title: Electrophysiological correlates of semantic memory retrieval in Gulf War Syndrome 2 patients.
abstract: Gulf War veterans meeting criteria for Haley Syndrome 2 of Gulf War illness endorse a particular constellation of symptoms that include difficulty with processing information, word-finding, and confusion. To explore the neural basis of their word-finding difficulty, we assessed event-related potentials (ERPs) associated with semantic memory retrieval in 22 veterans classified as Syndrome 2 and 28 veterans who served as controls. We recorded EEGs while subjects judged whether pairs of words that represented object features combined to elicit a retrieval of an object memory or no retrieval. Syndrome 2 subjects' responses were significantly slower, and those participants were less accurate than controls on the retrieval trials, but they performed similarly on the nonretrieval trials. Analysis of the ERPs revealed a difference between retrievals and nonretrievals that has previously been detected around 750ms at the left temporal region was present in both the Syndrome 2 patients and controls. However, the Syndrome 2 patients also showed an ERP difference between retrievals and nonretrievals at the midline parietal region that had a scalp voltage polarity opposite from that recorded at the left temporal area. We hypothesize that the similarities between task performance and ERP patterns in Syndrome 2 veterans and in patients with amnestic mild cognitive impairment reflect disordered thalamic cholinergic neural activity, possibly in the dorsomedial nucleus.
authors.affiliation: School of Behavioral and Brain Sciences, Center for BrainHealth, The University of Texas at Dallas, Dallas, TX, United States. Electronic address: gtillman@utdallas.edu.
authors.forename: Gail D
authors.initials: GD
authors.lastname: Tillman
authors.affiliation: School of Behavioral and Brain Sciences, Center for BrainHealth, The University of Texas at Dallas, Dallas, TX, United States.
authors.forename: Clifford S
authors.initials: CS
authors.lastname: Calley
authors.affiliation: School of Behavioral and Brain Sciences, Center for BrainHealth, The University of Texas at Dallas, Dallas, TX, United States.
authors.forename: Virginia I
authors.initials: VI
authors.lastname: Buhl
authors.affiliation: School of Behavioral and Brain Sciences, Center for BrainHealth, The University of Texas at Dallas, Dallas, TX, United States.
authors.forename: Hsueh-Sheng
authors.initials: HS
authors.lastname: Chiang
authors.affiliation: Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, United States.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Haley
authors.affiliation: School of Behavioral and Brain Sciences, Center for BrainHealth, The University of Texas at Dallas, Dallas, TX, United States.
authors.forename: John
authors.initials: J
authors.lastname: Hart
authors.affiliation: Department of Radiology, Division of Neuroradiology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Kraut
mesh_terms: D000328:Adult; D000368:Aged; D001921:Brain / Q000503:physiopathology*; D004569:Electroencephalography; D005071:Evoked Potentials; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D018923:Persian Gulf Syndrome / Q000503:physiopathology*; D012660:Semantics; D014728:Veterans
keywords: Cholinergic; EEG; ERP; Gulf War illness; Semantic memory; Word-finding