Brain Signal Training to Enhance Affect Down-regulation

Stage 1: 82 patients, stage 2: 82 patients Inclusion Criteria 1. 18-65 years 2. Diagnosis of Borderline Personality Disorder 3. Insufficient response to ≥2 therapies. 4. Sufficient German language skills to give informed consent to the study, to understand questions posed by used instruments, and capable of completing the fMRI tasks 5. Ability of subject to understand character and individual consequences of clinical investigation 6. Written informed consent (must be available before enrollment in the clinical investigation) 7. For women of childbearing potential (WOCBP) adequate contraception. Exclusion Criteria 1. Treatment with benzodiazepines within 7 days prior the initial screening 2. Current alcohol or substance dependence 3. Meeting the diagnostic criteria for a psychotic disorder or schizophrenia (life-time), as determined by clinical interview at initial screening 4. Current or history of significant neurological condition (such as stroke, traumatic brain injury, space occupying lesions, multiple sclerosis, Parkinson's disease, vascular dementia, transient ischemic attack) 5. Significant visual impairment that might interfere with the performance of the behavioural tasks or fMRI tasks 6. Change of treatment (psychopharmacologic, psychological) 2 weeks prior to study participation or before completion of the post-assessment. 7. Treatment with any neurofeedback three months prior to or during the study participation. 8. Unable or unwilling to comply with study procedures, including study prohibitions and restrictions 9. History of claustrophobia or inability to tolerate scanner environment 10. Fulfilling any of the MRI contraindications on the standard site radiography screening questionnaire (e.g. history of surgery involving metal implants) 11. Clinically relevant structural brain abnormality as determined by prior MRI scan 12. Planned medical treatment within the study period that might interfere with the study procedures 13. Participants deemed to be at significant risk of serious violence or suicide 14. BMI of 16.5 or lower 15. Participation in other clinical trials or observation period of competing trials, respectively 16. Previous participation in this trial 17. Pregnancy and lactation 18. Held in an institution by legal or official order 19. Legally incapacitated.