E-Mail IMAGE: A mouse brain section highlighting the hippocampus is overlaid with the molecular structures of the anesthetics isoflurane (purple), medetomidine/midazolam/fentanyl (orange), and ketamine/xylazine (red). The four panels in the lower part... view more Credit: Simon Wiegert, CC-BY Memory loss is common after general anesthesia, particularly for events occurring immediately before surgery--a phenomenon called retrograde amnesia. But a new study publishing on April 1st 2021 in the open access journal PLOS Biology, led by Simon Wiegert at the University Medical Center Hamburg-Eppendorf in Germany, shows that changes in the hippocampus--the part of the brain used to make new memories--differ depending on which general anesthetic is used. Consequently, their effects on memory formation also differ.