DAVIS, Calif. -- The California National Primate Research Center at the University of California, Davis is again the target of protests. This time, an animal rights group is claiming that monkeys are being abused in the name of research -- a charge the university is denying.

A small group of demonstrators gathered outside the facility Tuesday.

"The University of California, Davis is trying to put a good face on experimentation that is simply heinous," said protester Michael Budkie.

Budkie is head of an Ohio group called Stop Animal Exploitation Now, which is filing a complaint with the U.S. Department of Agriculture.

"When you look at Rhesus monkeys that are confined to primate restraint chairs, they have devices literally bolted on their skulls. Electrodes are forced into their brains, and these animals are not anesthetized when these procedures are going on," Budkie said.

John Capitanio, the assistant director of research at the Primate Center, said Budkie's statements are not exactly true.

"All of the animals that experience pain or distress out here get measures to mitigate the pain or distress. And there are no animals that did not get such measures for the three years covered by these reports," Capitanio said.

Researchers claim experimentation with monkeys has benefited humans.

"This involves research programs in AIDS, asthma, autism, stress, and vaccine development for diseases, including measles and AIDS," Capitanio said.

"It does not provide useful information for the benefit of human beings. The only thing it does is bring more tax dollars into this facility," Budkie said.

Capitanio said the Primate Center will respond to the complaint. He adds that federal and local authorities routinely inspect the facility.