In vivo imaging of adult neurogenesis.

As our understanding of adult neurogenesis increases, hopes rise that neurological disorders and neuronal losses might be addressed one day by neural stem cell-based regenerative therapies. However, evaluating the efficacy and safety of any neurogenesis-based intervention requires a means to monitor neurogenesis in vivo and, so far, no such imaging techniques are available for human studies. Nevertheless, using imaging techniques presently available to clinicians, i.e. magnetic resonance imaging, positron emission tomography and optical imaging, significant progress has been made in this direction over the last decade. This review describes the current state-of-the-art for each imaging technique, and shows that detection of neurogenesis could theoretically be achieved using current imaging devices. Indeed, in vivo imaging of neurogenesis has already been achieved in mice using transgenic model systems. However, the imaging of human neurogenesis still requires the development of methods to reliably target the neural stem cells and the neuronal precursors in vivo.