Serotonin transporter genotype (5-HTTLPR): effects of neutral and undefined conditions on amygdala activation.
BACKGROUND
A polymorphism of the human serotonin transporter gene (SCL6A4) has been associated with serotonin transporter expression and with processing of aversive stimuli in the amygdala. Functional imaging studies show that during the presentation of aversive versus neutral cues, healthy carriers of the short (s) allele showed stronger amygdala activation than long (l) carriers. However, a recent report suggested that this interaction is driven by amygdala deactivation during presentation of neutral stimuli in s carriers.


METHODS
Functional MRI was used to assess amygdala activation during the presentation of a fixation cross or affectively aversive or neutral visual stimuli in 29 healthy men.


RESULTS
Amygdala activation was increased in s carriers during undefined states such as the presentation of a fixation cross compared with emotionally neutral conditions.


CONCLUSIONS
This finding suggests that s carriers show stronger amygdala reactivity to stimuli and contexts that are relatively uncertain, which we propose are stressful.
Heinz
Andreas
A
Department of Psychiatry, Charité University Medicine Berlin, Campus Charité Mitte, Germany.
Smolka
Michael N
MN
Braus
Dieter F
DF
Wrase
Jana
J
Beck
Anne
A
Flor
Herta
H
Mann
Karl
K
Schumann
Gunter
G
Büchel
Christian
C
Hariri
Ahmad R
AR
Weinberger
Daniel R
DR
D000328:Adult; D000679:Amygdala / Q000098:blood supply / Q000502:physiology*; D004644:Emotions / Q000502:physiology*; D007839:Functional Laterality; D005787:Gene Frequency; D005838:Genotype; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010775:Photic Stimulation; D011110:Polymorphism, Genetic; D050486:Serotonin Plasma Membrane Transport Proteins / Q000235:genetics*
D050486:Serotonin Plasma Membrane Transport Proteins; D010100:Oxygen