Forward Dendritic Spikes

2011 ◽  
pp. 42-59
Author(s):  
Oscar Herreras ◽  
Julia Makarova ◽  
José Manuel Ibarz
Keyword(s):  
Action Potentials ◽  
Remarkable Property ◽  
Synaptic Inputs ◽  
Brain Circuits ◽  
Voltage Dependent ◽  
Dendritic Spikes ◽  
Underlying Mechanisms ◽  
The Brain ◽  
Made In

Neurons send trains of action potentials to communicate each other. Different messages are issued according to varying inputs, but they can also mix them up in a multiplexed language transmitted through a single cable, the axon. This remarkable property arises from the capability of dendritic domains to work semi autonomously and even decide output. We review the underlying mechanisms and theoretical implications of the role of voltage-dependent dendritic currents on the forward transmission of synaptic inputs, with special emphasis in the initiation, integration and forward conduction of dendritic spikes. When these spikes reach the axon, output decision was made in one of many parallel dendritic substations. When failed, they still serve as an internal language to transfer information between dendritic domains. This notion brakes with the classic view of neurons as the elementary units of the brain and attributes them computational/storage capabilities earlier billed to complex brain circuits.

scholarly journals Computational Approaches to Understanding the Role of Fibroblast-Myocyte Interactions in Cardiac Arrhythmogenesis

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Tashalee R. Brown ◽  
Trine Krogh-Madsen ◽  
David J. Christini
Keyword(s):  
Gap Junctions ◽  
Potential Role ◽  
Cardiac Tissue ◽  
Cardiac Fibroblasts ◽  
Cardiac Arrhythmogenesis ◽  
Voltage Dependent ◽  
Underlying Mechanisms ◽  
Slow Propagation

The adult heart is composed of a dense network of cardiomyocytes surrounded by nonmyocytes, the most abundant of which are cardiac fibroblasts. Several cardiac diseases, such as myocardial infarction or dilated cardiomyopathy, are associated with an increased density of fibroblasts, that is, fibrosis. Fibroblasts play a significant role in the development of electrical and mechanical dysfunction of the heart; however the underlying mechanisms are only partially understood. One widely studied mechanism suggests that fibroblasts produce excess extracellular matrix, resulting in collagenous septa. These collagenous septa slow propagation, cause zig-zag conduction paths, and decouple cardiomyocytes resulting in a substrate for arrhythmia. Another emerging mechanism suggests that fibroblasts promote arrhythmogenesis through direct electrical interactions with cardiomyocytes via gap junctions. Due to the challenges of investigating fibroblast-myocyte coupling in native cardiac tissue, computational modeling andin vitroexperiments have facilitated the investigation into the mechanisms underlying fibroblast-mediated changes in cardiomyocyte action potential morphology, conduction velocity, spontaneous excitability, and vulnerability to reentry. In this paper, we summarize the major findings of the existing computational studies investigating the implications of fibroblast-myocyte interactions in the normal and diseased heart. We then present investigations from our group into the potential role of voltage-dependent gap junctions in fibroblast-myocyte interactions.

scholarly journals Role of Intracellular Ca2+and Na+/Ca2+Exchanger in the Pathogenesis of Contrast-Induced Acute Kidney Injury

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Dingping Yang ◽  
Dingwei Yang
Keyword(s):  
Acute Kidney Injury ◽  
Cell Injury ◽  
Kidney Injury ◽  
Renal Tubular Cell ◽  
Voltage Dependent ◽  
Key Factor ◽  
Intracellular Ca ◽  
Underlying Mechanisms ◽  
Renal Tubular

The precise mechanisms underlying contrast-induced acute kidney injury (CI-AKI) are not well understood. Intracellular Ca2+overload is considered to be a key factor in CI-AKI. Voltage-dependent Ca2+channel (VDC) and Na+/Ca2+exchanger (NCX) system are the main pathways of intracellular Ca2+overload in pathological conditions. Here, we review the potential underlying mechanisms involved in CI-AKI and discuss the role of NCX-mediated intracellular Ca2+overload in the contrast media-induced renal tubular cell injury and renal hemodynamic disorder.

scholarly journals Novel Insight Into the Development and Function of Hypopharyngeal Glands in Honey Bees

2021 ◽  
Vol 11 ◽  
Author(s):  
Saboor Ahmad ◽  
Shahmshad Ahmed Khan ◽  
Khalid Ali Khan ◽  
Jianke Li
Keyword(s):  
Honey Bees ◽  
Future Research ◽  
Factors Affecting ◽  
Hypopharyngeal Glands ◽  
And Function ◽  
First Time ◽  
The Brain ◽  
Insight Into ◽  
Made In

Hypopharyngeal glands (HGs) are the most important organ of hymenopterans which play critical roles for the insect physiology. In honey bees, HGs are paired structures located bilaterally in the head, in front of the brain between compound eyes. Each gland is composed of thousands of secretory units connecting to secretory duct in worker bees. To better understand the recent progress made in understanding the structure and function of these glands, we here review the ontogeny of HGs, and the factors affecting the morphology, physiology, and molecular basis of the functionality of the glands. We also review the morphogenesis of HGs in the pupal and adult stages, and the secretory role of the glands across the ages for the first time. Furthermore, recent transcriptome, proteome, and phosphoproteome analyses have elucidated the potential mechanisms driving the HGs development and functionality. This adds a comprehensive novel knowledge of the development and physiology of HGs in honey bees over time, which may be helpful for future research investigations.

scholarly journals Eye-tracking and ERPs in multi-word expression research: A state-of-the-art review of the method and findings

2021 ◽  
Author(s):  
Anna Siyanova
Keyword(s):  
Eye Tracking ◽  
Native Speakers ◽  
Brain Potentials ◽  
Unique Role ◽  
Word Level ◽  
On Line ◽  
Underlying Mechanisms ◽  
The Brain ◽  
Linguistic Phenomenon

In recent years, there has been growing interest in the mechanisms that underlie on-line processing (comprehension and production) of units above the word level, known as multi-word expressions (MWEs). MWEs are a heterogeneous family of expressions that vary greatly in their linguistic properties but are perceived as highly conventional by native speakers. Extensive behavioural research has demonstrated that, due to their frequency and predictability, MWEs are processed differently from novel strings of language. At the very least, MWEs have been shown to be processed faster than matched control phrases. However, behavioural measures are limited in what they can tell us about MWE processing in the brain above and beyond the speed of processing. The present paper argues in favour of two powerful psycho-and neurolinguistic techniques-eye-tracking and event-related brain potentials (ERPs)-and presents a case for why these techniques are particularly suited for the investigation of phrasal frequency and predictive linguistic mechanisms. A number of studies that have drawn on these methods in their exploration of MWEs are reviewed, with a particular emphasis on the unique role of the method and its ability to tap into the underlying mechanisms implicated in MWE processing. It is argued that the two techniques complement, rather than duplicate each other, providing an ever richer account of the (psycho)linguistic phenomenon that MWEs are. © John Benjamins Publishing Company.

scholarly journals Molecular and Cellular Impact of Inflammatory Extracellular Vesicles (EVs) Derived from M1 and M2 Macrophages on Neural Action Potentials

2020 ◽  
Vol 10 (7) ◽  
pp. 424
Author(s):  
Sarah Vakili ◽  
Taha Mohseni Ahooyi ◽  
Shadan S. Yarandi ◽  
Martina Donadoni ◽  
Jay Rappaport ◽  
...  
Keyword(s):  
Extracellular Vesicles ◽  
Immune Cells ◽  
Action Potentials ◽  
M2 Macrophage ◽  
M2 Macrophages ◽  
Neuronal Functions ◽  
The Brain ◽  
Macrophage Subtypes ◽  
M1 And M2 Macrophages

Several factors can contribute to neuroinflammatory disorders, such as cytokine and chemokines that are produced and released from peripherally derived immune cells or from locally activated cells such as microglia and perivascular macrophages in the brain. The primary function of these cells is to clear inflammation; however, following inflammation, circulating monocytes are recruited to the central nervous system (CNS). Monocyte-derived macrophages in the CNS play pivotal roles in mediating neuroinflammatory responses. Macrophages are heterogeneous both in normal and in pathological conditions due to their plasticity, and they are classified in two main subsets, classically activated (M1) or alternatively activated (M2). There is accumulating evidence suggesting that extracellular vesicles (EVs) released from activated immune cells may play crucial roles in mediating inflammation. However, a possible role of EVs released from immune cells such as M1 and M2 macrophages on neuronal functions in the brain is not known. In order to investigate the molecular and cellular impacts of macrophages and EVs released from macrophage subtypes on neuronal functions, we used a recently established in vitro M1 and M2 macrophage culture model and isolated and characterized EVs from these macrophage subtypes, treated primary neurons with M1 or M2 EVs, and analyzed the extracellular action potentials of neurons with microelectrode array studies (MEA). Our results introduce evidence on the interfering role of inflammatory EVs released from macrophages in interneuronal signal transmission processes, with implications in the pathogenesis of neuroinflammatory diseases induced by a variety of inflammatory insults.

scholarly journals Visual stability

2011 ◽  
Vol 366 (1564) ◽  
pp. 468-475 ◽  
Author(s):  
David Melcher
Keyword(s):  
Cognitive Neuroscience ◽  
State Of The Art ◽  
Brain Regions ◽  
Clinical Neurology ◽  
Visual Stability ◽  
Retinal Motion ◽  
Brain Circuits ◽  
The World ◽  
The Brain

Our vision remains stable even though the movements of our eyes, head and bodies create a motion pattern on the retina. One of the most important, yet basic, feats of the visual system is to correctly determine whether this retinal motion is owing to real movement in the world or rather our own self-movement. This problem has occupied many great thinkers, such as Descartes and Helmholtz, at least since the time of Alhazen. This theme issue brings together leading researchers from animal neurophysiology, clinical neurology, psychophysics and cognitive neuroscience to summarize the state of the art in the study of visual stability. Recently, there has been significant progress in understanding the limits of visual stability in humans and in identifying many of the brain circuits involved in maintaining a stable percept of the world. Clinical studies and new experimental methods, such as transcranial magnetic stimulation, now make it possible to test the causal role of different brain regions in creating visual stability and also allow us to measure the consequences when the mechanisms of visual stability break down.

scholarly journals Temporal Event Association and Output-Dependent Learning: A Proposed Scheme of Neural Molecular Connections

1999 ◽  
Vol 3 (4) ◽  
pp. 234-244 ◽  
Author(s):  
Yukifumi Shigematsu ◽  
◽  
Hiroshi Okamoto ◽  
Kazuhisa Ichikawa ◽  
Gen Matsumoto ◽  
...  
Keyword(s):  
Action Potentials ◽  
Single Neuron ◽  
Calcium Concentration ◽  
Molecular Mechanisms ◽  
Learning Algorithm ◽  
Learning Rule ◽  
Voltage Dependent ◽  
Temporal Events ◽  
Dependent Learning ◽  
The Brain

We introduce a model of temporal-event-associated and output-dependent learning rule, genetically acquired and expressed in a single neuron. This is essentially indispensable for the brain to acquire algorithms, how to process its self-selected information, by itself. This proposed learning rule is revised-Hebbian with a synaptic history trace to correlate one temporal event to others. Temporal events are memorized to be expressed at the synaptic site of inputs and in the form of the asymmetric neural strength corrections associated with temporal events. This learning algorithm has an advantage to associate one temporal event with others, resulting in the neuron with predictability but also makes recalling flexible. Re ’ calling is, according to this learning, independent of timing, supposed to be crucial in learning. Underlying molecular mechanisms for our proposed learning rule are discussed and we identify three important factors: 1) the back-propagating action potentials experimentally observed a single neuron play a crucial role for outputdependent learning, 2) temporally associated, nonlinear couplings are modeled at molecular levels with glutamate receptors, voltage-dependent channels, intracellular calcium concentration, protein kinases and phosphatase, and 3) intracellular concentration of inositol-tri-phosphate [IP3] is the memory substrate of synaptic history.

scholarly journals Orbital and intracranial complications after acute rhinosinusitis

2010 ◽  
Vol 48 (4) ◽  
pp. 457-461
Author(s):  
Jan Kastner ◽  
Milos Taudy ◽  
Jiri Lisy ◽  
Paul Grabec ◽  
Jan Betka
Keyword(s):  
Rare Complication ◽  
Clinical Situation ◽  
Intracranial Abscess ◽  
Acute Rhinosinusitis ◽  
Cerebral Pathology ◽  
Intracranial Complications ◽  
Underlying Mechanisms ◽  
Orbital Complication ◽  
The Brain

Background/objectives: Nowadays, intracranial abscess is a rare complication of acute rhinosinusitis. The consequent orbital and intracranial complications of acute rhinosinusitis are rare but must be mutually excluded in complicated rhinosinusitis even when proper surgical and medical treatment tend to efficiently heal the orbital complication. Methods: We report a case of a patient who primarily revealed symptoms of orbitocellulitis as a complication of odontogenous rhinosinusitis. Proper diagnostic and therapeutical measures were undertaken to manage the disease immediately after stationary admission. Results: Two weeks after an inconspicuous healing period, hemiparesis due to formation of an intracranial abscess developed. An emergent situation reveals which was unusual to the clinical situation. Conclusion: The possible role of underlying mechanisms of intracranial abscess formation is discussed and review of literature concerning orbital and intracranial rhinosinusitis complications is performed. The correct indication of imaging methods and accurate evaluation of diminutive symptoms are essential. We assume that performance of a complementary CT of the brain or MRI even when previous CT scan of the orbit/paranasal sinuses reveals no cerebral pathology should be done to avoid or minimize future patients with consecutive orbital and intracranial complications of acute rhinosinusitis.

scholarly journals Neuronal Pathways and Synaptic Connexions in the Abdominal Cord of the Crayfish

1960 ◽  
Vol 37 (2) ◽  
pp. 291-307 ◽  
Author(s):  
G. M. HUGHES ◽  
C. A. G. WIERSMA
Keyword(s):  
Action Potentials ◽  
Procambarus Clarkii ◽  
Sensory Stimulation ◽  
Abdominal Ganglion ◽  
Nerve Fibres ◽  
Anterior Branch ◽  
Set Up ◽  
The Brain ◽  
Anterior Direction ◽  
Made In

1. An investigation has been made into the function and distribution of nerve fibres in the abdominal ganglion chain and its roots in the crayfish, Procambarus clarkii, by leading off action potentials from small prepared bundles following sensory stimulation. 2 .The sensory fields belonging to the first and second roots of each abdominal ganglion were determined, and the antero-posterior pathway of sensory fibres within the cord noted. It was found that the primary sensory fibres of the dorsal muscle receptor organs, entering through the second root, send out an anterior branch to the brain and a posterior one to the last ganglion. For most other sensory fibres much shorter intracentral branches are indicated, though some of them extend for two ganglia in the anterior direction and for one posteriorly. All sensory fibres in the connectives run on the same side as they enter. 3. The segmental divisions of the external skeleton and of the nervous system do not coincide, the neural segment slants in a posterior dorsal direction with respect to the skeletal one. 4. For the majority of the interneurones which innervate more than two abdominal segments it has been proved that they synapse with primary sensory fibres in each of the ganglia that these enter. Depending on the segment stimulated with respect to the leading-off position, both ascending and descending impulses are obtained in such interneurones and collision of the impulses has been observed. Some consequences of this type of integration are discussed. 5. For interneurones responding to bilateral or heterolateral stimulation the course of the impulses proved to be of at least two types. In some, cutting the fibre prevents the arrival of impulses except those set up on the side of the cut from which the recording is made. In others, recording from either side of the cut fibre does not exclude any of the sensory fields to which the fibre normally responded. 6. At least one interneurone is present in which all primary sensory fibres from the different segments to whose activity it responds collect in one ganglion.

Steroids and Plasticity

2017 ◽  
Author(s):  
Alyssa L. Pedersen ◽  
Colin J. Saldanha
Keyword(s):  
End Points ◽  
Cellular Processes ◽  
Vertebrate Brain ◽  
Synaptic Neurotransmission ◽  
And Function ◽  
And Behavior ◽  
The Brain ◽  
Vertebrate Central Nervous System ◽  
Made In

Given the profound influence of steroids on the organization and activation of the vertebrate central nervous system (CNS), it is perhaps not surprising that these molecules are involved in processes that restructure the cytoarchitecture of the brain. This includes processes such as neurogenesis and the connectivity of neural circuits. In the last 30 years or so, we have learned that the adult vertebrate brain is far from static; it responds to changes in androgens and estrogens, with dramatic alterations in structure and function. Some of these changes have been directly linked to behavior, including sex, social dominance, communication, and memory. Perhaps the most dramatic levels of neuroplasticity are observed in teleosts, where circulating and centrally derived steroids can affect several end points, including cell proliferation, migration, and behavior. Similarly, in passerine songbirds and mammals, testosterone and estradiol are important modulators of adult neuroplasticity, with documented effects on areas of the brain necessary for complex behaviors, including social communication, reproduction, and learning. Given that many of the cellular processes that underlie neuroplasticity are often energetically demanding and temporally protracted, it is somewhat surprising that steroids can affect physiological and behavioral end points quite rapidly. This includes recent demonstrations of extremely rapid effects of estradiol on synaptic neurotransmission and behavior in songbirds and mammals. Indeed, we are only beginning to appreciate the role of temporally and spatially constrained neurosteroidogenesis, like estradiol and testosterone being made in the brain, on the rapid regulation of complex behaviors.

Sign in / Sign up

Export Citation Format

Share Document