The study aims to explore whether acute tryptophan depletion can affect the emotion and interference processing whether this effect is moderated by the TPH2 genotype
Based on previous studies suggesting that serotonin, a neurotransmitter, is associated with social \& emotional behavior, including emotional reactivity and emotion regulation, the present study aims to explore effects of acute tryptophan depletion (ATD) on emotion processing and emotional interference processing within a randomized double-blind, with-subject, placebo-controlled pharmaco-fMRI experiment. To further examine the potential moderating effects of the genetic makeup of the serotonin system the present study will include a pharmacogenetics imaging approach. Given that TPH2 is the key regulator of the serotonergic signaling pathway, we therefore assessed whether such the effects of tryptophan depletion vary according to the TPH2 genotype. To this end, healthy male TPH2-GG or TPH2-TT carriers will be recruited and will receive ATD (100g) and placebo (102.3g) in a within subject design. To control for potential effects of pre-medication personality traits as well as effects of medicines on mood, subjects will be administered pre-treatment assessing relevant personality traits and post-treatment assessments of mood.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
DOUBLE
Enrollment
50
oral administration of ATD (100g)(Acute Tryptophan Depletion)
oral administration of placebo (102.3g)
School of Life Science and Technology
Chengdu, Sichuan, China
RECRUITINGNeural processing during emotion processing as assessed via fMRI
Subjects will undergo a validated emotional face paradigm. To assess genotype x ATD interaction effects on neural emotional reactivity effects of ATD depletion on the corresponding neural activity will be compared between the TPH2 genotype groups.
Time frame: 5-6h after administration of ATD, or placebo
Neural processing during interference processing as assessed via fMRI
Subjects will undergo a validated cognitive-emotional interference paradigm. To assess genotype x ATD interaction effects on neural interference control effects of ATD depletion on the corresponding neural activity will be compared between the TPH2 genotype groups.
Time frame: 5-6h after administration of ATD, or placebo
Neural processing during the resting state as assessed via fMRI
Subjects will undergo a validated resting state assessment. To assess genotype x ATD interaction effects on intrinsic brain activity in the emotion and interreference related neural networks effects of ATD depletion on the corresponding neural activity will be compared between the TPH2 genotype groups.
Time frame: 5-6h after administration of ATD, or placebo
Behavioral interference performance
Subjects will undergo a emotion-cognition interference paradigm. To assess genotype x ATD interaction effects on behavioral indices of interference (congruent vs incongruent trials) behavioral performance (accuracy/reaction time) effects of ATD depletion on the corresponding behavioral indices will be compared between the TPH2 genotype groups.
Time frame: 5-6h after administration of ATD, or placebo
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