MCE User’s Guide | MCE windows and dialogs |
Figure 12 Minimum norm estimate options dialog
The [Regularization] slider and text field select and show the number of singu- lar values of the data used in the estimate. If the noise level in the measurement is low, increase the value to correctly estimate more complex source distribu- tions. If the noise level is high, decrease its effect by decreasing the value. The default value (30) is usually reasonable for averaged evoked responses.
Keeping the [Depth normalization] button pressed compensates for the ten- dency of the estimate to produce too superficial sources.
The Elekta Neuromag™ and Vectorview™ have both magnetometer and gradi- ometer sensors. In the estimation, the signals are analyzed in relation to the noise level. The default values (5 fT/cm for gradiometers, 25 fT for magnetom- eters) are reasonable in evoked response measurements, but if for some reason their relative noise level changes, you can modify the values in this dialog. Press the [Set noise levels manually] button and change the values in the text fields.
If the options are changed, the windows displaying the previous estimate are closed.
Warning: If the regularization parameters are changed from the default ones,
!the new values must be validated using known data.
12.3Pre-processing dialog
The
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