Numenta turns attention to The Thalamus!


#1


The HTM canon is extending downward to the thalamus - sometimes referred to as “the seventh layer of the cortex.”


#2

That is daisy chain logic based on my theories.


#3

You might do better to learn the common vocabulary and paradigms.
This would facilitate searches to find out what other people have done and avoid duplicate/wasted effort.

An additional bonus is that people will immediately understand what you are saying when you express your ideas and will know where they fit in and the value of what you are saying. Using vague and unfamiliar descriptions is a barrier to gaining acceptance to any new idea you may be trying to express.


#4

I did a small posting of my theory on daisy chain here in a very vanilla way. I mean in a modest Feynman style so all could understand. But on my end this is a highly developed for a complete ANN brain.

Yes i want to learn the name that HTM uses to describe there ideas. So when i publish
my work, and the work i have, will be completely void of all HTM essence.

I can make conscious machine in any medium, steam, vacuum tube, and etc…
Except i cannot do it in wet ware, real nerves. Because no one know how they really
work.

Kinda interesting HTM took this direction after i mentioned it. And it it is the right
direction.


#5

:man_facepalming:


#6

Ray Guillery of Oxford, England was proposing this model in 1995, and referencing much prior art in his paper.

These names and pathways of these neurological structures are well established in the literature. I have been reading neurological papers since the 70’s and noticed at that time that much of the anatomical references have been around since the late 1800’s. I always thought it was spooky that they worked out so much of this that long ago.

As far as the cortico-thalamo-cortical routes, I don’t recall anyone using “daisy chains” in anything that I have read from the 80’s and 90’s when this interpretation was offered. See figure 5 in this material from the early 1980’s:
http://scholarpedia.org/article/Thalamus

As I said before, unless you intend to rewrite all of the existing neurological literature, you might do better to learn the common vocabulary and paradigms.


#7

I don’t see the connection myself. From what I can tell, your daisy chain concept is about holding onto a (presumably unmodified) signal for an extended period of time by passing it around in a loop of connections like the game “hot potato”.

But that isn’t how I interpret the image in Numenta’s article:

Now granted I am no neuroscientist, but this doesn’t look like it is designed for holding onto a signal to me. The thalamus section looks more like a two-level hierarchy which is driven by activity in cortical layer 6 combined with neighboring activity in the thalamus.

Assuming this circuit is related to attention (I recall from previous conversations that cortical layer 6 and the thalamus are involved in attention), my naive interpretation of this circuit is that layer 6 is informing the thalamus what its region is currently attending to, and that input gets combined and abstracted with other activity outside of the region (from this diagram can’t really tell if that is activity from other cortical regions or from subcortical structures) in order to ultimately provide more weight to some subset of the input, thus influencing what is being attended to.

I should point out that I haven’t had a chance to read and absorb the materials on the thalamus that @Bitking has posed on previous threads, so above is a very uninformed interpretation. I’m mainly making the point that there isn’t any obvious correlation between this and the daisy chain concept.


#8

@keghn_feem - There are a couple of ways making a memory device with ANN. One way is to daisy
chain of neurons in a loop. Also known as a delay line, that feed back in. Like a RNN. But it is a pure transmission line and data is not changed.

and

I am liked the concept of using a daisy chain of nerves in a loop to hold a pules. Just like mercury memory delay lines like in the days of old.

I know of mercury delay lines as memory; some of the older mainframes that I am familiar with used these. There is no analog to this in neural hardware. There is considerable delay in long nerves such as from the feet to the head but this is not used as any sort of memory.

When it comes to neural hardware one of the more common mechanisms proposed to hold short-term working memories is reverberant connections within a single layer or between maps. This paper shows examples of these methods:
Synaptic reverberation underlying mnemonic persistent activity
http://www.cns.nyu.edu/wanglab/publications/pdf/wang2001a.pdf

There are also some synapses that have been measured to have activation time in minutes once triggered but I would have to dig in my archives to get a reference to those.


#9

@Bitking - Do you have a github site? I see a lot of your posts on the site and look forward to seeing what you have figured out with the htm theory.


#10

Still working on it; not ready for public viewing yet.
But RSN (Real Soon Now!)
I think it is going to irritate a lot of people and I want it solid so I don’t waste my time arguing over the poorly implemented details.


#11

I have a bit of a naive observation here. I have not had much time to look deeper into the thalamus and its numerous interactions with the neocortex, but upon first impression it kinda seems to me like the thalamus is performing the role of spatial (and maybe temporal) pooling.

  • It sits between the sensory inputs (or inputs from other regions) and the cortical columns responsible for the temporal memory encoding.
  • The thalamic relay neurons operate in tonic and bursting modes which seem capable of both moderating and distributing sub-cortical activation patterns for expected stimulus and registering surprise for unexpected inputs.

Up to this point, I had been viewing the spatial pooler algorithms as a necessary artifact that assist with the translation of the primitive activation patterns from the encoding process into a proper SDR pattern ready for consumption by the cortical columns of the temporal sequence memory. If my reading of this article is correct, then the thalamus itself (or perhaps some even lower structure) may be performing this function.

I realize this is probably an oversimplification, but does anyone else see this as a potential correlation?


#12

I have been touting the “three visual streams” paper for a while now.
The Deepleabra model does about as good of a job as any in showing how the thalamus interacts with the cortex, with the “three streams” paper being a masterwork for showing the model doing useful work.

The Thalamus and layer 5 do the heavy lifting in the feedback direction.

The Deepleabra predictive model is compatible with the HTM model and I can see them co-existing in the same system. In fact - there is much to like about two entirely different predictive models working together; I think that Mr. O’Reilly could learn a thing or two from the HTM model in the feed-forward direction.

It is a hard read but if you make it through you should have a good idea of how the “double-ended” hierarchy works to guide learning for a rapid convergence to an internal model.


#13

In that paper, TRN (and corresponding L6 projections) seems a bit underestimated :slight_smile:


#14

How about the RAS? The ties to the the nest of thalamic nuclei? The other sub-cortical structures?
Where do you stop? It is all tied together into bowl of gooey spaghetti-like connections.
In the end these other systems will have to be addressed but it may be too much to expect that right out of the gate.

Part of why my own work is proceeding so slowly is that I am trying to tie together several models into a working whole. Connecting a subset of the whole requires “filling in the blanks” to make up for the bits that I am not incorporating; some of these band-aids get pretty sketchy.

I do see some value in trying to abstract some minimal stand-alone systems and work out how they function.


#15

I understand that you need to prune unnecessary details . But the TRN role, IMHO, seems to be relevant.

A little interesting video about it :slight_smile:


#16

Thanks @vpuente. Being a visual person myself, I tend to absorb information from videos a lot easier. The process they described looks like a good candidate for addressing the “switching between objects without a reset” problem that has been discussed on some other threads. You can basically blast the new context when it appears in the input stream to quickly switch from one object to another, then resume normal operation.


#17

The RAC/RAS has been postulated as the “Searchlight of Attention” since this paper by F. Crick:


If you google the term “searchlight of attention” you can see that many papers since this one explore this concept (pro and con) and add considerable insight to the workings of this structure.
It is certainly an important adjunct to the interplay between the Thalamus and Cortex - I am not sure if the attention function should be a stand-alone feature apart from the data path or an inseparably part of function of these structures.

My personal take runs something like this; I see that the thalamus does at least two different functions in relation to the cortex.

One is closely related to the feedback path in the general direction through various hierarchies as described in the first post above.

There is nothing controversial here. I will add that this path is in parallel with the direct corticocortical pathways. I see the cortico-thalamic-cortical loop as being a command and control pathway where the cortico-cortical pathway is an information pathway.

The second function is also a control function but with a very different purpose - to activate or coordinate the basic information processing method of the cortex. It would be very wasteful to activate large swaths of the cortex where this is no information to be processed. The signal that something is to be recognized and/or learned would be a widespread “surprise” signal from local areas of the cortex. I see that this would trigger the start of traveling waves in that area of the cortex. Due to the map-spanning connections of the thalamus this same C&C function would be relayed to corresponding areas of related maps.

You may have seen this before but I invite you to read it again in light of this discussion:

With these thoughts in mind - the RAS is positioned to compare the (relatively) local activity between the cortex and thalamus. Given the two functions I have outlined above - and assuming that form follows function - where would this fit in for comparing the activity levels of the two structures?

One uses bursting to signal surprise, one uses bursting to jump-start activity. The RAS is looking for something and bursting seems like a very easy to detect to signal that could be sensed. What if it is simply acting to equalize activity between the two structures? In the process it would act to detect surprise and activate processing on the related information pathway, all using simple and relatively local functions.

This is agnostic as the WHAT/WHERE functions and is instead - a cortex wide processing method. Please note: Hierarchy/pathways is established here by genetic programming and is outside the scope of this discussion.


#18

This is a consciousness pointer that index through temporal memory.


#19

Um, give this a read and get back to me …

and


#20

Cool @Bitking. I see we have common thoughts. Have any thing new to tell? This from
a year ago.
I use pattern loop too. They are also a good way to compress data.