Phenotype, function and genotype

Over the past thirty years, non-invasive brain imaging has become the tool of choice for quantifying brain structure and function in humans. The principle behind imaging studies is to gather information on brain structures whose variability is potentially associated with behavioral variability, which may also be explained by genetic variability. The use of imaging thus enables a correlative analysis that translates into a diagnosis, rather than a modeling or causal explanation of phenomena.

Among the various types of imaging, functional imaging is particularly valuable as it reflects neuronal activity itself, so that we can expect sensitive and early markers for many pathologies. In practice, however, the use of functional imaging raises many difficulties, and its clinical impact is currently modest.

In this seminar, we will review the quantification of brain function made possible by non-invasive functional imaging, explaining the potential and limitations of current observation modalities.

Next, we will describe the two types of correlative analysis that are commonly performed: those linking functional imaging to behavior, and those linking functional imaging with genetic data. From a methodological point of view, we will discuss the different statistical association models available for analyzing correlations between different types of variables.

Finally, we will conclude with an analysis of the challenges facing the use of functional neuroimaging, as well as those relating to explanation by genetic data.