Orig URL: 
http://news.bbc.co.uk/2/hi/science/nature/471786.stm
Monday, October 11, 1999 Published at 19:10 GMT 20:10 UK
Sci/Tech
Looking through cats' eyes
Fuzzy but recognisable
By BBC News Online Science Editor Dr David
Whitehouse
These are the first pictures from an extraordinary experiment which has probed what it
is like to look through the eyes of another creature.
As reported on BBC News Online last week, a team of US scientists have wired a computer
to a cat's brain and created videos of what the animal was seeing.
By recording the electrical activity of nerve cells in the thalamus, a region of the
brain that receives signals from the eyes, researchers from the University of California
at Berkeley were able to view these shapes.
The team used what they describe as a "linear decoding technique" to convert
the signals from the stimulated cells into visual images.
Dr Yang Dan, Assistant Professor of Neurobiology at UC Berkeley, Fei Li and Garrett
Stanley, now Assistant Professor of Biomedical Engineering at Harvard University conducted
11 experiments.
They recorded the output from 177 brain cells that responded to light and dark in the
cat's field of view.
![[ image: A cat's-eye view of a woodland scene]](_471786_catimage3300.jpg) |
| A cat's-eye view of a woodland
scene |
In total, the 177 cells were sensitive to a field of view of 6.4 by 6.4 degrees. As the
brain cells were stimulated, an image of what the cat saw was reconstructed.
The first example is a face. Although the reconstructed image is rather fuzzy, it is
clearly recognisable as a version of the original scene. It is possible that a clearer
image could be obtained by sampling the electrical output of more cells.
In the cat's brain, as in ours, the signals from the thalamus cells undergo
considerable signal processing in the higher regions of the brain that improve the quality
of the image that is perceived.
Taking an image from a region of the brain before this image enhancement has taken
place will result in a poorer image than the cat is able to see.
The other two examples show two woodland scenes, with tree trunks being the most
prominent objects.
By being able to tap directly into the brain and extract a visual image the researchers
have produced a "brain interface" that may one day allow the control of
artificial organs and indeed machines by thought alone. It is also conceivable that, given
time, it will be possible to record what one person sees and "play it back" to
someone else either as it is happening or at a later date.
![[ image: A clearer image could be obtained by sampling more cells]](_471786_catimage2300.jpg) |
| A clearer image could be obtained
by sampling more cells |
Orig URL: http://news.bbc.co.uk/2/hi/science/nature/468857.stm
Friday, October 8, 1999 Published at 20:57 GMT 21:57 UK
Sci/Tech
Computer uses cat's brain to see
Scientists have literally seen the world through
cat's eyes
By BBC News Online Science Editor Dr David
Whitehouse
In what is bound to become a much debated and highly controversial experiment, a team
of US scientists have wired a computer to a cat's brain and created videos of what the
animal was seeing.
According to a paper published in the Journal of Neuroscience, Garrett Stanley, Yang
Dang and Fei Li, from the Department of Molecular and Cell Biology, University of
California, Berkeley, have been able to "reconstruct natural scenes with recognizable
moving objects".
The researchers attached electrodes to 177 cells in the so-called thalamus region of
the cat's brain and monitored their activity.
The thalamus is connected directly to the cat's eyes via the optic nerve. Each of its
cells is programmed to respond to certain features in the cat's field of view. Some cells
"fire" when they record an edge in the cat's vision, others when they see lines
at certain angles, etc. This way the cat's brain acquires the information it needs to
reconstruct an image.
Recognisable objects
The scientists recorded the patterns of firing from the cells in a computer. They then
used a technique they describe as a "linear decoding technique" to reconstruct
an image.
![[ image: Scientists saw recognisable objects]](_468857_sparkey150.jpg) |
| Scientists saw recognisable
objects |
To their amazement they say they saw natural scenes with recognisable objects such as
people's faces. They had literally seen the world through cat's eyes.
Other scientists have hailed this as an important step in our understanding of how
signals are represented and processed in the brain.
It is research that has enormous implications.
Artificial brain extensions
It could prove a breakthrough in the hoped-for ability to wire artificial limbs
directly into the brain. More amazingly, it could lead to artificial brain extensions.
By understanding how information can be presented to the brain, some day, scientists
may be able to build devices that interface directly with the brain, providing access to
extra data storage or processing power or the ability to control devices just by thinking
about them.
One of the scientists behind this current breakthrough, Garrett Stanley, now working at
Harvard University, has already predicted machines with brain interfaces.
Such revolutionary devices should not be expected in the very near future. They will
require decoding information from elsewhere in the brain looking at signals that are far
more complicated than those decoded from the cat's thalamus but, in a way, the principle
has been demonstrated.
