Music Therapy Today - World Federation of Music Therapy

Brain Reader Part 1: Researchers can now see what your brain is doing just by
sue and depending on whether the neurons are active or inactive the
bounces will change," Fabiani says.
Gratton says they can tell whether brain cells are active by how long it
takes for the light to travel from the sources back to the detectors.
"So light, of course, moves very quickly, but we can, with our instrumen-
tation, detect changes in the time light takes to move through the head,"
he says.
A computer program can then create statistically-generated images of
brain activity by mapping these delays.
But you can't use just any color of light -- only certain wavelengths pro-
duce reflections. If you try pressing a green laser pointer against your fin-
ger rather than a red one, you'll see that it doesn't make your finger glow.
That's because, green light, which is actually a higher-energy (but shorter
wavelength) kind of light than red, gets mostly absorbed by the tissues
inside our bodies.
Red light and near-infrared light (longer wavelengths), on the other hand,
get reflected back out. "Near-infrared light, which is a low-energy light is
very useful for imaging because the substances that are in the human
body tend to absorb very little light at this particular wavelength," Grat-
ton says.
Using such low-energy light, makes EROS particularly safe. Gratton says
that in fact, much more light travels through our heads when we're just
sitting indoors under normal lighting than during any of their experi-
ments.
Odds and ends - themes and trends 452