AcquisitionTips - Meg Wiki

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Acquisition tips

Averaging data

The acquisition software can average your data in real time and show the results as the experiment is running. The online averaged data will also be saved in a separate file. This option isn't as useful as you would think, as active shielding interferes with the results and makes them almost unusable. Therefore it is much better to average you data offline, using the saved raw data. However, to do so requires you to have specified all necessary details at the time of the recording. Changing or adding averaging details is difficult. For that reason it is highly recommended to fully specify all averaging information before running any experiment, and checking that everything is working correctly by using the online averager, even if its output is irrelevant.

Using continuous HPI

If using continuous head position indication (cHPI), acquire and save ~20s of data before turning on cHPI (ie before first stimulus). Otherwise MaxFilter has problems detecting bad channels (info from Matti Kajola).