Gulf War Illness Research Findings

This in from a Research medical meeting, CNS2010 in Canada:Pre-frontal Cortex Dysfunction in Gulf War IllnessG. Andrew J. Hillis1, Traci I. Sandoval1, Michael A. Motes1,2, Ilana J. Bennett1,2, Mary Jo Maciejewski1,2, Joanna Hutchison1,2, Bart Rypma1,2;1Center for BrainHealth & School of Behavioral & Brain Sciences University of Texas at Dallas, 2Department of Psychiatry University of Texas Southwestern Medical CenterGulf War Illness (GWI) is an amalgamation of symptoms that might result from neurotoxic exposure.One GWI syndrome group is primarily characterized by cognitive deficits (Impaired Cognition) possibly resulting from neural dysfunction. To test this hypothesis, we assessed neural activity during working memory (WM) performance in this Impaired Cognition group and an age-matched control group. Individuals performed a modified Sternberg WM task in which they were instructed to encode a memory set of 2, 4, or 6 letters, maintain this material over an unfilled delay period, and then judge whether or not a single probe letter was present in a retrieval period. Behavioral results revealed that both groups were faster and more accurate for lower vs. higher set sizes, but there were no significant group differences in these WM load-related effects. Imaging results revealed load-related (set size 2 vs. 6) activity in pre-frontal (PFC) and parietal cortex. The magnitude of these WM load effects differed between patients and controls, with the direction of these effects varying across task periods. Relative to controls the GWI patient group showed decreased PFC and parietal activity at encoding, similar PFC activity but increased parietal activity during maintenance, and increased PFC and parietal activity during retrieval. In sum, this Impaired Cognition GWI group had distinct patterns of WM-related neural changes compared to controls, but these were not associated with significant WM deficits. Such syndrome-specific neural effects may reflect strategy changes that allow participants to optimize WM performance despite reduced brain function from neurotoxic exposure.