scholarly journals The Caudal Medial Entorhinal Cortex: a Selective Role in Recollection-Based Recognition Memory

2010 ◽  
Vol 30 (46) ◽  
pp. 15695-15699 ◽  
Author(s):  
M. M. Sauvage ◽  
Z. Beer ◽  
M. Ekovich ◽  
L. Ho ◽  
H. Eichenbaum
Keyword(s):  
Recognition Memory ◽  
Entorhinal Cortex ◽  
Medial Entorhinal Cortex

scholarly journals Mouse entorhinal cortex encodes a diverse repertoire of self-motion signals

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Caitlin S. Mallory ◽  
Kiah Hardcastle ◽  
Malcolm G. Campbell ◽  
Alexander Attinger ◽  
Isabel I. C. Low ◽  
...  
Keyword(s):  
Entorhinal Cortex ◽  
Medial Temporal Lobe ◽  
Visual Cues ◽  
Neural Circuits ◽  
Sensory Cues ◽  
Medial Entorhinal Cortex ◽  
Representation Of Space ◽  
Self Motion ◽  
Information Streams ◽  
Representations Of Space

AbstractNeural circuits generate representations of the external world from multiple information streams. The navigation system provides an exceptional lens through which we may gain insights about how such computations are implemented. Neural circuits in the medial temporal lobe construct a map-like representation of space that supports navigation. This computation integrates multiple sensory cues, and, in addition, is thought to require cues related to the individual’s movement through the environment. Here, we identify multiple self-motion signals, related to the position and velocity of the head and eyes, encoded by neurons in a key node of the navigation circuitry of mice, the medial entorhinal cortex (MEC). The representation of these signals is highly integrated with other cues in individual neurons. Such information could be used to compute the allocentric location of landmarks from visual cues and to generate internal representations of space.

A role for medial entorhinal cortex in spatial and nonspatial forms of memory in rats

2021 ◽  
pp. 113259
Author(s):  
Jena B. Hales ◽  
Nicole T. Reitz ◽  
Jonathan L. Vincze ◽  
Amber C. Ocampo ◽  
Stefan Leutgeb ◽  
...  
Keyword(s):  
Entorhinal Cortex ◽  
Medial Entorhinal Cortex

scholarly journals P2-071: IMPAIRED IN VIVO GAMMA OSCILLATIONS IN THE MEDIAL ENTORHINAL CORTEX OF KNOCK-IN ALZHEIMER MODEL

2019 ◽  
Vol 15 ◽  
pp. P598-P598
Author(s):  
Heechul Jun ◽  
Shogo Soma ◽  
Ananya Dasgupta ◽  
Kei Igarashi
Keyword(s):  
Entorhinal Cortex ◽  
Gamma Oscillations ◽  
Medial Entorhinal Cortex

Ionic mechanisms for the subthreshold oscillations and differential electroresponsiveness of medial entorhinal cortex layer II neurons

1993 ◽  
Vol 70 (1) ◽  
pp. 144-157 ◽  
Author(s):  
R. Klink ◽  
A. Alonso
Keyword(s):  
Membrane Potential ◽  
Entorhinal Cortex ◽  
Inward Rectification ◽  
Voltage Level ◽  
Medial Entorhinal Cortex ◽  
Potential Oscillations ◽  
Subthreshold Oscillations ◽  
Outward Rectification ◽  
Ionic Mechanisms ◽  
Membrane Potential Oscillations

1. Layer II of the medial entorhinal cortex is composed of two electrophysiologically and morphologically distinct types of projection neurons: stellate cells (SCs), which are distinguished by rhythmic subthreshold oscillatory activity, and non-SCs. The ionic mechanisms underlying their differential electroresponsiveness, particularly in the subthreshold range of membrane potentials, were investigated in an "in vitro" slice preparation. 2. In both SCs and non-SCs, the apparent membrane input resistance was markedly voltage dependent, respectively decreasing or increasing at hyperpolarized or subthreshold depolarized potential levels. Thus the neurons displayed inward rectification in the hyperpolarizing and depolarizing range. 3. In the depolarizing range, inward rectification was blocked by tetrodotoxin (TTX, 1 microM) in both types of neurons and thus shown to depend on the presence of a persistent low-threshold Na+ conductance (gNap). However, in the presence of TTX, pronounced outward rectification became manifest in the subthreshold depolarizing range of membrane potentials (positive to -60 mV) in the SCs but not in the non-SCs. 4. The rhythmic subthreshold membrane potential oscillations that were present only in the SCs were abolished by TTX and not by Ca2+ conductance block with Cd2+ or Co2+. Subthreshold oscillations thus rely on the activation of voltage-gated Na+, and not Ca2+, conductances. The Ca2+ conductance block also had no effect on the subthreshold outward rectification. 5. Prominent time-dependent inward rectification in the hyperpolarizing range in the SCs persisted after Na(+)- and Ca2+ conductance block. This rectification was not affected by Ba2+ (1 mM), but was blocked by Cs+ (1-4 mM). Therefore, it is most probably generated by a hyperpolarization-activated cationic current (Q-like current). However, the Q-like current appears to play no major role in the generation of subthreshold rhythmic membrane potential oscillations, because these persisted in the presence of Cs+. 6. On the other hand, in the SCs, the fast, sustained, outward rectification that strongly developed (after Na+ conductance block) at the oscillatory voltage level was not affected by Cs+ but was blocked by Ba2+ (1 mM). Barium was also effective in blocking the subthreshold membrane potential oscillations. 7. In the non-SCs, which do not generate subthreshold rhythmic membrane potential oscillations or manifest subthreshold outward rectification in TTX, Ca2+ conductance block abolished spike repolarization and caused the development of long-lasting Na(+)-dependent plateau potentials at a high suprathreshold voltage level. At this level, where prominent delayed rectification is present, the Na+ plateaus sustained rhythmic membrane potential oscillations.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Rebound spiking properties of mouse medial entorhinal cortex neuronsin vivo

2015 ◽  
Vol 42 (11) ◽  
pp. 2974-2984 ◽  
Author(s):  
Yusuke Tsuno ◽  
George W. Chapman ◽  
Michael E. Hasselmo
Keyword(s):  
Entorhinal Cortex ◽  
Medial Entorhinal Cortex ◽  
Rebound Spiking

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 Laminar Localization and Projection-Specific Properties of Presubicular Neurons Targeting the Lateral Mammillary Nucleus, Thalamus, or Medial Entorhinal Cortex

eNeuro ◽  
2017 ◽  
Vol 4 (2) ◽  
pp. ENEURO.0370-16.2017 ◽  
Author(s):  
Li-Wen Huang ◽  
Jean Simonnet ◽  
Mérie Nassar ◽  
Louis Richevaux ◽  
Roxanne Lofredi ◽  
...  
Keyword(s):  
Entorhinal Cortex ◽  
Medial Entorhinal Cortex

scholarly journals A geometric attractor mechanism for self-organization of entorhinal grid modules

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Louis Kang ◽  
Vijay Balasubramanian
Keyword(s):  
Entorhinal Cortex ◽  
Network Models ◽  
Recurrent Inhibition ◽  
Modular Structure ◽  
Self Organization ◽  
Periodic Lattice ◽  
Grid Cells ◽  
Medial Entorhinal Cortex ◽  
Attractor Network ◽  
Discrete Values

Grid cells in the medial entorhinal cortex (MEC) respond when an animal occupies a periodic lattice of ‘grid fields’ in the environment. The grids are organized in modules with spatial periods, or scales, clustered around discrete values separated on average by ratios in the range 1.4–1.7. We propose a mechanism that produces this modular structure through dynamical self-organization in the MEC. In attractor network models of grid formation, the grid scale of a single module is set by the distance of recurrent inhibition between neurons. We show that the MEC forms a hierarchy of discrete modules if a smooth increase in inhibition distance along its dorso-ventral axis is accompanied by excitatory interactions along this axis. Moreover, constant scale ratios between successive modules arise through geometric relationships between triangular grids and have values that fall within the observed range. We discuss how interactions required by our model might be tested experimentally.

scholarly journals Shedding light on stellate cells

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Andrew S Alexander ◽  
Michael E Hasselmo
Keyword(s):  
Entorhinal Cortex ◽  
Stellate Cells ◽  
Grid Cells ◽  
Medial Entorhinal Cortex ◽  
The Relationship

The relationship between grid cells and two types of neurons found in the medial entorhinal cortex has been clarified.

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