The study, published in Psychiatry Research: Neuroimaging, says the findings may lead to diagnostic tests and treatments.
"Before this study, we didn't know exactly what parts of the brain were damaged and causing the symptoms in these veterans," lead author Dr. Robert Haley of the University of Texas Southwestern Medical Center in Dallas says in a statement. "We designed an experiment to test areas of the brain that would have been damaged if the illness was caused by sarin or pesticides, and the results were positive."
Areas that would have been damaged -- cholinergic receptors -- were stimulated in 21 chronically ill Gulf War veterans and 17 well veterans. The ill veterans showed abnormal responses when brain cell responses were measured using brain scans.
"What we found was that some of the brain areas we previously suspected responded abnormally to the cholinergic challenge," Haley says. "Changes in functioning of these brain structures can certainly cause problems with concentration and memory, body pain, fatigue, abnormal emotional responses and personality changes that we commonly see in ill Gulf War veterans."