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. Author manuscript; available in PMC: 2016 Jan 1.
Published in final edited form as: Brain Topogr. 2014 Sep 19;28(1):70–86. doi: 10.1007/s10548-014-0400-8

Table 1.

Registrations and Transformations Applied to Electrode Positions and Locations

Individual Participant Electrodes and Locations
Fiducials External scalp locations Identified on MRI with masks and locations
10-10 (N=174) International 10-10 Virtual electrodes calculated for 81 locations
10-5 (N=174) Simulated 10-5 Virtual electrodes derived from 10-10 inter-electrode locations
GSN128 (N=86) EGI GSN GPS, EGI positioning, fit on individual MRI
HGSN128 (N=86) EGI HGSN GPS, EGI positioning, fit on individual MRI
Simulated 470 (N=86) Simulated HGSN Simulated electrodes derived from HGSN 128 inter-electrode locations
Average MRI Templates Electrodes and Locations
Analytic Averages
Name External scalp locations Identified on MRI with masks and locations
10-10 (N=174) International 10-10 Virtual electrode positions calculated for 81 locations
10-5 (N=174) Simulated 10-5 Virtual electrode positions derived from 10-10 inter-electrode locations
Averages from Transformed Individual Data
Name Data to be Transformed Transformation Description
CPD-Fiducials-Rigid Fiducials CPD rigid registration (6 dof)
CPD-Fiducials-Affine Fiducials CPD full affine registration (12 dof)
CPD-TenTen-Rigid 10-10 Locations CPD rigid registration (6 dof)
CPD-TenTen-Affine 10-10 Locations CPD full affine registration (12 dof)
FLIRT-Head-Rigid whole-head MRI FLIRT rigid registration (6 dof)
FLIRT-Head-Affine whole head MRI FLIRT full affine registration (12 dof)
Untransformed Participant electrodes No registration or transformation
Inverse Transformations from Average MRI Template to Participant
Name Data to be transformed Transformation Description
CPD-Fiducials-Affine Fiducials CPD full affine registration (12 dof)
CPD-TenTen-Affine Fiducials CPD full affine registration (12 dof)
FLIRT-Head-Affine Fiducials CPD full affine registration (12 dof)
Untransformed Average electrodes No registration or transformation
CPD-Electrodes-Affine GSN or HGSN positions CPD affine registration between all locations on average MRI template and participant
CPD-Partial-Affine GSN or HGSN positions CPD affine registration between selected locations on average MRI template and participant