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Electroencephalographic surface activity (EEG) in healthy individuals is a well-established study area. However, the accumulated knowledge about normal intracranial EEG activity (iEEG) is very low. This is because patients with refractory focal epilepsies are the only human subjects where the iEEG is allowed and therefore, most of the studies are geared towards epileptic activity. This leaves a small window to study the normal iEEG activity, placing some electrodes in non-epileptic areas and recording activity not associated with epileptic events.

At the beginning of 2018, the first iEEG normal activity atlas [https://mni-open-ieegatlas.research.mcgill.ca/] was published, offering open access to a multicenter data collection composed of 1772 channels with normal brain activity of 106 patients with refractory epilepsy. The atlas provides dense coverage of all cortical regions in a common stereotactic space, which allows direct comparisons of EEG between subjects.

On the other hand, it has been suggested that the brain at rest operates in a regime of critical dynamic instability that manifests itself in the presence of spatial and temporal correlations free of scale, see for example [Plenz D.  y Niebur E. (Eds.). Criticality in neural systems, Wiley-VCH (2014) in Emergent complex neural dynamics]. Although there are studies that analyze the aspects of criticality in iEEG signals, in most cases these are reduced populations.

In this work we analyze the scaling properties of different quantities associated with the iEEG signal in normal and waking states, such as the amplitude and phase of the signal and the spectral power, as well as avalanche distributions using the data from the mentioned atlas.