Neural Substrates of Executive Dysfunction in Fragile X-Associated Tremor/Ataxia Syndrome (FXTAS): A Brain Potential Study

Jin Chen Yang, Shiao Hui Chan, Sara Khan, Andrea Schneider, Rawi Nanakul, Sara Teichholtz, Yu Qiong Niu, Andreea Seritan, Flora Tassone, Jim Grigsby, Paul J Hagerman, Randi J Hagerman, John M Olichney

Research output: Contribution to journalArticle

16 Scopus citations

Abstract

Executive dysfunction in fragile X-associated tremor/ataxia syndrome (FXTAS) has been suggested to mediate other cognitive impairments. In the present study, event-related potentials and neuropsychological testing were combined to investigate the brain mechanisms underlying the executive dysfunction in FXTAS. Thirty-two-channel electroencephalography was recorded during an auditory oddball task requiring dual responses. FXTAS patients (N= 41, mean age= 62) displayed prolonged latencies of N1 and P3 and reduced amplitudes of P2 and P3, whereas their N2 measures remained within the normal range, indicating relatively preserved early-stage auditory attention but markedly impaired late-stage attention and working memory updating processes (as indexed by P3). Topographical mapping revealed a typical parietal P3 peak preceded by a prominent fronto-central P3 in normal control subjects (N= 32), whereas FXTAS patients had decreased parietal P3 amplitude and diminished fronto-central positivities with a delayed onset (∼50 ms later than controls, P < 0.002). The P3 abnormalities were associated with lower executive function test (e.g., BDS-2) scores. Smaller P3 amplitudes also correlated with increased CGG repeat length of fragile X mental retardation 1 (FMR1) gene and higher FMR1 mRNA levels. These results indicate that abnormal fronto-parietal attentional network dynamics underlie executive dysfunction, the cardinal feature of cognitive impairment in FXTAS.

Original languageEnglish (US)
Pages (from-to)2657-2666
Number of pages10
JournalCerebral Cortex
Volume23
Issue number11
DOIs
StatePublished - Nov 2013

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Keywords

  • attention
  • executive function
  • FMR1
  • P300
  • working memory

ASJC Scopus subject areas

  • Cognitive Neuroscience
  • Cellular and Molecular Neuroscience

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