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PDF, English - main document Download (3MB) | Lizenz: Context-specificity of spatially selective neurons in the medial entorhinal cortex by Pérez Escobar, José Antonio underlies the terms of Creative Commons Attribution 4.0

Abstract

This work has investigated the activity of spatially selective neurons in the medial entorhinal cortex following manipulations of non-metric properties of the environment. The types of neurons investigated were head-direction cells, border cells, speed cells, and especially, grid cells. The latter type of cells is thought to encode a universal Euclidian metric of space and be the main neurobiological substrata for path integration.

The main findings are: 1) The removal of visual landmarks caused the grid cell and head-direction cell signals to break down, the speed code to change, and the border cell activity to be less confined to the borders of the arena, and 2) the manipulation of non-metric, visual features of the environment affected the firing rate code of grid cells, head-direction cells, border cells and speed cells, thus revealing the context specificity of their activity.

Because of such a context specificity, these fundings argue against the notion that grid cells act as the neurobiological substratum of a cognitive representation of a universal Euclidian metric of space. A similar conclusion holds for other cell types. In turn, these results raise doubt about the possibility of ascribing intuitive spatial categories (maps, compasses, speedometers…) to specific cell types in a way that the brain and our intuitions display similar conceptual structures. However, this does not undermine the possibility that certain cell types may play prominent roles in behaviors like path integration; instead, it suggests a much more complicated functional role than what our heuristic spatial intuitions may capture.