MentalHealthDaily

Adult Hippocampal Neurogenesis Added 670,000 Rat Dentate Neurons

by GLOOM

MHD featured image for adult hippocampal neurogenesis and dentate gyrus neuron turnover.

A 2026 rat study estimated that adult hippocampal neurogenesis added 670,000 dentate gyrus granule neurons from 2 to 18 months of age, but the total dentate gyrus population grew by only 385,000 cells because older developmentally born neurons were also being lost.1 The result makes adult neurogenesis look numerically larger than the usual “tiny trickle” …

PTSD Trauma Memories Are Encoded in Hippocampal Semantic Maps

by GLOOM

Photoreal illustration of the hippocampus with semantic encoding pathways highlighted, representing trauma memory processing in PTSD.

A 2026 fMRI study of 79 women with interpersonal-violence-related PTSD found that the hippocampus does encode the meaning of autobiographical trauma narratives, t(140) = 4.05, p < 0.001, even though average hippocampal encoding did not rise for trauma vs. neutral memories. Research Highlights Hippocampal semantic encoding was significant: Cisler et al. analyzed 3,928 narrative sentences …