Introducing the brain: one cubic millimeter pictured (Introduction)

by David Turell , Friday, May 10, 2024, 15:07 (195 days ago) @ David Turell

Amazingly complex; view the illustrations:

https://www.sciencealert.com/amazingly-detailed-images-reveal-a-single-cubic-millimeter...

"It's just a millimeter on each side – but 57,000 cells, 150 million synapses, and 230 millimeters of ultrafine veins are all packed into that microscopic space.

"The work of almost a decade, it's the largest and most detailed reproduction of the human brain to date down to the resolution of the synapses, the structures that allow neurons to transmit signals between them.

"'The word 'fragment' is ironic," says neuroscientist Jeff Lichtman of Harvard University. "A terabyte is, for most people, gigantic, yet a fragment of a human brain – just a miniscule, teeny-weeny little bit of human brain – is still thousands of terabytes."

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"The team's reconstruction was based on a sample of human brain excised from an epilepsy patient during surgery to access an underlying lesion. The sample was fixed, stained with heavy metals to accentuate the details, embedded in resin, and sectioned into 5,019 slices, with a mean thickness of 33.9 nanometers, collected on tape.

"The researchers used high-throughput serial section electron microscopy to image this tiny piece of tissue in mind-numbing detail, generating 1.4 petabytes (1,400 terabytes) of data.

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"This reconstruction, named H01, has already revealed some previously unseen fine details about the human brain. The team was surprised to note that glia, or non-neuronal cells, outnumbered neurons 2:1 in the sample, and the most common cell type was oligodendrocytes – cells that help coat axons in protective myelin.

"Each neuron had thousands of relatively weak connections, but the researchers found rare, powerful sets of axons connected by 50 synapses. And they found that a small number of axons are arranged in unusual, extensive whorls."

Comment: see the mind-blowing illustrations in the article, a three-minute adventure. We can never fully understand the connectome. Darwin theory type of evolution cannot create this.