New research provides the first visual clues that AIDS selectively destroys regions of the brain controlling movement and language and that certain drugs that shelter the immune system from the disease don't appear to protect the brain.

University of Pittsburgh scientists, working with neurologists at the University of California at Los Angeles, used a new 3-D imaging technique to pinpoint for the first time where AIDS strikes in the brain. Their findings were published online this week in the Proceedings of the National Academy of Science.

Preliminary data indicate that powerful antiretroviral drugs -- which can prevent HIV from destroying the immune system -- don't protect the brain from HIV.

"This was the most terrifying aspect of our findings," said Paul Thompson, the paper's first author and associate professor of neurology at the David Geffen School of Medicine at the UCLA. "Even though antiretroviral drugs rescue the immune system, AIDS is still stalking the brain."

A blood barrier prevents antiretroviral drugs from entering the brain, transforming it into a protected reservoir where HIV can multiply and attack nerve cells unchecked, Thompson said.

Physicians have long recognized the havoc AIDS can wreak on the brain, but understanding this damage has been slowed by the lack of detailed maps that show the impact of the disease on living tissue.

Pitt psychiatrist Dr. James Becker and his colleagues used magnetic resonance imaging to produce cross-sectional maps of the brains of 26 AIDS patients and 14 healthy people.

UCLA scientists then generated high-resolution, 3-D color scans that measured the thickness of tissue in the brain's outer layer.

"These tools have allowed us to look at the brain in ways we couldn't have otherwise," said Becker.

The researchers were surprised to discover that AIDS doesn't ravage brain tissue at random, but is highly selective.

Parts of the brain that regulate motor skills and sensory function were found to be 15 percent thinner in AIDS patients than in their healthy counterparts. The scientists also linked tissue loss in the brain's language and reasoning centers to depletion of immune system cells due to HIV infection.

This may explain why the disease causes neurological problems such as difficulty planning, memory loss, slowed reflexes, impaired coordination and, in the worst cases, dementia, said Becker.

The imaging techniques also could be useful in tracking the progression of AIDS and evaluating the effects of new drugs before the onset of symptoms, said Michael Boska of the Center for Neurovirology and Neurodegenerative Disorders at the University of Nebraska Medical Center.

"If these types of analyses become clinically available, you'd be able detect the earliest stages of neuronal loss in patients with HIV and monitor the efficacy of treatments once they become available," said Boska, the center's radiology research director, who was not involved in the study.