Meeting the Challenges of Neuroimaging Genetics

Abstract

As research encompassing neuroimaging and genetics gains momentum, extraordinary information will be uncovered on the genetic architecture of the human brain. However, there are significant challenges to be addressed first. Not the least of these challenges is to accomplish the sample size necessary to detect subtle genetic influences on the morphometry and function of the healthy brain. Aside from sample size, image acquisition and analysis methods need to be refined in order to ensure optimum sensitivity to genetic and complementary environmental influences. Then there is the vexing issue of interpreting the resulting data. We describe how researchers from the east coast of Australia and the west coast of America have embarked upon a collaboration to meet these challenges using data currently being collected from a large-scale twin study, and offer some opinions about future directions in the field.

Fig. 1

Orientation distribution functions (ODFs) of brain white matter fiber pathways calculated from HARDI data from (left) a single subject, (middle) a second subject after data alignment to match the first subject, and (right) an average of 90 subjects. Zoomed views of each image are shown at top. Note that the average HARDI from 90 subjects retains significant shape characteristics

Fig. 2

Brain maps of white matter fiber integrity (GFA; top) and complexity (JSD; bottom) color-coded according to genetic or environmental effects. Voxels where the AE model fit best are coded red (indicating significant heritability), CE green and E blue (indicating common and unique environmental effects, respectively). Note that for both HARDI measures AE and CE models fit best. The cingulum AE model fit is circled in yellow

Fig. 3

Color-coded tractography through the orientation distribution functions (ODFs) of brain white matter fiber pathways from a single subject’s HARDI acquisition