, will remember that this person is red and blue first before remembering the name Nelly. Again, this would difficult to prove with only evidence of first person accounts, although it is not negligible. Even more with brain scans and a trend of different brain activity in people with synesthesia versus people with out would not be able to really narrow down synesthesia to a basic neural level. Science must take small steps to get there, and I believe it is very worth it.In our everyday life we are able to gather and analyze information such as color, shape, size, scent, texture, all to produce a collected idea of what the object is. In this way we can identify a banana. It is yellow, smooth, long and curved, and smells sweet. How our brain collects and binds all various information to allow a person to identify a banana is still unknown. People with synesthesia have an extra special perception that allows them to identify a banana. Exploring their extra perception may help researchers get a better scientific story of how our brain functions this way. So next time you reach for a banana ask yourself, is this a banana and how do I know? Think about how you perceive objects and perhaps gain a better understanding of how our brain and we, humans function.
1. Bakalar, Nicholas. "Sweet and Sour Tones for the Record Books." New York Times 08 Mar. 2005. 20 Feb. 2008 <http://www.nytimes.com/2007/12/25/health/25brai.html?_r=1&sq=synesthesia&st=nyt&adxnnl=1&scp=4&adxnnlx=1204031219-DuWVZs/ETS2HxNXU6S21pg>.
2. Blakeslee, Sandra. "When the Senses Become Confused." New York Times 25 Dec. 2007. 20 Feb. 2008 <http://www.nytimes.com/2007/12/25/health/25brai.html?_r=1&sq=synesthesia&st=nyt&adxnnl=1&scp=4&adxnnlx=1204031219-DuWVZs/ETS2HxNXU6S21pg>.
3. Cytowic, Richard E. "Synesthesia: Phenomenology and Neuropsychology." Psyche. July 1995. 20 Feb. 2008 <http://psyche.csse.monash.edu.au/v2/psyche-2-10-cytowic.html>.
4. Kher, Unmesh. "Ah, the Blue Smell of It!" Time Magazine 21 May 2001. 20 Feb. 2008 <http://www.time.com/time/magazine/article/0,9171,999926,00.html>.
5. Tammet, Daniel. Born on a Blue Day. New York, NY: Simon & Schuster, Inc, 2006.
For More Information:
Watch You Tube Video when Daniel Tammet appeared on the David Letterman Show! http://www.youtube.com/watch?v=qXG-1YLGAS0 
Watch Clip of “Brain Man” on you tube a documentary aired on science channel.