Connectionists: Real or virtual? Grandmother cells or "virtual" grandmother patterns?

[David Kappel]

Theory offers another possible solution to the puzzle that brains can 
function in a stable manner, although neural codes drift, as 
demonstrated most recently through experimental data in the Neuron paper 
by Driscoll et al. from the Harvey Lab. The preprint

Reward-based stochastic self-configuration of neural circuits

https://arxiv.org/abs/1704.04238

shows that from a theoretical perspective stable reward-based learning 
does not require stable neural codes or stable synaptic connections. In 
fact, it is likely to work better without them.

-- 
David Kappel
Institute for Theoretical Computer Science
Graz University of Technology
Inffeldgasse 16b,  A-8010 Graz,  Austria
Tel.:  ++43/316/873-5847
http://www.igi.tugraz.at/kappel/


On 2017-08-27 05:54, Richard Loosemore wrote:
>
> Back in 2010 I wrote a paper with T.A. Harley in which we argued that 
> "concepts" (like [grandmother]) are likely to be *virtual* patterns of 
> activity on neural circuits and NOT hard coded into the circuits 
> themselves.
>
> So, for example, a virtual pattern of activity might come and go 
> between active and dormant states, or it could move around the brain 
> (perhaps from one column to another).
>
> In support of this conclusion, we pointed out that  common 
> interpretations of brain imaging data were simply not consistent with 
> the usual assumption, which is that neurons directly represented 
> concepts.  We pointed, in particular, to the infamous Jennifer Aniston 
> Cell paper, where the virtual concept hypothesis was the only viable one.
>
> And yet, the "virtual" idea is almost completely absent from the 
> literature.  Why?  If concepts are virtual, this would make a nonsense 
> of many interpretations of neuroscience results, because firing 
> patterns would only have a weak relationship to meaningful entities 
> like concepts.  (Think about it:  if concepts can wander around the 
> cortex, what is the point in saying that a particular place in cortex 
> corresponds to a semantically tangible thing?).
>
> Anyway, I note that a recent paper from Laura N. Driscoll, Noah L. 
> Pettit, Matthias Minderer, Selmaan N. Chettih, and Christopher D. 
> Harvey (Dynamic Reorganization of Neuronal Activity Patterns in 
> Parietal Cortex): Dynamic Reorganization of Neuronal Activity Patterns 
> in Parietal Cortex
>
> http://www.cell.com/cell/pdf/S0092-8674(17)30828-0.pdf
>
> (Overview here: 
> http://news.harvard.edu/gazette/story/2017/08/brain-flexibility-changes-the-way-we-remember-and-learn/)
>
> ... brings yet another confirmation of the "virtual" concept 
> hypothesis.  The most parsimonious interpretation of their results is 
> that the activity patterns are changing precisely because the 
> "concepts" (when active) are not identifable with fixed hardware, but 
> are actually virtual.
>
> It seems to me this is one of the most important issues in all of 
> neuroscience, since it changes the flavour of every result out there.
>
> What do you think?
>
> ---
>
> Richard Loosemore
>
>
>
> Reference
>
> Loosemore, R.P.W. & Harley, T.A. (2010). Brains and Minds: On the 
> Usefulness of Localization Data to Cognitive Psychology. In M. Bunzl & 
> S.J. Hanson (Eds.), Foundational Issues in Human Brain 
> Mapping.Cambridge, MA: MIT Press
>
> https://www.academia.edu/563588/Brains_and_Minds_On_the_Usefulness_of_Localization_Data_to_Cognitive_Psychology
>
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