The influence of estrogen of hippocampus and amygdala dependent emotional memory
Final Report Abstract
The most important findings across our studies are the relatively subtle effects even of high E2 doses on neural activity and the absence of any behavioral effects with exception a subtle effect of very high doses on mental rotation. These null-findings are of great relevance because our study was the so far best-controlled and only placebo controlled double-blind fMRI study at all on E2 in humans, E2 levels were elevated across a wide range of concentrations and we recruited an unusual large sample (n = 125). Importantly however, the subtle effects on neural activity were in both fMRI-studies highly specific and only observed in brain regions actively involved in the task, e.g. the hippocampus and the nucleus accumbens. But in addition to these core regions of the tasks also activity in other contributing areas as the insula or the precuneus that have not yet been in the focus of the animal literature on E2 showed a relationship with E2. This ‘whole-brain’ approach is an advantage of the method fMRI and our results might inspire animal studies to explore E2’s action in these areas also on the cellular level. Moreover, feeding the continuously distributed E2 levels over a wide range into regression analyses to test for linear as well as inverted U-shaped dose response functions does not require a priori assumptions about the inflexion point of the inverted U-curve which is another advantage and might inform animal studies where only few doses can be tested. Because the shape of the dose response function is dependent on the ratio of α-/β E2 receptors our results might stimulate also with respects to this cellular work in the areas we identified.
Publications
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(2018). Effects of the experimental administration of oral estrogen on prefrontal functions in healthy young women. Psychopharmacology; 235(12):3465-3477
Sommer T, Richter K, Singer F, Derntl B, Rune GM, Diekhof E, Bayer J
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(2018). Linear and inverted U-shaped dose-response functions describe estrogen effects on hippocampal activity in young women. Nature communications; 9(1):1220
Bayer J, Gläscher J, Finsterbusch J, Schulte LH, Sommer T
