Genetic imaging: Promises and pitfalls

Abstract

Genetic factors play an important role in the pathogenesis of various neuropsychiatric disorders, such as schizophrenia, autism, or bipolar disorder. Genetic Imaging is the investigation of neuroimaging correlates for genetic variation and aims to provide a link between the genetic and the neural systems level. In this chapter, we provide an overview over the different approaches in the field and discuss potential pitfalls. Classical approaches ("reverse genetics") stratify a neuroimaging population by genotype. The introduction of large cohorts has enabled so-called forward genetics approaches, that is, the identification of genetic variation associated with a given neuroimaging endophenotype. The small effect sizes of common gene variants are the major obstacles for these types of studies, which may lead to false-positive results due to sampling effects. The study of rare variants with high effect sizes is a newly emerging and promising field of research. The use of genetic animal models-mainly rodents-is another new, yet rapidly growing field that offers a rather homogenous genetic background, standardized environmental conditions, and a broad experimental repertoire for molecular biological follow-up studies. Together, these different approaches within the field of Genetic Imaging might help to get a better understanding about the genetic underpinnings of brain structure and function.