The Relationship Between Impulsivity Traits and In Vivo Cerebral Serotonin Transporter and Serotonin 2A Receptor Binding in Healthy Individuals: A Double-Tracer PET Study with C-11 DASB and C-11 MDL100907

초록

To elucidate the potential roles of presynaptic and postsynaptic serotonergic activity in impulsivity traits, we investigated the relationship between self-reported impulsiveness and serotonin transporter (5-HTT) and 5-HT2A receptors in healthy individuals. In this study, 26 participants completed 3-Tesla magnetic resonance imaging and positron emission tomography with [11C]DASB and [11C]MDL100907. To quantify 5-HTT and 5-HT2A receptor availability, the binding potential (BPND) of [11C]DASB and [11C]MDL100907 was derived using the simplified reference tissue model with cerebellar gray matter as the reference region. The participants' impulsivity levels were assessed using the Barratt Impulsiveness Scale-11 (BIS-11). The region of interest (ROI)-based partial correlation analysis with age, sex, and temperament traits as covariates revealed a significant positive correlation between non-planning impulsiveness and [11C]MDL100907 BPND in the caudate (CAU) at Bonferroni-corrected p < 0.0045. Non-planning impulsiveness was also positively correlated with [11C]MDL100907 BPND in the prefrontal cortex (PFC), ventromedial PFC, orbitofrontal cortex (OFC), insula (INS), amygdala (AMYG), putamen, ventral striatum, and thalamus, and the total score of BIS-11 was positively correlated with [11C]MDL100907 BPND in the OFC, INS, AMYG, and CAU at uncorrected p < 0.05. Motor impulsiveness had a positive correlation with [11C]DASB BPND in the CAU at uncorrected p < 0.05. Our results suggest that impulsivity traits, characterized by focusing on the present moment without considering future consequences, may be involved in serotonergic neurotransmission, particularly 5-HT2A receptor-mediated postsynaptic signaling in the CAU, which plays an important role in cognitive processes related to executive function, judgment of alternative outcomes, and inhibitory control.

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