Electrophysiological correlates of semantic memory retrieval in Gulf War Syndrome 2 patients

Gail D. Tillman, Clifford S. Calley, Virginia I. Buhl, Hsueh Sheng Chiang, Robert W. Haley, John Hart, Michael A. Kraut

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


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 750 ms 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.

Original languageEnglish (US)
Pages (from-to)66-72
Number of pages7
JournalJournal of the Neurological Sciences
StatePublished - Feb 15 2017


  • Cholinergic
  • EEG
  • ERP
  • Gulf War illness
  • Semantic memory
  • Word-finding

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology


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