scholarly journals Entorhinal velocity signals reflect environmental geometry

2019 ◽  
Author(s):  
Robert G K Munn ◽  
Caitlin S Mallory ◽  
Kiah Hardcastle ◽  
Dane M Chetkovich ◽  
Lisa M Giocomo
Keyword(s):  
Environmental Change ◽  
Grid Cell ◽  
Cell Types ◽  
Dependent Manner ◽  
Head Direction ◽  
Neural Signals ◽  
Head Direction Cells ◽  
Knockout Mouse Model ◽  
Size And Shape ◽  
Environmental Geometry

SummaryThe entorhinal cortex contains neural signals for representing self-location, including grid cells that fire in periodic locations and velocity signals that encode an animal’s speed and head direction. Recent work revealed that the size and shape of the environment influences grid patterns. Whether entorhinal velocity signals are equally influenced or provide a universal metric for self-motion across environments remains unknown. Here, we report that changes to the size and shape of the environment result in re-scaling in entorhinal speed codes. Moreover, head direction cells re-organize in an experience-dependent manner to align with the axis of environmental change. A knockout mouse model allows a dissociation of the coordination between cell types, with grid and speed, but not head direction, cells responding in concert to environmental change. These results align with predictions of grid cell attractor models and point to inherent flexibility in the coding features of multiple functionally-defined entorhinal cell types.

Entorhinal Cortex

2017 ◽  
pp. 227-244
Author(s):  
Edvard I. Moser ◽  
Menno P. Witter ◽  
May-Britt Moser
Keyword(s):  
Entorhinal Cortex ◽  
Grid Cell ◽  
Cell Types ◽  
Structure And Function ◽  
Modular Organization ◽  
Head Direction ◽  
Head Direction Cells ◽  
Terra Incognita ◽  
And Function ◽  
Hippocampal Structure

While decades of study have unraveled some of the basic principles of hippocampal structure and function, the adjacent entorhinal cortex (EC) has remained terra incognita in many respects. Recent studies suggest that the medial part of the entorhinal cortex is part of a two-dimensional metric map of the animal’s changing location in the environment. A key component of this map is the grid cell, which fires selectively at hexagonally spaced positions in the animal’s environment. Grid cells colocalize with other recently discovered medial entorhinal cell types, such as head direction cells, conjunctive grid × head direction cells, border cells, and speed cells. This chapter provides an overview of these functional cell types, their possible relationship to morphological cell types, the intrinsic architecture of the system (including laminar, longitudinal, and modular organization), and the extrinsic connectivity and possible function of both the medial and lateral subdivisions of the entorhinal cortex.

scholarly journals Functional connectivity of the entorhinal–hippocampal space circuit

2014 ◽  
Vol 369 (1635) ◽  
pp. 20120516 ◽  
Author(s):  
Sheng-Jia Zhang ◽  
Jing Ye ◽  
Jonathan J. Couey ◽  
Menno Witter ◽  
Edvard I. Moser ◽  
...  
Keyword(s):  
Entorhinal Cortex ◽  
Cell Types ◽  
Place Cells ◽  
Projection Neurons ◽  
Border Cells ◽  
Head Direction ◽  
Grid Cells ◽  
Head Direction Cells ◽  
Dynamic Interactions ◽  
Cell Groups

The mammalian space circuit is known to contain several functionally specialized cell types, such as place cells in the hippocampus and grid cells, head-direction cells and border cells in the medial entorhinal cortex (MEC). The interaction between the entorhinal and hippocampal spatial representations is poorly understood, however. We have developed an optogenetic strategy to identify functionally defined cell types in the MEC that project directly to the hippocampus. By expressing channelrhodopsin-2 (ChR2) selectively in the hippocampus-projecting subset of entorhinal projection neurons, we were able to use light-evoked discharge as an instrument to determine whether specific entorhinal cell groups—such as grid cells, border cells and head-direction cells—have direct hippocampal projections. Photoinduced firing was observed at fixed minimal latencies in all functional cell categories, with grid cells as the most abundant hippocampus-projecting spatial cell type. We discuss how photoexcitation experiments can be used to distinguish the subset of hippocampus-projecting entorhinal neurons from neurons that are activated indirectly through the network. The functional breadth of entorhinal input implied by this analysis opens up the potential for rich dynamic interactions between place cells in the hippocampus and different functional cell types in the entorhinal cortex (EC).

scholarly journals Home, head direction stability, and grid cell distortion

2020 ◽  
Vol 123 (4) ◽  
pp. 1392-1406 ◽  
Author(s):  
Juan Ignacio Sanguinetti-Scheck ◽  
Michael Brecht
Keyword(s):  
Entorhinal Cortex ◽  
Home Cage ◽  
Cell Activity ◽  
Grid Cell ◽  
Head Direction ◽  
Grid Cells ◽  
Head Direction Cells ◽  
Medial Entorhinal Cortex ◽  
Abstract Approach ◽  
Globally Stable

The home is a unique location in the life of humans and animals. In rats, home presents itself as a multicompartmental space that involves integrating navigation through subspaces. Here we embedded the laboratory rat’s home cage in the arena, while recording neurons in the animal’s parasubiculum and medial entorhinal cortex, two brain areas encoding the animal’s location and head direction. We found that head direction signals were unaffected by home cage presence or translocation. Head direction cells remain globally stable and have similar properties inside and outside the embedded home. We did not observe egocentric bearing encoding of the home cage. However, grid cells were distorted in the presence of the home cage. While they did not globally remap, single firing fields were translocated toward the home. These effects appeared to be geometrical in nature rather than a home-specific distortion and were not dependent on explicit behavioral use of the home cage during a hoarding task. Our work suggests that medial entorhinal cortex and parasubiculum do not remap after embedding the home, but local changes in grid cell activity overrepresent the embedded space location and might contribute to navigation in complex environments. NEW & NOTEWORTHY Neural findings in the field of spatial navigation come mostly from an abstract approach that separates the animal from even a minimally biological context. In this article we embed the home cage of the rat in the environment to address some of the complexities of natural navigation. We find no explicit home cage representation. While both head direction cells and grid cells remain globally stable, we find that embedded spaces locally distort grid cells.

scholarly journals Towards a Predictive Bio-Inspired Navigation Model

Information ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 100
Author(s):  
Simon Gay ◽  
Kévin Le Le Run ◽  
Edwige Pissaloux ◽  
Katerine Romeo ◽  
Christèle Lecomte
Keyword(s):  
Predictive Model ◽  
Large Scale ◽  
Environmental Changes ◽  
Grid Cell ◽  
Visual Navigation ◽  
Place Cells ◽  
Head Direction ◽  
Head Direction Cells ◽  
Visually Impaired People ◽  
Proposed Model

This paper presents a novel bio-inspired predictive model of visual navigation inspired by mammalian navigation. This model takes inspiration from specific types of neurons observed in the brain, namely place cells, grid cells and head direction cells. In the proposed model, place cells are structures that store and connect local representations of the explored environment, grid and head direction cells make predictions based on these representations to define the position of the agent in a place cell’s reference frame. This specific use of navigation cells has three advantages: First, the environment representations are stored by place cells and require only a few spatialized descriptors or elements, making this model suitable for the integration of large-scale environments (indoor and outdoor). Second, the grid cell modules act as an efficient visual and absolute odometry system. Finally, the model provides sequential spatial tracking that can integrate and track an agent in redundant environments or environments with very few or no distinctive cues, while being very robust to environmental changes. This paper focuses on the architecture formalization and the main elements and properties of this model. The model has been successfully validated on basic functions: mapping, guidance, homing, and finding shortcuts. The precision of the estimated position of the agent and the robustness to environmental changes during navigation were shown to be satisfactory. The proposed predictive model is intended to be used on autonomous platforms, but also to assist visually impaired people in their mobility.

scholarly journals Functional network topography of the medial entorhinal cortex

2021 ◽  
Author(s):  
Horst A. Obenhaus ◽  
Weijian Zong ◽  
R. Irene Jacobsen ◽  
Tobias Rose ◽  
Flavio Donato ◽  
...  
Keyword(s):  
Entorhinal Cortex ◽  
Grid Cell ◽  
Cell Types ◽  
List Type ◽  
Head Direction ◽  
Grid Cells ◽  
Activity Data ◽  
Medial Entorhinal Cortex ◽  
Depth Analysis ◽  
Low Levels

SummaryThe medial entorhinal cortex (MEC) creates a map of local space, based on the firing patterns of grid, head direction (HD), border, and object-vector (OV) cells. How these cell types are organized anatomically is debated. In-depth analysis of this question requires collection of precise anatomical and activity data across large populations of neurons during unrestrained behavior, which neither electrophysiological nor previous imaging methods fully afford. Here we examined the topographic arrangement of spatially modulated neurons in MEC and adjacent parasubiculum using miniaturized, portable two-photon microscopes, which allow mice to roam freely in open fields. Grid cells exhibited low levels of co-occurrence with OV cells and clustered anatomically, while border, HD and OV cells tended to intermingle. These data suggest that grid-cell networks might be largely distinct from those of border, HD and OV cells and that grid cells exhibit strong coupling among themselves but weaker links to other cell types.Highlights- Grid and object vector cells show low levels of regional co-occurrence- Grid cells exhibit the strongest tendency to cluster among all spatial cell types- Grid cells stay separate from border, head direction and object vector cells- The territories of grid, head direction and border cells remain stable over weeks

scholarly journals Head-direction cells recorded from the postsubiculum in freely moving rats. II. Effects of environmental manipulations

1990 ◽  
Vol 10 (2) ◽  
pp. 436-447 ◽  
Author(s):  
JS Taube ◽  
RU Muller ◽  
JB Ranck
Keyword(s):  
Head Direction ◽  
Head Direction Cells ◽  
Freely Moving Rats ◽  
Freely Moving

Effects of cytochrome c on the mitochondrial apoptosis-induced channel MAC

2004 ◽  
Vol 286 (5) ◽  
pp. C1109-C1117 ◽  
Author(s):  
Liang Guo ◽  
Dawn Pietkiewicz ◽  
Evgeny V. Pavlov ◽  
Sergey M. Grigoriev ◽  
John J. Kasianowicz ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Outer Membrane ◽  
Cell Types ◽  
Rnase A ◽  
Mitochondrial Outer Membrane ◽  
Dependent Manner ◽  
Mitochondrial Apoptosis ◽  
Noise Type ◽  
Voltage Dependent

Recent studies indicate that cytochrome c is released early in apoptosis without loss of integrity of the mitochondrial outer membrane in some cell types. The high-conductance mitochondrial apoptosis-induced channel (MAC) forms in the outer membrane early in apoptosis of FL5.12 cells. Physiological (micromolar) levels of cytochrome c alter MAC activity, and these effects are referred to as types 1 and 2. Type 1 effects are consistent with a partitioning of cytochrome c into the pore of MAC and include a modest decrease in conductance that is dose and voltage dependent, reversible, and has an increase in noise. Type 2 effects may correspond to “plugging” of the pore or destabilization of the open state. Type 2 effects are a dose-dependent, voltage-independent, and irreversible decrease in conductance. MAC is a heterogeneous channel with variable conductance. Cytochrome c affects MAC in a pore size-dependent manner, with maximal effects of cytochrome c on MAC with conductance of 1.9–5.4 nS. The effects of cytochrome c, RNase A, and high salt on MAC indicate that size, rather than charge, is crucial. The effects of dextran molecules of various sizes indicate that the pore diameter of MAC is slightly larger than that of 17-kDa dextran, which should be sufficient to allow the passage of 12-kDa cytochrome c. These findings are consistent with the notion that MAC is the pore through which cytochrome c is released from mitochondria during apoptosis.

scholarly journals A Bio-inspired 3-D Neural Compass Based on Head Direction Cells

IEEE Access ◽  
2021 ◽  
pp. 1-1
Author(s):  
Baozhong Li ◽  
Yanming Liu ◽  
Lei Lai
Keyword(s):  
Head Direction ◽  
Head Direction Cells

Hippocampal Place-Cell Firing During Movement in Three-Dimensional Space

2001 ◽  
Vol 85 (1) ◽  
pp. 105-116 ◽  
Author(s):  
James J. Knierim ◽  
Bruce L. McNaughton
Keyword(s):  
Hippocampal Neurons ◽  
Horizontal Plane ◽  
Three Dimensional ◽  
Place Cell ◽  
Place Cells ◽  
Limbic Cortex ◽  
Head Direction ◽  
Head Direction Cells ◽  
Recording Apparatus ◽  
Place Fields

“Place” cells of the rat hippocampus are coupled to “head direction” cells of the thalamus and limbic cortex. Head direction cells are sensitive to head direction in the horizontal plane only, which leads to the question of whether place cells similarly encode locations in the horizontal plane only, ignoring the z axis, or whether they encode locations in three dimensions. This question was addressed by recording from ensembles of CA1 pyramidal cells while rats traversed a rectangular track that could be tilted and rotated to different three-dimensional orientations. Cells were analyzed to determine whether their firing was bound to the external, three-dimensional cues of the environment, to the two-dimensional rectangular surface, or to some combination of these cues. Tilting the track 45° generally provoked a partial remapping of the rectangular surface in that some cells maintained their place fields, whereas other cells either gained new place fields, lost existing fields, or changed their firing locations arbitrarily. When the tilted track was rotated relative to the distal landmarks, most place fields remapped, but a number of cells maintained the same place field relative to the x-y coordinate frame of the laboratory, ignoring the z axis. No more cells were bound to the local reference frame of the recording apparatus than would be predicted by chance. The partial remapping demonstrated that the place cell system was sensitive to the three-dimensional manipulations of the recording apparatus. Nonetheless the results were not consistent with an explicit three-dimensional tuning of individual hippocampal neurons nor were they consistent with a model in which different sets of cells are tightly coupled to different sets of environmental cues. The results are most consistent with the statement that hippocampal neurons can change their “tuning functions” in arbitrary ways when features of the sensory input or behavioral context are altered. Understanding the rules that govern the remapping phenomenon holds promise for deciphering the neural circuitry underlying hippocampal function.

scholarly journals Landmark control and updating of self-movement cues are largely maintained in head direction cells after lesions of the posterior parietal cortex.

2008 ◽  
Vol 122 (4) ◽  
pp. 827-840 ◽  
Author(s):  
Jeffrey L. Calton ◽  
Carol S. Turner ◽  
De-Laine M. Cyrenne ◽  
Brian R. Lee ◽  
Jeffrey S. Taube
Keyword(s):  
Parietal Cortex ◽  
Posterior Parietal Cortex ◽  
Head Direction ◽  
Head Direction Cells ◽  
Posterior Parietal
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