DIPFIT and model co-registration
Task 1Task 1Co-register electrodes with model
Task 2Autofit equivalent dipoles
Task 3Fine fit options
Task 43D headplot() co registration3D headplot() co-registration
Exercise...
EEGLAB Workshop VII, Apr. 20-22, 2009, Bloomington, IN: Julie Onton – Dipole modeling and DIPFIT 1
DIPFIT and model co-registration
Task 1Task 1Co-register electrodes with model
Task 2Autofit equivalent dipoles
Task 3Fine fit options
Task 43D headplot() co registration3D headplot() co-registration
Exercise...
EEGLAB Workshop VII, Apr. 20-22, 2009, Bloomington, IN: Julie Onton – Dipole modeling and DIPFIT 2
Finding dipole locations
EEGLAB Workshop VII, Apr. 20-22, 2009, Bloomington, IN: Julie Onton – Dipole modeling and DIPFIT 3
Co-register to model
If you used a standard electrode location file, co-registration is automatic.
If you proceed to overwrite co-registration for standard locations:
• Your choice of 4-shell vs BEM must correspond
EEGLAB Workshop VII, Apr. 20-22, 2009, Bloomington, IN: Julie Onton – Dipole modeling and DIPFIT 4
to your choice in Edit-> Channel locations
Co-register to model, cont'd
EEGLAB Workshop VII, Apr. 20-22, 2009, Bloomington, IN: Julie Onton – Dipole modeling and DIPFIT 5
Perform translation of electrode positions
-pi/2
EEGLAB Workshop VII, Apr. 20-22, 2009, Bloomington, IN: Julie Onton – Dipole modeling and DIPFIT 6
Perform translation of electrode positions
Requires a shift toward back of the headRequires a shift toward back of the head
AND
an expansion along the X-axis
shift backward
EEGLAB Workshop VII, Apr. 20-22, 2009, Bloomington, IN: Julie Onton – Dipole modeling and DIPFIT 7
Perform translation of electrode positions
shift leftresizeresize
EEGLAB Workshop VII, Apr. 20-22, 2009, Bloomington, IN: Julie Onton – Dipole modeling and DIPFIT 8
Confirm electrode transformation
EEGLAB Workshop VII, Apr. 20-22, 2009, Bloomington, IN: Julie Onton – Dipole modeling and DIPFIT 9
Alternatively, warp to standard montage
Ch k t th tCheck to see that
electrodes are
correctly matched
stats toolbox required
EEGLAB Workshop VII, Apr. 20-22, 2009, Bloomington, IN: Julie Onton – Dipole modeling and DIPFIT 10
for warping
Check coregistration with model
EEGLAB Workshop VII, Apr. 20-22, 2009, Bloomington, IN: Julie Onton – Dipole modeling and DIPFIT 11
DIPFIT and model co-registration
Task 1Task 1Co-register electrodes with model
Task 2Autofit equivalent dipoles
Task 3Fine fit options
Task 43D headplot() co registration3D headplot() co-registration
Exercise...
EEGLAB Workshop VII, Apr. 20-22, 2009, Bloomington, IN: Julie Onton – Dipole modeling and DIPFIT 12
Autofit equivalent dipoles
EEGLAB Workshop VII, Apr. 20-22, 2009, Bloomington, IN: Julie Onton – Dipole modeling and DIPFIT 13
Plot dipoles
EEGLAB Workshop VII, Apr. 20-22, 2009, Bloomington, IN: Julie Onton – Dipole modeling and DIPFIT 14
Scroll through dipoles
EEGLAB Workshop VII, Apr. 20-22, 2009, Bloomington, IN: Julie Onton – Dipole modeling and DIPFIT 15
DIPFIT and model co-registration
Task 1Task 1Co-register electrodes with model
Task 2Autofit equivalent dipoles
Task 3Fine fit options
Task 43D headplot() co registration3D headplot() co-registration
Exercise...
EEGLAB Workshop VII, Apr. 20-22, 2009, Bloomington, IN: Julie Onton – Dipole modeling and DIPFIT 16
Fine fit options in DIPFIT
EEGLAB Workshop VII, Apr. 20-22, 2009, Bloomington, IN: Julie Onton – Dipole modeling and DIPFIT 17
Fine fit menu
EEGLAB Workshop VII, Apr. 20-22, 2009, Bloomington, IN: Julie Onton – Dipole modeling and DIPFIT 18
Bilateral dipoles
Bilateral Ambiguous
EEGLAB Workshop VII, Apr. 20-22, 2009, Bloomington, IN: Julie Onton – Dipole modeling and DIPFIT 19
EEG.dipfit structure
>> EEG.dipfit
ans =
hdmfile: [1x76 char]
mrifile: [1x71 char]
chanfile: [1x83 char]
chansel: [1x33 double]
coordformat: 'spherical'
d l [1 33 t t]model: [1x33 struct]
current: 32
vol: [1x1 struct]
d t f [0 0 1 570796 100 76 90 87264 1 1 1]coord_transform: [0 0 -1.570796 100 76 90.87264 1 1 1]
From head model transformations
EEGLAB Workshop VII, Apr. 20-22, 2009, Bloomington, IN: Julie Onton – Dipole modeling and DIPFIT 20
EEG.dipfit structure
>> EEG.dipfit.modelans =
1x33 struct array with fields:posxyzmomxyzrvrvactiveselect
>> EEG di fit d l(1)>> EEG.dipfit.model(1)ans =
posxyz: [1x3 double]
X Y Z
[14.9791 -86.0094 47.9448]
momxyz: [1x3 double]rv: 0.0288
active: 1select: 1
EEGLAB Workshop VII, Apr. 20-22, 2009, Bloomington, IN: Julie Onton – Dipole modeling and DIPFIT 21
DIPFIT and model co-registration
Task 1Task 1Co-register electrodes with model
Task 2Autofit equivalent dipoles
Task 3Fine fit options
Task 43D headplot() co registration3D headplot() co-registration
Exercise...
EEGLAB Workshop VII, Apr. 20-22, 2009, Bloomington, IN: Julie Onton – Dipole modeling and DIPFIT 22
Plot scalp maps in 3D
EEGLAB Workshop VII, Apr. 20-22, 2009, Bloomington, IN: Julie Onton – Dipole modeling and DIPFIT 23
Headplot co-registration
Go through co-registration
in the same a asin the same way as
with dipfit co-registration
EEGLAB Workshop VII, Apr. 20-22, 2009, Bloomington, IN: Julie Onton – Dipole modeling and DIPFIT 24
Confirm headplot co-registration
EEGLAB Workshop VII, Apr. 20-22, 2009, Bloomington, IN: Julie Onton – Dipole modeling and DIPFIT 25
Spline file in EEG structure
>> EEG
…
icasplinefile = ‘C:\ \EEGLAB WORKSHOP\faces 3 spl’icasplinefile = C:\…\EEGLAB_WORKSHOP\faces_3.spl
…
2D scalp map for IC 12 3D scalp map for IC 12
EEGLAB Workshop VII, Apr. 20-22, 2009, Bloomington, IN: Julie Onton – Dipole modeling and DIPFIT 26
Exercise
• NovicePl t di l f th GUI d ll- Plot dipoles from the GUI and scroll through components individually, Try all viewing parameters- Try all viewing parameters
• Intermediate / Advanced- In the Finefit menu, try fitting a bilateralIn the Finefit menu, try fitting a bilateral
dipole, what happens to the residual variance?- Co-register the head model for 3D scalp
map plotting. Then plot some ICs in 3D.- Can you gain any further insight about
EEGLAB Workshop VII, Apr. 20-22, 2009, Bloomington, IN: Julie Onton – Dipole modeling and DIPFIT 27
source projections using this display?
