Adult-born hippocampal neurons bidirectionally modulate entorhinal inputs into the dentate gyrus

Abstract

Afferents modulate newborn neurons What is the role of adult neurogenesis in learning, memory, and mood? Luna et al. found that adult-born neurons either inhibited or excited the dentate gyrus, depending on whether synaptic inputs originated from the lateral or the medial entorhinal cortex (see the Perspective by Llorens-Martín). These opposing mechanisms were driven by extrasynaptic transmission from adult-born neurons directly onto mature granule cells via metabotropic glutamate receptors or N -methyl- D -aspartate receptors, respectively. The balance between these mechanisms could explain the differences in dentate gyrus activity during two versions of an active place-avoidance task. The action of adult-born neurons thus depended entirely on the demands of the environment, which can be defined by the activity of cortical and subcortical regions sending inputs to the dentate gyrus. Science , this issue p. 578 ; see also p. 530