A ventral view on antidepressant action: roles for adult hippocampal neurogenesis along the dorsoventral axis

• The hippocampus (Hi) is functionally segregated along its longitudinal axis.
• The ventral hippocampus (vHi) preferentially regulates stress and anxiety responses.
• Stress affects neurogenesis preferentially in the vHi.
• Neurogenesis in vHi but not dHi is required for a behavioural effect of fluoxetine.
• Antidepressants increase neurogenesis in anterior but not posterior Hi in primates.

Adult hippocampal neurogenesis is implicated in antidepressant action, stress responses, and cognitive functioning. The hippocampus is functionally segregated along its longitudinal axis into dorsal (dHi) and ventral (vHi) regions in rodents, and analogous posterior and anterior regions in primates, whereby the vHi preferentially regulates stress and anxiety, while the dHi preferentially regulates spatial learning and memory. Given the role of neurogenesis in functions preferentially regulated by the dHi or vHi, it is plausible that neurogenesis is preferentially regulated in either the dHi or vHi depending upon the stimulus. We appraise here the literature on the effects of stress and antidepressants on neurogenesis along the hippocampal longitudinal axis and explore whether preferential regulation of neurogenesis in the vHi/anterior hippocampus contributes to stress resilience and antidepressant action.