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Every mammal brain contains hordes of pyramidal neurons, a common type of brain cell found in the cerebral cortex. Pyramidal cells take in information from multiple sources then send out a single message to the next neuron in the circuit. These cells possess a thick forest of short dendrites and a single long dendrite — like a tree with its roots pulled out of the ground. But not elephants. Their pyramidal cells look more like long-legged spiders with a few long branches.
Yet, elephant pyramidal neurons have the same total length of dendrites as primate neurons. This implies both cell types can process the same amount of information — so why are they organized in different ways? The long-reaching dendrites might be a consequence of the stretched-out elephant cortex. Compared to humans, elephant brains have more cortical real estate and fewer neurons to accommodate: their brains are three times bigger than humans’, but their cortices contain only two-thirds of the neurons. That means neuronal cell bodies and their dendrites can spread out as the elephant cortex forms.
The different shape also might allow elephants to be elephants. A few long, meandering dendrites on a single cell may combine information from many cells over an extended period of time, while the dense, short dendrites in primate neurons may be best suited for rapid-fire decisions. This more thoughtful cell structure might contribute to elephants’ special qualities, like their creative problem-solving, empathy, complex social structures, and tool use.
Bekkers, J. M. (n.d.). Pyramidal neurons. Retrieved from https://www.cell.com/current-biology/pdf/S0960-9822(11)01198-5.pdf
Jacobs, B. (2019, August 09). What elephants' unique brain structures suggest about their mental abilities. Retrieved October 28, 2020, from https://theconversation.com/what-elephants-unique-brain-structures-suggest-about-their-mental-abilities-100421
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