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> These individuals probably also exhibit diminished cognitive function as well. I wonder how much of that is "the cerebellum is also involved in cognition" an

> These individuals probably also exhibit diminished cognitive function as well. I wonder how much of that is "the cerebellum is also involved in cognition" and how much of that is "with the rest of the brain picking up the additional load, there's less "processing power" available for other things".

yohanatan 12y ago
Could it be that the cerebellum is merely a communication channel for other parts of the brain which are more focused on cognition. After injury one would not expect immediate re-routing of these channels.
ekr 12y ago
I'm not very invested in this field, however, this "processing power" metaphor sound like those ideas "where people only use 10% of their brain". The brain doesn't work like that, it's not a general purpose computer. It's made up of several independent mechanisms, that have little to do with each other, and that have emerged at different points in evolution, driven by different forces. So their creation is rather chaotic.
- SupremumLimit 12y ago
  Generally yes, but neuroplasticity does in fact exist: http://en.wikipedia.org/wiki/Neuroplasticity http://en.wikipedia.org/wiki/Neuroplasticity
- jnem 12y ago
  Are you saying our brains follow the Law of Demeter?
- icambron 12y ago
  I think that sort of misses the point of the metaphor as used here. If one big part of the brain is missing, and thus the mechanisms it enables are unavailable, some other part of the brain (at least in this case) makes up for it by providing an approximation of that mechanism. That other part of the brain is thus not able to perform whatever its normal function would be; even if it's doing double-duty, you expect that there's some capacity limit. When and if that deprioritized function involves reasoning, then you'd expect a drop in reasoning ability. Thus the "processing power" metaphor is simply saying that if a neuron is busy doing something, it can't also be busy doing other things.
- jacquesm 12y ago
  There is very interesting book called 'the brain that heals itself' that argues quite strongly against that.
wpietri 12y ago
A very interesting question! For me, some of the way I think things through seems very physical to me. The sort of thing you do when you pick up lunch table objects and say, "Ok, this salt shaker is the web server, this fork is the firewall, and..." Except I'm more likely to do it with just gestures, or just thinking about placing things in an imaginary space. I wonder how much of that is really enlisting the cerebellum versus it being an output-only thing. Perhaps nominally output-only devices do more. As in rubber-duck debugging or Flannery O'Connor's line, "I write because I don't know what I think until I read what I say."
blennon 12y ago
My PhD adviser and I have had that debate a number of times. For the congenital case, we can't say one way or the other. But in the acute case, where there are localized lesions to the parts of the cerebellum thought to be involved in cognition, the effect seems to be primarily cognitive. From anatomical studies, we also know that there are "loops" formed between non-motor areas of the cerebral cortex and the cerebellum.
- TheLoneWolfling 12y ago
  But couldn't that alternatively be explained by the cerebral cortex being able to act as a "backup" of sorts for the cerebellum, to the extent of "neglecting" its ordinary tasks? It would make sense if the brain were to "consider" motor control to be at a higher priority than cognition, and was designed as such. (Sort of like in a pinch a kitchen might use a cook as a dishwasher.) I'm using wishy-washy words here, sorry. I don't know how better to explain it.
  - blennon 12y ago
    It's unclear whether the circuitry of the cerebral cortex has the ability to implement the function of the cerebellum (whatever that may be, which we don't really understand). I think we're a long ways off from answering that question.
    - TheLoneWolfling 12y ago
      Well, given this development, I think it's fair to say there's something else that can implement the function of the cerebellum.
      - blennon 12y ago
        Something that can partially implement the function of the cerebellum.
        TheLoneWolfling 12y ago
Pxtl 12y ago
Or just "if there's something so wrong with your brain that the cerebellum is completely missing, odds are there is some hard-to-detect abnormalities in the rest of the brain".
- TheLoneWolfling 12y ago
  Good point, hadn't considered that.
- Sharlin 12y ago
  Ah, always look for confounders :)

yohanatan 12y ago

Could it be that the cerebellum is merely a communication channel for other parts of the brain which are more focused on cognition. After injury one would not expect immediate re-routing of these channels.

ekr 12y ago

I'm not very invested in this field, however, this "processing power" metaphor sound like those ideas "where people only use 10% of their brain". The brain doesn't work like that, it's not a general purpose computer. It's made up of several independent mechanisms, that have little to do with each other, and that have emerged at different points in evolution, driven by different forces. So their creation is rather chaotic.

SupremumLimit 12y ago
Generally yes, but neuroplasticity does in fact exist: http://en.wikipedia.org/wiki/Neuroplasticity http://en.wikipedia.org/wiki/Neuroplasticity
jnem 12y ago
Are you saying our brains follow the Law of Demeter?
icambron 12y ago
I think that sort of misses the point of the metaphor as used here. If one big part of the brain is missing, and thus the mechanisms it enables are unavailable, some other part of the brain (at least in this case) makes up for it by providing an approximation of that mechanism. That other part of the brain is thus not able to perform whatever its normal function would be; even if it's doing double-duty, you expect that there's some capacity limit. When and if that deprioritized function involves reasoning, then you'd expect a drop in reasoning ability. Thus the "processing power" metaphor is simply saying that if a neuron is busy doing something, it can't also be busy doing other things.
jacquesm 12y ago
There is very interesting book called 'the brain that heals itself' that argues quite strongly against that.

wpietri 12y ago

A very interesting question! For me, some of the way I think things through seems very physical to me. The sort of thing you do when you pick up lunch table objects and say, "Ok, this salt shaker is the web server, this fork is the firewall, and..." Except I'm more likely to do it with just gestures, or just thinking about placing things in an imaginary space. I wonder how much of that is really enlisting the cerebellum versus it being an output-only thing. Perhaps nominally output-only devices do more. As in rubber-duck debugging or Flannery O'Connor's line, "I write because I don't know what I think until I read what I say."

blennon 12y ago

My PhD adviser and I have had that debate a number of times. For the congenital case, we can't say one way or the other. But in the acute case, where there are localized lesions to the parts of the cerebellum thought to be involved in cognition, the effect seems to be primarily cognitive. From anatomical studies, we also know that there are "loops" formed between non-motor areas of the cerebral cortex and the cerebellum.

TheLoneWolfling 12y ago
But couldn't that alternatively be explained by the cerebral cortex being able to act as a "backup" of sorts for the cerebellum, to the extent of "neglecting" its ordinary tasks? It would make sense if the brain were to "consider" motor control to be at a higher priority than cognition, and was designed as such. (Sort of like in a pinch a kitchen might use a cook as a dishwasher.) I'm using wishy-washy words here, sorry. I don't know how better to explain it.
- blennon 12y ago
  It's unclear whether the circuitry of the cerebral cortex has the ability to implement the function of the cerebellum (whatever that may be, which we don't really understand). I think we're a long ways off from answering that question.
  - TheLoneWolfling 12y ago
    Well, given this development, I think it's fair to say there's something else that can implement the function of the cerebellum.
    - blennon 12y ago
      Something that can partially implement the function of the cerebellum.
      - TheLoneWolfling 12y ago

Pxtl 12y ago

Or just "if there's something so wrong with your brain that the cerebellum is completely missing, odds are there is some hard-to-detect abnormalities in the rest of the brain".

TheLoneWolfling 12y ago
Good point, hadn't considered that.
Sharlin 12y ago
Ah, always look for confounders :)