scholarly journals Identifying Core Regions for Path Integration on Medial Entorhinal Cortex of Hippocampal Formation

2020 ◽  
Vol 10 (1) ◽  
pp. 28
Author(s):  
Ayako Fukawa ◽  
Takahiro Aizawa ◽  
Hiroshi Yamakawa ◽  
Ikuko Eguchi Yairi
Keyword(s):  
Entorhinal Cortex ◽  
Path Integration ◽  
Firing Pattern ◽  
Hippocampal Formation ◽  
Pyramidal Cells ◽  
Core Region ◽  
Medial Entorhinal Cortex ◽  
Position Information ◽  
The Core ◽  
Cell Firing

Path integration is one of the functions that support the self-localization ability of animals. Path integration outputs position information after an animal’s movement when initial-position and movement information is input. The core region responsible for this function has been identified as the medial entorhinal cortex (MEC), which is part of the hippocampal formation that constitutes the limbic system. However, a more specific core region has not yet been identified. This research aims to clarify the detailed structure at the cell-firing level in the core region responsible for path integration from fragmentarily accumulated experimental and theoretical findings by reviewing 77 papers. This research draws a novel diagram that describes the MEC, the hippocampus, and their surrounding regions by focusing on the MEC’s input/output (I/O) information. The diagram was created by summarizing the results of exhaustively scrutinizing the papers that are relative to the I/O relationship, the connection relationship, and cell position and firing pattern. From additional investigations, we show function information related to path integration, such as I/O information and the relationship between multiple functions. Furthermore, we constructed an algorithmic hypothesis on I/O information and path-integration calculation method from the diagram and the information of functions related to path integration. The algorithmic hypothesis is composed of regions related to path integration, the I/O relations between them, the calculation performed there, and the information representations (cell-firing pattern) in them. Results of examining the hypothesis confirmed that the core region responsible for path integration was either stellate cells in layer II or pyramidal cells in layer III of the MEC.

scholarly journals How to build a grid cell

2014 ◽  
Vol 369 (1635) ◽  
pp. 20120520 ◽  
Author(s):  
Christoph Schmidt-Hieber ◽  
Michael Häusser
Keyword(s):  
Entorhinal Cortex ◽  
Action Potentials ◽  
Path Integration ◽  
Grid Cell ◽  
Medial Entorhinal Cortex ◽  
Synaptic Inputs ◽  
New Findings ◽  
Cell Firing

Neurons in the medial entorhinal cortex fire action potentials at regular spatial intervals, creating a striking grid-like pattern of spike rates spanning the whole environment of a navigating animal. This remarkable spatial code may represent a neural map for path integration. Recent advances using patch-clamp recordings from entorhinal cortex neurons in vitro and in vivo have revealed how the microcircuitry in the medial entorhinal cortex may contribute to grid cell firing patterns, and how grid cells may transform synaptic inputs into spike output during firing field crossings. These new findings provide key insights into the ingredients necessary to build a grid cell.

Hyperexcitability of entorhinal cortex and hippocampus after application of aminooxyacetic acid (AOAA) to layer III of the rat medial entorhinal cortex in vitro

1996 ◽  
Vol 76 (5) ◽  
pp. 2986-3001 ◽  
Author(s):  
H. E. Scharfman
Keyword(s):  
Nmda Receptor ◽  
Evoked Potentials ◽  
Entorhinal Cortex ◽  
Pyramidal Cells ◽  
Aminooxyacetic Acid ◽  
Field Potentials ◽  
Medial Entorhinal Cortex ◽  
Extracellular Recordings ◽  
Extracellular Potentials

1. Injection of aminooxyacetic acid (AOAA) into the entorhinal cortex in vivo produces acute seizures and cell loss in medial entorhinal cortex. To understand these effects, AOAA was applied directly to the medial entorhinal cortex in slices containing both the entorhinal cortex and hippocampus. Extracellular and intracellular recordings were made in both the entorhinal cortex and hippocampus to study responses to angular bundle stimulation and spontaneous activity. 2. AOAA was applied focally by leak from a micropipette or by pressure ejection. Evoked potentials increased gradually within 5 min of application, particularly the late, negative components. Evoked potentials continued to increase for up to 1 h, and these changes persisted for the remainder of the experiment (up to 5 h after drug application). 3. Paired pulse facilitation (100-ms interval) was also enhanced after AOAA application. Increasing stimulus frequency to 1-10 Hz increased evoked potentials further, and after several seconds of such stimulation multiple field potentials occurred. When stimulation was stopped at this point, repetitive field potentials occurred spontaneously for 1-2 min. These recordings, and simultaneous extracellular recordings in different layers, indicated that spontaneous synchronous activity occurred in entorhinal neurons. Intracellularly labeled cortical pyramidal cells depolarized and discharged during spontaneous and evoked field potentials. 4. The effects of AOAA were blocked reversibly by bath application of the N-methyl-D-aspartate (NMDA) receptor antagonist D-amino-5-phosphonovalerate (D-APV; 25 microM) or focal application of D-APV to the medial entorhinal cortex. 5. Simultaneous extracellular recordings from the entorhinal cortex and hippocampus demonstrated that spontaneous synchronous activity in layer III was often followed within several milliseconds by negative field potentials in the terminal zones of the perforant path (stratum moleculare of the dentate gyrus and stratum lacunosum-moleculare of area CA1). The extracellular potentials recorded in the dentate gyrus corresponded to excitatory postsynaptic potentials and action potentials in dentate granule cells. However, extracellular potentials in area CA1 were small and rarely correlated with discharge in CA1 pyramidal cells. 6. The results demonstrate that AOAA application leads to an NMDA-receptor-dependent enhancement of evoked potentials in medial entorhinal cortical neurons, which appears to be irreversible. The potentials can be facilitated by repetitive stimulation, and lead to synchronized discharges of entorhinal neurons. The discharges invade other areas such as the hippocampus, indicating how seizure activity may spread after AOAA injection in vivo. These data suggest that AOAA may be a useful tool to study longlasting changes in NMDA receptor function that lead to epileptiform activity and neurodegeneration.

scholarly journals Neuronal rebound spiking, resonance frequency and theta cycle skipping may contribute to grid cell firing in medial entorhinal cortex

2014 ◽  
Vol 369 (1635) ◽  
pp. 20120523 ◽  
Author(s):  
Michael E. Hasselmo
Keyword(s):  
Resonance Frequency ◽  
Entorhinal Cortex ◽  
Functional Role ◽  
Grid Cell ◽  
Medial Septum ◽  
Medial Entorhinal Cortex ◽  
Spatial Periodicity ◽  
Cell Firing ◽  
Rebound Spiking ◽  
Relationship Of

Data show a relationship of cellular resonance and network oscillations in the entorhinal cortex to the spatial periodicity of grid cells. This paper presents a model that simulates the resonance and rebound spiking properties of entorhinal neurons to generate spatial periodicity dependent upon phasic input from medial septum. The model shows that a difference in spatial periodicity can result from a difference in neuronal resonance frequency that replicates data from several experiments. The model also demonstrates a functional role for the phenomenon of theta cycle skipping in the medial entorhinal cortex.

scholarly journals Functional correlates of the lateral and medial entorhinal cortex: objects, path integration and local–global reference frames

2014 ◽  
Vol 369 (1635) ◽  
pp. 20130369 ◽  
Author(s):  
James J. Knierim ◽  
Joshua P. Neunuebel ◽  
Sachin S. Deshmukh
Keyword(s):  
Entorhinal Cortex ◽  
Path Integration ◽  
Sensory Input ◽  
Reference Frames ◽  
External Input ◽  
Frame Of Reference ◽  
Medial Entorhinal Cortex ◽  
Motion Cues ◽  
Cortical Input ◽  
Self Motion

The hippocampus receives its major cortical input from the medial entorhinal cortex (MEC) and the lateral entorhinal cortex (LEC). It is commonly believed that the MEC provides spatial input to the hippocampus, whereas the LEC provides non-spatial input. We review new data which suggest that this simple dichotomy between ‘where’ versus ‘what’ needs revision. We propose a refinement of this model, which is more complex than the simple spatial–non-spatial dichotomy. MEC is proposed to be involved in path integration computations based on a global frame of reference, primarily using internally generated, self-motion cues and external input about environmental boundaries and scenes; it provides the hippocampus with a coordinate system that underlies the spatial context of an experience. LEC is proposed to process information about individual items and locations based on a local frame of reference, primarily using external sensory input; it provides the hippocampus with information about the content of an experience.

scholarly journals Tuning of Synaptic Integration in the Medial Entorhinal Cortex to the Organization of Grid Cell Firing Fields

Neuron ◽  
2008 ◽  
Vol 60 (5) ◽  
pp. 875-889 ◽  
Author(s):  
Derek L.F. Garden ◽  
Paul D. Dodson ◽  
Cian O'Donnell ◽  
Melanie D. White ◽  
Matthew F. Nolan
Keyword(s):  
Entorhinal Cortex ◽  
Grid Cell ◽  
Synaptic Integration ◽  
Medial Entorhinal Cortex ◽  
Cell Firing

scholarly journals Linking Cellular Mechanisms to Behavior: Entorhinal Persistent Spiking and Membrane Potential Oscillations May Underlie Path Integration, Grid Cell Firing, and Episodic Memory

2008 ◽  
Vol 2008 ◽  
pp. 1-12 ◽  
Author(s):  
Michael E. Hasselmo ◽  
Mark P. Brandon
Keyword(s):  
Membrane Potential ◽  
Episodic Memory ◽  
Entorhinal Cortex ◽  
Path Integration ◽  
Grid Cell ◽  
Physiological Data ◽  
Cellular Mechanisms ◽  
Potential Oscillations ◽  
Cell Firing ◽  
Membrane Potential Oscillations

The entorhinal cortex plays an important role in spatial memory and episodic memory functions. These functions may result from cellular mechanisms for integration of the afferent input to entorhinal cortex. This article reviews physiological data on persistent spiking and membrane potential oscillations in entorhinal cortex then presents models showing how both these cellular mechanisms could contribute to properties observed during unit recording, including grid cell firing, and how they could underlie behavioural functions including path integration. The interaction of oscillations and persistent firing could contribute to encoding and retrieval of trajectories through space and time as a mechanism relevant to episodic memory.

scholarly journals Recurrent circuits within medial entorhinal cortex superficial layers support grid cell firing

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Ipshita Zutshi ◽  
Maylin L. Fu ◽  
Varoth Lilascharoen ◽  
Jill K. Leutgeb ◽  
Byung Kook Lim ◽  
...  
Keyword(s):  
Entorhinal Cortex ◽  
Grid Cell ◽  
Medial Entorhinal Cortex ◽  
Cell Firing ◽  
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