Evidence of Abnormal Amygdala Functioning in BPD

I found an interesting little study paper titled: Evidence of Abnormal Amygdala Functioning in

Borderline Personality Disorder: A Functional MRI Study

Background: Intense and rapidly changing mood states are a major feature of BPD; however, there have only been a few studies investigating affective processing in BPD, and in particular no neurofunctional correlates for abnormal emotional processing have been identified so far.

Methods: Six female BPD patients without additional major psychiatric disorder and six age-matched female control subjects underwent functional magnetic resonance imaging (FMRI) to measure regional cerebral hemodynamic changes following brain activity when viewing 12 standardized emotionally aversive slides compared to 12 neutral slides, which were presented in random order.

Results: Our main finding was that BPD subjects but not control subjects were characterized by an elevated blood oxygenation level dependent fMRI signal in the amygdala on both sides. In addition, activation of the medial and inferolateral prefrontal cortex was seen in BPD patients. Both groups showed activation in the temporo-occipital cortex including the fusiform gyrus in BPD subjects but not in control subjects.

Conclusions: Enhanced amygdala activation in BPD is suggested to reflect the intense and slowly subsiding emotions commonly observed in response to even low-level stressors. Borderline subjects’ perceptual cortex may be modulated through the amygdala leading to increased attention to emotionally relevant environmental stimuli.

Borderline personality disorder is thought to arise from affective vulnerability. The inability to regulate one’s affective responses leads to marked, rapidly changing mood states and predisposes patients to various kinds of self-destructive behavior. However, there have been very few medical studies that support this. In this study BPD subjects were checked to ensure that they were neither suffering from additional Axis-I disorders or signs of current alcohol/drug abuse. This was important because the conclusion that this is a BPD trait can be reached, and not a co-morbid symptom attributed to something else. Before each study all the BPD and control patients were assessed to be in a similar baseline emotional state, loaded into an fMRI machine, and shown both neutral and stimulating slides. Brian scans were taken after each slide. The signal intensity was show to be significantly higher in the patients with BPD and not activated at all in the control group. When shown the negative stimuli, the BPD patients showed intense activation patterns in the amygdala. This was not found at all in the control group. The group went on to compare their study findings with other research and found that enhanced amygdala activation is similar to other psychiatric disorders like those noted with Post Traumatic Stress Disorder and Obsessive Compulsive Disorder. From this and other studies it’s suggested that not only is the amygdala active directly by sensory information but also by thoughts and memories. Activation of the amygdala may be regarded as a manifestation of a neurobiological fear reaction. As a conclusion the activation of the amygdala could be a biological indicator of intense unpleasant emotions, especially in relation to certain {perceived negative} stimuli.

It concludes with saying that these findings are consistent with the suggestion that the amygdala serves as a rapid, transient information processing pathway for stimuli that affects behavior. For people with BPD this adaptation may be disturbed which causes emotional reactions to take longer to return to an emotional baseline.

This fear reaction, I find interesting. For those of us with BPD we quite obviously have a fear of abandonment {amongst other things}. But what causes this particular fear itself? To me the answer to this would most likely be found in the childhood/adolescent environment. So is it the environment that alters the development of the brain function, or the brain function that makes one more receptive to certain environmental factors?

Borderline Personality Disorder, Impulsivity, and the Orbitofrontal Cortex

Borderline Personality Disorder, Impulsivity, and the Orbitofrontal Cortex 

Yeah it’s a mouthful, I know. Since I’ve been talking about impulsive behavior I thought I’d take a look into one potential neurological explanation for impulsivity in Borderline Personality Disorder. Specifically this article focuses on the Orbitofrontal Cortex as a main cause for impulsive behavior.

It was a really well designed study that compared people with BPD to those with legions on the orbitofrontal cortex (damaged OFC), legions in other regions of the brain, and to healthy individuals. They subjected each group to various questionnaires and tests and produced an array of fascinating data which I will attempt to share concisely. So let’s begin shall we.

The goal of this study was to determine if certain aspects of BPD, in particular impulsive behavior, are associated with orbitofrontal cortex dysfunction since this has been associated with disinhibited or socially inappropriate behavior and emotional irregularities; all common features of BPD.

There were many similarities but also some significant differences. However these differences came in areas that were looking to draw conclusions in other areas of the Big 5 personality traits: openness, conscientiousness, extraversion, agreeableness, and neuroticism. This leads to the conclusion that many behaviors may be due to other brain regions, however, since impulsive activity was so similar in both groups it supports the fact that impulsive behavior may be linked to the orbitofrontal cortex.

What are some of the findings?

Similarities:

–        –   Personality: Significantly more impulsive.

–          – Behavioral Impulsivity: More behaviorally impulsive.  

–          – Time Production:  Produced significantly less time than the other two groups

–          – Impaired openness to new experience

–          – Subjective anger was higher and subjective happiness was lower

Differences:

–         –  BPD patients were significantly less extraverted and conscientious, and more neurotic than the other groups.

–          – BPD patients had increased levels of sadness, anger, and fear    (<~~~~~ Totally darksiders I don’t care what anyone says).

–         –  OFC groups reported a greater overestimation of time passing – indicating a faster subjective sense of time.

–          – OFC patients were more insensitive to reward

So what does this all mean? There was significant evidence that both groups were more impulsive as assessed with both behavioral and self-report measures. Since patients with OFC lesions and patients with BPD both performed similarly on tests that indicated more impulsivity and reported more inappropriate behaviors, more BPD traits, more anger, and less happiness than subjects in both of the comparison groups,it can be assumed that there is a connection in these areas. The tests also indicated they were less open to experience and have faster perceptions of time. These findings suggest that the orbitofrontal cortex functions may be related to these aspects of BPD but not to other BPD traits (such as levels of extraversion, conscientiousness, neuroticisms, and emotion).   Therefore it concludes that impulsive behavior could be related to orbitofrontal cortex function.

One thing I found interesting was the time studies. Patients with BPD and OFC lesions both had significantly lower time latencies on behavioral impulsivity tasks.  This result may be related to a desire to complete a task fast, combined with a lack of sensitivity to punishment (OFC lesions) and perhaps with the desire for the reward of finishing sooner (BPD). So, since those with BPD are more emotionally receptive to reward we are likely to rush into something in anticipation of gaining the end benefit. Both groups also produced less time than the other groups. A common cause could be a higher level of frustration in waiting for time to elapse. This study supports evidence that impulsivity and time perception are related. “The frustration in waiting and/or the faster cognitive tempo that may cause patients with orbitofrontal cortex lesions and patients with BPD to under produce time may also be related to some of the inappropriate social and emotional behaviors they display.”

However this study also found that patients with BPD were more neurotic, less extraverted and less conscientious than all other groups. Since the OFC legion group was similar to the other groups this shows that these areas are not related to the orbitofrontal cortex region. Other areas that are probably unrelated to the orbitofrontal cortex region are: higher levels of emotionality. One of the studies showed that an increased sensitivity to punishment might make patients with BPD more emotional, and the higher level of emotionality might then contribute to impulsive behavior.

This study was very well rounded in it does support exactly what it set out to prove, by both demonstrating direct correlations to impulsive behavior and by ruling out behavior that is not associated with that area of the brain. It goes on to say, “Our findings relate well to the hypothesis that the amygdale and orbitofrontal cortex act as part of an integrated neural system, as well as alone, in guiding decision making and adaptive response{s}. Patients with BPD have some deficits that can be related to the functions performed by the orbitofrontal cortex. These deficits might be related to smaller volume of the orbitofrontal cortext or to lower levels of activity in the orbitofrontal cortex.”

Fascinating. I’ve been meaning to take a look at more neurological and biogenetic causes for Borderline Personality Disorder for quite a while now. I think this is an interesting start, if not a bit dry. I hope it was informative at least.