I have been wondering how grid cells might function on an infinite plane. Even a sufficiently large number of cells in a module and/or periodicity would still cause a particlar pattern of firings to repeat if one were to travel in a particular direction overtime. Is this mitigated by displacement cells? That is, “yes, i have seen this grid cell pattern before but we have not gone backwards to get there”. If displacement cells are the key, does this require something like the sequential temporal memory to track the sequence of displacements to ensure that we have, indeed, traveled far enough before encountering the repeating pattern and, therefore, we must be walking in an infinite (sufficiently large) plane?
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I’m not an expert, and I know far too little about grid cells…
But think grid cell modules re-anchor themselves to each new object you observe, or to each location where you are. So I don’t think there is need for an infinite plane.
Still, your question is interesting in a theoretical sense.
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I will offer that if you were on a featureless plane with no landmarks or visible sun you would feel disoriented after walking around a while.
You are not completely without reference - you have your posture, gravity reference/resistance, and inner ear; your vestibular system. This is a powerful driver of your grid cells. If you do walk around you have your self motion which is a known input to the grid system.
There would be some activation of the grid system; there would still be your local frame of references - your peripersonal space and your body position in that space.
Note that this describes several frames of reference local to body parts:
https://www.sciencedirect.com/science/article/abs/pii/S0028393214004230
All of this ripples up to the temporal lobe through the WHAT and WHERE streams to form the location signals that we know as grid cells in the hippocampus.
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Maybe that’s what you experience in sensory deprivation tank?
I have been wondering how grid cells might function on an infinite plane. Even a sufficiently large number of cells in a module and/or periodicity would still cause a particlar pattern of firings to repeat if one were to travel in a particular direction overtime.
I think that this should be incredibly large space if we are considering human as the agent subject. I would say that evolution makes each species to fit the environment size. This non ambiguity that can occur in grid cells is not then any problem. But maybe it occurs more often than we think, and it is what we can call “location dejavu”?
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