UW Subutai Presentation Slides

vpuente · October 4, 2018, 2:48pm

vpuente · October 4, 2018, 2:58pm

I hope to see the papers soon to clarify my doubts* about this approach

*My main concern is that grid cells are in the Entorhinal cortex, which seems pretty integrated within the hippocampal function. I can’t reconcile the double copy of cortex/hippocampus and (SWR) learning cycles [1] with this vision. My wild guess is that grid cell is involved into that (v.gr. replay over the proper cortex region the hippocampus temporal content).

[1] https://www.youtube.com/watch?v=8AHRRyzYyUI&list=PLr61GWfwVkofCN7we64nIMlw4okbwYKtG&index=5&t=0s

Bitking · October 4, 2018, 4:53pm

@vpuente From what I understand - Grid cell behavior has been documented in the hub areas of all cortical lobes; this does seem to be the Lingua franca between the hub areas.

My take is that the various hierarchies work to pick apart as many features as possible as the processing ascends the chain. The end product in the association areas is a vast constellation of points of features that are combined in the grid areas to signal abstracted meaning.

This take is slightly different than what has been offered as the new HTM canon but I am sticking with my interpretation for now.

rhyolight · October 5, 2018, 10:16pm

20 posts were split to a new topic: Cortical grid cells and Abstract ideas

vpuente · October 5, 2018, 8:20am

@Bitking I didn’t know that. Do you have some reference? My (incorrect) understanding was that they are pretty integrated with CA1 place cells.

Bitking · October 6, 2018, 1:52am

Evidence for grid cells in a human memory network

ncbi.nlm.nih.gov

Evidence for grid cells in a human memory network.

CF Doeller, C Barry and N Burgess, Nature, Feb 2010 04

Grid cells in the entorhinal cortex of freely moving rats provide a strikingly periodic representation of self-location which is indicative of very specific computational mechanisms. However, the existence of grid cells in humans and their distribution throughout the brain are unknown. Here we show that the preferred firing directions of directionally modulated grid cells in rat entorhinal cortex are aligned with the grids, and that the spatial organization of grid-cell firing is more strongly apparent at faster than slower running speeds. Because the grids are also aligned with each other, we predicted a macroscopic signal visible to functional magnetic resonance imaging (fMRI) in humans. We then looked for this signal as participants explored a virtual reality environment, mimicking the rats' foraging task: fMRI activation and adaptation showing a speed-modulated six-fold rotational symmetry in running direction. The signal was found in a network of entorhinal/subicular, posterior and medial parietal, lateral temporal and medial prefrontal areas. The effect was strongest in right entorhinal cortex, and the coherence of the directional signal across entorhinal cortex correlated with spatial memory performance. Our study illustrates the potential power of combining single-unit electrophysiology with fMRI in systems neuroscience. Our results provide evidence for grid-cell-like representations in humans, and implicate a specific type of neural representation in a network of regions which supports spatial cognition and also autobiographical memory.

These papers follow these same macro pathways described above. These confirm the activity pattern without the enlightened interpretation

Neural representations of location outside the hippocampus.

ncbi.nlm.nih.gov

Neural representations of location outside the hippocampus.

JJ Knierim, Learning & memory (Cold Spring Harbor, N.Y.), Jul-Aug 2006

Place cells of the rat hippocampus are a dominant model system for understanding the role of the hippocampus in learning and memory at the level of single-unit and neural ensemble responses. A complete understanding of the information processing and computations performed by the hippocampus requires detailed knowledge about the properties of the representations that are present in hippocampal afferents and efferents in order to decipher the transformations that occur to these representations in the hippocampal circuitry. Neural recordings in behaving rats have revealed a number of brain areas that contain place-related firing properties in the parahippocampal regions and in other brain regions that are thought to interact with the hippocampus in certain behavioral tasks. Although investigators have just begun to scratch the surface in terms of understanding these properties, differences in the precise nature of the spatial firing between the hippocampus and these other regions promise to reveal important clues regarding the exact role of the hippocampus in learning and memory and the nature of its interactions with other brain systems to support adaptive behavior.

Differential Recruitment of the Hippocampus, Medial Prefrontal Cortex, and the Human Motion Complex during Path Integration in Humans

vpuente · October 7, 2018, 9:16pm

Thanks! Thats a lot of information to process

Bitking · October 8, 2018, 12:24am

Here is some more direct support:

ncbi.nlm.nih.gov

Organizing conceptual knowledge in humans with a gridlike code.

AO Constantinescu, JX O'Reilly and TEJ Behrens, Science (New York, N.Y.), Jun 2016 17

It has been hypothesized that the brain organizes concepts into a mental map, allowing conceptual relationships to be navigated in a manner similar to that of space. Grid cells use a hexagonally symmetric code to organize spatial representations and are the likely source of a precise hexagonal symmetry in the functional magnetic resonance imaging signal. Humans navigating conceptual two-dimensional knowledge showed the same hexagonal signal in a set of brain regions markedly similar to those activated during spatial navigation. This gridlike signal is consistent across sessions acquired within an hour and more than a week apart. Our findings suggest that global relational codes may be used to organize nonspatial conceptual representations and that these codes may have a hexagonal gridlike pattern when conceptual knowledge is laid out in two continuous dimensions.

This grid-like signal is not unique to the entorhinal cortex, but can be measured during spatial navigation in prescribed parts of the medial frontal, medial parietal and lateral temporal cortices. Despite no report in rodents of grid cells outside the hippocampal formation, direct recordings during brain surgery in humans have confirmed grid-like firing patterns in some of these areas. This same network of brain regions, often referred to as the ‘default mode network’, is also regularly activated in non-spatial tasks that involve the manipulation of conceptual knowledge, such as memory, imagination, scene construction, valuation and theory of mind, and in situations when subjects must generalize learnt concepts to novel situations.

This should address any objections to my assertions that hex-grid cells are found in hub areas of the cortex.
And more support:

sgaseretto · October 9, 2018, 3:06pm

Are there any recordings of this presentation?

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Locations in the Neocortex: A Theory of Sensorimotor Object Recognition Using Cortical Grid Cells Related Papers location , grid-cells , displacement-cells	13	1384	December 20, 2020
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Numenta Research Meeting, Nov 25, 2019 Current Research research , live	10	1014	November 27, 2019
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UW Subutai Presentation Slides

Neural representations of location outside the hippocampus.

Differential Recruitment of the Hippocampus, Medial Prefrontal Cortex, and the Human Motion Complex during Path Integration in Humans

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