A Cat's Eye Marvel
by Leander Kahney
In a dramatic demonstration of mind reading, neuroscientists have
created videos of what a cat sees by using electrodes implanted in the
Garrett Stanley of Harvard,
and Fei Li and Yang Dan of the University
of California, Berkeley, were able to reconstruct in startling
detail scenes flashed before a cat's eyes.
The reconstructed scenes clearly demonstrate the scientist's
ability to decode the language of the cat's visual system.
The researchers attached electrodes to 177 cells in an anesthetized
cat's thalamus, a region of the brain falling about half-way in the
visual processing pathway.
Having recorded patterns of firing as various scenes were flashed
before the cat's eyes, the team was able to reconstruct very closely what
the animal saw, which varied from people's faces to scenes of a
The research was applauded by other neuroscientists.
"The demonstration that you can reconstruct a movie from the
multiple cells in the thalamus is an important step in our
understanding of how signals are represented in the activity of
populations of cells," said Fred Rieke, an assistant professor of
physiology and biophysics at the University
Stanley, an assistant professor of biomedical engineering, said the
research provides clues about how prosthetics may one day be wired
into the mammalian nervous system. By understanding the language of
the brain, scientists will be able to create devices that talk to it,
"Trying to understand how the brain codes information leads to
the possibility of replacing parts of the nervous system with an
artificial device," he said.
Stanley predicted that in the next couple of decades, as more and
more of the neural code is decoded, brain interfaces may start to
But he cautioned it may take a lot longer. He noted that the team
also recorded the activity of cells higher up in the cat's visual
pathway -- in the visual cortex -- but the results were not as
startling because of the greater complexity of the cells.
"So little is understood about thoughts, perceptions, dreams,
it's impossible to predict how much progress we'll make in
understanding them," he said.
However, Ken Miller, as associate professor at the University
of California, San Francisco, said researchers around the world
are using similar techniques to decode higher brain functions.
"These methods could be applied to further up the visual
pathway," he said. "It will become more difficult ... but
it's a promising direction."
The experiments were reported in the September issue of the Journal