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entorhinal stellate cells

Johanna Sigl-Glöckner, Michael Brecht
In many species, polyploidy, in which an increase in nuclear DNA content is accompanied by an increase in cell size, contributes to cellular diversity. In the rat visual cortex, most neurons are small and homogeneous in size, while layer 5 cells are heterogeneous, containing some very large neurons. To measure DNA content, we quantified nuclear chromocenters and integrated DNA/DAPI fluorescence. The results suggest that most cortical neurons, non-neuronal cells, parvalbumin-positive interneurons, and large entorhinal layer 2 stellate projection neurons are diploid...
September 12, 2017: Cell Reports
Kristian Kinden Lensjø, Ane Charlotte Christensen, Simen Tennøe, Marianne Fyhn, Torkel Hafting
Perineuronal nets (PNNs) are specialized extracellular matrix (ECM) structures that condense around the soma and proximal dendrites of subpopulations of neurons. Emerging evidence suggests that they are involved in regulating brain plasticity. However, the expression of PNNs varies between and within brain areas. A lack of quantitative studies describing the distribution and cell-specificity of PNNs makes it difficult to reveal the functional roles of PNNs. In the current study, we examine the distribution of PNNs and the identity of PNN-enwrapped neurons in three brain areas with different cognitive functions: the dorsal hippocampus, medial entorhinal cortex (mEC) and primary visual cortex (V1)...
May 2017: ENeuro
Jochen Winterer, Nikolaus Maier, Christian Wozny, Prateep Beed, Jörg Breustedt, Roberta Evangelista, Yangfan Peng, Tiziano D'Albis, Richard Kempter, Dietmar Schmitz
The distinctive firing pattern of grid cells in the medial entorhinal cortex (MEC) supports its role in the representation of space. It is widely believed that the hexagonal firing field of grid cells emerges from neural dynamics that depend on the local microcircuitry. However, local networks within the MEC are still not sufficiently characterized. Here, applying up to eight simultaneous whole-cell recordings in acute brain slices, we demonstrate the existence of unitary excitatory connections between principal neurons in the superficial layers of the MEC...
May 9, 2017: Cell Reports
Lene C Olsen, Kally C O'Reilly, Nina B Liabakk, Menno P Witter, Pål Sætrom
The medial entorhinal cortex (MEC) is important in spatial navigation and memory formation and its layers have distinct neuronal subtypes, connectivity, spatial properties, and disease susceptibility. As little is known about the molecular basis for the development of these laminar differences, we analyzed microRNA (miRNA) and messenger RNA (mRNA) expression differences between rat MEC layer II and layers III-VI during postnatal development. We identified layer and age-specific regulation of gene expression by miRNAs, which included processes related to neuron specialization and locomotor behavior...
March 4, 2017: Brain Structure & Function
Flavio Donato, R Irene Jacobsen, May-Britt Moser, Edvard I Moser
The neural representation of space relies on a network of entorhinal-hippocampal cell types with firing patterns tuned to different abstract features of the environment. To determine how this network is set up during early postnatal development, we monitored markers of structural maturation in developing mice, both in naïve animals and after temporally restricted pharmacogenetic silencing of specific cell populations. We found that entorhinal stellate cells provide an activity-dependent instructive signal that drives maturation sequentially and unidirectionally through the intrinsic circuits of the entorhinal-hippocampal network...
March 17, 2017: Science
Daniel Justus, Dennis Dalügge, Stefanie Bothe, Falko Fuhrmann, Christian Hannes, Hiroshi Kaneko, Detlef Friedrichs, Liudmila Sosulina, Inna Schwarz, David Anthony Elliott, Susanne Schoch, Frank Bradke, Martin Karl Schwarz, Stefan Remy
The medial septum and diagonal band of Broca (MSDB) send glutamatergic axons to medial entorhinal cortex (MEC). We found that this pathway provides speed-correlated input to several MEC cell-types in layer 2/3. The speed signal is integrated most effectively by pyramidal cells but also excites stellate cells and interneurons. Thus, the MSDB conveys speed information that can be used by MEC neurons for spatial representation of self-location.
January 2017: Nature Neuroscience
Christoph Hönigsperger, Maximiliano J Nigro, Johan F Storm
KEY POINTS: Kv2 channels underlie delayed-rectifier potassium currents in various neurons, although their physiological roles often remain elusive. Almost nothing is known about Kv2 channel functions in medial entorhinal cortex (mEC) neurons, which are involved in representing space, memory formation, epilepsy and dementia. Stellate cells in layer II of the mEC project to the hippocampus and are considered to be space-representing grid cells. We used the new Kv2 blocker Guangxitoxin-1E (GTx) to study Kv2 functions in these neurons...
February 1, 2017: Journal of Physiology
Christian Laut Ebbesen, Eric Torsten Reifenstein, Qiusong Tang, Andrea Burgalossi, Saikat Ray, Susanne Schreiber, Richard Kempter, Michael Brecht
The medial entorhinal cortex (MEC) and the adjacent parasubiculum are known for their elaborate spatial discharges (grid cells, border cells, etc.) and the precessing of spikes relative to the local field potential. We know little, however, about how spatio-temporal firing patterns map onto cell types. We find that cell type is a major determinant of spatio-temporal discharge properties. Parasubicular neurons and MEC layer 2 (L2) pyramids have shorter spikes, discharge spikes in bursts, and are theta-modulated (rhythmic, locking, skipping), but spikes phase-precess only weakly...
July 26, 2016: Cell Reports
Michele Ferrante, Babak Tahvildari, Alvaro Duque, Muhamed Hadzipasic, David Salkoff, Edward William Zagha, Michael E Hasselmo, David A McCormick
Inhibitory interneurons are an important source of synaptic inputs that may contribute to network mechanisms for coding of spatial location by entorhinal cortex (EC). The intrinsic properties of inhibitory interneurons in the EC of the mouse are mostly undescribed. Intrinsic properties were recorded from known cell types, such as, stellate and pyramidal cells and 6 classes of molecularly identified interneurons (regulator of calcineurin 2, somatostatin, serotonin receptor 3a, neuropeptide Y neurogliaform (NGF), neuropeptide Y non-NGF, and vasoactive intestinal protein) in acute brain slices...
June 1, 2017: Cerebral Cortex
James G Heys, Christopher F Shay, Katrina M MacLeod, Menno P Witter, Cynthia F Moss, Michael E Hasselmo
UNLABELLED: Medial entorhinal cortex (MEC) grid cells exhibit firing fields spread across the environment on the vertices of a regular tessellating triangular grid. In rodents, the size of the firing fields and the spacing between the firing fields are topographically organized such that grid cells located more ventrally in MEC exhibit larger grid fields and larger grid-field spacing compared with grid cells located more dorsally. Previous experiments in brain slices from rodents have shown that several intrinsic cellular electrophysiological properties of stellate cells in layer II of MEC change systematically in neurons positioned along the dorsal-ventral axis of MEC, suggesting that these intrinsic cellular properties might control grid-field spacing...
April 20, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Saikat Ray, Michael Brecht
We investigated the structural development of superficial-layers of medial entorhinal cortex and parasubiculum in rats. The grid-layout and cholinergic-innervation of calbindin-positive pyramidal-cells in layer-2 emerged around birth while reelin-positive stellate-cells were scattered throughout development. Layer-3 and parasubiculum neurons had a transient calbindin-expression, which declined with age. Early postnatally, layer-2 pyramidal but not stellate-cells co-localized with doublecortin - a marker of immature neurons - suggesting delayed functional-maturation of pyramidal-cells...
April 2, 2016: ELife
Xiaojun Li, Ke Pan, Dan Zhu, Yuping Li, Guocai Tao
The entorhinal cortex (EC) provides a majority of the excitatory inputs to the hippocampus and is part of the neural circuitry that is involved in memory formation. Although many studies have investigated the effects of propofol in the hippocampus, the function of propofol in the EC remains unclear. Here, using whole-cell patch clamp recordings, we found that propofol induced a postsynaptic outward current and dramatically suppressed the firing rates in the entorhinal stellate neurons, the axons of which form the perforant pathway and relay the main inputs to hippocampus...
April 21, 2016: Neuroscience Letters
Michele Ferrante, Christopher F Shay, Yusuke Tsuno, G William Chapman, Michael E Hasselmo
Medial entorhinal cortex Layer-II stellate cells (mEC-LII-SCs) primarily interact via inhibitory interneurons. This suggests the presence of alternative mechanisms other than excitatory synaptic inputs for triggering action potentials (APs) in stellate cells during spatial navigation. Our intracellular recordings show that the hyperpolarization-activated cation current (Ih) allows post-inhibitory-rebound spikes (PIRS) in mEC-LII-SCs. In vivo, strong inhibitory-post-synaptic potentials immediately preceded most APs shortening their delay and enhancing excitability...
March 1, 2017: Cerebral Cortex
Eric T Reifenstein, Christian L Ebbesen, Qiusong Tang, Michael Brecht, Susanne Schreiber, Richard Kempter
UNLABELLED: The identity of phase-precessing cells in the entorhinal cortex is unknown. Here, we used a classifier derived from cell-attached recordings to separate putative pyramidal cells and putative stellate cells recorded extracellularly in layer II of the medial entorhinal cortex in rats. Using a novel method to identify single runs as temporal periods of elevated spiking activity, we find that both cell types show phase precession but putative stellate cells show steeper slopes of phase precession and larger phase ranges...
February 17, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Gülşen Sürmeli, Daniel Cosmin Marcu, Christina McClure, Derek L F Garden, Hugh Pastoll, Matthew F Nolan
Deep layers of the medial entorhinal cortex are considered to relay signals from the hippocampus to other brain structures, but pathways for routing of signals to and from the deep layers are not well established. Delineating these pathways is important for a circuit level understanding of spatial cognition and memory. We find that neurons in layers 5a and 5b have distinct molecular identities, defined by the transcription factors Etv1 and Ctip2, and divergent targets, with extensive intratelencephalic projections originating in layer 5a, but not 5b...
December 2, 2015: Neuron
Christopher F Shay, Michele Ferrante, G William Chapman, Michael E Hasselmo
Rebound spiking properties of medial entorhinal cortex (mEC) stellate cells induced by inhibition may underlie their functional properties in awake behaving rats, including the temporal phase separation of distinct grid cells and differences in grid cell firing properties. We investigated rebound spiking properties using whole cell patch recording in entorhinal slices, holding cells near spiking threshold and delivering sinusoidal inputs, superimposed with realistic inhibitory synaptic inputs to test the capacity of cells to selectively respond to specific phases of inhibitory input...
March 2016: Neurobiology of Learning and Memory
Saad Abbasi, Sanjay S Kumar
Temporal lobe epilepsy (TLE) is the most common form of epilepsy in adults and is often refractory to antiepileptic medications. The medial entorhinal area (MEA) is affected in TLE but mechanisms underlying hyperexcitability of MEA neurons require further elucidation. Previous studies suggest that inputs from the presubiculum (PrS) contribute to MEA pathophysiology. We assessed electrophysiologically how PrS influences MEA excitability using the rat pilocarpine model of TLE. PrS-MEA connectivity was confirmed by electrically stimulating PrS afferents while recording from neurons within superficial layers of MEA...
November 2015: Journal of Neurophysiology
Camilla Alessi, Alessandra Raspanti, Jacopo Magistretti
Two types of principal neurons, stellate cells and pyramidal-like cells, are found in medial entorhinal-cortex (mEC) layer II, and are believed to represent two distinct channels of information processing and transmission in the entorhinal cortex-hippocampus network. In this study, we found that depolarizing afterpotentials (DAPs) that follow single action potentials (APs) evoked from various levels of holding membrane voltage (Vh ) show distinct properties in the two cells types. In both, an evident DAP followed the AP at near-threshold Vh levels, and was accompanied by an enhancement of excitability and spike-timing precision...
March 2016: Hippocampus
Robert K Naumann, Saikat Ray, Stefan Prokop, Liora Las, Frank L Heppner, Michael Brecht
To understand the structural basis of grid cell activity, we compare medial entorhinal cortex architecture in layer 2 across five mammalian species (Etruscan shrews, mice, rats, Egyptian fruit bats, and humans), bridging ∼100 million years of evolutionary diversity. Principal neurons in layer 2 are divided into two distinct cell types, pyramidal and stellate, based on morphology, immunoreactivity, and functional properties. We confirm the existence of patches of calbindin-positive pyramidal cells across these species, arranged periodically according to analyses techniques like spatial autocorrelation, grid scores, and modifiable areal unit analysis...
March 1, 2016: Journal of Comparative Neurology
Chen Sun, Takashi Kitamura, Jun Yamamoto, Jared Martin, Michele Pignatelli, Lacey J Kitch, Mark J Schnitzer, Susumu Tonegawa
Entorhinal-hippocampal circuits in the mammalian brain are crucial for an animal's spatial and episodic experience, but the neural basis for different spatial computations remain unknown. Medial entorhinal cortex layer II contains pyramidal island and stellate ocean cells. Here, we performed cell type-specific Ca(2+) imaging in freely exploring mice using cellular markers and a miniature head-mounted fluorescence microscope. We found that both oceans and islands contain grid cells in similar proportions, but island cell activity, including activity in a proportion of grid cells, is significantly more speed modulated than ocean cell activity...
July 28, 2015: Proceedings of the National Academy of Sciences of the United States of America
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