Unicog Wiki | Main / MEGCombinedWithEEG

Part I : nurse part

- welcome the subject and explain the procedure of the recording : duration, the installation of the EEG cap, the MEG recording, the general protocol of you experiment etc …

- make sure that the nurse has all the proper material

- the subject goes with the nurse who will install the ECG and the EOG after putting some pyjamas

Part II: installation of the EEG cap

- Tell your subject what you’re going to do (installation of the cap) and ask authorization to manipulate his head

- measure the dimension of the skull of the subject and choose which cap to use ( 46-52 cm, 52-58 cm or 58-62 cm)

- clean the scalp of the subject with alcohol if the subject has something in his hair

- put the cap to the subject

- check the position of the cap by measuring the position of the Cz electrode : it must be at the middle between LPA and RPA and Nasion and Anion

Part III: installation of the HPI coils :

- scotchtape the cables of you HPI coils on the right shoulder of your subject. Be careful to let enough length for the subject to move his head

- scotchtape each coil at its correct position : two in front of the (plastic cable) head and two in a more posterior position (we should mark the position on the cap)

Part IV: Digitization with isotrak system

- put on the glasses to your subject and tighten the string

- on the acquisition computer, check :

	*that your project and your settings are selected
	*that your subject is selected
	*the position of the MEG gantry
	*the averaging online category (do it before)
	*the channel you want to record (MEG on and EEG on), the filter (highpass and lowpass). Check that your ECG and EOG are correctly named
        *the EEG gain: go to Tools/Squidler EEG and check that the gain of 5000 is well selected

- do the digitization in this order

	*LPA, Nasion, RPA
	*4 HPI coils
	*EEG electrodes in the right order (ask your subject to hold you the map of the electrode and check every electrode. At one point we should write down the number of each electrode on the cap)

Part V: Gelling of each EEG electrode

- inject gel in each electrode after gently removing the hair and rubbing the skin with the syringe,. Be careful not to make bridges between electrodes by injecting too much gel.

- soak the syringe in a bassin