scholarly journals Ion channel distributions in cortical neurons are optimized for energy-efficient active dendritic computations

2021 ◽  
Author(s):  
Arco Bast ◽  
Marcel Oberlaender
Keyword(s):  
Ion Channel ◽  
Cortical Neurons ◽  
Energy Efficient ◽  
Action Potentials ◽  
Expression Patterns ◽  
Morphological Variability ◽  
Mammalian Brain ◽  
Entire Body ◽  
Empirical Observation ◽  
Calcium Action Potentials

The mammalian brain uses more than 20% of the energy consumed by the entire body. This enormous demand for energy is thought to impose strong selective pressure by which neurons evolve in ways that ensure robust function at minimal energy cost. Here we demonstrate that the ion channel expression patterns by which pyramidal tract neurons - the major output cell type of the cerebral cortex - could implement their complex intrinsic physiology is extremely widespread. Surprisingly, this wide spectrum does not reflect morphological variability, but the energy costs for generating dendritic calcium action potentials. We found that energy-efficient calcium action potentials require a low expression of slow inactivating potassium channels in the distal dendrites, an empirical observation whose significance remained unclear for more than a decade. Thus, cortical neurons do not utilize all theoretically possible ways to implement their functions, but instead appear to select those optimized for energy-efficient active dendritic computations.

scholarly journals Transgenic Silencing of Neurons in the Mammalian Brain by Expression of the Allatostatin Receptor (AlstR)

2009 ◽  
Vol 102 (4) ◽  
pp. 2554-2562 ◽  
Author(s):  
M. Wehr ◽  
U. Hostick ◽  
M. Kyweriga ◽  
A. Tan ◽  
A. P. Weible ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Cortical Neurons ◽  
Action Potentials ◽  
Neural Circuits ◽  
Hippocampal Slices ◽  
Neuronal Cell ◽  
Cell Types ◽  
Mammalian Brain ◽  
Specific Cell ◽  
Membrane Hyperpolarization

The mammalian brain is an enormously complex set of circuits composed of interconnected neuronal cell types. The analysis of central neural circuits will be greatly served by the ability to turn off specific neuronal cell types while recording from others in intact brains. Because drug delivery cannot be restricted to specific cell types, this can only be achieved by putting “silencer” transgenes under the control of neuron-specific promoters. Towards this end we have created a line of transgenic mice putting the Drosophila allatostatin (AL) neuropeptide receptor (AlstR) under the control of the tetO element, thus enabling its inducible expression when crossed to tet-transactivator lines. Mammals have no endogenous AL or AlstR, but activation of exogenously expressed AlstR in mammalian neurons leads to membrane hyperpolarization via endogenous G-protein-coupled inward rectifier K+ channels, making the neurons much less likely to fire action potentials. Here we show that this tetO/AlstR line is capable of broadly expressing AlstR mRNA in principal neurons throughout the forebrain when crossed to a commercially-available transactivator line. We electrophysiologically characterize this cross in hippocampal slices, demonstrating that bath application of AL leads to hyperpolarization of CA1 pyramidal neurons, making them refractory to the induction of action potentials by injected current. Finally, we demonstrate the ability of AL application to silence the sound-evoked spiking responses of auditory cortical neurons in intact brains of AlstR/tetO transgenic mice. When crossed to other transactivator lines expressing in defined neuronal cell types, this AlstR/tetO line should prove a very useful tool for the analysis of intact central neural circuits.

AMPA and Kainate Receptors

2020 ◽  
Author(s):  
G. Brent Dawe ◽  
Patricia M. G. E. Brown ◽  
Derek Bowie
Keyword(s):  
Ion Channel ◽  
Glutamate Receptor ◽  
Single Channel ◽  
Channel Gating ◽  
Regulatory Proteins ◽  
Kainate Receptors ◽  
Mammalian Brain ◽  
Receptor Field ◽  
Neuronal Excitation ◽  
Ion Channel Proteins

α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and kainate-type glutamate receptors (AMPARs and KARs) are dynamic ion channel proteins that govern neuronal excitation and signal transduction in the mammalian brain. The four AMPAR and five KAR subunits can heteromerize with other subfamily members to create several combinations of tetrameric channels with unique physiological and pharmacological properties. While both receptor classes are noted for their rapid, millisecond-scale channel gating in response to agonist binding, the intricate structural rearrangements underlying their function have only recently been elucidated. This chapter begins with a review of AMPAR and KAR nomenclature, topology, and rules of assembly. Subsequently, receptor gating properties are outlined for both single-channel and synaptic contexts. The structural biology of AMPAR and KAR proteins is also discussed at length, with particular focus on the ligand-binding domain, where allosteric regulation and alternative splicing work together to dictate gating behavior. Toward the end of the chapter there is an overview of several classes of auxiliary subunits, notably transmembrane AMPAR regulatory proteins and Neto proteins, which enhance native AMPAR and KAR expression and channel gating, respectively. Whether bringing an ion channel novice up to speed with glutamate receptor theory and terminology or providing a refresher for more seasoned biophysicists, there is much to appreciate in this summation of work from the glutamate receptor field.

scholarly journals Inhibition of Acid Sensing Ion Channel Currents by Lidocaine in Cultured Mouse Cortical Neurons

2011 ◽  
Vol 112 (4) ◽  
pp. 977-981 ◽  
Author(s):  
Jun Lin ◽  
Xiangping Chu ◽  
Samaneh Maysami ◽  
Minghua Li ◽  
Hongfang Si ◽  
...  
Keyword(s):  
Ion Channel ◽  
Cortical Neurons ◽  
Channel Currents

scholarly journals Ion channel expression patterns in glioblastoma stem cells with functional and therapeutic implications for malignancy

PLoS ONE ◽  
2017 ◽  
Vol 12 (3) ◽  
pp. e0172884 ◽  
Author(s):  
Julia Pollak ◽  
Karan G. Rai ◽  
Cory C. Funk ◽  
Sonali Arora ◽  
Eunjee Lee ◽  
...  
Keyword(s):  
Stem Cells ◽  
Ion Channel ◽  
Expression Patterns ◽  
Glioblastoma Stem Cells ◽  
Therapeutic Implications ◽  
Channel Expression

scholarly journals Taste quality representation in the human brain

2019 ◽  
Author(s):  
Jason A. Avery ◽  
Alexander G. Liu ◽  
John E. Ingeholm ◽  
Cameron D. Riddell ◽  
Stephen J. Gotts ◽  
...  
Keyword(s):  
Human Brain ◽  
Cortical Neurons ◽  
Brain Regions ◽  
Taste Quality ◽  
7 Tesla ◽  
Mammalian Brain ◽  
High Magnetic Field Strength ◽  
Magnetic Resonance Imaging Mri ◽  
Spatial Locations ◽  
Univariate Analyses

SUMMARYIn the mammalian brain, the insula is the primary cortical substrate involved in the perception of taste. Recent imaging studies in rodents have identified a gustotopic organization in the insula, whereby distinct insula regions are selectively responsive to one of the five basic tastes. However, numerous studies in monkeys have reported that gustatory cortical neurons are broadly-tuned to multiple tastes, and tastes are not represented in discrete spatial locations. Neuroimaging studies in humans have thus far been unable to discern between these two models, though this may be due to the relatively low spatial resolution employed in taste studies to date. In the present study, we examined the spatial representation of taste within the human brain using ultra-high resolution functional magnetic resonance imaging (MRI) at high magnetic field strength (7-Tesla). During scanning, participants tasted sweet, salty, sour and tasteless liquids, delivered via a custom-built MRI-compatible tastant-delivery system. Our univariate analyses revealed that all tastes (vs. tasteless) activated primary taste cortex within the bilateral dorsal mid-insula, but no brain region exhibited a consistent preference for any individual taste. However, our multivariate searchlight analyses were able to reliably decode the identity of distinct tastes within those mid-insula regions, as well as brain regions involved in affect and reward, such as the striatum, orbitofrontal cortex, and amygdala. These results suggest that taste quality is not represented topographically, but by a combinatorial spatial code, both within primary taste cortex as well as regions involved in processing the hedonic and aversive properties of taste.

scholarly journals Electrophysiological and Transcriptomic Features Reveal a Circular Taxonomy of Cortical Neurons

2021 ◽  
Vol 15 ◽  
Author(s):  
Alejandro Rodríguez-Collado ◽  
Cristina Rueda
Keyword(s):  
Cortical Neurons ◽  
Cell Types ◽  
Mammalian Brain ◽  
Neuronal Dynamics ◽  
Electrophysiological Signals ◽  
Visual Cortex Neurons ◽  
Line Level ◽  
Mouse Visual Cortex ◽  
Different Levels

The complete understanding of the mammalian brain requires exact knowledge of the function of each neuron subpopulation composing its parts. To achieve this goal, an exhaustive, precise, reproducible, and robust neuronal taxonomy should be defined. In this paper, a new circular taxonomy based on transcriptomic features and novel electrophysiological features is proposed. The approach is validated by analysing more than 1850 electrophysiological signals of different mouse visual cortex neurons proceeding from the Allen Cell Types database. The study is conducted on two different levels: neurons and their cell-type aggregation into Cre lines. At the neuronal level, electrophysiological features have been extracted with a promising model that has already proved its worth in neuronal dynamics. At the Cre line level, electrophysiological and transcriptomic features are joined on cell types with available genetic information. A taxonomy with a circular order is revealed by a simple transformation of the first two principal components that allow the characterization of the different Cre lines. Moreover, the proposed methodology locates other Cre lines in the taxonomy that do not have transcriptomic features available. Finally, the taxonomy is validated by Machine Learning methods which are able to discriminate the different neuron types with the proposed electrophysiological features.

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