De Connectie Raakvlakken 2
De Connectie Raakvlakken 2
De Connectie Raakvlakken 2
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:: AI news<br />
Brain-Controlled Cursor<br />
ScienceDaily (Feb. 16, 2010) — Harnessing<br />
brain signals to control keyboards, robots<br />
or prosthetic devices is an active area of<br />
medical research. Now a rare peek at a<br />
human brain hooked up to a computer<br />
shows that the two can adapt to each other<br />
quickly, and possibly to the brain’s benefit.<br />
Researchers at the University<br />
of Washington looked at signals on<br />
the brain’s surface while using imagined<br />
movements to control a cursor. The team<br />
of computer scientists, physicists, physiologists<br />
and neurosurgeons studied eight<br />
patients awaiting epilepsy surgery at two<br />
Seattle hospitals. Patients had electrodes<br />
attached to the surface of their brains during<br />
the week leading up to the surgery.<br />
Organized chaos gets robots going<br />
Physorg.com, Jan. 17, 2010 — Scientists at<br />
the Max Planck Institute for Dynamics and<br />
Self-Organization have developed a walking<br />
robot that can flexibly and autonomously<br />
switch between different gaits, modeled on<br />
human-animal neural circuits called “central<br />
pattern generators” (CPG). This is a<br />
simple network with just a few sensors that<br />
can create very diverse movement patterns.<br />
The secret of its functioning<br />
lies in “chaos control”. If uncontrolled,<br />
the CPG produces a chaotic activity pattern,<br />
but this activity can be very easily<br />
controlled by the sensor inputs into periodic<br />
patterns that determine the gait.<br />
Even simple insects can generate<br />
quite different movement patterns<br />
with their six legs. They use various gaits<br />
The brain forgets things on purpose<br />
Physorg.com, Feb. 18, 2010 — Learning<br />
requires removing memories to allow for<br />
new information to come in, experiments<br />
with flies suggest.<br />
Researchers have traced the<br />
process to a molecular pathway including<br />
a small protein known as Rac.<br />
Asking people to imagine doing a movement<br />
- such as moving their arm - is commonly<br />
done to produce a brain signal that can<br />
be used to control a device. The researchers<br />
first recorded brain patterns when<br />
human subjects clenched and unclenched<br />
a fist, stuck out a tongue, shrugged their<br />
shoulders or said the word “move”.<br />
Next, the scientists recorded<br />
brain patterns when subjects imagined<br />
performing the same actions. These patterns<br />
were similar to the patterns for actual<br />
action but much weaker, as expected<br />
from previous studies. The researchers<br />
linked these partterns to moving a cursor<br />
toward a target on a computer screen.<br />
After less than 10 minutes of prac<br />
depending on whether they crawls uphill<br />
or downhill, slowly or fast. In humans<br />
and animals, periodically recurring movements<br />
like walking or breathing are also<br />
controlled by central pattern generators.<br />
Scientists have been using this<br />
principle in the development of walking<br />
When that mechanism is blocked, flies<br />
hold on to newly acquired memories<br />
for longer than they otherwise would.<br />
Rac switches on when flies simply<br />
forget with the passage of time. It<br />
just switches on faster when the insects<br />
either get distracted by new information<br />
or “confused” by conflicting experiences.<br />
tice, brain signals from imagined movement<br />
became significantly stronger than when<br />
actually performing the physical motion.<br />
The rapid change of activity during<br />
this type of learning bears testimony to<br />
the remarkable plasticity of the brain as it<br />
learns to control a non-biological device.<br />
After less than 10 minutes of training, two<br />
of the subjects also reported they no longer<br />
had to imagine moving the body part and<br />
could just think about moving the cursor.<br />
The finding holds promise for<br />
rehabilitating patients after stroke or other<br />
neurological damage. It also suggests that a<br />
human brain could quickly become adept<br />
at manipulating an external device such as<br />
a computer interface or a prosthetic limb.<br />
machines. To date, typically one<br />
separate CPG was needed for<br />
every gait. <strong>De</strong>pending on the<br />
information it receives from it’s<br />
environment - about whether<br />
there is an obstacle in front of<br />
it or whether it climbs a slope<br />
- it selects the CPG controlling<br />
the gait that is appropriate<br />
for the respective situation.<br />
The robot developed by<br />
the Göttingen scientists now manages<br />
the same task with only one<br />
CPG that generates entirely different gaits,<br />
and which can switch between these gaits<br />
in a flexible manner. In the future, the robot<br />
will be equipped with a memory device<br />
which will enable it to complete movements<br />
even after the sensory input ceases to exist.<br />
When Rac was blocked, new memories<br />
decayed more slowly, extending<br />
their life from a few hours to more than<br />
a day. When Rac levels were artificially<br />
increased however, the insects’ new<br />
memories were erased more rapidly.