With the help of a computer, monkeys using only their brain signals are now able to move a robotic arm to feed themselves pieces of fruit and vegetables, researchers report.The achievement could mark a major advance in the development of brain-controlled artificial limbs for people, the scientists said."The beneficiaries of such technology will be patients with spinal cord injuries or nervous system disorders such as amyotrophic lateral sclerosis [ALS],” project senior researcher Andrew Schwartz, professor of neurobiology at the University of Pittsburgh School of Medicine, said in a prepared statement.His team presented their findings Thursday at the annual meeting of the American Association for the Advancement of Science, in Washington, D.C.