# CC layers interconnections according to TBT?

**URL:** <https://discourse.numenta.org/t/cc-layers-interconnections-according-to-tbt/8341>\
**Category:** Numenta Theory\
**Created:** [March 20, 2021, 7:49pm UTC](https://discourse.numenta.org/t/cc-layers-interconnections-according-to-tbt/8341 "2021-03-20T19:49:46Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![mraptor](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.numenta.org/mraptor/32/4469_2.png) [@mraptor](https://discourse.numenta.org/u/mraptor)\
**Post date:** [March 20, 2021, 7:49pm UTC](https://discourse.numenta.org/t/cc-layers-interconnections-according-to-tbt/8341/1 "2021-03-20T19:49:46Z")

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Can we get the full list of layers and their connectivity according to TBT ?

I have those extracted from somewhere :

```auto

L2,L3a,L3b,L4,L5tt, L5cc,L5ccns, L6a,L6b,L6ip,L6mp,L6bp

Cotex,Thalamus ==> Layer 4 (10%)
L6a ==> L4 (50%)
L4 ==> L3a
L3a ==> L5st
L5tt ==> L6b
L3a ==> Cortex
L5tt ==> Thalamus, Motor cortex
----

    L3b => L5cc
    L5cc => L5tt
    L5tt => Th
    L5cc <=> L6b

and this from a video :

Thalamus => L6
L4 => L2/3
L2/3 => L5, Cortex
L5 => BG & Ctx
L6 => Th

```

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**Author:** ![adam](https://avatars.discourse-cdn.com/v4/letter/a/4af34b/32.png) [@adam](https://discourse.numenta.org/u/adam)\
**Post date:** [March 20, 2021, 8:31pm UTC](https://discourse.numenta.org/t/cc-layers-interconnections-according-to-tbt/8341/2 "2021-03-20T20:31:50Z")

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Sorry to be so pessimistic but without a full theory of how the neocortex works this approach is in my mind doomed to fail. There are a lot of classifications out there and none / all of them are correct.

To provide an example:  
What do you mean with L6b cells, as you classified them? Are those L6CT cells, L6CC cells? or L6CT cells of the lower half and a half of L6CC cells. Is this classification solely by layer height or connectivity?

I have spent a long time reading neuroscience papers and you cant get information which is as simple as you would like it. Only when a theory and a biological observation agree that there are two sublayers and we have a way of interpretation it makes sense in my mind to start a specific classification scheme.

- Why do you classify neurons at all?

Only when you have a goal for your model, it makes sense to start a classification.

- What do you want your model to do?
- Do you need orientation and location in L6 and because of that it makes sense to have two sub-layers?

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**Author:** ![mraptor](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.numenta.org/mraptor/32/4469_2.png) [@mraptor](https://discourse.numenta.org/u/mraptor)\
**Post date:** [March 20, 2021, 9:17pm UTC](https://discourse.numenta.org/t/cc-layers-interconnections-according-to-tbt/8341/3 "2021-03-20T21:17:10Z")

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i was asking about classification according to the **CURRENT** version of TBT !