5HT(3) antagonism abolishes the emotion potentiated startle effect in humans.

Rationale: The serotonergic system has been implicated in emotional processing in animals and humans. Although the contribution of different receptor subtypes has been hypothesised, there have been few direct tests of this in human subjects.

Objectives: The current study aimed to explore the involvement of the serotonin type 3 (5HT3) receptor subtype in a battery of emotional processing tasks previously found to be sensitive to SSRI administration.

Antidepressant drug treatment modifies the neural processing of nonconscious threat cues.

Background: The amygdala is believed to play a key role in processing emotionally salient, threat-relevant, events that require further online processing by cortical regions. Emotional disorders such as depression and anxiety have been associated with hyperactivity of the amygdala, but it is unknown whether antidepressant treatment directly affects amygdala responses to emotionally significant information.

Methods: The current study assessed the effects of 7 days administration of the selective serotonin reuptake inhibitor (SSRI), citalopram, on amygdala responses to masked presentations of fearful and happy facial expressions in never-depressed volunteers using blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging.