Induced and Evoked Properties of Vibrotactile Adaptation in the Primary Somatosensory Cortex

Nicolaas A.J. Puts, Richard A.E. Edden, Suresh Muthukumaraswamy, Krish D. Singh, David J. McGonigle

Research output: Contribution to journalArticlepeer-review

Abstract

Prolonged exposure to afferent stimulation ("adaptation") can cause profound short-term changes in the responsiveness of cortical sensory neurons. While several models have been proposed that link adaptation to single-neuron dynamics, including GABAergic inhibition, the process is currently imperfectly understood at the whole-brain level in humans. Here, we used magnetoencephalography (MEG) to examine the neurophysiological correlates of adaptation within SI in humans. In one condition, a 25 Hz adapting stimulus (5 s) was followed by a 1 s 25 Hz probe ("same"), and in a second condition, the adapting stimulus was followed by a 1 s 180 Hz probe ("different"). We hypothesized that changes in the mu-beta activity band (reflecting GABAergic processing) would be modulated differently between the "same" and "different" probe stimuli. We show that the primary somatosensory (SI) mu-beta response to the "same" probe is significantly reduced (p=0.014) compared to the adapting stimulus, whereas the mu-beta response to the "different" probe is not (p=n.s.). This reduction may reflect sharpening of the spatiotemporal pattern of activity after adaptation. The stimulus onset mu-beta response did not differ between a 25 Hz adapting stimulus and a 180 Hz probe, suggesting that the mu-beta response is independent of stimulus frequency. Furthermore, we show a sustained evoked and induced desynchronization for the duration of the adapting stimulus, consistent with invasive studies. Our findings are important in understanding the neurophysiology underlying short-term and stimulus-induced plasticity in the human brain and shows that the brain response to tactile stimulation is altered after only brief stimulation.

Original languageEnglish (US)
Article number5464096
JournalNeural Plasticity
Volume2019
DOIs
StatePublished - 2019

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology

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