Neural synchronization deficits linked to cortical hyper-excitability and auditory hypersensitivity in fragile X syndrome

Lauren E. Ethridge, Stormi P. White, Matthew W. Mosconi, Jun Wang, Ernest V. Pedapati, Craig A. Erickson, Matthew J. Byerly, John A. Sweeney

Research output: Contribution to journalArticlepeer-review

34 Scopus citations

Abstract

Background: Studies in the fmr1 KO mouse demonstrate hyper-excitability and increased high-frequency neuronal activity in sensory cortex. These abnormalities may contribute to prominent and distressing sensory hypersensitivities in patients with fragile X syndrome (FXS). The current study investigated functional properties of auditory cortex using a sensory entrainment task in FXS. Methods: EEG recordings were obtained from 17 adolescents and adults with FXS and 17 age- and sex-matched healthy controls. Participants heard an auditory chirp stimulus generated using a 1000-Hz tone that was amplitude modulated by a sinusoid linearly increasing in frequency from 0-100 Hz over 2 s. Results: Single trial time-frequency analyses revealed decreased gamma band phase-locking to the chirp stimulus in FXS, which was strongly coupled with broadband increases in gamma power. Abnormalities in gamma phase-locking and power were also associated with theta-gamma amplitude-amplitude coupling during the pre-stimulus period and with parent reports of heightened sensory sensitivities and social communication deficits. Conclusions: This represents the first demonstration of neural entrainment alterations in FXS patients and suggests that fast-spiking interneurons regulating synchronous high-frequency neural activity have reduced functionality. This reduced ability to synchronize high-frequency neural activity was related to the total power of background gamma band activity. These observations extend findings from fmr1 KO models of FXS, characterize a core pathophysiological aspect of FXS, and may provide a translational biomarker strategy for evaluating promising therapeutics.

Original languageEnglish (US)
Article number22
JournalMolecular autism
Volume8
Issue number1
DOIs
StatePublished - Jun 7 2017

Keywords

  • Chirp
  • EEG
  • Fragile X syndrome
  • Gamma
  • Sensory

ASJC Scopus subject areas

  • Molecular Biology
  • Developmental Neuroscience
  • Developmental Biology
  • Psychiatry and Mental health

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