Understanding the Relationship Between Aggression and Amygdala Size

[biferi]

Am I right that the level of aggression in a person will make the Amygdala Biger?

What I meen is if you are always aggressive your Amygdala will be very big in Size and stay Big in size?

 

[Pythagorean]

Hrm... I'm actually not sure about causation, but a bigger left amygdala is certainly correlated with aggression.

But it's been found that dysfunction in the amygdala can be a correlate, too:
http://www.sciencedirect.com/science/article/pii/S000632230601064X

And amygdala size also correlates with social networking:
http://www.ncbi.nlm.nih.gov/pubmed/21186358

Amygdala size was also correlated with sexual/play behavior.
http://psycnet.apa.org/journals/com/120/1/31/

 

[biferi]

So if the Left Amygdala isis Bigger then the Right the person will be more aggressive all the time?
And is everybody Born with a Bigger Left Amygdala?

And I know it is Almond Shape but is it the same size as an Almond?

 

[Pythagorean]

It appears I may have it backwards, though this is opposite of what I remember, so I'll look a little more.

" Volunteers with higher aggression scores displayed a 16-18% reduction of amygdala volumes."
http://www.ncbi.nlm.nih.gov/pubmed/22256828

I don't know how amygdalas are in a neurotypical brain, I'll see if I can find anything. Harder to search for that than disease basis.

 

[Pythagorean]

A striking feature of the studies that have addressed the measurement of the amygdala is the wide range of volumes encountered, with reports of volumes ranging from 1 to almost 4 cm(3). Another striking feature is the number of discrepancies in the landmarks adopted for manual tracing in magnetic resonance imaging (MRI). The goal of our study was to assess the anatomical volume of the amygdala on the basis of its cytoarchitecture while comparing the differences in age and sex. This study was performed on 21 normal male brains (mean age of 56.8 years) and 9 normal female brains (mean age of 61.2 years). The volume of the amygdala was measured by planimetry of Nissl-stained serial sections using ImageJ software. To address the complexity of the amygdala, we elected to use two types of amygdalar measurement that differ mainly in the definition of anterior pole boundaries. The average size of the classic amygdala was 1.24 cm(3) (S.D.=0.14), while the average size of the amygdala with wider borders was 1.63 cm(3) (S.D.=0.2). No interhemispheric or intersexual differences were observed for either type of amygdalar measurement. Neither sex revealed any statistically important relationship between volume of the amygdala and age. Our study was concerned exclusively with the anatomical volume of the amygdala rather than the MRI volume. Nevertheless, our results may have important implications for MRI studies because as of yet there is no gold standard for manual volumetry of the amygdala.

http://www.ncbi.nlm.nih.gov/pubmed/20227858

 

[Pythagorean]

Also, a note on the complexity of the amygdala:

The limbic system, and in particular the amygdala, have been implicated in autism. The amygdala is a complex structure that in rodents consists of at least 12 different nuclei or subnuclei. A comparative analysis of amygdala neuroanatomy in normal vs. autistic brains would be aided by the availability of molecular markers to unambiguously recognize these different amygdala substructures. Here we report on the development of methods to identify genes enriched in the central, lateral and medial nuclei of the rodent amygdala. Our results suggest that laser-capture microdissection of specific amygdala subnuclei, when combined with linear amplification of cRNA probes for oligonucleotide microarray hybridization, can efficiently identify genes whose expression is confined to these substructures. Importantly, many of these genes were missed in previous gene expression-profiling experiments using whole amygdala tissue. The isolation of human orthologs of these subnucleus-specific genes, and/or the application of these methods directly to human tissue, may provide useful markers for characterizing neuropathological correlates of autism, as well as for identifying molecular differences between normal and autistic brains.

http://www.ncbi.nlm.nih.gov/pubmed/14606693

 

[biferi]

So someone with a High Aggressive will have both left and right Amygdala smaller or just the left?

 

[biferi]

They say the Hypothalamas is as big as an Almond.

How Big is the Amygdala?

 

[Pythagorean]

I wasn't able to find out whether they measured left/right amygdala. No access to the paper, sorry.

This paper describes measurements of amygdala ranging form 1 to 4 cubed centimeters in volume:
http://www.ncbi.nlm.nih.gov/pubmed/20227858

 

[biferi]

Well I am in the USA so if you had to give a round about gess is the Amygdala the size of a Pea?

 

[mazinse]

wouldnt it be smaller, it processes primal emotions not causes aggression. A small one would mean one that's atrophied? I mean this would correlate with people who had brain injuries in their amydgala that are more prone to emotional issues.

 

[biferi]

Well when I look up Amygdala it says it controls Flight or Fight.

And people that always worring about things and think people are out to get them I thought it would be Biger?

 

[mazinse]

in the studies involving brain trauma and later criminal activity, the hippocampus actually plays a bigger role relative to the amygdala, try to look that up