(NaturalNews) More than 20 years after the end of the Gulf War, tens of thousands of US veterans are still complaining of a host of symptoms developed during or after their tour of duty.They suffer from memory and concentration problems, chronic headaches, widespread pain, depression, balance disturbances, gastrointestinal problems, chronic fatigue and more. The latest figures from the U.S. Department of Veterans Affairs scientific advisory committee on the Gulf War illness show about 25 percent of the 700,000 military personnel deployed to the 1991 Persian Gulf War are affected.The cause of what is often called Gulf War Syndrome (GWS) is still unknown but prime suspects are exposure to depleted uranium weapons, neurotoxic chemicals including pesticides, nerve gas, and multiple vaccines given to the soldiers by the military. Another explanation that has been widely circulated over the decades is that GWS is simply a bogus disease of malingerers and hypochondriacs --- a condition that is "all in their heads."This dismissal of the suffering of veterans who insist they are severely ill with GWS has come from a wide spectrum of so-called experts including doctors, journalists and some government officials. For example, formereditor Marcia Angell sarcastically called it a "will o the wisp" syndrome in a New York Times interview. And self-styled health claims debunker journalist and lawyer Michael Fumento have scoffed that anyone who hasn't had the kind of symptoms GWS sufferers claim to experience would have to be an android.Now there's new and compelling evidence that GWS really is a disease that is, in fact, "in the heads" of veterans suffering with the cluster of health problems that make up the controversial syndrome. Specifically, it is in their brains.A new study just published online in the journaldocuments blood flow abnormalities found in the brains of veterans with Gulf War illness that have persisted 20 years after the war. In some veterans, the blood flow abnormalities have gotten worse over time.principal investigator Robert W. Haley, M.D., chief of epidemiology in the Departments of Internal Medicine and Clinical Sciences at the University of Texas (UT) Southwestern Medical Center in Dallas, said in a statement to the media.The hippocampus is the part of the brain responsible for forming long-term memories and helping navigate space. The UT researchers noted that many of the GWS neurological symptoms, including memory loss, confusion, irritability and disorders in motion control, are clues that the hippocampus may be impaired.For the just published study, Dr. Haley's research team used a new technique called arterial spin labeled (ASL) MRI to assess hippocampal regional cerebral blood flow (rCBF) in 13 control participants and 35 patients with GWS. The scientists noted that there appears to be predominance of one of three types of symptoms in GWS patients : impaired cognition; confusion and ataxia (lack of voluntary muscle control); and central neuropathic (nerve) pain.Each patient in the study first received intravenous infusions of saline and then, after 48 hours, an infusion of a short-acting cholinesterase inhibitor called physostigmine. Physostigmine is used to test how well the cholinergic system (a neurotransmitter system involved in the regulation of memory and learning) is working in the brain.Richard W. Briggs, Ph.D., professor of radiology at UT Southwestern and co-author of the new research paper, pointed out in the media statement that scanning the brain after giving the cholinesterase inhibitor medication is particularly well suited to diagnosing Gulf War illness because it picks up brain abnormalities too subtle for regular MRIs to detect. "This allows us to make the diagnosis in a single two-hour session without the need for exposure to ionizing radiation," Dr. Briggs said.The findings replicated the results of a previous nuclear imaging test called a SPECT (single-photon emission computerized tomography) scan which was performed by Dr. Haley largely on the same group of veterans over a decade ago. The new study shows that the abnormal brain blood flow detected then had persisted.In fact, the new findings revealed something else very troublesome: