LINDA DALZIEL was sitting in a sixth-form French class when she first realised not everyone's brain worked the same way as hers.
Her teacher was discussing a work by an author who had described the days of the week as colours. Of course, said the teacher, he's using artistic licence here. "And three out of the six of us, said 'No he's not!'" laughs Linda.
For Linda, a 54-y
ear-old careers advisor from Morningside, Thursday is always brown – but then so is any word with a 'th' in it.
This is because Linda has a curious condition called synaesthesia – although it would be many years after that French class before she could put a name to it, and learnt that the condition is caused by cross-wiring in the brain. Synaesthetes, as those with the condition are known, seem to have their senses mixed up.
Some can "taste" words – a few of which are so rancid they actually make the sufferer feel nauseous – while others see precise locations for the months of the year or days of the week.
Linda, as well as seeing colours for some of the days of the week, also sees the personalities of letters. For instance, Linda says that Q and F aren't the nicest of people. "They are both quite sharp – nippy sweeties, not like S, who's a girl next door, or M, who's dull and boring," she explains.
It is Linda's particular form of the condition – known as Ordinal Linguistic Personification, or OLP –which makes her so interesting to Edinburgh University researchers.
Scientists there are looking for volunteers to help them carry out a six-month study into the phenomenon.
They hope that finding out how synaesthetes' brains differ from those of ordinary people's, will help them understand how the brain works – or doesn't work, in the case of stroke or dementia victims.
The research will involve using MRI scans to look at the white matter in volunteers' brains. That's the part responsible for the connections within the brain.
Dr Mark Bastin, a medical physicist at the Western General Hospital, says: "White matter is like a computer's cable, carrying information, as opposed to grey matter, which is like a computer and responsible for information processing.
"We are interested to see if the white matter of synaesthetes works differently to the white matter of normal people.
"You see damaged white matter when people have things like strokes, dementia or depression. We would like to find out if maybe synaesthete's brains are connected in a more unusual way."
His colleague, Dr Marie Rehme, who conducted research on synaesthetes two years ago at the Medical University of Hanover, adds: "The synaesthetes in my last study had all grapheme-colour and colour-hearing synaesthesia, which means they see specific colours when they read letters and when they hear words.
"We found that when synaesthetes like this hear a word, the part of their brain which sees colour also lights up – that doesn't happen in people without synaesthesia."
Some report synaesthetic feelings after experimenting with psychedelic drugs, having a stroke or temporal lobe epilepsy.
Dr Rehme has found that the people with the condition often work in creative jobs. "The volunteers I see are usually very intelligent, creative people, like musicians and architects."
The condition can run in families and it's estimated that it could affect up to one in 23 people – it's difficult to gauge, say researchers, because people who have it don't view it as abnormal.
That was certainly the case for Linda, who hadn't thought to mention it to anyone before the incident in her French class. It was only her teacher's reaction which gave her a slight insight into how differently some people's mind work.
"She just didn't believe us, it seemed so alien to her," she laughs. "I think she thought we had all got together beforehand and we were having some sort of game with her.
"I always assumed everyone had it – and of course there were three of us out of six in that class that did. I didn't think it was unusual, and even now I don't think about it unless someone asks me."
The condition is not a day-to-day problem for Linda – in fact, she thinks it adds a sensory richness to her life. Her husband, Jim, 55, has no qualms with it either. "He makes ceramics and teaches art, so he's quite creative anyway," says Linda.
"It doesn't faze me. I think it's more interesting to those who don't have it. I find it's a good memory aid," she adds.
"I don't know why I have got it. I was very late learning to read and I wonder if that was why it became so pronounced.
"I am a perfect speller now, although I'm not very good at things like mental arithmetic. I can spell anything and I think the reason is the synaesthesia."
Linda discovered she had the condition while watching a TV documentary on it. The programme set up a website with tests to try, and Linda found she was a classic case. She says she's delighted to take part in the tests.
"The more they know about connections in the brain, the more they can do for people who have problems or brain damage. I'm also interested to find out what it's all about for myself!"
To volunteer to take part in the study, contact Dr Marie Rehme at marie.rehme@googlemail.com. For more information on the study, go to www.syn.psy.ed.ac.uk
FAMED SUFFERERSTHE word "synaesthesia" comes from the Greek words "syn", meaning together and "aethesia" meaning sensation. Possibly the most famous synaesthete is pop art pioneer David Hockney.
Hockney didn't know there was anything unusual about his synaesthesia until he began painting opera sets. When critics commented on how strange the sets he created were, he explained: "Well, I listened to the Ravel music and there's a tree in one part of it and there's music which accompanies the tree. When I listened to that music, the tree just painted itself."
For Lolita author and fellow synaesthete Vladimir Nabokov, the sound of "a" in English had "the tint of weathered wood" but a French "a" evoked polished ebony, the letter g was "the colour of vulcanised rubber" and r "a sooty rag bag being ripped".
Musicians are also well-represented – jazz composer Duke Ellington once said: "I hear a note by one of the fellows in the band and it's one colour. I hear the same note played by someone else and it's a different colour."
And 19th century composer Franz Liszt astonished the Weimar orchestra in 1842 by giving them instructions such as: "O please, gentlemen, a little bluer, if you please!"
