Grid cells in mice

Abstract

ABSTRACT:The medial entorhinal cortex (EC) is a part of the neural network for the representation of self-location in the rat. The key cell type of this system is the grid cell, whose multiple firing fields span the environment in a remarkably regular triangular or hexagonal pattern. The basic properties of grid cells and other cell types have been described, but the neuronal mechanisms responsible for the formation and maintenance of the place code remain elusive. These mechanisms can be investigated by genetic intervention strategies, where specific components of the entorhinal-hippocampal network are activated or silenced. Because of the common use of knockout mice for such targeted interventions, we asked if grid activity is expressed also in the mouse. Principal neurons in the superficial layers of mouse medial EC had stable grid fields similar to those of the rat. Neighboring grid cells shared a common spacing and orientation but had a different spatial phase, such that a small number of grid cells collectively represented all locations in the environment. The spacing of the grid increased with distance from the dorsal border of the medial EC. The lowest values for grid spacing, recorded at the dorsal end, were comparable to those of the rat, suggesting that grid fields do not scale up proportionally with body size. Grid cells were colocalized with head-direction cells and conjunctive place 3 head-direction cells, as in the rat. The demonstration of grid cells in mice prepares the ground for transgenic analyses of the entorhinal-hippocampal network. V

Cellular resolution optical access to brain regions in fissures: Imaging medial prefrontal cortex and grid cells in entorhinal cortex

“…All six cells had similar slice angles relative to the lattices, and their different activity patterns corresponded to different offsets of the slice within the lattice. These features are consistent with the properties of electroderecorded grid cells in the MEC, in that nearby grid cells typically have similar field spacing and widths in 2D arenas, and similar slice angles through a model 2D grid lattice during navigation along a 1D track (4,12,21). Finally, in a population analysis based on the spatial autocorrelation, imaged MEC neurons exhibited increased field spacing and width from dorsal to ventral cell body locations within layer 2 ( Fig.…”

“…S7 and S8). This correlation between the field patterns and anatomical location is a feature of electrophysiologically recorded grid cells, which show a progressive increase in grid field spacing and width along the dorsoventral axis of the MEC (4,5,13,21,22). The spacing of calcium transient fields along the track was comparable in scale to electrophysiologically measured grid cell firing fields along real and virtual linear tracks (13).…”

“…In parallel, the field width increased from 94 ± 10 cm in the most dorsal FOV to 150 ± 10 cm in the most ventral FOV. This gradual increase in field width and spacing along the dorsoventral axis of the MEC is a well-established property of grid cells (4,5,13,21,22).…”

Grid cells and cortical representation

“…Place cells and grid cells were discovered in rats but similar cells have subsequently been reported in mice [13][14][15] , bats 16,17 , monkeys [18][19][20][21] , and humans 22,23 , although the bulk of work on entorhinal-hippocampal spatial representation is still performed in rodents. The strong correspondence in each species between entorhinal-hippocampal firing patterns and a measurable property of the external world -the location of the animal -makes the spatial representation circuit a powerful experimental model system for understanding neural computation at the highest levels of the association cortices, many synapses away from sensory receptors and motor outputs.…”

How Animals Find Their Way in Space. Experiments and Modeling

“…6). Позднее клетки решетки были обнаружены у других млекопитающих, мышей [40], летучих мышей [41], обезьян [42], людей [43]. По различным оценкам доля клеток решетки во втором слое энторинальной коры составляет от 68% [44] до 26% [45].…”