Fig. 7.

A working model of ID/anemia-suppressed hippocampal IGF signaling. Hippocampal ID-lowered IGF/PI3K/Akt signaling (downward light gray arrows) preferentially leads to reduced neurogenesis and synaptogenesis. In contrast, PI3K-independent activation of the Erk1/2 pathway (upward black arrows) may overcome its PI3K-dependent repression. In an adaptive sense, this may have a stimulatory effect on promoting cellular survival. mTOR, mammalian target of rapamycin; FoxO1, forkhead box O1; Hif1α, hypoxia-inducible factor 1α.