Figure 4.
Modulation of pattern separation by adult neurogenesis and its impact on mood. Novel sensory representations can be disambiguated from stored representations through pattern separation on inputs from entorhinal cortex. Under stressful conditions, neurogenesis is low, leading to low discrimination and to generalization of contexts with substantial emotional valence. This may lead to increased anxiety owing to impaired contextual processing through modulation of exploration through dorsal outputs and increased stress responses by influencing outputs from the ventral pole. In conditions with high neurogenesis, such as enrichment or antidepressant treatment, enhanced pattern separation leads to high discrimination and greater ability to disambiguate similar contexts with differing emotional valence. This may influence output of the dorsal hippocampus to increase exploration and contextual encoding, and the ventral hippocampus to modulate stress responses. DG, dentate gyrus; Sub, subiculum.