Circulating Insulin-Like Growth Factor I Mediates Exercise-Induced Increases in the Number of New Neurons in the Adult Hippocampus

This work was supported by Grants PM97–0018 from Direccion General de Enseñanza Superiore Investigación Cientı́fica and 08.5/0051/98 from Comunidad Autonoma de Madrid (CAM). E.C. is a CAM postdoctoral fellow. We thank Joaquin Sancho and Fernando Lozano for their expert help.

Correspondence should be addressed to Ignacio Torres-Aleman, Cajal Institute, Consejo Superior de Investigaciones Cientı́ficas, Avenida Dr. Arce 37, 28002 Madrid, Spain. E-mail:torres{at}cajal.csic.es.