MEG
During The Acquisition
Signal quality check
- Once you have placed the subject in the MSR (see Subject Placement In MEG), close the MSR door and ask your subject to relax.
- Check the quality of the signals again (you should have done this before the subject arrives) by browsing through all channels and following the indications in the Signal Quality Troubleshooting page.
HPI recording
- Once you start the acquisition and at the beginning of each run, you will be prompted to record HPI. Ask your subject to remain still before you measure HPI. See Section 5.2 of the Acquisition Software Manual for details. See Head Positioning Troubleshooting for help.
- Once HPI measurement is ok, you can start recording by using the Record raw button in the acquisition controls (Acquisition Software Manual, section 5).
- CHPI : If continuous HPI signals set on after the start of raw data recording, program MaxFilter crashes if automatic bad channel detection is attempted. Continuous HPI needs to be activated before starting raw data recording.
During the measurement
- Continuously inspect the quality of your data!
- If individual bad channel appears during the recording, mark it as bad channel (On-line -> mark bad channels).
- If you suddenly see many bad channels (strangely behaving), turn SSP vectors off to see if the problem is only in few channels, and mark them as bad channels
- If the interference seems to be external (e.g. seen in most of the channels), it will be removed in MaxFilter processing -> do not panic if the channels are not saturated.
- If you need to reset all channels, see here.
- If the acquisition software crashes just after your acquisition and the "save" window does not appear, see here
- If you feel uncertain about something, ask assistance to the MEG staff.
Problem with isotrak
- If you have a computer crash during the digitization with isotrak system (a lot of windows of error message appear), click on "exit" button (on the bottom of the screen) to log out you. Click Ok and then enter username; "meg" and the password. Start again the acquisition software, load your project, your setting and your subject and start again the isotrak digitization.
Problem with Audiophone
- If you have a problem to communicate with the subject inside the Magnetic Shielded Room (MSR), push the button X to turn off the device and push on the button "MSR". If the audiophone rings continuously, disconnect it (the plug is on the back) and reconnect it.