Neurogenetic Imaging

Abstract

This chapter discusses the use of functional MRI (FMRI) and other neuroimaging techniques in genetics. FMRI is a relatively new technique, but it has already provided many helpful insights into the anatomy, mapping, and functioning of many components of the central nervous system (CNS), as well as the body at large. The technique measures contrast between oxy- and deoxy-hemoglobin content in the form of a ratio, which changes during activation of brain areas. FMRI has several advantages that extend beyond its noninvasive nature and resolution benefits. Within the field of neuroimaging, task-associated activation not only allows for a global view of brain activity, but does so without the need for injections of radioactive isotopes and can be performed in a relatively short total scan time. Neurogenetic imaging is generally used to pioneer molecular therapeutics and research, and it is highly dependent on targeting-specific biological markers that correctly identify the disease in question. These markers include cells that reflect a variety of disease characteristics, an element of the disease process itself, an intermediate stage between exposure and disease onset, or an independent factor associated with the disease state but not causative of pathogenesis. The possible uses of neurogenetic imaging can be divided into two clear categories, the physiological/behavioral/cognitive screening of healthy individuals and interventions that alter brain activity. From schizophrenia and Alzheimer's to pain and language, functional MRI (FMRI) and other neuroimaging techniques are lighting up the dark world of genetics. With the advent of gene expression visualisation as well as simple comparisons of genetic variants and their neural structural and functional correlates, the finer details of molecular biology are coming together with the “bigger picture” of neuroimaging. Within the last two years, however, these advances and exciting cooperative efforts have created their own scare within the public domain. Concerns over “brain privacy” invasion and ethical misuse have made a new and very real public enemy out of a technique, which is fast becoming invaluable in both the clinical and academic domains. Some of the positives and most of the negatives of the technique are now being widely broadcast, usually in an exaggerated form, to the general public. It is therefore crucial that we as a scientific community catch the wave before it breaks by providing a clear picture of where we are now and where we hope to go with this technology. Gene therapy is quite possibly our most powerful clinical tool; a way of targeting the root of disease. Imaging provides us with an image of the disease and possibly the cure. Together these techniques, however, have the scope of extending beyond research and therapeutic application. It therefore seems wise to consider and address the fears of neuro-genetic screening of physiological as well as emotional and cognitive states in healthy individuals. Although we are still several years away from the frightening reality of profiling and “mind reading” described by the press, let us take advantage of the time available to prepare the public in an informed way so that the decision of how and when the technique is used can be shared.