Dr Gunnar Waterstraat | Evoked somatosensory high-frequency oscillations as model potentials to study human cortical population spikes non-invasively

While EEG and MEG (MEEG) are mainly generated by postsynaptic potentials in common frequency bands (<100 Hz), at higher frequency bands (>400-500 Hz) spiking activity contributes significantly. Accordingly, evoked somatosensory high-frequency oscillations (≈600 Hz), accessible by non-invasive scalp recordings, where shown to represent cortical population spike bursts. Traditionally, recordings of evoked somatosensory high-frequency oscillations required massive averaging (typically of several thousand stimuli). However, averaging masks the single-trial variability of the responses. The availability of low-noise MEEG equipment permits single-trial analysis of these non-invasive correlates of cortical population spike burst responses. Our recent work demonstrated that, despite the low signal-to-noise ratio of the responses, spatial filtering techniques and state-of-the-art classifiers permit single-trial detection of evoked somatosensory high-frequency oscillations. Additionally, the responses to consecutive stimuli were shown to be (auto)correlated. Analysis of evoked somatosensory high-frequency EEG oscillations allows to study the physiology of cortical population spike bursts non-invasively. Recent analysis demonstrated non-random behaviour in the variability of the responses.

Poster