# Numenta Research Meeting, Nov 25, 2019

**URL:** <https://discourse.numenta.org/t/numenta-research-meeting-nov-25-2019/6847>\
**Category:** Current Research\
**Tags:** research, live\
**Created:** [November 25, 2019, 4:55pm UTC](https://discourse.numenta.org/t/numenta-research-meeting-nov-25-2019/6847 "2019-11-25T16:55:47Z")\
**Posts on this page:** 1\
**Showing post:** 6

<div class="post-metadata">

**Author:** ![gmirey](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.numenta.org/gmirey/32/2245_2.png) [@gmirey](https://discourse.numenta.org/u/gmirey)\
**Post date:** [November 25, 2019, 11:41pm UTC](https://discourse.numenta.org/t/numenta-research-meeting-nov-25-2019/6847/6 "2019-11-25T23:41:51Z")

</div>

@Falco: in the case of responsiveness to specific edge orientations, we have that kind of topological map all over V1:  
[![](https://www.researchgate.net/profile/Alexandre_Afgoustidis/publication/278793924/figure/fig3/AS:279951849869331@1443757130689/Modified-from-Bosking-et-al-7-An-Orientation-Preference-Map-observed-in-the-visual.png) ](https://www.researchgate.net/profile/Alexandre_Afgoustidis/publication/278793924/figure/fig3/AS:279951849869331@1443757130689/Modified-from-Bosking-et-al-7-An-Orientation-Preference-Map-observed-in-the-visual.png)

a pinwheel in that context is any of those particular spots where you have a central point surrounded by each possible color… and when he said the abstract schema of a circular arrangement surrounding an inhibitor was inspired by those, that triggered Jeff to look for it in the subsequent slides…

not all places are pinwheels, yet they are found with relative regularity. It seems to me it is quite “natural” that they do so in that topological context… but surely some tricky local inhibition has to be pervasive for arranging those beautiful color patches just the way they are.

not sure it was worth arguing about pinwheels specifically, though.

@CollinsEM : constraint on SDR yes.  
but I believe there’s still much encoding space to mess around…

> [@Stable-Enforced Pooling](https://discourse.numenta.org/t/stable-enforced-pooling/4028/25):
>
> About capacity concerns. Let’s say we consider a 2D patch of 2,000 cells, sparsely filled at 2% (40 of them active). SDR maths, if we were to pick those 40 at random, account for a staggeringly large number of encoding possibilities. Now if we add constraints relative to a grid Each triangle of roughly 50 cells has only one ‘position’ possibility. That consideration already greatly reduces the number of distinct encodable concepts here. But… it’s still somewhat huge (50 to the 40th power) N…

---

_[View the full topic](https://discourse.numenta.org/t/numenta-research-meeting-nov-25-2019/6847)._