#define nvar 2 ! brain volume (gray or white matter) and Working Memory scale of WAIS-IIIR G1: calculation Data Calc NGroups=4 Begin Matrices; X Lower nvar nvar Free ! genetic structure Y Lower nvar nvar Free ! common environmental structure Z Lower nvar nvar Free ! specific environmental structure G Full 1 nvar free ! means H Full 1 1 End Matrices; st 1 all Start 62 G 1 1 !starting value mean working memory st 700 G G 1 2 !starting value mean MRI variable st 4 X 1 1 Y 1 1 Z 1 1 st 18 X 2 2 Y 2 2 Z 2 2 Begin Algebra; A= X*X' ; C= Y*Y' ; E= Z*Z' ; P = A%(A+C+E) | C%(A+C+E) | E%(A+C+E) ; !standardized estimates K=\stnd(X*X') ; !genetic correlation L=\stnd(Y*Y'); !common environmental correlation M=\stnd(Z*Z'); !specific environmental correlation end algebra; Matrix H .5 END G2: MZ twin pairs Da NINPUT_VARS=11 Missing=-200.00 REctangular file=mri3.dat labels eegfamnr zyg wm1 bbgmt1 bbwmt1 wm2 bbgmt2 bbwmt2 wm3 bbgmt3 bbwmt3 select if zyg < 3; !select wm1 bbgmt1 wm2 bbgmt2 ; select wm1 bbwmt1 wm2 bbwmt2 ; Matrices = G 1 Means G|G; !model for means Covariances ! model for covariances A+C+E | A+C _ A+C | A+C+E / Options RSidual End G3: DZ twin pairs Da NINPUT_VARS=11 Missing=-200.00 REctangular file=mri3.dat labels eegfamnr zyg wm1 bbgmt1 bbwmt1 wm2 bbgmt2 bbwmt2 wm3 bbgmt3 bbwmt3 select if zyg > 2; !select wm1 bbgmt1 wm2 bbgmt2 ; select wm1 bbwmt1 wm2 bbwmt2 ; Matrices = G 1 Means G|G; !model for means Covariances ! model for covariances A+C+E | H@A+C _ H@A+C | A+C+E / Options RSidual End G4: twin1-sib pairs Da NINPUT_VARS=11 Missing=-200.00 REctangular file=mri3.dat labels eegfamnr zyg wm1 bbgmt1 bbwmt1 wm2 bbgmt2 bbwmt2 wm3 bbgmt3 bbwmt3 !select wm1 bbgmt1 wm3 bbgmt3 ; select wm1 bbwmt1 wm3 bbwmt3 ; Matrices = G 1 Means G|G; !model for means Covariances ! model for covariances A+C+E | H@A+C _ H@A+C | A+C+E / Options RSidual End