Introduction
depressive disorder, MDD
Ketamine has revolutionized the treatment of major depressive disorder (MDD) by displaying an antidepressant effect within 24 h after a single application in subanesthetic dosesThe startle reflex is an evolutionary well-conserved brain stem reflex that is elicited by an unexpected stimulus. Lang and colleagues suggested that the AMSR is the result of an interaction between the motivational state (defensive or appetitive) induced by affective stimuli and the following activation of defensive circuits by the startling probesThe primary acoustic startle reflex pathway begins with the nucleus cochlearis, which relays the auditory information to the nucleus reticularis pontis caudalis (PnC)The typical pattern across valence in the AMSR has been repeatedly reported to be abolished in MDD patientsIn the current randomized, double-blind, placebo-controlled, cross-over study, we investigated the effect of a single S-Ketamine infusion on the AMSR one day after infusion in a sample of healthy male participants. Since ketamine was shown to dampen the amygdalar processing of affective stimuli, particularly unpleasant stimuli, in the amygdala in MDD patients