scholarly journals Learning an efficient place cell map from grid cells using non-negative sparse coding

2020 ◽  
Author(s):  
Yanbo Lian ◽  
Anthony N. Burkitt
Keyword(s):  
Dentate Gyrus ◽  
Sparse Coding ◽  
Granule Cells ◽  
Experimental Studies ◽  
Place Cells ◽  
Grid Cells ◽  
Single Location ◽  
Spatial Environment ◽  
Navigational System ◽  
The Brain

AbstractExperimental studies of grid cells in the Medial Entorhinal Cortex (MEC) have shown that they are selective to an array of spatial locations in the environment that form a hexagonal grid. However, in a small environment, place cells in the hippocampus are only selective to a single-location of the environment while granule cells in the dentate gyrus of the hippocampus have multiple discrete firing locations, but lack spatial periodicity. Given the anatomical connection from MEC to the hippocampus, previous feedforward models of grid-to-place have been proposed. Here, we propose a unified learning model that can describe the spatial tuning properties of both hippocampal place cells and dentate gyrus granule cells based on non-negative sparse coding. Sparse coding plays an important role in many cortical areas and is proposed here to have a key role in the navigational system of the brain in the hippocampus. Our results show that the hexagonal patterns of grid cells with various orientations, grid spacings and phases are necessary for model cells to learn a single spatial field that efficiently tile the entire spatial environment. However, if there is a lack of diversity in any grid parameters or a lack of cells in the network, this will lead to the emergence of place cells that have multiple firing locations. More surprisingly, the model shows that place cells can also emerge even when non-negative sparse coding is used with weakly-tuned MEC cells, instead of MEC grid cells, as the input to place cells. This work suggests that sparse coding may be one of the underlying organizing principles for the navigational system of the brain.

scholarly journals Modeling place cells and grid cells in multi-compartment environments: hippocampal-entorhinal loop as a multisensory integration circuit

2019 ◽  
Author(s):  
Tianyi Li ◽  
Angelo Arleo ◽  
Denis Sheynikhovich
Keyword(s):  
Experimental Studies ◽  
Place Cells ◽  
Grid Cells ◽  
Visual Cue ◽  
Conflicting Evidence ◽  
Hexagonal Grids ◽  
Continuous Interaction ◽  
Self Motion ◽  
High Degree ◽  
Key Parameter

AbstractHippocampal place cells and entorhinal grid cells are thought to form a representation of space by integrating internal and external sensory cues. Experimental studies show that different subsets of place cells are controlled by vision, self-motion or a combination of both. Moreover, recent studies in environments with a high degree of visual aliasing suggest that a continuous interaction between place cells and grid cells can result in a deformation of hexagonal grids or in a progressive loss of visual cue control. The computational nature of such a bidirectional interaction remains unclear. In this work we present a neural network model of a dynamic loop between place cells and grid cells. The model is tested in two recent experimental paradigms involving double-room environments that provide conflicting evidence about visual cue control over self-motion-based spatial codes. Analysis of the model behavior in the two experiments suggests that the strength of hippocampal-entorhinal dynamical loop is the key parameter governing differential cue control in multi-compartment environments. Construction of spatial representations in visually identical environments requires weak visual cue control, while synaptic plasticity is regulated by the mismatch between visual- and self-motion representations. More gener-ally our results suggest a functional segregation between plastic and dynamic processes in hippocampal processing.

scholarly journals Parallel processing of sensory cue and spatial information in the Dentate Gyrus

2020 ◽  
Author(s):  
Sebnem Tuncdemir ◽  
Andres Grosmark ◽  
Gergely Turi ◽  
Amei Shank ◽  
John Bowler ◽  
...  
Keyword(s):  
Parallel Processing ◽  
Dentate Gyrus ◽  
Granule Cell ◽  
Spatial Information ◽  
Granule Cells ◽  
Spatial Location ◽  
Place Cells ◽  
On Line ◽  
Sensory Cue ◽  
Self Motion

Abstract During exploration, animals form an internal map of an environment by combining information about specific sensory cues or landmarks with the animal’s motion through space, a process which critically depends on the mammalian hippocampus. The dentate gyrus (DG) is the first stage of the hippocampal trisynaptic circuit where self-motion and sensory cue information are integrated, yet it remains unknown how neurons within the DG encode both cue related (“what”) and spatial (“where”) information during cognitive map formation. Using two photon calcium imaging in head fixed mice running on a treadmill, along with on-line sensory cue manipulation at specific track locations, we have identified robust sensory cue responses in DG granule cells largely independent of spatial location. Granule cell cue responses are stable for long periods of time, selective for the modality of the stimulus and accompanied by strong inhibition of the firing of other active neurons. At the same time, there is a smaller fraction of neurons whose firing is spatially tuned but insensitive to the presentation of nearby cues, similar to traditional place cells. These results demonstrate the existence of “cue cells” in addition to the better characterized “place cells” in the DG, an important heterogeneity that has been previously overlooked. We hypothesize that the observed diversity of representations within the granule cell population may support parallel processing of complementary sensory and spatial information and impact the role of the dentate gyrus in spatial navigation and episodic memory.

scholarly journals Sparse activity of identified dentate granule cells during spatial exploration

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Maria Diamantaki ◽  
Markus Frey ◽  
Philipp Berens ◽  
Patricia Preston-Ferrer ◽  
Andrea Burgalossi
Keyword(s):  
Dentate Gyrus ◽  
Structure Function ◽  
Sparse Coding ◽  
Granule Cells ◽  
High Accuracy ◽  
Functional Heterogeneity ◽  
Coding Scheme ◽  
Memory Circuits ◽  
Spatial Exploration ◽  
Freely Moving

In the dentate gyrus – a key component of spatial memory circuits – granule cells (GCs) are known to be morphologically diverse and to display heterogeneous activity profiles during behavior. To resolve structure–function relationships, we juxtacellularly recorded and labeled single GCs in freely moving rats. We found that the vast majority of neurons were silent during exploration. Most active GCs displayed a characteristic spike waveform, fired at low rates and showed spatial activity. Primary dendritic parameters were sufficient for classifying neurons as active or silent with high accuracy. Our data thus support a sparse coding scheme in the dentate gyrus and provide a possible link between structural and functional heterogeneity among the GC population.

scholarly journals Place cell maps slowly develop via competitive learning and conjunctive coding in the dentate gyrus

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Soyoun Kim ◽  
Dajung Jung ◽  
Sébastien Royer
Keyword(s):  
Dentate Gyrus ◽  
Spatial Information ◽  
Granule Cells ◽  
Place Cells ◽  
Competitive Learning ◽  
Spatial Representations ◽  
Mossy Cells ◽  
Object Locations ◽  
Treadmill Belt ◽  
The Continuum

Abstract Place cells exhibit spatially selective firing fields that collectively map the continuum of positions in environments; how such activity pattern develops with experience is largely unknown. Here, we record putative granule cells (GCs) and mossy cells (MCs) from the dentate gyrus (DG) over 27 days as mice repetitively run through a sequence of objects fixed onto a treadmill belt. We observe a progressive transformation of GC spatial representations, from a sparse encoding of object locations and spatial patterns to increasingly more single, evenly dispersed place fields, while MCs show little transformation and preferentially encode object locations. A competitive learning model of the DG reproduces GC transformations via the progressive integration of landmark-vector cells and spatial inputs and requires MC-mediated feedforward inhibition to evenly distribute GC representations, suggesting that GCs slowly encode conjunctions of objects and spatial information via competitive learning, while MCs help homogenize GC spatial representations.

scholarly journals Inhibition of Hepatic Acyl Coa Oxidase 1 (ACOX1), A Peroxisome Β-Oxidation Enzyme, Modifies Brain Fatty Acid Profile And Intrinsic Membrane Properties in Granule Cells of Rat Dentate Gyrus

2021 ◽  
pp. 1-23
Author(s):  
Fereshteh Motamedi ◽  
◽  
Fariba Khodagholi ◽  
Leila Dargahi ◽  
Hamid Gholami Pourbadie ◽  
...  
Keyword(s):  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Dentate Gyrus ◽  
Fatty Acid Profile ◽  
Acid Composition ◽  
Granule Cells ◽  
Membrane Properties ◽  
Electrophysiological Properties ◽  
The Brain ◽  
Oxidation Enzyme

Peroxisomes are the essential organelles in lipid metabolism. They contain enzymes for β-oxidation of very-long-chain fatty acids, which cannot break down in mitochondria. A reduced expression in hepatic Acyl-CoA oxidase1 (ACOX1), a peroxisome β-oxidation enzyme, followed by modification of the brain fatty acid profile has been seen in aged rodents. These studies have suggested a potential role for peroxisome β-oxidation in brain aging. This study was designed to examine the effect of hepatic ACOX1 inhibition on brain fatty acid composition and neuronal cell activities of young rats (200-250 g). A specific ACOX1 inhibitor, 10, 12- tricosadiynoic acid (TDYA), 100 μg/kg (in olive oil) was given by daily gavage administration for 25 days in male Wistar rats. The brain fatty acid composition and electrophysiological properties of dentate gyrus granule cells were determined by gas chromatography and whole-cell patch-clamp, respectively. A significant increase in C20, C22, C18:1, C20:1, and a decrease of C18, C24, C20:3n6 and C22:6n3 were found in TDYA treated rats compared to the control group. The results show that ACOX1 inhibition changes fatty acid composition similar to old rats. ACOX1 inhibition caused hyperpolarization of resting membrane potential, and also reduction of input resistance, action potential duration, and spike firing. Moreover, ACOX1 inhibition increased rheobase current and afterhyperpolarization amplitude in granule cells. The results indicate, systemic inhibition of ACOX1 causes hypo-excitability of neuronal cells. These findings provide a new evidence on the involvement of peroxisome function and hepatic ACOX1 activity in brain fatty acid profile and the electrophysiological properties of dentate gyrus cells.

scholarly journals Parallel processing of sensory cue and spatial information in the Dentate Gyrus

2020 ◽  
Author(s):  
Sebnem N. Tuncdemir ◽  
Andres D. Grosmark ◽  
Gergely Turi ◽  
Amei Shank ◽  
Jack Bowler ◽  
...  
Keyword(s):  
Parallel Processing ◽  
Dentate Gyrus ◽  
Granule Cell ◽  
Spatial Information ◽  
Granule Cells ◽  
Spatial Location ◽  
Place Cells ◽  
On Line ◽  
Sensory Cue ◽  
Self Motion

AbstractDuring exploration, animals form an internal map of an environment by combining information about specific sensory cues or landmarks with the animal’s motion through space, a process which critically depends on the mammalian hippocampus. The dentate gyrus (DG) is the first stage of the hippocampal trisynaptic circuit where self-motion and sensory cue information are integrated, yet it remains unknown how neurons within the DG encode both cue related (“what”) and spatial (“where”) information during cognitive map formation. Using two photon calcium imaging in head fixed mice running on a treadmill, along with on-line sensory cue manipulation at specific track locations, we have identified robust sensory cue responses in DG granule cells largely independent of spatial location. Granule cell cue responses are stable for long periods of time, selective for the modality of the stimulus and accompanied by strong inhibition of the firing of other active neurons. At the same time, there is a smaller fraction of neurons whose firing is spatially tuned but insensitive to the presentation of nearby cues, similar to traditional place cells. These results demonstrate the existence of “cue cells” in addition to the better characterized “place cells” in the DG, an important heterogeneity that has been previously overlooked. We hypothesize that the observed diversity of representations within the granule cell population may support parallel processing of complementary sensory and spatial information and impact the role of the dentate gyrus in spatial navigation and episodic memory.

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