Asperger's Syndrome and the left amygdala
A few days ago I started writing a currently still private essay about my experiences with Asperger's Syndrome and I gathered some information about the biochemistry behind Asperger's Syndrome that's very fascinating and provides an interesting explanation for several of our main symptoms. It seems like our social deficits, our prioritising deficits, our lack of emotional empathy (we can feel along with others only after rational analysis of someone elses's emotions), our problems with filtering audiovisual imput and even our tendendy to focus on details rather than the big picture are all related to the decreased activation of one particular part of our brain known as the left amygdala. I elaborated a bit on this in my essay and though it might be appropriate to publish that part (which is not personal) on this website and have it peer-reviewed by other Aspies.
I published this particular text on my blog. I would like to post a link here, but as I'm a new user I'm not yet allowed to post any links.
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I'll post the text in full here since it seems you guys can't read it. I'm new to WrongPlanet so I still have some stuff to figure out.
So here it is :
The left amygdala operates something like this. When visual and other sensory experiences enter your brain, the left amygdala analyses the whole and automatically attaches a different priority on different parts of the image based on genetically determined instincts and life experience. As such, this both biological and cultural filter turns an unbiased image into a biased image and pre-filters any content based on subconscious emotional criteria. Biological and especially the cultural bias can at times make an individual unable to believe his own eyes or ears when that bias was based on a fallacy, which often leads to cognitive dissonance rather than a change in bias.
Nevertheless, the benefits of the filtering on emotional bias clearly surpass the negative aspects. This filter allows a complex image of many objects and sounds to be fragmented in numerous little parts as an automatic process and on top of that the automatic maintenance of a virtual task list based on a complex grade-based prioritising system. Basically, this filter tells you almost immediately how to respond to emotional impulses (e.g. when to be scared or when to trust someone) and it also tells you what impulses are more important than others. For example, the emotional bias filter of the left amygdala is involved in regulating which faces to recognise, which tasks are more important, who’s most likely to flirt with you, who’s most likely to get into a fight with you, when is your spouse telling you something important and what words expressed by a teacher are most important. I cannot stress enough the importance of such a filter, since it eliminates many thought processes that would often lead to similar conclusions but that require a great amount of brain power in comparison with little to nothing brainpower when using the filter.
Numerous mental conditions are directly related to deficiencies within the left and/or right amygdala, such as Schizophrenia, Klüver-Bucy syndrome, Bi-Polar disorder, Borderline Personality disorder (BPD) and Asperger’s Syndrom. With regards to deficiencies to the left amygdala in specific, BPD seems to be related to hyperactivity of the left amygdala where Asperger’s Syndrom seems to be related to reduced or nullified activity of the left amygdala. Sometimes because of a genetic impairment of the biological bias but more often because physical abuse and/or mental abuse during early childhood had a negative influence on the cultural bias applied by the left amygdala, people with BPD have an increased tendency to fear or question what to normal people appear to be neutral or positive conditions. They tend to be most comfortable when people are at a safe distance and they are often affected by mood swings and radical changes of attitude towards other people. Wikipedia gives among others the following characteristics for BPD :
The negative emotional states particularly associated with BPD have been grouped into four categories: extreme feelings in general; feelings of destructiveness or self-destructiveness; feelings of fragmentation or lack of identity; and feelings of victimization.
Individuals with BPD can be very sensitive to the way others treat them, reacting strongly to perceived criticism or hurtfulness. Their feelings about others often shift from positive to negative, generally after a disappointment or perceived threat of losing someone. Self-image can also change rapidly from extremely positive to extremely negative. Impulsive behaviors are common, including alcohol or drug abuse, unsafe sex, gambling and recklessness in general. Attachment studies suggest individuals with BPD, while being high in intimacy- or novelty-seeking, can be hyper-alert to signs of rejection or not being valued and tend toward insecure, avoidant or ambivalent, or fearfully preoccupied patterns in relationships. They tend to view the world generally as dangerous and malevolent, and themselves as powerless, vulnerable, unacceptable and unsure in self-identity.
Individuals with BPD are often described, including by some mental health professionals (and in the DSM-IV), as deliberately manipulative or difficult, but analysis and findings generally trace behaviors to inner pain and turmoil, powerlessness and defensive reactions, or limited coping and communication skills.There has been limited research on family members' understanding of borderline personality disorder and the extent of burden or negative emotion experienced or expressed by family members.
Parents of individuals with BPD have been reported to show co-existing extremes of over-involvement and under-involvement. BPD has been linked to increased levels of chronic stress and conflict in romantic relationships, decreased satisfaction of romantic partners, abuse and unwanted pregnancy. Suicidal or self-harming behavior is one of the core diagnostic criteria in DSM IV-TR, and management of and recovery from this can be complex and challenging. The suicide rate is approximately 8 to 10 percent.
For people with Asperger’s Syndrome, the emotional bias filter is not or barely active. This forces us to do all the pre-processed unconscious activity of the left amygdala consciously by means of rational processes. Although this makes certain tasks and thought processes easier or more objective when they are normally hindered by bias, the disadvantages of the lack of such a filter are clearly more significant. Because it requires complex rational processes for prioritizing, recognising social cues but also cooking, riding a bike or driving a car, a very high IQ is needed to make normal life even remotely possible but even in such cases the emotional bias filter cannot be replaced by logics alone as the sheer number of parameters required to logically analyse many social situations or certain behavioural strategies and come to a situation as reliable as or more reliable than with the emotional bias filter is at times just too large to be applicable which leaves the individual with nothing more but educated guessing where a normal person would easily have known what to do by mere instinct or intuition alone.
Also, the inability to filter leaves someone with Asperger’s Syndrome with a decreased ability to find items, to figure out when something important is said, to pay attention to someone when pre-occupied with something else and in some cases even the inability to untangle different ongoing conversations in the same room and receiving them all together as one big blurry sound.
Although people with Asperger’s Syndrome are not necessarily less emotional than normal people or even people with BPD, our lack of emotional filtering does make us blind for empathic impulses, leaving only sensory impulses to judge a situation. That makes it much harder for us to assess how to behave in different situations and it makes it harder for us to judge other people’s behaviour and attitude.
In short, having Asperger’s Syndrome basically means having elaborate plans and thought schemes for almost everything normal people do instinctively or intuitively because you simply lack that instinct or intuition. Although seemingly less affected emotionally than someone with BPD, the lack of an emotional filter often leads to increased anxiety, stress and depression because replacing instinctive behaviour with rational behaviour is extremely exhausting and the lack of situations where pre-conceived task lists can be used in order to fulfil tasks beyond a certain complexity has a significant effect on anxiety and stress levels, whereas depression is related to both the difficulty of life with Asperger’s and a decreased level or serotonin due the lack of emotional filtering.
In my own case, I believe there was damage to the left hemisphere, due to severe asphyxiation during birth and delivery, which is seen with what appears to be right-brain compensation evident in my visual/spatial capabilities with visual art. Also language which is believed to be left brain also has been affected. I have a significant gift or talent in the visual arts that I believe is at least partly due to this right-brain compensation as a result of what appears to be significant enough left hemisphere damage, so in that regard this would make sense. And though I was a victim of severe abuse, I don't display any of the Borderline Personality traits.
What's the source of this text? (who found these results and when, and when and where was it published?)
_________________
1975, ASD: Asperger's Syndrome (diagnosed: October 22, 2009)
Interests: science, experimental psychology, psychophysics, music (listening and playing (guitar)) and visual arts
Don't focus on your weaknesses, focus on your strengths
The text is self-written and based on a compilation of data I got from various sources. As I never intended to publish is and rather wrote it as a personal rant after my girlfriend dumped me last week I didn't really care to source reference it although I probably should be able to find the primary sources I based this article on if you really want me to look for them.
The text is self-written and based on a compilation of data I got from various sources. As I never intended to publish is and rather wrote it as a personal rant after my girlfriend dumped me last week I didn't really care to source reference it although I probably should be able to find the primary sources I based this article on if you really want me to look for them.
i'm curious what is the research that supports a connection between the left amygdala and AS? btw i really enjoyed the essay, interesting theory thanks for posting it
A few basic google searches give among others the following results :
Many boys and men with autism suffer from diminished social and communication skills. They may also suffer from a diminished number of neurons in their amygdala, according to the results of a new study. David Amaral and Cynthia Mills Schumann of the University of California, Davis, surveyed the number of neurons in the amygdala of nine autistic males and 10 nonautistic males ranging in age from 10 to 44. Painstakingly counting them under a microscope revealed significantly fewer neurons (electrical signaling cells) in the area of the brain associated with fear and memory.
"This is the first quantitative evidence of an abnormal number of neurons in the autistic amygdala," Amaral notes. "We were able to analyze more than double the number of previously examined postmortem brains, none of which had seizure disorders or any major neurological disorder other than autism."
Previous studies had relied on measures of the density of neurons as well as the brains of autistic males who had also suffered from epileptic seizures--a condition known to produce defects in the amygdala. Amaral and Schumann counted neurons with a three-dimensional probe at high magnification. They found that although there was no variance among amygdala volumes in all the brains, the autistic males as a group had roughly 1.5 million fewer neurons than their peers.
Other brain imaging studies have shown that autistic boys develop adult-size amygdala by around the age of eight, compared to late adolescence for other young males. And it remains unclear whether other brain regions in autistics might face a neuron deficit as well. "One possibility is that there are always fewer neurons in the amygdala of people with autism. Another possibility is that a degenerative process occurs later in life and leads to neuron loss," Schumann says. "More studies are needed to refine our findings." Their results appear in a paper published today in The Journal of Neuroscience.
source : http://bgrh.websitetoolbox.com/post?id=1270535
Of course, there are problems with the use of false belief tasks in testing theory of mind abilities. He and his colleagues have also conducted neuroimaging research, focusing on the amygdala. The amygdala is thought to be important for social reasoning, particularly in the recognition of thought, intention, and emotion in the faces of other individuals. In one experiment, individuals with Asperger syndrome and normal individuals (matched for IQ, again) looked at photos of people's eyes (which also show the eyebrows, and parts of the nose and forehead), and attempted to guess what the people were thinking. Non-autistic individuals perform quite well on this task, while Asperger patients perform very poorly. While the participants were performing the task, their brains were scanned using an fMRI machine. Consistent with the theory of mind theory of autism, non-autistic participants displayed increased activation in the amygdala, while Asperger participants displayed no increased activation, when performing the task4. If you want to look at the figure above (from the Baron-Cohen et al. paper, see footnote 4), the sides are reversed (the right side of the figure is the left side of the brain), the yellow indicates that the area was only active in the non-autistic participants, the red indicates that the area was only active in the Asperger participants, and the blue indicates that the area was active in both. The left amygdala is that little yellow area of activation that is in the middle (from top to bottom) and slightly to the right (meaning it's on the left side of the brain) in the image labeled.
source : http://mixingmemory.blogspot.com/2005/0 ... -mind.html
source : http://www.ncbi.nlm.nih.gov/pubmed/17321555
source :
page layout disrupting link packaged by lau
[...]
Subjects were asked to judge inner states from photographs of faces in which only the eyes could be seen, and to decide which of two simultaneously presented words best described the mental/emotional state. The baseline condition involved judging gender from the eyes. During performance of the mentalizing task, activity was seen in many brain areas including the three listed above. People with autism showed significantly less activity in the amygdala.
source : http://brain.oxfordjournals.org/cgi/con ... 125/8/1839
source : page layout disrupting link packaged by lau
No problem.
The text I wrote is basically a compilation of knowledge gained from personal observations by comparing my own experiences as an Aspie with those of NT people as well as BPD people and analyse how they differ with knowledge gained from reading texts like the ones I quoted hereabove.
I never realized NTs could untangle those conversations. That's quite amazing, and I almost envy it.
What a fascinating article. Perhaps you should formalize it and cite your sources; see if you can't publish somehow.
Or maybe you could present at Autreat . . . I'd be in the first row for an insider neurological piece.
If there is a growth/systemization issue here, as the previous quote suggests, is there any possibility that Asperger's, with no language delay, could relate to the proclivity towards certain neurological pathways being reinforced?
Even many Aspies can untangle conservations. As I pointed out in my article, the inability to untangle conversations is not something all Aspies have.
Thanks. I'll remind it.
People with Asperger's use different logical mechanisms for bypassing their filtering limitations. One would therefore expect that an impaired part of the brain related to filtering is compensated by parts of the brain related to logics being reinforced.
This was a very interesting article indeed! I came upon it when searching for info on the amydyla. I've been watching a fascinating series of shows on the National Geographic channel called Brain Games in which brain function is discussed and then demonstrated through a series of experiments/games. Most especially I focused on brain function during fear and anxiety experiences. My son has diagnosed Asperger's and his most significant hurdle right now is a lack of being able to assess whether something is a real threat requiring "life or death" type of reaction. For instance, he has difficulty imagining himself in a job or even being able to do some of what I do as his mom because he sees the skills involved as "super-human" and when very upset, imagines that he should be working in a coal mine 20 hours a day in order to be a productive member of society. He is 26. When he was 9, he felt he should go out and get a job to be productive, so the unrealistic thoughts have been there for quite awhile. We are working on finding someone to help him manage this so he can find his purpose and not find the world quite so frightening.
I have always felt that we had some brain function differences in our family, and a big one has always been anxiety.
Thank you for sharing that article
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