Du Young Kim: Long-term memory impairment following general anaesthesia varies with circadian time of exposure in Drosophila melanogaster

We tested this in Drosophila melanogaster using a 24-hour appetitive memory assay. Flies were trained to associate an odour with a sugar reward, then exposed to 2% isoflurane for 3 hours at one of 17 circadian timepoints.

Isoflurane impaired long-term memory at every exposure time compared with untreated controls. Severity varied across the cycle, with performance lowest around circadian time (CT) 9.5 to 10.5 and least impaired at CT 22.5. The low point aligns with expected low abundance of PERIOD, a core circadian clock protein, while CT 22.5 aligns with expected high abundance.