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.

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 Inter- and intra-animal variation of integrative properties of stellate cells in the medial entorhinal cortex

2019 ◽  
Author(s):  
Hugh Pastoll ◽  
Derek Garden ◽  
Ioannis Papastathopoulos ◽  
Gülşen Sürmeli ◽  
Matthew F. Nolan
Keyword(s):  
Entorhinal Cortex ◽  
Ex Vivo ◽  
Spatial Scales ◽  
Phenotypic Variability ◽  
Grid Cell ◽  
Stellate Cells ◽  
Cell Types ◽  
Functional Variation ◽  
Medial Entorhinal Cortex ◽  
Nervous System Function

AbstractDistinctions between cell types underpin organisational principles for nervous system function. Functional variation also exists between neurons of the same type. This is exemplified by correspondence between grid cell spatial scales and synaptic integrative properties of stellate cells (SCs) in the medial entorhinal cortex. However, we know little about how functional variability is structured either within or between individuals. Using ex-vivo patch-clamp recordings from up to 55 SCs per mouse, we find that integrative properties vary between mice and, in contrast to modularity of grid cell spatial scales, have a continuous dorsoventral organisation. Our results constrain mechanisms for modular grid firing and provide evidence for inter-animal phenotypic variability among neurons of the same type. We suggest that neuron type properties are tuned to circuit level set points that vary within and between animals.

scholarly journals Rebound spiking in layer II medial entorhinal cortex stellate cells: Possible mechanism of grid cell function

2016 ◽  
Vol 129 ◽  
pp. 83-98 ◽  
Author(s):  
Christopher F. Shay ◽  
Michele Ferrante ◽  
G. William Chapman ◽  
Michael E. Hasselmo
Keyword(s):  
Entorhinal Cortex ◽  
Cell Function ◽  
Grid Cell ◽  
Stellate Cells ◽  
Medial Entorhinal Cortex ◽  
Rebound Spiking

scholarly journals Inter- and intra-animal variation in the integrative properties of stellate cells in the medial entorhinal cortex

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Hugh Pastoll ◽  
Derek L Garden ◽  
Ioannis Papastathopoulos ◽  
Gülşen Sürmeli ◽  
Matthew F Nolan
Keyword(s):  
Entorhinal Cortex ◽  
Ex Vivo ◽  
Spatial Scales ◽  
Phenotypic Variability ◽  
Grid Cell ◽  
Stellate Cells ◽  
Cell Types ◽  
Functional Variation ◽  
Medial Entorhinal Cortex ◽  
Nervous System Function

Distinctions between cell types underpin organizational principles for nervous system function. Functional variation also exists between neurons of the same type. This is exemplified by correspondence between grid cell spatial scales and the synaptic integrative properties of stellate cells (SCs) in the medial entorhinal cortex. However, we know little about how functional variability is structured either within or between individuals. Using ex-vivo patch-clamp recordings from up to 55 SCs per mouse, we found that integrative properties vary between mice and, in contrast to the modularity of grid cell spatial scales, have a continuous dorsoventral organization. Our results constrain mechanisms for modular grid firing and provide evidence for inter-animal phenotypic variability among neurons of the same type. We suggest that neuron type properties are tuned to circuit-level set points that vary within and between animals.

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.

scholarly journals Cholinergic Modulation of the Resonance Properties of Stellate Cells in Layer II of Medial Entorhinal Cortex

2010 ◽  
Vol 104 (1) ◽  
pp. 258-270 ◽  
Author(s):  
James G. Heys ◽  
Lisa M. Giocomo ◽  
Michael E. Hasselmo
Keyword(s):  
Patch Clamp ◽  
Resonance Frequency ◽  
Entorhinal Cortex ◽  
Stellate Cells ◽  
Cholinergic Modulation ◽  
Medial Entorhinal Cortex ◽  
Whole Cell ◽  
Whole Cell Patch Clamp ◽  
Resonance Properties

In vitro whole cell patch-clamp recordings of stellate cells in layer II of medial entorhinal cortex show a subthreshold membrane potential resonance in response to a sinusoidal current injection of varying frequency. Physiological recordings from awake behaving animals show that neurons in layer II medial entorhinal cortex, termed “grid cells,” fire in a spatially selective manner such that each cell's multiple firing fields form a hexagonal grid. Both the spatial periodicity of the grid fields and the resonance frequency change systematically in neurons along the dorsal to ventral axis of medial entorhinal cortex. Previous work has also shown that grid field spacing and acetylcholine levels change as a function of the novelty to a particular environment. Using in vitro whole cell patch-clamp recordings, our study shows that both resonance frequency and resonance strength vary as a function of cholinergic modulation. Furthermore, our data suggest that these changes in resonance properties are mediated through modulation of h-current and m-current.

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