mne.preprocessing.cortical_signal_suppression(evoked, picks=None, mag_picks=None, grad_picks=None, n_proj=6, *, verbose=None)[source]

Apply cortical signal suppression (CSS) to evoked data.

evokedinstance of Evoked

The evoked object to use for CSS. Must contain magnetometer, gradiometer, and EEG channels.

picksstr | list | slice | None

Channels to include. Slices and lists of integers will be interpreted as channel indices. In lists, channel type strings (e.g., ['meg', 'eeg']) will pick channels of those types, channel name strings (e.g., ['MEG0111', 'MEG2623'] will pick the given channels. Can also be the string values “all” to pick all channels, or “data” to pick data channels. None (default) will pick good data channels. Note that channels in info['bads'] will be included if their names or indices are explicitly provided.

mag_picksarray_like of int

Array of the magnetometer channel indices that will be used to find the reference data. If None (default), all magnetometers will be used.

grad_picksarray_like of int

Array of the gradiometer channel indices that will be used to find the reference data. If None (default), all gradiometers will be used.


The number of projection vectors.

verbosebool | str | int | None

Control verbosity of the logging output. If None, use the default verbosity level. See the logging documentation and mne.verbose() for details. Should only be passed as a keyword argument.

evoked_subcorticalinstance of Evoked

The evoked object with cortical contributions to the EEG data suppressed.


This method removes the common signal subspace between the magnetometer data and the gradiometer data from the EEG data. This is done by a temporal projection using n_proj number of projection vectors. For reference, see 1.



John Samuelsson, Sheraz Khan, Padma Sundaram, Noam Peled, and Matti Hämäläinen. Cortical signal suppression (css) for detection of subcortical activity using meg and eeg. Brain Topography, 32:215–228, 2019. doi:10.1007/s10548-018-00694-5.

Examples using mne.preprocessing.cortical_signal_suppression