Ancient Cave Behavior

People have been acting like people—in other words, they've been making tools, creating rituals, and sharing food—for a long time. That's the conclusion of a recent study from South Africa's southern coast.

There, in a cave perched above the sea, researchers from Arizona State University in Tempe have found evidence that humans were behaving in surprisingly complex ways as early as 164,000 years ago. Our species, Homo sapiens, emerged an estimated 200,000 years ago.

The cave held three important clues about the behavior of these Stone Age people.
First, the researchers found the remains of a variety of shellfish, including mussels, giant periwinkles, and limpets. The cave dwellers probably collected these creatures from rocky shores and tide pools and brought them to the cave to eat.

The researchers propose that the early Africans moved to the South African coast between 195,000 and 130,000 years ago. Around that time, the climate inland turned relatively cold and dry. As a result, there were fewer plants and animals to eat away from the coast.

When these ancient people moved to the coast, they probably experienced a major cultural shift, the researchers suspect. That's because observations of modern hunter-gatherer societies suggest that men are more likely to hunt for big animals when people live inland. On the coast, women play a more important role in providing food by gathering plants and shellfish.

As for the second clue, the researchers unearthed 57 pieces of reddish pigment. The researchers think that the cave dwellers used the pigment for coloring their bodies or for other rituals. Symbolic behavior is a distinctly human trait.

Finally, the search turned up more than 1,800 stone tools, including well-crafted blades. These double-edged blades came in a variety of sizes. The smallest were just less than a half-inch wide. Ancient people may have attached these blades to the end of a stick to make spears or other tools. Until now, the earliest evidence of similar blades dates back just 70,000 years.

The new discoveries support the theory that modern human behavior developed gradually, starting about 285,000 years ago, say some experts.

An alternative theory proposes that people developed modern behavior much more recently—perhaps around 45,000 years ago. It's also possible that complex behavior developed at different rates in different places.—Emily Sohn


Credits: http://www.sciencenewsforkids.org/articles/20071024/Note2.asp

Chakradhar
www.chakradhar.net

Monkey Brains In U.S. Make Robot Walk In Japan

Researchers believe their latest work will be used to develop prototypes of robotic leg braces for human use.

By K.C. Jones InformationWeek January 16, 2008 11:37 AM


Researchers at Duke University Medical Center have used a monkey's brain activity to control a robot on the other side of the globe.

In what researchers tout as a first-of-its-kind experiment, monkeys' thoughts controlled the walking patterns of a robot in Japan.

"They can walk in complete synchronization," said Dr. Miguel Nicolelis, who also is the Anne W. Deane Professor of Neuroscience at Duke. "The most stunning finding is that when we stopped the treadmill and the monkey ceased to move its legs, it was able to sustain the locomotion of the robot for a few minutes -- just by thinking -- using only the visual feedback of the robot in Japan."

Implanted electrodes gathered feedback from brain cells of two rhesus monkeys as they walked forward and backward at different paces on a treadmill. Sensors on the monkeys' legs tracked walking patterns while researchers used math models to analyze the relationship between leg movement and activity in the brain's motor and sensory cortex. From there, researchers in North Carolina and Japan determined how well brain cell activity predicted speed and stride.
"We found that certain neurons in multiple areas of the brain fire at different phases and at varying frequency, depending on their role in controlling the complex, multi-muscle process of motion," senior research investigator Nicolelis said in a statement.

Researchers recorded brain activity, predicted the pattern of locomotion, and sent the signal from the motor commands of the animal to the robot, he said.

"We also created a real-time transmission of information that allowed the brain activity of the monkey in North Carolina to control the commands of a robot in Japan," Nicolelis said. "Each neuron provides us with a small piece of the puzzle that we compile to predict the walking pattern of the monkeys with high accuracy."

The research, funded by the Anne W. Deane Endowed Chair Fund, expanded on previous experiments in Nicolelis' laboratory that showed monkeys could control the reaching and grasping movements of a robotic arm with their brain signals. Researchers believe that, within a year, their latest work will be used to develop prototypes of robotic leg braces for human use. They hope that robotic braces can help severely paralyzed patients walk again.

"In essence, we are seeking to capture the information that the foot sends to your brain when it touches the ground as you walk," Nicolelis said.

Mitsuo Kawato, M.E., Ph.D., director of ATR Computational Neuroscience Laboratories and research director of the Computational Brain Project of the Japan Science and Technology Agency, said the findings will be used to advance research on how the brain processes information.


http://www.informationweek.com/internet/showArticle.jhtml?articleID=205801020


Chakradhar
www.chakradhar.net