Read on TwitterDiscussion this week about it being organized as a *heterarchy*, which can be defined as something lacking a hierarchical organization.
Here& #39;s a thread about this and why a heterarchy doesn& #39;t mean the brain is spaghetti!
I suggested the following principle of brain organization : *Massive Combinatorial Anatomical Connectivity*
Rich connectivity is not limited to specific sectors of the brain such as the popular PFC.
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Rich connectivity is not limited to specific sectors of the brain such as the popular PFC.
It encompasses all brain sectors, cortical and subcortical (amygdala, thalamus, brainstem, cerebellum).
Anatomical properties include: (i) massive
interconnectivity; (ii) high global accessibility; and (iii) the existence of a ‘connectivity core’ or ‘rich-club’ of regions.
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Anatomical properties include: (i) massive
interconnectivity; (ii) high global accessibility; and (iii) the existence of a ‘connectivity core’ or ‘rich-club’ of regions.
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Another outstanding treatment of this idea is that by Markov, Kennedy and collaborators who suggest a bow-tie organization.
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Markov et al. described a core set of 17 regions spanning
parietal, temporal, and frontal cortex that was marked by 92% connectivity density (92% of the
connections that could exist were present).
This was only cortex, imagine when we add thalamus, amygdala, etc.!
https://abs.twimg.com/emoji/v2/... draggable="false" alt="▶️" title="Nach rechts zeigendes Dreieck" aria-label="Emoji: Nach rechts zeigendes Dreieck">
parietal, temporal, and frontal cortex that was marked by 92% connectivity density (92% of the
connections that could exist were present).
This was only cortex, imagine when we add thalamus, amygdala, etc.!
When people emphasize *heterarchy* the point is NOT to suggest that anything goes. The brain is highly structured anatomically, in a way that has a deep evolutionary history of at least 500 million years with vertebrates.
(that discussion for another day!)
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(that discussion for another day!)
*Amygdala*: basolateral and separately central.
There are lots and lots of other examples that can be highlighted against hierarchical organization, the above were relatively arbitrary. I like the amygdala so much that I& #39;ll described that another time!
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There are lots and lots of other examples that can be highlighted against hierarchical organization, the above were relatively arbitrary. I like the amygdala so much that I& #39;ll described that another time!
