Published eLetters
Guidelines
As a forum for professional feedback, submissions of letters are open to all. You do not need to be a subscriber. To avoid redundancy, we urge you to read other people's letters before submitting your own. Name, current appointment, place of work, and email address are required to send a letter, and will be published with your review. We also require that you declare any competing financial interests. Unprofessional submissions will not be considered or responded to.
- Page navigation anchor for Transcortical polarity inversion and choice of bipolar or referential EEG montagesTranscortical polarity inversion and choice of bipolar or referential EEG montages
This fascinating paper suggests the existence of small, focal K-complexes in human sleep, adding to growing evidence that sleep may be a focal phenomenon (Krueger et al., 2008). I would just like to briefly respond to the authors’ criticisms of my previous paper examining the large intracranial fields associated with classical scalp EEG K-complexes (Wennberg, 2010).
Mak-McCully et al. (2015) argue that my presentation of intracranial EEG in a common average reference montage was ambiguous, and that the resultant waveforms could be interpreted to suggest K-complex generation in subcortical white matter. However, such an interpretation would be incompatible with analysis of the combined intracranial/extracranial field in its entirety (and entirely at odds with my own interpretation in the paper). The reasons behind the choice of using the average reference – for the specific purposes of that study – were explained in the paper’s Methods, and comparative examples of other referential derivations (linked ears, O2, Sp2, FCz) were provided in a Supplementary figure (Wennberg, 2010).
The bipolar transcortical derivations in Mak-McCully et al. (2015) are perfectly valid, and their Figure 3 showing a dorsal frontal K-complex depicts an intracranial electrical field identical to those presented in Wennberg (2010) and more recently in Voysey et al. (2015). Nevertheless, the bipolar derivations do not provide information not already present in the referential recording...
Show MoreCompeting Interests: None declared.