Volumetric neuroimaging and low-dose early-life exposures: loose coupling of pathogenesis-brain-behavior links.

The interface of developmental neuroimaging with developmental neurotoxicology can, broadly speaking, address two complementary concerns. The first is to study the impact of specific exposures on brain development. The second is to study known neurobehavioral disorders with an eye to discerning toxicological contributions to pathogenesis. Pathogenesis targets brain based upon physical properties (receptors, growth factors, etc.) while behavior is modulated by regional and neural systems alterations. The distribution of pathogenesis-brain relationships overlaps only partially with that of brain-behavior relationships. The goal of this paper is to highlight methodological issues involved in designing and interpreting volumetric neuroimaging studies in the light of this loose coupling.