[Eeglablist] High frequency narrow-band peaks in spontaneous EEG

[Dickinson, Abigail]

Hi everyone,

I wondered if anyone who studies spontaneous EEG/high frequency oscillations has ever come across individuals who show high frequency narrow-band peaks?

In a substantial number of data sets we are seeing a distinct peak which varies substantially in frequency between participants (17-33Hz). The peak in power is present to some degree in all channels throughout the original recording. In addition, removing EMG and EOG using ICA does not impact the presence of the peak, which is also present in all reconstructed channel data.

We have tested for coherence (short circuit) between channels and the phase coherence is random, suggesting that this is not a volume conductance issue. Alternative filtering and referencing techniques have also been tested, none of which have any impact on the presence of the peak.

Details of the recording & processing are included below, and figures demonstrating examples of the peaks in two different participants can be seen here: https://db.tt/22JIkdun

I'd be really grateful to know if this is something others have seen in spontaneous EEG, or if anyone had any ideas as to what might be causing these peaks?

Best wishes,

Abby


Original data: 128 Channel EEG; Fs= 500Hz; Eyes-open resting state
Filter : 1 to 120 Hz FIR
Average Reference
Cleaned by visual inspection, later ICA
Power Spectrum calculation: Average of every 1000ms using Welch method




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