Somatosensory Stimulus Intensity Encoding in Borderline Personality Disorder

Area of Science:

• Neuroscience
• Psychiatry
• Pain Perception

Background:

• Borderline Personality Disorder (BPD) is marked by emotional instability and self-injurious behaviors, often accompanied by altered pain perception.
• Previous research on BPD and pain has primarily focused on affective-motivational and cognitive-evaluative neural aspects.
• The neural encoding of basic somatosensory stimulus intensity in BPD remains underexplored.

Purpose of the Study:

• To investigate neural differences in processing unpleasant sensory stimulus intensity between individuals with BPD and healthy controls (HC).
• To examine the somatosensory neural response to parametrically increasing stimulus intensities using functional magnetic resonance imaging (fMRI).
• To determine if neural intensity encoding differs between BPD and HC groups.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to study 15 females with BPD and 15 HCs.
• Participants underwent unpleasant electrical stimulation at four individually adjusted intensity levels.
• Analyses of Variance (ANOVA) were applied to fMRI data, with a statistical threshold of p < 0.05 FWE-corrected on cluster level.

Main Results:

• Both BPD and HC groups exhibited similar subjective intensity ratings and accurate identification of stimulus levels.
• Significant neural activations for intensity encoding were found in the somatosensory cortex, insula, pMCC, and SMA in both groups.
• No significant differences in neural intensity encoding were observed between the BPD and HC groups, even at reduced significance thresholds.

Conclusions:

• Neural processing of unpleasant sensory stimulus intensity is similar in individuals with BPD and healthy controls.
• Observed alterations in affective-motivational or cognitive-evaluative pain components in BPD may be specific to pain, not general unpleasant stimuli.
• Basic somatosensory intensity encoding appears intact in BPD, contrasting with reported affective processing differences.