Table III.

Maximum likelihood correlations and Falconer's estimatesa

	Maximum likelihood correlation		Falconer estimates
	MZ	DZ	a 2	c 2	e 2
ICV	0.84	0.55	0.57	0.27	0.16
Lateral Ventricles	0.62	0.26	0.72	−0.10	0.38
Total GM	0.82	0.62	0.40	0.42	0.18
Total WM	0.87	0.53	0.69	0.18	0.13
Total EM	0.25	−0.02	0.53	−0.28	0.75
Total CSF	0.63	0.25	0.76	−0.13	0.37
Cortical GM	0.82	0.60	0.44	0.38	0.18
Cortical WM	0.86	0.52	0.68	0.19	0.14
SubCortGM	0.63	0.22	0.83	−0.19	0.37
Cerebellum	0.72	0.75	−0.05	0.77	0.28
Prefrontal GM	0.66	0.51	0.29	0.36	0.34
Frontal GM	0.65	0.53	0.24	0.41	0.35
Parietal GM	0.74	0.46	0.56	0.18	0.26
Occipital GM	0.74	0.52	0.43	0.31	0.26
Prefrontal WM	0.79	0.58	0.41	0.38	0.21
Frontal WM	0.81	0.32	0.99	−0.18	0.19
Parietal WM	0.73	0.46	0.53	0.20	0.27
Occipital WM	0.81	0.46	0.69	0.12	0.19
Total Prefrontal	0.79	0.59	0.40	0.39	0.21
Total Frontal	0.71	0.46	0.50	0.21	0.29
Total Parietal	0.77	0.48	0.58	0.19	0.23
Total Occipital	0.82	0.52	0.59	0.23	0.18
RHem GM	0.76	0.62	0.28	0.48	0.24
LHem GM	0.86	0.54	0.65	0.21	0.14
RHem WM	0.83	0.55	0.57	0.26	0.17
LHem WM	0.80	0.51	0.58	0.22	0.20
RHem Tot	0.85	0.61	0.48	0.37	0.15
LHem Tot	0.86	0.57	0.59	0.27	0.14
Corpus Callosum	0.61	0.45	0.31	0.29	0.39

Abbreviations: ICV, intracranial volume; GM, gray matter; WM, unmyelinated white matter; EM, early myelinated white matter; CSF, cerebrospinal fluid; SubCortGM, subcortical gray matter; RHem, right hemisphere; LHem, left hemisphere.

^aAdjusted for gender, gestational age at birth, and gestational age at MRI.