Introducing the brain: human neurons different (Introduction)

by David Turell , Thursday, November 11, 2021, 20:23 (890 days ago) @ David Turell

Differ from all other mammalians:

https://www.sciencedaily.com/releases/2021/11/211110131613.htm

"Human neurons have a lower density of ion channels than expected, compared to neurons of other mammals, according to a new study. The researchers hypothesize that a lower channel density may have helped the human brain evolve to operate more efficiently.

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"Harnett and his colleagues analyzed neurons from 10 different mammals, the most extensive electrophysiological study of its kind, and identified a "building plan" that holds true for every species they looked at -- except for humans. They found that as the size of neurons increases, the density of channels found in the neurons also increases.

"However, human neurons proved to be a striking exception to this rule.

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"The researchers found that in nearly every mammalian species they looked at, the density of ion channels increased as the size of the neurons went up. The one exception to this pattern was in human neurons, which had a much lower density of ion channels than expected.

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"The human brain represents a striking deviation from this building plan, however. Instead of increased density of ion channels, the researchers found a dramatic decrease in the expected density of ion channels for a given volume of brain tissue.

"The researchers believe this lower density may have evolved as a way to expend less energy on pumping ions, which allows the brain to use that energy for something else, like creating more complicated synaptic connections between neurons or firing action potentials at a higher rate.

"'We think that humans have evolved out of this building plan that was previously restricting the size of cortex, and they figured out a way to become more energetically efficient, so you spend less ATP per volume compared to other species," Harnett says." (my bold)

Comment: My bold may hold the key. Our big brain burns 20% of daily energy expenditure, and this may be a trick to hold down the energy requirement. Makes humans different in another way. Close apes and monkey brains need to be reviewed to see how their neurons relate to us.