- I think that we're all lucky that it exists, because without it, there would not be the magnificent art that we get to have all around us.

- [Michelle San Miguel] Artist Alyn Carlson has a neurological condition that she says makes her life and her artwork more interesting.

- I was probably five, and I started seeing numbers in color.

Three was yellow.

Five was red.

Zero was white.

Seven was sort of a purpley-blue.

- Not only does Carlson see numbers in color, but she says she can also hear them and smell them.

You've been open about the fact that you feel self-conscious, somewhat, even talking about this.

- I know.

Yeah, a little.

- Why is that?

- Well, it's kind of... because other people can't really relate to it.

(serene music) - [Michelle San Miguel] Artist and musician Lennie Peterson certainly can.

- So, when I hear music, I see shapes, - [Michelle San Miguel] What kind of shapes?

- Well, they're in my art, and they're anywhere from a straight line, depending on the note, to all kinds of atmosphere within squares and circles, - [Michelle San Miguel] Both Lenny Peterson and Alyn Carlson have synesthesia, a rare condition where a person's senses, including the sense of smell and sound, get mixed together.

We asked neurologist Dr. Richard Cytowic to explain just what synesthesia is.

- It's pretty easy.

Everybody knows the word "anesthesia," which means no sensation, so synesthesia means joined or coupled sensation.

And there are kids who are born with two, three, or all five of their senses hooked together, so that my voice, for example, is not only something that they hear, but something that they might also see or taste or feel as a physical touch.

- [Michelle San Miguel] Dr. Cytowic is credited with bringing synesthesia back to mainstream science.

He's written six books on the phenomenon.

He says colleagues initially dismissed it as too weird and new age.

- What happened is that, you know, I caused a paradigm shift in how we think about how the brain is organized.

If we don't have five senses traveling down five tubes that never intermingle, there are huge numbers of cross connections in the brain all the time.

(tool scraping) - Carlson says the artwork featured in her new Bedford studio was created, in large part, thanks to her synesthesia.

- If I'm working, and two colors seem to come together and I smell them, they kind of lead me into an area to continue.

And because my work is abstract, very often what I'm doing is I'm reacting to a color combination.

- [Michelle San Miguel] Take, for instance, this abstract painting.

Carlson says she painted it by mixing colors that smelled like one of her favorite things, a low tide.

- So, I started to be able to pull in whole family of those colors that smelled that way to me.

It was like an undercurrent in the whole palette.

And so, from that, I painted a, you know, 80-inch wide abstract landscape just from the smell, those two colors that came together.

And that happened.

Boom.

That was so fast.

- [Michelle San Miguel] Synesthesia is more common than some might think.

Dr. Cytowic says 4% of the population has this union of the senses, including Lady Gaga.

♪ Poker face ♪ ♪ She got me like nobody ♪ - [Michelle San Miguel] And Billy Joel.

♪ We didn't start the fire ♪ ♪ It was always burning, since the world's been turning ♪ - [Michelle San Miguel] Russian writer Vladimir Nabokov, who wrote "Lolita" also had it.

(chilled jazz music) So did Composer and pianist Duke Ellington.

Is anesthesia more common among artists and musicians?

- Well, you know, we're more familiar with famous artists who happen to be synesthetes than we are famous synesthetes who happen to be artists.

And it's a chicken and egg question of "Are they artistic because they're synesthetic, or are they synesthetic because they're artistic?"

But I think it's the former, and they're used to unusual things going together.

(relaxing orchestral music) - [Michelle San Miguel] It's those unusual things that inspire the work of Newport-based artist Lennie Peterson.

He listens to music as he works and draws the shapes that he sees.

Now, these shapes appear three dimensional in front of you.

They're floating in the air.

- They are being created in front of me.

They're not in the room, they're forming in front of me as I listen to music.

And the more I concentrate on it, the more they're gonna form, and the clearer they're gonna form.

(relaxing notes) - [Michelle San Miguel] Peterson was in his late twenties, teaching at the Berkeley College of Music, when he realized the way he experiences the world isn't like most people.

- I was producing a student's project of music, and we were tracking keyboards.

And I said, I got on the, you know, the talk mic, and I said, "Can you make that chord more round?"

And I just got this stunned silence, you know, like, "Wait, what?"

So, I turned to the engineer and he said to me, "What?"

I said, "I want 'em to make it more round?"

He said, "You must have synesthesia."

- [Michelle San Miguel] Peterson's paintings are heavily influenced by the music he listens to.

(calming jazz music) - So, this is specifically around a Miles Davis song, actually, called "In a Silent Way", and it's a very mystical kind of setting for this song.

Then the synesthesia kicks in here.

I start in the top left-hand corner, and I let my hand go, and it's just a free flow of while the music's playing.

(calming jazz music) - [Michelle San Miguel] At times, Peterson says it feels like an overload of the senses, which he says isn't a bad thing.

- If I get extremely sick, like high fever, a lot of people have hallucinations when they get really super sick.

But ever since I was a little kid, I would hear these gigantic symphonies in my head that would just like crazy huge, like, (indistinct), Mahler type symphonies.

- Do you ever wish you didn't have synesthesia?

- No, never.

Never.

It's almost like saying you wish the sky wasn't blue.

There's nothing I can do about it, and it's there, you know, and it's part of my life.

- [Michelle San Miguel] Is it hereditary?

- Oh, yes, absolutely, very strongly so.

It runs strongly in families.

Either sex parent can pass it down to either sex child, and you'll see it in multiple generations.

So, the most I have is four living generations with synesthesia.

But historically, we've been able to trace it back even more so.

- [Michelle San Miguel] According to the National Institutes of Health, some researchers think people with synesthesia have extra connections between brain cells in some areas of the brain.

Others think the direction that information can flow between brain cells might be different.

Dr. Cytowic says synesthesia is a left brain phenomenon.

- There's a difference between actually viewing colors and seeing synesthetic colors.

And it's as if synesthesia has hijacked a normal brain function that is viewing colors by connecting it with other senses in the left hemisphere.

- [Michelle San Miguel] Colorful experiences can also evoke pleasant sounds.

For Alyn Carlson, this combination of blue has a distinct pitch.

- Every time I started to put them together, I would hear cello.

I would hear cello music, just a long note.

Just a long note.

It's not a complicated piece of music.

- [Michelle San Miguel] As the paint is being mixed.

- Yeah, as the paint is being mixed.

When I would get still with it, I would just hear it.

- [Michelle San Miguel] And sometimes, she can smell it too.

- I would hold her and, of course, smell her.

- [Michelle San Miguel] Carlson says this painting captures the smell of her youngest granddaughter when she was a baby.

- And I just wanted to replicate it somehow.

And these colors came to mind.

It wasn't hard at all; they just popped in.

And that's where this came from.

- Can you smell your granddaughter when you look at this?

- Well, she's three and a half now, but I can smell a baby.

- You can?

- Yeah.

- For Carlson, Synesthesia allows her to hold onto precious memories.

What would a world without synesthesia look like for you?

- I don't know.

I probably wouldn't be, obviously, doing what I do, making what I make.

I'd be lost.

I'd be really lost, I think.