Auditory stimulation enhances thalamic somatosensory high-frequency oscillations in healthy humans: A neurophysiological marker of cross-sensory sensitization?

Domenico Restuccia, Gianluca Coppola

Research output: Contribution to journalArticle

Abstract

Electrical stimulation of upper limb nerves evokes a train of high-frequency wavelets (high-frequency oscillations, HFOs) on the human scalp. These HFOs are related to the influence of arousal-promoting structures on somatosensory input processing, and are generated in the primary somatosensory cortex (post-synaptic HFOs) and the terminal tracts of thalamocortical radiations (pre-synaptic HFOs). We previously reported that HFOs do not undergo habituation to repeated stimulations; here, we verified whether HFOs could be modulated by external sensitizing stimuli. We recorded somatosensory evoked potentials (SSEPs) in 15 healthy volunteers before and after sensitization training with an auditory stimulus. Pre-synaptic HFO amplitudes, reflecting somatosensory thalamic/thalamocortical activity, significantly increased after the sensitizing acoustic stimulation, whereas both the low-frequency N20 SSEP component and post-synaptic HFOs were unaffected. Cross-talk between subcortical arousal-related structures is a probable mechanism for the pre-synaptic HFO effect observed in this study. We propose that part of the ascending somatosensory input encoded in HFOs is specifically able to convey sensitized inputs. This preferential involvement in sensitization mechanisms suggests that HFOs play a critical role in the detection of potentially relevant stimuli, and act at very early stages of somatosensory input processing.

Original languageEnglish
Pages (from-to)1079-1085
Number of pages7
JournalEuropean Journal of Neuroscience
Volume41
Issue number8
DOIs
Publication statusPublished - Apr 1 2015

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Keywords

  • Cross-sensory
  • Evoked potentials
  • High-frequency oscillations
  • Multisensory
  • Sensitization
  • Thalamus

ASJC Scopus subject areas

  • Neuroscience(all)
  • Medicine(all)

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