In this research meeting, Marcus Lewis discusses the importance of explaining grid cell distortions, and to generate discussion he proposes a possible explanation, showing some results from an experiment he conducted. He hypothesized that an animal localizes by detecting distance from various points of boundaries and those points “vote” on the location. The weight of the votes is determined by nearness, and distortions occur when the animal’s idealized map differs from the actual environment. The team then discusses the hypothesis and raises further questions.
Jeff then explores the possible processes and mechanisms that underlie reference frame transformations in the neocortex. He describes a few problems with a previous hypothesis he proposed about rf transformations in the thalamus and further explores the role of the thalamus. He then suggests the relationship between rf transformations and temporal memory.
Papers from Marcus’ presentation:
- “Framing the grid: effect of boundaries on grid cells and navigation” (2016) by John O’Keefe et al.
- “The hippocampus as a predictive map” (2017) by Stachenfeld et al.
- “Flexible modulation of sequence generation in the entorhinal–hippocampal system” (2021) by McNamee et al.
You can find more discussion on the topic in open source community forum here.