Mind-reading machine knows what you see
Posted on Monday, April 25 @ 16:54:49 GMT
by Thoth <http://www.the-book-of-thoth.com>

It is possible to read someone's mind by remotely measuring their
brain activity, researchers have shown. The technique can even
extract information from subjects that they are not aware of
themselves.

So far, it has only been used to identify visual patterns a subject
can see or has chosen to focus on. But the researchers speculate the
approach might be extended to probe a person's awareness, focus of
attention, memory and movement intention.

In the meantime, it could help doctors work out if patients
apparently in a coma are actually conscious.

Scientists have already trained monkeys to move a robotic arm with
the power of thought and to recreate scenes moving in front of cats
by recording information directly from the feline's neurons (New
Scientist print edition, 2 October 1999). But these processes involve
implanting electrodes into their brains to hook them up to a computer.

Now Yukiyasu Kamitani, at ATR Computational Neuroscience Laboratories
in Kyoto, Japan, and Frank Tong at Princeton University in New
Jersey, US, have achieved similar "mind reading" feats remotely using
functional MRI scanning.

Between the lines

The pair showed patterns of parallel lines in 1 of 8 orientations to
four volunteers. By focussing on brain regions involved in visual
perception they were able to recognise which orientation the subjects
were observing.

Each line orientation corresponded to a different pattern of brain
activity, although the patterns were different in each person. What
is more, when two sets of lines were superimposed and the subjects
were asked to focus on one set, the researchers could work out which
one they were thinking of from the brain images.

In a separate study, also published in Nature Neuroscience, John-
Dylan Haynes and Geraint Rees at University College London, UK,
showed two patterns in quick succession to 6 volunteers. The first
appeared for just 15 milliseconds - too quick to be consciously
perceived by the viewer.

But by viewing fMRI images of the brain, the researchers were able to
say which image had been flashed in front of the subjects. The
information was perceived in the brain even if the volunteers were
not consciously aware of it.

The study probed the part of the visual cortex that detects a visual
stimulus, but does not perceive it. "It encodes what we don't see,"
Haynes says. He thinks that, further along the visual pathway, brain
regions consciously take note that there has been a stimulus. But
this does not happen for the "invisible" stimulus.

Consciousness kicks in

By understanding the perception pathway and working out the point at
which consciousness kicks in, patient consciousness could be
diagnosed. This would mean the setup could be used as
a "consciousness-meter," says Haynes; "a device that allows us to
assess whether a patient is consciously perceiving his or her outside
environment."

Yang Dan, a neurobiologist at the University of California in
Berkeley, agrees this would be possible. But she cautions that there
is little agreement over what consciousness actually is.

More subtle forms of mind-reading such as working out intentions or
beliefs are much more speculative, she argues. Even if such subtle
information could be gleaned from brain scans both studies suggest
the patterns are unique to individuals.

And using the technique as an alternative to the polygraph would be
very risky, says Dan. "The relationship between brain patterns and
lies may be very loose."

Article Source <http://www.newscientist.com/article.ns?id=dn7304>