[ExI] 1 mm^3 of brain

[Jason Resch]

On Tue, May 14, 2024 at 8:13 AM Stuart LaForge via extropy-chat <
extropy-chat at lists.extropy.org> wrote:

> I have not had time for a close look yet, but I thought you guys would
> appreciate this:
>
>
> https://www.technologyreview.com/2024/05/09/1092223/google-map-cubic-millimeter-human-brain/
>
> "A team led by scientists from Harvard and Google has created a 3D,
> nanoscale-resolution map of a single cubic millimeter of the human
> brain. Although the map covers just a fraction of the organ—a whole
> brain is a million times larger—that piece contains roughly 57,000
> cells, about 230 millimeters of blood vessels, and nearly 150 million
> synapses. It is currently the highest-resolution picture of the human
> brain ever created."
>

Stuart,

Thank you for sharing this. I've incorporated it into an article I am
working on which covers this exact topic. I am including a link here in
case it might be of further interest to you or other members of this list:
https://drive.google.com/file/d/17hj92VycZd5ZHY9P1FU3PGhiOqjsKfPQ/view?usp=drive_link

These subsections cover some of the recent (and past) progress in
integrating with, simulating, and scanning human (and non-human) brains.


>
> That is some crazy resolution, but how much resolution constitutes
> functional isomorphism? Are rational numbers sufficient to preserve
> identity or are real numbers required?
>

I think it is doubtful that real numbers (i.e. infinite precision) are
important to the workings of our brains. As Chalmers writes:

"There is good reason to believe that absolute continuity cannot be
essential to our cognitive competence, however. The presence of background
noise in biological systems implies that no process can depend on requiring
more than a certain amount of precision. Beyond a certain point,
uncontrollable fluctuations in background noise will wash out any further
precision. This means that if we approximate the state of the system to
this level of precision, then we will be doing as well as the system itself
can reliably do. It is true that due to nonlinear effects, this
approximation may lead to behavior different from the behavior produced by
the system on a given occasion--but it will lead to behavior that the
system might have produced, had biological noise been a little different."
-- David Chalmers in "The Conscious Mind
<https://www.google.com/books/edition/The_Conscious_Mind/0fZZQHOfdAAC?hl=en&gbpv=1&printsec=frontcover&bsq=%22There%20is%20good%20reason%20to%20believe%20that%20absolute%20continuity%22>"
(1996)

I cover this topic in great detail in these subsections, which deal with
the question of computability, both in physics, and in our brains:
https://drive.google.com/file/d/1et-TdQ6oVKcHGv0fJ1k0njFTGb9T93j1/view?usp=drive_link

Jason
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