Impulsivity With Borderline Personality Disorder/tMS

Borderline personality disorder (BPD) is a mental disorder characterized by unstable interpersonal relationships, emotional lability and marked impulsivity. The latter manifests itself through risky behaviors such as substance abuse, self-harm and suicidal behavior.

Studies suggest that 1.3% of the general population suffers from BPD. However, in clinical settings, BPD patients represent 20% of all inpatients in psychiatric wards and up to 50% of patients hospitalized in emergency departments following a suicide attempt (SA). Moreover, it is estimated that nearly 84% of BPD patients will make at least one SA in their lifetime and up to 10% of them will die by suicide, a rate 50 times higher than the general population. Impulsivity, reflected in difficulties holding back action or stopping an action that has already begun, is one of the key symptoms of BPD.

Recent advances in non-invasive brain stimulation have led to the emergence of a new stimulation protocol known as Paired Cortico-Cortical Associative Stimulation (ccPAS), which consists of repeating paired stimulations using two TMS coils placed respectively on two cortical regions of interest. Paired stimulations' repetition induces plasticity by strengthening synaptic connectivity between the two targeted regions.

The aim of this project is to test the efficacy of a ccPAS protocol in enhancing effective connectivity between the IFC and pre-SMA in order to reduce impulsivity in BPD patients.

The Sponsor hypothesized that one ccPAS session, using two coils simultaneously, targeting the IFC and pre-SMA with a 'physiological' inter-stimulus interval of 4ms will improve motor inhibition abilities (reduce SSRT), compared to the group receiving 'control' ccPAS (100ms inter-stimulus interval (ccPAS100-ms)).

• Increased effective inhibitory connectivity within the fronto-striatal network (DLPFC-M1), intracortical inhibition (short and long interval) and cortical silent period for the ccPAS4-ms group, when compared with the ccPAS100-ms group [Срок оценки: 2 times: Outcome measure will be assessed: immediately before the ccPAS protocol and immediately after the ccPAS protocol, for both groups]
• Levels of intracortical inhibition within M1. [Срок оценки: 1 time: Measured before the ccPAS protocol, in both groups.]
• Duration of cortical silence period (in ms). [Срок оценки: 1 time: Measured before the ccPAS protocol, in both groups]
• Cognitive task manipulating environment-emotion-behavior interactions. [Срок оценки: 1 time: Measured before the ccPAS protocol, in both groups.]