Implicit learning of emotional information under anesthesia

Surgical stress activates the amygdala and secretion of norepinephrine, both involved in memory and unconscious processing of emotionally negative information. This study examined surgically induced facilitation of implicit learning of emotionally negative information. Thirty patients undergoing laparoscopic cholecystectomy under general anesthesia were tested. Between 2 and 4 h after surgery, patients provided word-associates to cues previously presented (old) or not previously presented during anesthesia (new). Half the cues were emotionally negative and half neutral. Patients took less time to provide correct associates to old emotionally negative cues than to new emotionally negative cues (p < 0.05). Spectral edge frequency (SEF) of cerebral activity during surgery converged with this finding. Implicit learning during general anesthesia may be stronger for emotionally negative information and is detected by SEF.