Figure 6.

Model of Tiam1's role in regulating DG development and function. During late development, Tiam1 promotes the maturation and stabilization of DG granule cell dendritic arbors and spines, resulting in WT mice with normal excitatory synaptic transmission, adult-born granule cell (orange) survival, and hippocampal-dependent memory. In the absence of Tiam1, the arbors and spines of DG granule cells from Tiam1 KO mice grow normally but fail to stabilize during a period of activity-dependent refinement, resulting in dendrite and spine loss and reduced excitatory synaptic transmission. Tiam1 KO mice also display increased adult-born granule cell survival, possibly because of decreased competition with mature granule cells (blue) for synaptic input, and enhanced contextual fear memory and context discrimination.