Figure 8.

Unique place cell ensemble activity in hippocampus could be generated from multiple grid cell maps in medial entorhinal cortex. (a) Four example grids with distinct inter‐field spacing. Neuronal spikes (black dots) overlaid on the trajectory of the rat (grey). Dorsoventral location from the brain surface is indicated. Note the increasing inter‐field spacing at consecutively more ventrally recorded grid cells. Adapted from Stensola et al. (2012). (b) Suggested mechanism for the formation of unique place cell maps in hippocampus. In different environments, grid cells within one module shift and rotate together, whereas grid cells in different modules could shift and rotate independently. In this way, a small number of grid modules can encode a vast number of environments by the vast number of combinations of shifts and rotations, like the number combinations on a locker. Source: Drawing by Håkon Fyhn. Adapted from Rowland and Moser (2014). (c) Color‐coded rate maps from three example place cells showing distribution of firing rate between 11 environments (blue, no firing; red, peak firing). Each row comprises ratemaps from one neuron recorded in a familiar room (F, first and last column) and 10 novel rooms (N1–N10). Note that a population of place cells form unique ensemble activity in each room, with cells being active in one room and silent in another. If active, the position of the fields in two different rooms do not correlate, thus, an example of global remapping. Adapted from Alme et al. (2014) [Color figure can be viewed at wileyonlinelibrary.com]