Genetic contributions of the serotonin transporter to social learning of fear and economic decision making

Abstract

Serotonin (5-HT) modulates emotional and cognitive functions such as fear conditioning (FC) and decision making. This study investigated the effects of a functional polymorphism in the regulatory region (5-HTTLPR) of the human 5-HT transporter (5-HTT) gene on observational FC, risk taking and susceptibility to framing in decision making under uncertainty, as well as multidimensional anxiety and autonomic control of the heart in healthy volunteers. The present results indicate that in comparison to the homozygotes for the long (l) version of 5-HTTLPR, the carriers of the short (s) version display enhanced observational FC, reduced financial risk taking and increased susceptibility to framing in economic decision making. We also found that s-carriers have increased trait anxiety due to threat in social evaluation, and ambiguous threat perception. In addition, s-carriers also show reduced autonomic control over the heart, and a pattern of reduced vagal tone and increased sympathetic activity in comparison to l-homozygotes. This is the first genetic study that identifies the association of a functional polymorphism in a key neurotransmitter-related gene with complex social-emotional and cognitive processes. The present set of results suggests an endophenotype of anxiety disorders, characterized by enhanced social learning of fear, impaired decision making and dysfunctional autonomic activity.

Serotonergic modulation of suicidal behaviour: integrating preclinical data with clinical practice and psychotherapy

“…More neurons mean a stronger connection and may be associated with a greater capacity to detect the emotional context of an environment. Short allele carriers express greater sympathetic reactivity when observing another person receiving a shock (Crişan et al 2009), suggesting a possible link to a greater capacity for empathy. In another study, it was found that seeing a favourite person led to significantly higher amygdala activity in short allele carriers suggesting a higher reward value of positive interpersonal experience (Matsunagaa et al 2010).…”

Psychophysiological Markers of Anxiety Disorders and Anxiety Symptoms

“…HRV is positively related to serotonin turnover (DePetrillo et al, 1999). Individuals carrying s allele of serotonin transporter gene showed reduced HRV compared to l-homozygotes (Crişan et al, 2009). Lower levels of serotonin induced by tryptophan depletion were associated with reduced HRV in remitted depressed patients (Booij et al, 2005).…”

“…High trait anxiety was associated with autonomic dysreguation indexed by reduced HRV . Thus, reduced HRV may play a critical role in the development of anxiety disorders and can be considered as an important endophenotype of anxiety (Friedman, 2007;Crişan et al, 2009). In a recent review of the literature, Friedman (2007) provided a number of studies that linked reduced HRV with a variety of anxiety disorders over the past 15 years and provided the summary of the Neurovisceral Integration model of anxiety.…”

Variant at serotonin transporter gene predicts increased imitation in toddlers: relevance to the human capacity for cumulative culture

“…Homberg & Lesch [11], as well as Falk et al [16], propose that the short allele may therefore result in greater social conformity. Further evidence that 5HTTLPR influences social learning or imitation per se is provided by an association between the short allele and increased observational fear conditioning [17], as well as anatomical differences in the mirror neuron system [18] and activational differences upon viewing emotional expressions [18] and performing a joint action task [19].…”