Overview
Background: Stress plays an essential role in the pathophysiology of mental disorders. However, individual differences in the vulnerability to acute and repeated stress are not well understood.
Aim: This work aims to investigate individual differences in glucose metabolism and directional connectivity regulating the neuronal stress response.
Design: 68 healthy volunteers will undergo two simultaneous PET/MRI measurements one week apart. Participants will complete the Montreal Imaging Stress Test during each measurement and in-between. Effects of stress on cognitive performance will be assessed using the n-back working memory task. Individual cortisol levels will be acquired to identify stress (non)responders as well as (non)habituators.
Implications: This work will characterize differences between stress responders vs. non-responders and stress habituators vs. non-habituators in terms of energy metabolism and network connectivity. This individual difference in the stress response may represent an important cornerstone for future evaluation of patients with mental disorders.
Description
Methodological details: Each participant will undergo two PET/MRI scans. Imaging will include functional PET and as well as structural and functional MRI. Stress-specific glucose metabolism will be quantified with the radioligand \[18F\]FDG. Functional connectivity will be combined with glucose metabolism to assess directional connectivity. Based on previous literature, changes are expected to occur in the anterior cingulate cortex.
Eligibility
Inclusion Criteria:
- 18-40 years
- right-handedness
- willingness and competence to sign the informed consent form
Exclusion Criteria:
- History of or current physical, neurological or psychiatric disorder
- History of or current substance abuse or medication, including antipsychotic, antidepressant and antianxiety agents
- Pregnancy of current breast-feeding
- Contraindications for MRI-scanning (e.g., metal implants, steel grafts, etc.), including dental implants causing signal artifacts
- For subjects participating in earlier studies using ionizing radiation, the total radiation exposure of 30 mSv over the last 10 years must not be exceeded, as specified in the Austrian legislation on radiation protection Accordingly, body weight \> 105 kg is an exclusion criterion.
- Failure to comply with the study protocol or to follow the instructions of the investigating team.