scholarly journals Theta oscillations coordinate grid-like representations between ventromedial prefrontal and entorhinal cortex

2021 ◽  
Vol 7 (44) ◽  
Author(s):  
Dong Chen ◽  
Lukas Kunz ◽  
Pengcheng Lv ◽  
Hui Zhang ◽  
Wenjing Zhou ◽  
...  
Keyword(s):  
Entorhinal Cortex ◽  
Theta Oscillations ◽  
Coordinate Grid

scholarly journals Hippocampus and Entorhinal Cortex Recruit Cholinergic and NMDA Receptors Separately to Generate Hippocampal Theta Oscillations

Cell Reports ◽  
2017 ◽  
Vol 21 (12) ◽  
pp. 3585-3595 ◽  
Author(s):  
Zhenglin Gu ◽  
Georgia M. Alexander ◽  
Serena M. Dudek ◽  
Jerrel L. Yakel
Keyword(s):  
Nmda Receptors ◽  
Entorhinal Cortex ◽  
Theta Oscillations ◽  
Hippocampal Theta

scholarly journals Theta Modulation in the Medial and the Lateral Entorhinal Cortices

2010 ◽  
Vol 104 (2) ◽  
pp. 994-1006 ◽  
Author(s):  
Sachin S. Deshmukh ◽  
D. Yoganarasimha ◽  
Horatiu Voicu ◽  
James J. Knierim
Keyword(s):  
Entorhinal Cortex ◽  
Hippocampal Neurons ◽  
Theta Oscillations ◽  
Neural Firing ◽  
Physiological Mechanisms ◽  
Cortical Input ◽  
Theta Frequency ◽  
Temporal Encoding ◽  
Cortical Inputs ◽  
Delta Oscillations

Hippocampal neurons show a strong modulation by theta frequency oscillations. This modulation is thought to be important not only for temporal encoding and decoding of information in the hippocampal system, but also for temporal ordering of neuronal activities on timescales at which physiological mechanisms of synaptic plasticity operate. The medial entorhinal cortex (MEC), one of the two major cortical inputs to the hippocampus, is known to show theta modulation. Here, we show that the local field potentials (LFPs) in the other major cortical input to the hippocampus, the lateral entorhinal cortex (LEC), show weaker theta oscillations than those shown in the MEC. Neurons in LEC also show weaker theta modulation than that of neurons in MEC. These findings suggest that LEC inputs are integrated into hippocampal representations in a qualitatively different manner than the MEC inputs. Furthermore, MEC grid cells increase the scale of their periodic spatial firing patterns along the dorsoventral axis, corresponding to the increasing size of place fields along the septotemporal axis of the hippocampus. We show here a corresponding gradient in the tendency of MEC neural firing to skip alternate theta cycles. We propose a simple model based on interference of delta oscillations with theta oscillations to explain this behavior.

scholarly journals Shared rhythmic subcortical GABAergic input to the entorhinal cortex and presubiculum

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Tim James Viney ◽  
Minas Salib ◽  
Abhilasha Joshi ◽  
Gunes Unal ◽  
Naomi Berry ◽  
...  
Keyword(s):  
Entorhinal Cortex ◽  
Gamma Oscillations ◽  
Medial Septum ◽  
Theta Oscillations ◽  
Cortical Circuits ◽  
Cellular Mechanisms ◽  
Neuronal Synchrony ◽  
Theta Frequency ◽  
Episodic Memories ◽  
Gabaergic Modulation

Rhythmic theta frequency (~5–12 Hz) oscillations coordinate neuronal synchrony and higher frequency oscillations across the cortex. Spatial navigation and context-dependent episodic memories are represented in several interconnected regions including the hippocampal and entorhinal cortices, but the cellular mechanisms for their dynamic coupling remain to be defined. Using monosynaptically-restricted retrograde viral tracing in mice, we identified a subcortical GABAergic input from the medial septum that terminated in the entorhinal cortex, with collaterals innervating the dorsal presubiculum. Extracellularly recording and labeling GABAergic entorhinal-projecting neurons in awake behaving mice show that these subcortical neurons, named orchid cells, fire in long rhythmic bursts during immobility and locomotion. Orchid cells discharge near the peak of hippocampal and entorhinal theta oscillations, couple to entorhinal gamma oscillations, and target subpopulations of extra-hippocampal GABAergic interneurons. Thus, orchid cells are a specialized source of rhythmic subcortical GABAergic modulation of ‘upstream’ and ‘downstream’ cortico-cortical circuits involved in mnemonic functions.

scholarly journals Theta oscillations decrease spike synchrony in the hippocampus and entorhinal cortex

2014 ◽  
Vol 369 (1635) ◽  
pp. 20120530 ◽  
Author(s):  
Kenji Mizuseki ◽  
György Buzsaki
Keyword(s):  
Entorhinal Cortex ◽  
Slow Wave Sleep ◽  
Temporal Distribution ◽  
Theta Oscillations ◽  
Spike Synchrony ◽  
Wide Range ◽  
Multiple Cell ◽  
Theta Phase ◽  
Oscillatory Mechanisms ◽  
Phase Preference

Oscillations and synchrony are often used synonymously. However, oscillatory mechanisms involving both excitation and inhibition can generate non-synchronous yet coordinated firing patterns. Using simultaneous recordings from multiple layers of the entorhinal–hippocampal loop, we found that coactivation of principal cell pairs (synchrony) was lowest during exploration and rapid-eye-movement (REM) sleep, associated with theta oscillations, and highest in slow wave sleep. Individual principal neurons had a wide range of theta phase preference. Thus, while theta oscillations reduce population synchrony, they nevertheless coordinate the phase (temporal) distribution of neurons. As a result, multiple cell assemblies can nest within the period of the theta cycle.

Grid cells without theta oscillations in the entorhinal cortex of bats

Nature ◽  
2011 ◽  
Vol 479 (7371) ◽  
pp. 103-107 ◽  
Author(s):  
Michael M. Yartsev ◽  
Menno P. Witter ◽  
Nachum Ulanovsky
Keyword(s):  
Entorhinal Cortex ◽  
Theta Oscillations ◽  
Grid Cells

scholarly journals Theta oscillations gate the transmission of reliable sequences in the medial entorhinal cortex

eNeuro ◽  
2021 ◽  
pp. ENEURO.0059-20.2021
Author(s):  
Arun Neru ◽  
Collins Assisi
Keyword(s):  
Entorhinal Cortex ◽  
Theta Oscillations ◽  
Medial Entorhinal Cortex

scholarly journals Theta oscillations gate the transmission of reliable sequences in the medial entorhinal cortex

2019 ◽  
Author(s):  
Arun Neru ◽  
Collins Assisi
Keyword(s):  
Entorhinal Cortex ◽  
Receptive Fields ◽  
Grid Cell ◽  
Stellate Cells ◽  
Theta Oscillations ◽  
Inhibitory Interneurons ◽  
Medial Entorhinal Cortex ◽  
Sensory Inputs ◽  
Recurrent Excitation ◽  
Spatial Periodicity

Reliable sequential activity of neurons in the entorhinal cortex is necessary to encode spatially guided behavior and memory. In a realistic computational model of a medial entorhinal cortex (MEC) microcircuit, with stellate cells coupled via a network of inhibitory interneurons, we show how intrinsic and network mechanisms interact with theta oscillations to generate reliable outputs. Sensory inputs activate interneurons near their most excitable phase during each theta cycle. As the inputs change, different groups of interneurons are recruited and postsynaptic stellate cells are released from inhibition causing a sequence of rebound spikes. Since the rebound time scale of stellate cells matches theta oscillations, its spikes get relegated to the least excitable phase of theta ensuring that the network encodes only the external drive and ignores recurrent excitation by rebound spikes. In the absence of theta, rebound spikes compete with external inputs and disrupt the sequence that follows. Our simulations concur with experimental data that show, subduing theta oscillations disrupts the spatial periodicity of grid cell receptive fields. Further, the same mechanism where theta modulates the gain of incoming inputs may be used to select between competing sources of input and create transient functionally connected networks.

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