This prospective, double-blind, parallel-group controlled trial aims to investigate the consequence of early trauma on dopamine release evoked by positive valence odors.
The occurrence of early trauma has been linked to alterations in the development of emotion regulation circuits and functional brain connectivity (particularly in the dorsolateral prefrontal cortex - DLPFC), the dopaminergic response to stress and an alteration in hedonicity (including olfactory hedonicity), which can lead to the onset of psychiatric disorders such as anxiety or depression. However, few studies have investigated the influence of early trauma on the release of dopamine (DA) evoked by odors with a positive emotional valence. Yet hedonicity is a key component of olfaction, as a positive odor leads to reinforced behavior in areas such as food intake and social interaction. This reinforcement process is thought to be underpinned by the very close link between the olfactory system (olfactory tubercle), the emotional regulation system (DLPFC) and the reward system (striatum), including the release of DA. The aim of the study is to investigate the influence of early trauma on DAergic transmission evoked by odorants with a positive emotional valence. To this end, 30 participants will be recruited and divided into two groups: those with early trauma and those without, according to their score on the Childhood Trauma Questionnaire. They will undergo an MRI-PET scan during which they will be exposed to pleasant odors. Subcortical dopaminergic transmission will be analyzed using the PET activity of \[11C\]Raclopride (a D2 receptor antagonist). Investigators hypothesize that early trauma resulting in abnormal cortico-subcortical and cortico-cortical connectivity would lead to a deficit in the hedonic appreciation of a pleasant odor, associated with a reduction in DAergic reactivity evoked in the reward system.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
TRIPLE
Enrollment
30
In the "presence of early trauma" arm, 15 participants are recruited based on a high Childhood Trauma Questionnaire total score.
In the "absence of early trauma" arm, 15 participants are recruited based on a low Childhood Trauma Questionnaire total score.
Dopamine transmission measured with positron emission tomography
Subcortical dopaminergic transmission will be analyzed, using \[11C\]raclopride PET activity (D2 receptor antagonist)
Time frame: 24 months
Odor hedonic appreciation.
The pleasantness of the odors presented will be assessed on a scale of 1 to 9.
Time frame: 24 months
Functional brain connectivity.
Resting-state functional connectivity assessed with fMRI.
Time frame: 24 months
Effective brain connectivity
Effective brain connectivity will be assessed using a dual-coil TMS protocol that stimulates the motor cortex and dorsolateral prefrontal cortex during odor presentation. Measurement of the amplitude of the motor response reflects the connectivity between these two regions of interest.
Time frame: 24 months
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.