Influence of the serotonin transporter promoter gene and shyness on children's cerebral responses to facial expressions.
BACKGROUND
Childhood shyness can predate social anxiety disorder and may be associated with biased discrimination of facial expressions of emotions.


OBJECTIVE
To determine whether childhood shyness, or the serotonin transporter promoter polymorphism genotype, can predict participants' visual event-related potentials in response to expressions of children of similar ages.


METHODS
Study group drawn from an inception cohort of 149 subjects characterized 1 year before the present study by their degree of shyness.


METHODS
Third- and fourth-grade schoolchildren.


METHODS
Forty-nine of the inception cohort children, randomly selected.


METHODS
Latencies and amplitudes of the N400 waveform in response to happy, neutral, and angry expressions.


RESULTS
Shyness predicted significantly smaller N400 amplitudes in response to anger (at Pz: P < or = .04) and to a neutral expression (at Pz: P < or = .047). Shyness was significantly different across the 3 genotypes, the SS genotype being associated with higher shyness levels (analysis of variance: F(2,42) = 4.47, P < or = .02; Tukey honestly significant difference, SS vs LL, P < or = .01). An analysis of covariance showed that neither the type of expression nor the genotype per se influenced the N400 amplitudes, but a significant expression X genotype interaction was found (F(4,72) = 3.57, P < or = .01), sustained by the difference in amplitude of the SS and S carrier subjects compared with the LL subjects when exposed to the anger expression (Tukey honestly significant difference, P < or = .02).


CONCLUSIONS
Children who manifest higher levels of shyness or have 1 or 2 copies of the short allele of the serotonin transporter promoter gene appear to have a different pattern of processing affective stimuli of interpersonal hostility.
Battaglia
Marco
M
Department of Psychology, Vita-Salute San Raffaele University at the Department of Neuropsychiatric Sciences, Istituto Scientifico San Raffaele, Milan, Italy. marco.battaglia@hsr.it
Ogliari
Anna
A
Zanoni
Annalisa
A
Citterio
Alessandra
A
Pozzoli
Uberto
U
Giorda
Roberto
R
Maffei
Cesare
C
Marino
Cecilia
C
D000339:Affect / Q000502:physiology; D000786:Anger / Q000502:physiology; D001921:Brain / Q000502:physiology*; D002648:Child; D002652:Child Behavior / Q000502:physiology*; D015331:Cohort Studies; D005071:Evoked Potentials / Q000235:genetics / Q000502:physiology*; D005149:Facial Expression; D005260:Female; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation / Q000502:physiology; D005838:Genotype; D006791:Hostility; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics*; D026901:Membrane Transport Proteins / Q000235:genetics*; D009419:Nerve Tissue Proteins / Q000235:genetics*; D010698:Phobic Disorders / Q000175:diagnosis / Q000235:genetics; D011110:Polymorphism, Genetic / Q000502:physiology; D011401:Promoter Regions, Genetic / Q000235:genetics*; D050486:Serotonin Plasma Membrane Transport Proteins; D012792:Shyness; D014796:Visual Perception / Q000502:physiology
D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins