Combined MEG and EEG

The MEG laboratory is equipped with several MEG-compatible EEG caps (Easycap). The caps have special holders for some of the HPI coils and they don't have any magnetic materials. Some things about the EEG in MEG:

• Before applying the cap, remember to screen the participant first in the MEG for metallic "contaminants"
• The impedance for the electrodes can be checked with our wireless impedance checker. Check "Hardware/Small devices"
• The MEG's data acquisition system also can measure impedance for the EEG electrodes. However, due to electrical reasons, the values might differ some from the wireless system. Do not be too much alarmed of this.
• While doing the digitization of the HPI coils and such, it is often enough to digitize the EEG electrode positions for the "extra" points. Naturally, this is true, if you are using several of the EEG electrodes. Some instructions on how to proceed with the EEG electrode digitizing can be found in "Preparing the subject".
• Remember to clean the cap thoroughly after use. The 2nd floor has a maintenance room where this is easiest to do and there you can leave to cap to dry. Remember to take the cap back to the laboratory after it has dried.
• Some of the EEG caps used in the 2nd floor EEG laboratories are of the same brand. However, the connectors are distinctly different so there is little risk in mixing the caps.