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Crystals of the brain.

Moser MB, Moser EI - EMBO Mol Med (2011)

View Article: PubMed Central - PubMed

Affiliation: Norwegian University of Science and Technology, Trondheim, Norway.

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When we find our way in the environment, we need to integrate information about location, direction and distance into a coherent map-like representation... A key component of the entorhinal network for spatial mapping is the grid cell, which we discovered, together with our colleagues, in 2005... Together, these entorhinal cells establish a coherent generic map of local space that is maintained across environments, independently of the animal's speed and direction and independently of the identity of the particular landmarks of the place. »Grid cells have attracted attention because the crystal-like structure underlying their firing fields is not, like in sensory systems, imported from the outside world, but is created within the brain itself. « “One synapse” downstream, in the hippocampus, the map is associated with specific features and experiences, forming individualized maps that are stored in the neural networks of this brain region... Studies of grid cells may thus provide access to some of the basic computational operations of cortical circuits... In this Perspective, we shall review the work that led to the discovery of grid cells and the entorhinal spatial map, concluding with a brief look to the future... Both of us were born on remote islands on the outer west coast of Norway... Our interests in science were raised by our parents, who wanted an education themselves but did not have this opportunity... The anatomical component of the work was performed in collaboration with Menno Witter from the Free University of Amsterdam, one of the key members of the EU grant... To our surprise, the disconnection from the associative circuitry of the hippocampus did not abolish place coding in CA1... To understand how grid cells operate and how they are generated, we saw it as necessary to characterize the wider network in which they are embedded... In 2006, we observed that the medial entorhinal cortex also contains cells that signal the animal's head direction, like the head direction cells of the presubiculum (Taube et al, ), and we found that many cells signal direction and position conjunctively (Sargolini et al, )... Further work showed that grid cells determine how memory is stored downstream in the hippocampus (Fyhn et al, ), and gamma oscillations were found to be instrumental in routing information between grid networks in the entorhinal cortex and place and memory networks in the hippocampus (Colgin et al, )... These new tools can certainly be used to determine how the activity of individual cell groups in the entorhinal–hippocampal spatial representation circuit contributes to the performance of network... This brings us back to the Scientific American issue from 1979... In this issue, there was one paper that differed from the others—the concluding essay by Francis Crick.

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Border cells, grid cells and head direction cells are the elements of a metric representation of local space and are likely to be used when animals navigate through the environmentColour-coded firing rates for a border cell and a grid cell, respectively, are shown. Red is high rate; blue is low rate. The border cell fires along one of the walls only; the grid cell fires at locations that collectively form a hexagonal pattern. The ‘direction’ plot shows the firing rate (black trace) as a function of direction in a head direction-selective cell. This particular cell fires exclusively when the animal faces the North–East direction of the environment.
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fig02: Border cells, grid cells and head direction cells are the elements of a metric representation of local space and are likely to be used when animals navigate through the environmentColour-coded firing rates for a border cell and a grid cell, respectively, are shown. Red is high rate; blue is low rate. The border cell fires along one of the walls only; the grid cell fires at locations that collectively form a hexagonal pattern. The ‘direction’ plot shows the firing rate (black trace) as a function of direction in a head direction-selective cell. This particular cell fires exclusively when the animal faces the North–East direction of the environment.

Mentions: When we find our way in the environment, we need to integrate information about location, direction and distance into a coherent map-like representation. Our work over the last 10 years has suggested that the medial entorhinal cortex plays a central role in this process. A key component of the entorhinal network for spatial mapping is the grid cell, which we discovered, together with our colleagues, in 2005. Grid cells fire only when animals move through specific, regularly spaced positions. Their active firing positions form a hexagonal pattern that spans, for each cell, the entire local space available to the animal (Fig 1). The periodic pattern is reminiscent of the cross-points of graphic paper but the repeating units are equilateral triangles, not squares. Grid cells interact with other specialized cell types, such as head-direction cells and border cells. Head-direction cells signal orientation whereas border cells fire only near the edge of the local environment (Fig 2). Together, these entorhinal cells establish a coherent generic map of local space that is maintained across environments, independently of the animal's speed and direction and independently of the identity of the particular landmarks of the place.


Crystals of the brain.

Moser MB, Moser EI - EMBO Mol Med (2011)

Border cells, grid cells and head direction cells are the elements of a metric representation of local space and are likely to be used when animals navigate through the environmentColour-coded firing rates for a border cell and a grid cell, respectively, are shown. Red is high rate; blue is low rate. The border cell fires along one of the walls only; the grid cell fires at locations that collectively form a hexagonal pattern. The ‘direction’ plot shows the firing rate (black trace) as a function of direction in a head direction-selective cell. This particular cell fires exclusively when the animal faces the North–East direction of the environment.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3377059&req=5

fig02: Border cells, grid cells and head direction cells are the elements of a metric representation of local space and are likely to be used when animals navigate through the environmentColour-coded firing rates for a border cell and a grid cell, respectively, are shown. Red is high rate; blue is low rate. The border cell fires along one of the walls only; the grid cell fires at locations that collectively form a hexagonal pattern. The ‘direction’ plot shows the firing rate (black trace) as a function of direction in a head direction-selective cell. This particular cell fires exclusively when the animal faces the North–East direction of the environment.
Mentions: When we find our way in the environment, we need to integrate information about location, direction and distance into a coherent map-like representation. Our work over the last 10 years has suggested that the medial entorhinal cortex plays a central role in this process. A key component of the entorhinal network for spatial mapping is the grid cell, which we discovered, together with our colleagues, in 2005. Grid cells fire only when animals move through specific, regularly spaced positions. Their active firing positions form a hexagonal pattern that spans, for each cell, the entire local space available to the animal (Fig 1). The periodic pattern is reminiscent of the cross-points of graphic paper but the repeating units are equilateral triangles, not squares. Grid cells interact with other specialized cell types, such as head-direction cells and border cells. Head-direction cells signal orientation whereas border cells fire only near the edge of the local environment (Fig 2). Together, these entorhinal cells establish a coherent generic map of local space that is maintained across environments, independently of the animal's speed and direction and independently of the identity of the particular landmarks of the place.

View Article: PubMed Central - PubMed

Affiliation: Norwegian University of Science and Technology, Trondheim, Norway.

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

When we find our way in the environment, we need to integrate information about location, direction and distance into a coherent map-like representation... A key component of the entorhinal network for spatial mapping is the grid cell, which we discovered, together with our colleagues, in 2005... Together, these entorhinal cells establish a coherent generic map of local space that is maintained across environments, independently of the animal's speed and direction and independently of the identity of the particular landmarks of the place. »Grid cells have attracted attention because the crystal-like structure underlying their firing fields is not, like in sensory systems, imported from the outside world, but is created within the brain itself. « “One synapse” downstream, in the hippocampus, the map is associated with specific features and experiences, forming individualized maps that are stored in the neural networks of this brain region... Studies of grid cells may thus provide access to some of the basic computational operations of cortical circuits... In this Perspective, we shall review the work that led to the discovery of grid cells and the entorhinal spatial map, concluding with a brief look to the future... Both of us were born on remote islands on the outer west coast of Norway... Our interests in science were raised by our parents, who wanted an education themselves but did not have this opportunity... The anatomical component of the work was performed in collaboration with Menno Witter from the Free University of Amsterdam, one of the key members of the EU grant... To our surprise, the disconnection from the associative circuitry of the hippocampus did not abolish place coding in CA1... To understand how grid cells operate and how they are generated, we saw it as necessary to characterize the wider network in which they are embedded... In 2006, we observed that the medial entorhinal cortex also contains cells that signal the animal's head direction, like the head direction cells of the presubiculum (Taube et al, ), and we found that many cells signal direction and position conjunctively (Sargolini et al, )... Further work showed that grid cells determine how memory is stored downstream in the hippocampus (Fyhn et al, ), and gamma oscillations were found to be instrumental in routing information between grid networks in the entorhinal cortex and place and memory networks in the hippocampus (Colgin et al, )... These new tools can certainly be used to determine how the activity of individual cell groups in the entorhinal–hippocampal spatial representation circuit contributes to the performance of network... This brings us back to the Scientific American issue from 1979... In this issue, there was one paper that differed from the others—the concluding essay by Francis Crick.

Show MeSH