
The cerebellum is your “little brain”, and it does some pretty big things - LinuxBender
https://www.scientificamerican.com/article/the-cerebellum-is-your-little-brain-and-it-does-some-pretty-big-things/
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ryanmetz
Back when I was a neuroscientist I had a fun conversation at SfN (the largest
neuro conf in the world) with a big up-and-coming researcher about the
cerebellum. Her take was "I hate that thing. If I never have to read another
paper about it again that would be great. It's dumb. I wish we could get rid
of it." I wonder how she's feeling about it these days...

~~~
Animats
That attitude is a big problem. The cerebellum is where all the important
stuff happens. In the lower mammals, the cerebellum is most of the brain. The
cortex is just the back-seat driver sending goals to the cerebellum.

Bio researchers have done work on decorticated cats. "The cats ate, drank and
groomed themselves adequately. Adequate maternal and female sexual behaviour
was observed. They utilized the visual and haptic senses with respect to
external space."[1] The cortex is optional for basic survival.

The cerebellum had been far too neglected in AI research. I used to refer to
this as the "hole in the middle" of AI. We had the expert systems guys working
on logical abstractions, and the behavior-based people working on near-
stateless stimulus-response systems. Not much in the middle. That's what got
me interested in legged running for robots. But it turns out that's better
approached as a dynamics problem than as an AI problem, so that didn't lead to
a cerebellum. Just a lot of banging on differential equations. On most
practical problems, it's easier to engineer a special case solution than to
develop something cerebellum like. So there's been low pressure to fix this
hole.

The really important stuff in life is getting through the next 10 seconds
without a major screwup. If that doesn't work well, and consistently well,
survival is unlikely. AI remains bad at this. Robots have this problem big-
time. For self-driving cars, vast efforts have been required to make it work
at all.

The cerebellum evolved first. The cortex is a relatively modern development.
If we really knew how it worked and could make a good functional one for a
robot, we'd probably have most of the parts needed for a cortex. But we don't.

When you see a paper like this, [2] you realize the extent of our ignorance.
This is like cutting an IC into little chunks and doing a chemical analysis on
each chunk to figure out what it does.

[1]
[https://link.springer.com/article/10.1007/BF00234897](https://link.springer.com/article/10.1007/BF00234897)
[2] [https://www.mpg.de/12027342/molecular-atlas-reptile-
brain](https://www.mpg.de/12027342/molecular-atlas-reptile-brain)

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georgewfraser
Decorticated cats have their whole midbrain, it's not the cerebellum that's
doing all that. Also, the cortex is more dominant in primates. Decorticate
humans can't do much of anything. Also, humans can live without a cerebellum:

[https://en.wikipedia.org/wiki/Cerebellar_agenesis](https://en.wikipedia.org/wiki/Cerebellar_agenesis)

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SubiculumCode
Cool, but the direct link needs to be confirmed in humans. I recently recall
David Amaral, who has done a lot of the great post-mortem work on the
hippocampus and amygdala, telling me that it used to be thought that left and
right hippocampi were connected by axon projections in humans just like they
were in rodents, but this proved not to be the case.

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jamesblonde
Great talk on speculative links between the cerebellum and deep learning here
by Martin Nilsson in RISE SICS, Sweden:
[https://www.youtube.com/watch?time_continue=951&v=OQ_-01V44D...](https://www.youtube.com/watch?time_continue=951&v=OQ_-01V44DE)

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hyperpallium
\tangent In the spirit of understanding the mind in terms of the engineering
of the day, the cerebellum's striated structure seems something of a DSP, for
linear processing, especially where timing is involved.

There's a dramatic contrast between the sophistication of optogenetics, and
the primitive hypotheses being tested: is this connected to that?

Does there need to be a direct connection, or could other parts of the brain
use the cerebellum, when limear/timing is needed, for particular stages of
processing, like a math co-processor?

e.g. Is it possible that instead of direct "wired" connections, there's a
packet radio or UDP-like system, where neurons (or columns of neurons) aren't
directly signalling, but passing on a packet of information to be shunted
elsewhere in the brain.

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outworlder
> For about two centuries the scientific community believed the cerebellum
> (Latin for “little brain”), which contains approximately half of the brain’s
> neurons, was dedicated solely to the control of movement.

This is mind-boggling. Considering the chaotic nature of natural selection,
why would such a big structure be neatly organized and compartmentalized like
a computer processor?

