Irradiation as an experimental tool in studies of adult neurogenesis.

"Loss of function" experiments have been the mainstay approach in studies seeking to determine functional roles of various brain regions in learning and memory. The hippocampal formation consists of several distinct regions that are thought to play different, yet interrelated, roles in the memory processes. Ionizing radiation offers a selective and highly flexible, relatively uninvasive method to further advance such studies. Focused applications of the radiation beam to the head under general anesthesia can selectively reduce ongoing adult neurogenesis in the dentate gyrus without causing any detectable damage to mature neurons. Further refinements of the methodology should offer many opportunities to extend our present knowledge of how and when adult neurogenesis plays a role in learning and memory. (c) 2006 Wiley-Liss, Inc.