Liisa Heller (III)
How we can use SSS methods for different head position related tasks?
The relation between the head position and sensor array is detemrinad by the HPI coils. Therefore, if we only measure the HPI locations in the beginning, we need to assume that the head has been setationary during the whole recording.
We can perform two procedures:
Head position transformation (large transformations are not recomended becaue reconstruction noise can occur in the data and, for this reason, initial head position or averaged head position are recomended)
Head position correction can be used if continuous hpi (cHPI) is on during the measurement. After estimating the head position, HPI measurements can be removed from the data.
The demo video offers an example of data measured with continuos HPI on.
Lecture 13: Head Position Tasks
Lecture 14: Head Position Tasks Demo
In this last video you will find some guidelines for method selection in MaxFilter preprocessing:
How to select parameters (i.e. was internal active shielding on?).
SSS or tSSS?
Select between head position tasks
Different methods for different datasets.
Lecture 15: Guidelines and Summary