[Eeglablist] Baseline correction in ERSP
Mohammad Hasan Ghafari Saravi
Ghafari_m at iricss.org
Thu May 27 08:13:47 PDT 2021
Dear EEGLAB experts,
I have a question regarding baseline correction methods and their impact on the interpretation of results.
Some brief background; we are measuring event-related spectral perturbation (ERSP) to measure the magnitude of responses to external periodic stimuli (in 80 trials) for each participant. In the 'newtimef' function in EEGLAB, there are several methods for baseline correction (e.g., classical baseline correction and single-trial baseline correction).
However, after applying STFT to each trial, we need to perform single-trial (pre-stimulus) baseline correction due to additional analyses across single trials (instead of averaging the trials). As Grandchamp and Delorme (2011) mentioned in their study, single-trial (pre-stimulus) baseline correction is associated with a bias in the post-stimulus period.
Is this baseline correction method the optimal way to measure the magnitude of responses? Does this bias affect further statistical analyses significantly in terms of Interpretability? Are there other alternatives I could try in EEGLAB?
Your help and advice on this matter would be highly appreciated.
Thanks and best regards,
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