Parvalbumin interneurons provide grid cell–driven recurrent inhibition in the medial entorhinal cortex

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.

Download Full-text

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

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2012.0523 ◽

2014 ◽

Vol 369 (1635) ◽

pp. 20120523 ◽

Cited By ~ 28

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.

Download Full-text

Systemic administration of two different anxiolytic drugs decreases local field potential theta frequency in the medial entorhinal cortex without affecting grid cell firing fields

Neuroscience ◽

10.1016/j.neuroscience.2017.08.056 ◽

2017 ◽

Vol 364 ◽

pp. 60-70 ◽

Cited By ~ 8

Author(s):

Caitlin K. Monaghan ◽

G. William Chapman ◽

Michael E. Hasselmo

Keyword(s):

Entorhinal Cortex ◽

Local Field ◽

Local Field Potential ◽

Field Potential ◽

Grid Cell ◽

Systemic Administration ◽

Medial Entorhinal Cortex ◽

Theta Frequency ◽

Anxiolytic Drugs ◽

Cell Firing

Download Full-text

How to build a grid cell

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2012.0520 ◽

2014 ◽

Vol 369 (1635) ◽

pp. 20120520 ◽

Cited By ~ 8

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.

Download Full-text

ARM-Cortex M3-Based Two-Wheel Robot for Assessing Grid Cell Model of Medial Entorhinal Cortex: Progress towards Building Robots with Biologically Inspired Navigation-Cognitive Maps

Journal of Robotics ◽

10.1155/2017/8069654 ◽

2017 ◽

Vol 2017 ◽

pp. 1-9

Author(s):

J. Cuneo ◽

L. Barboni ◽

N. Blanco ◽

M. del Castillo ◽

J. Quagliotti

Keyword(s):

Embedded System ◽

Entorhinal Cortex ◽

Cell Model ◽

Systems Design ◽

Grid Cell ◽

Network Models ◽

Time Algorithm ◽

Neural Network Models ◽

Biologically Inspired ◽

Medial Entorhinal Cortex

This article presents the implementation and use of a two-wheel autonomous robot and its effectiveness as a tool for studying the recently discovered use of grid cells as part of mammalian’s brains space-mapping circuitry (specifically the medial entorhinal cortex). A proposed discrete-time algorithm that emulates the medial entorhinal cortex is programed into the robot. The robot freely explores a limited laboratory area in the manner of a rat or mouse and reports information to a PC, thus enabling research without the use of live individuals. Position coordinate neural maps are achieved as mathematically predicted although for a reduced number of implemented neurons (i.e., 200 neurons). However, this type of computational embedded system (robot’s microcontroller) is found to be insufficient for simulating huge numbers of neurons in real time (as in the medial entorhinal cortex). It is considered that the results of this work provide an insight into achieving an enhanced embedded systems design for emulating and understanding mathematical neural network models to be used as biologically inspired navigation system for robots.

Download Full-text

Theta-frequency resonance as the scale of input-output mapping in the medial entorhinal cortex

10.1101/369025 ◽

2018 ◽

Author(s):

Nupur Katyare ◽

Sujit Sikdar

Keyword(s):

Firing Rate ◽

Entorhinal Cortex ◽

Grid Cell ◽

Synaptic Activity ◽

Spatial Period ◽

Hcn Channels ◽

Medial Entorhinal Cortex ◽

Frequency Resonance ◽

Theta Frequency

Grid cell spatial period is thought to be dictated by a mapping between the speed-direction modulated excitatory inputs, and consequent modulation of the firing rate, yet, the exact underlying mechanisms are not known. Here, through experiments on the medial entorhinal cortex stellate cells, subjected to in-vivo like stochastic synaptic activity through the dynamic clamp, we show that such mapping can emerge from a theta-frequency resonance in the signal gain, which is HCN sensitive, robust to noise, and is potent enough to modulate the synaptic responses in the theta frequency. This modulation also extends to the corresponding theta-gamma modulation of the firing rate, the slope of whose excitation mediated increase is steeper in the presence of HCN channels. We also show that in the cells devoid of HCN channels, inhibition can emulate their role. Considering the dorso-ventral gradients of HCN and inhibition, which are present aligned to the grid spacing gradient in the medial entorhinal cortex, these findings should be noteworthy.

Download Full-text

Author response: Visual landmarks sharpen grid cell metric and confer context specificity to neurons of the medial entorhinal cortex

10.7554/elife.16937.019 ◽

2016 ◽

Author(s):

José Antonio Pérez-Escobar ◽

Olga Kornienko ◽

Patrick Latuske ◽

Laura Kohler ◽

Kevin Allen

Keyword(s):

Entorhinal Cortex ◽

Grid Cell ◽

Author Response ◽

Context Specificity ◽

Visual Landmarks ◽

Medial Entorhinal Cortex

Download Full-text

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

10.1101/678565 ◽

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.

Download Full-text