Cortical thickness is influenced by regionally specific genetic factors.
BACKGROUND
Although global brain structure is highly heritable, there is still variability in the magnitude of genetic influences on the size of specific regions. Yet, little is known about the patterning of those genetic influences, i.e., whether the same genes influence structure throughout the brain or whether there are regionally specific sets of genes.


METHODS
We mapped the heritability of cortical thickness throughout the brain using three-dimensional structural magnetic resonance imaging in 404 middle-aged male twins. To assess the amount of genetic overlap between regions, we then mapped genetic correlations between three selected seed points and all other points comprising the continuous cortical surface.


RESULTS
There was considerable regional variability in the magnitude of genetic influences on cortical thickness. The primary visual (V1) seed point had strong genetic correlations with posterior sensory and motor areas. The anterior temporal seed point had strong genetic correlations with anterior frontal regions but not with V1. The middle frontal seed point had strong genetic correlations with inferior parietal regions.


CONCLUSIONS
These results provide strong evidence of regionally specific patterns rather than a single, global genetic factor. The patterns are largely consistent with a division between primary and association cortex, as well as broadly defined patterns of brain gene expression, neuroanatomical connectivity, and brain maturation trajectories, but no single explanation appears to be sufficient. The patterns do not conform to traditionally defined brain structure boundaries. This approach can serve as a step toward identifying novel phenotypes for genetic association studies of psychiatric disorders and normal and pathological cognitive aging.
Rimol
Lars M
LM
Department of Radiology, University of California, San Diego, La Jolla, California 92093-0738, USA.
Panizzon
Matthew S
MS
Fennema-Notestine
Christine
C
Eyler
Lisa T
LT
Fischl
Bruce
B
Franz
Carol E
CE
Hagler
Donald J
DJ
Lyons
Michael J
MJ
Neale
Michael C
MC
Pacheco
Jennifer
J
Perry
Michele E
ME
Schmitt
J Eric
JE
Grant
Michael D
MD
Seidman
Larry J
LJ
Thermenos
Heidi W
HW
Tsuang
Ming T
MT
Eisen
Seth A
SA
Kremen
William S
WS
Dale
Anders M
AM
D000328:Adult; D002540:Cerebral Cortex / Q000033:anatomy & histology* / Q000166:cytology*; D005260:Female; D014644:Genetic Variation / Q000235:genetics*; D005838:Genotype; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010641:Phenotype; D014427:Twins / Q000235:genetics