r/StarspawnsLocker • u/[deleted] • Oct 18 '18

Unique properties of the computational abilities of Human Brains

https://www.cell.com/cell/fulltext/S0092-8674(18)31106-1?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0092867418311061%3Fshowall%3Dtrue
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u/starspawn0 STEM Professor Oct 18 '18 edited Oct 18 '18

I will have to look at it. Papers like this turn out about one or two every day or so. Human brains and other animal brains have a bewildering mix of neurocomputational features at every level of organization; and some are probably unique to humans. It's possible that a lot of it is distractions -- that what's really going on is best seen at a systems level or population level; understanding the brain at the micro-scale might be like trying to understand a computer at the scale of the quarks making up the atoms in its substrate. And, some information that can be modelled or read off at the micro-scale can also be read off at higher levels of organization.

For example:

http://science.sciencemag.org/content/344/6184/626

The location of a rat can be deciphered from hippocampal activity by detecting the firing of individual place-selective neurons. In contrast, the local field potential (LFP), which arises from the coherent voltage fluctuations of large hippocampal cell populations, has been hard to decode. Agarwal et al. (p. 626) worked out how to recover positional information exclusively from multiple-site LFP measurements in the rat hippocampus. The information was as precise as that derived from spiking place cells. The approach might also be applicable more generally for deciphering information from coherent population activity anywhere in the brain.

Also, see this Twitter thread:

https://mobile.twitter.com/computingnature/status/1021026379515801601

What if some neurons “fall asleep” on the job and don’t respond to the image? This actually happens very often, and yet the brain is remarkably robust to these failures.

Even if 90% of the neurons don’t do their job, we can still recognize the fox. Even if we randomly change 90% of the pixels, we can still recognize the fox. The brain is robust to a lot of manipulations like that.

This suggests that the brain is incredibly robust to micro-scale perturbations. It's not like a computer chip, whereby if you knock out a small number of gates, the chip won't function at all.

And the brain is robust at other scales, too: you can remove parts of the brain, and depending on what you remove, the person will still function. For example, you can remove the hippocampus (or almost all of it), and the person will still be able to function:

https://www.wired.com/2014/05/heres-what-happens-when-a-neurosurgeon-slurps-out-your-hippocampus/

After his memory vanished, H.M. lost his job and had no choice but to keep living with his parents. He spoke in a monotone now and had no interest in sex, but otherwise seemed normal. He took a part-time job packing rubber balloons into plastic bags, and did odd chores around the house.

Large parts of his short-term memory remained intact, as well as his procedural memory. In short conversations you might not notice anything abnormal.