I ran across a study from a couple of years ago by Rachel Brans and colleagues, which has an interesting result showing a genetic correlation between plasticity of cortex thickness and performance on psychometric tests . Plasticity is essential for brains to respond to pathological conditions like stroke; other studies have suggested that plasticity is likewise important to normal brain function. By means of conventional quantitative genetic analysis, Brans and colleagues suggest that plasticity is mechanistically related to the factors that underlie variation in cognitive performance:
Our finding that intelligence and change in cortical thickness are partly associated through shared genes is consistent with the dependence of learning and memory formation on the plasticity of neural circuits (Escobar et al., 2008). The association between intelligence and structural brain changes may also reflect an association between intelligence and plasticity in structural (Chiang et al., 2009) and functional brain networks during the resting-state (van den Heuvel et al., 2009). Moreover, because functional brain activity during cognitive tasks was recently found to be heritable (Koten et al., 2009), genes for structural brain plasticity and intellectual ability may also be relevant for brain function while performing cognitive tasks.
This is a classic twin study, examining the additive genetic variance of the change in cortical thickness measures in individuals sampled five years apart. As in almost all fMRI studies, the sample size is relatively small. But in comparison to previous studies that showed the relationship between psychometric test outcomes and the volumes of particular cortical areas, this one is much more functionally directed, looking at the change in cortical thickness across time.
- Brain plasticity and intellectual ability are influenced by shared genes. J Neurosci. 2010 ;30(16):5519-24.