scholarly journals Brain circuitry outside the synaptic cleft

2014 ◽  
Vol 369 (1654) ◽  
pp. 20130591 ◽  
Author(s):  
Dmitri A. Rusakov ◽  
Alexander E. Dityatev
Keyword(s):  
Neural Circuits ◽  
Field Potential ◽  
Synaptic Cleft ◽  
Synaptic Connections ◽  
Informative Signal ◽  
Research Teams ◽  
Brain Circuitry ◽  
Neurological Conditions ◽  
Molecular Signals ◽  
The Brain

A growing body of experimental evidence suggests that astroglia, and possibly microglia, play an important part in regulating synaptic networking of the brain. It has also emerged that extracellular matrix (ECM) structures that enwrap synaptic connections can generate molecular signals affecting both neuronal and glial activity. Thus it appears that the mechanism of information processing in the brain, which has hitherto been associated almost exclusively with neural circuits, could also involve informative signal exchange outside the synaptic cleft. In this Theme Issue , research teams including leading experts on astroglia–neuron communication and on ECM signalling report their recent findings, share their views and discuss future conceptual advances in the field. Potential implications for drug development and new therapeutic targets with regard to some common neurological conditions are discussed throughout the issue.

Dissecting the Therapeutic Relevance of Gene Therapy in NeuroAIDS: An Evolving Epidemic

2020 ◽  
Vol 20 (3) ◽  
pp. 174-183
Author(s):  
Bushra Nabi ◽  
Saleha Rehman ◽  
Faheem Hyder Pottoo ◽  
Sanjula Baboota ◽  
Javed Ali
Keyword(s):  
Viral Entry ◽  
Due Process ◽  
Intrinsic Property ◽  
Antiretroviral Drugs ◽  
Viral Reservoir ◽  
Primary Concern ◽  
Cellular Delivery ◽  
Formidable Challenge ◽  
Neurological Conditions ◽  
The Brain

: NeuroAIDS, a disease incorporating both infectious and neurodegenerative pathways, is still a formidable challenge for the researchers to deal with. The primary concern for the treatment of neuroAIDS still remains the inaccessibility of the viral reservoir, making it indispensable for novel techniques to be continuously innovated. Since the brain serves as a reservoir for viral replication, it is pragmatic and a prerequisite to overcome the related barriers in order to improve the drug delivery to the brain. The current treatment ideology is based on the combinatorial approach of a mocktail of antiretroviral drugs. However, complete eradication of the disease could not be achieved. Thereby the arena of gene-based cellular delivery is trending and has created a niche for itself in the present scenario. To establish the supremacy of gene delivery, it is advisable to have a better understanding of the molecular mechanism involved in the due process. The mechanism associated with the activity of the anti-HIV gene lies in their intrinsic property to impart resistance to the HIV infection by targeting the viral entry channels. This review principally emphasizes on different types of gene therapies explored so far for the management of AIDS and its associated neurological conditions. Therefore it could rightly be said that we are at the crossroad where the need of the hour is to develop novel strategies for curbing AIDS and its associated neurological conditions.

scholarly journals The emulation theory of representation: Motor control, imagery, and perception

2004 ◽  
Vol 27 (3) ◽  
pp. 377-396 ◽  
Author(s):  
Rick Grush
Keyword(s):  
Motor Control ◽  
Sensory Feedback ◽  
Sensory Input ◽  
Neural Circuits ◽  
Sensory Information ◽  
The Body ◽  
Feedback Delay ◽  
Run Off ◽  
Effects Of Feedback ◽  
The Brain

The emulation theory of representation is developed and explored as a framework that can revealingly synthesize a wide variety of representational functions of the brain. The framework is based on constructs from control theory (forward models) and signal processing (Kalman filters). The idea is that in addition to simply engaging with the body and environment, the brain constructs neural circuits that act as models of the body and environment. During overt sensorimotor engagement, these models are driven by efference copies in parallel with the body and environment, in order to provide expectations of the sensory feedback, and to enhance and process sensory information. These models can also be run off-line in order to produce imagery, estimate outcomes of different actions, and evaluate and develop motor plans. The framework is initially developed within the context of motor control, where it has been shown that inner models running in parallel with the body can reduce the effects of feedback delay problems. The same mechanisms can account for motor imagery as the off-line driving of the emulator via efference copies. The framework is extended to account for visual imagery as the off-line driving of an emulator of the motor-visual loop. I also show how such systems can provide for amodal spatial imagery. Perception, including visual perception, results from such models being used to form expectations of, and to interpret, sensory input. I close by briefly outlining other cognitive functions that might also be synthesized within this framework, including reasoning, theory of mind phenomena, and language.

scholarly journals GEOFFREY HARRIS PRIZE LECTURE 2018: Novel pathways regulating neuroendocrine function, energy homeostasis and metabolism in humans

2019 ◽  
Vol 180 (2) ◽  
pp. R59-R71 ◽  
Author(s):  
Aimilia Eirini Papathanasiou ◽  
Eric Nolen-Doerr ◽  
Olivia M Farr ◽  
Christos S Mantzoros
Keyword(s):  
Energy Homeostasis ◽  
Endocrine System ◽  
Current Evidence ◽  
Energy Reserves ◽  
Neuroendocrine Function ◽  
Available Energy ◽  
Neuroendocrine Response ◽  
Leptin Deficiency ◽  
Molecular Signals ◽  
The Brain

The discovery of leptin, an adipocyte-secreted hormone, set the stage for unraveling the mechanisms dictating energy homeostasis, revealing adipose tissue as an endocrine system that regulates appetite and body weight. Fluctuating leptin levels provide molecular signals to the brain regarding available energy reserves modulating energy homeostasis and neuroendocrine response in states of leptin deficiency and to a lesser extent in hyperleptinemic states. While leptin replacement therapy fails to provide substantial benefit in common obesity, it is an effective treatment for congenital leptin deficiency and states of acquired leptin deficiency such as lipodystrophy. Current evidence suggests that regulation of eating behavior in humans is not limited to homeostatic mechanisms and that the reward, attention, memory and emotion systems are involved, participating in a complex central nervous system network. It is critical to study these systems for the treatment of typical obesity. Although progress has been made, further studies are required to unravel the physiology, pathophysiology and neurobehavioral mechanisms underlying potential treatments for weight-related problems in humans.

scholarly journals Oscillatory integration windows in neurons

2016 ◽  
Author(s):  
Nitin Gupta ◽  
Swikriti Saran Singh ◽  
Mark Stopfer
Keyword(s):  
Neural Circuits ◽  
Neural Circuit ◽  
Field Potential ◽  
Coincidence Detection ◽  
Uniform Structure ◽  
Detection Mechanism ◽  
Oscillation Frequencies ◽  
Local Field Potential Lfp ◽  
Oscillatory Cycle

AbstractOscillatory synchrony among neurons occurs in many species and brain areas, and has been proposed to help neural circuits process information. One hypothesis states that oscillatory input creates cyclic integration windows: specific times in each oscillatory cycle when postsynaptic neurons become especially responsive to inputs. With paired local field potential (LFP) and intracellular recordings and controlled stimulus manipulations we directly tested this idea in the locust olfactory system. We found that inputs arriving in Kenyon cells (KCs) sum most effectively in a preferred window of the oscillation cycle. With a computational model, we found that the non-uniform structure of noise in the membrane potential helps mediate this process. Further experiments performed in vivo demonstrated that integration windows can form in the absence of inhibition and at a broad range of oscillation frequencies. Our results reveal how a fundamental coincidence-detection mechanism in a neural circuit functions to decode temporally organized spiking.

scholarly journals A Robust and Reproducible Connectome Fingerprint of Ketamine is Highly Associated with the Connectomic Signature of Antidepressants

2020 ◽  
Author(s):  
Chadi G. Abdallah ◽  
Kyung-Heup Ahn ◽  
Lynnette A. Averill ◽  
Samaneh Nemati ◽  
Christopher L. Averill ◽  
...  
Keyword(s):  
Brain Connectivity ◽  
Imaging Study ◽  
Seed Selection ◽  
Major Depressive ◽  
Brain Circuitry ◽  
Brain Functional Connectivity ◽  
The Brain ◽  
Healthy Participants ◽  
Placebo Cohort ◽  
Model Approach

ABSTRACTOver the past decade, various N-Methyl-D-Aspartate modulators have failed in clinical trials, underscoring the challenges of developing novel rapid-acting antidepressants based solely on the receptor or regional targets of ketamine. Thus, identifying the effect of ketamine on the brain circuitry and networks is becoming increasingly critical. In this longitudinal functional magnetic resonance imaging study of data from 265 participants, we used a validated predictive model approach that allows the full assessment of brain functional connectivity, without the need for seed selection or connectivity summaries. First, we identified a connectome fingerprint (CFP) in healthy participants (Cohort A, n=25) during intravenous infusion of a subanesthetic dose of ketamine, compared to normal saline. We then demonstrated the robustness and reproducibility of the discovered Ketamine CFP in two separate healthy samples (Cohort B, n=22; Cohort C, n=18). Finally, we investigated the Ketamine CFP connectivity at 1-week post treatment in major depressive disorder patients randomized to 8 weeks of sertraline or placebo (Cohort D, n=200). We found a significant, robust, and reproducible Ketamine CFP, consistent with reduced connectivity within the primary cortices and within the executive network, but increased connectivity between the executive network and the rest of the brain. Compared to placebo, the Ketamine CFP connectivity changes at 1-week predicted response to sertraline at 8-weeks. In each of Cohort A-C, ketamine significantly increased connectivity in a previously identified Antidepressant CFP. Investigating the brain connectivity networks, we successfully identified a robust and reproducible ketamine biomarker that is related to the mechanisms of antidepressants.Graphical Abstract

scholarly journals Recovery of Brain in Chick Embryos by Growing Second Heart and Brain

2019 ◽  
Vol 7 (18) ◽  
pp. 3085-3089
Author(s):  
Massimo Fioranelli ◽  
Alireza Sepehri ◽  
Maria Grazia Roccia ◽  
Cota Linda ◽  
Chiara Rossi ◽  
...  
Keyword(s):  
Subventricular Zone ◽  
Blood Cells ◽  
Neural Circuits ◽  
Circulatory System ◽  
Egg Cell ◽  
Chick Embryos ◽  
Injured Brain ◽  
Embryo Heart ◽  
Healthy Part ◽  
The Brain

To recover chick embryos damaged the brain, two methods are presented. In both of them, somatic cells of an embryo introduced into an egg cell and an embryo have emerged. In one method, injured a part of the brain in the head of an embryo is replaced with a healthy part of the brain. In the second method, the heart of brain embryo dead is transplanted with the embryo heart. In this mechanism, new blood cells are emerged in the bone marrow and transmit information of transplantation to subventricular zone (SVZ) of the brain through the circulatory system. Then, SVZ produces new neural stem cells by a subsequent dividing into neurons. These neurons produce new neural circuits within the brain and recover the injured brain. To examine the model, two hearts of two embryos are connected, and their effects on neural circuits are observed.  

The Boundaries of Babel

2016 ◽  
Author(s):  
Andrea Moro
Keyword(s):  
Hierarchical Structure ◽  
Linear Order ◽  
Neural Circuits ◽  
Recursive Procedure ◽  
The Brain ◽  
Neuroimaging Techniques

One of the major discoveries of modern linguistics is that languages do not vary arbitrarily: for example, all syntactic rules must be based on hierarchical structure generated by recursive procedure rather than linear order. Neuroimaging techniques have shown that these formal restrictions constituting the boundaries of Babel are in fact represented in the brain for people who learn non-recursive artificially designed rules do not involve those neural circuits that underpin language computation. The boundaries of Babels cannot be cultural and arbitrary.

Neurosurgery nursing

2020 ◽  
pp. 279-352
Keyword(s):  
Spinal Cord ◽  
Nervous System ◽  
Spinal Surgery ◽  
Deep Brain Stimulator ◽  
Disease Symptoms ◽  
Knowledge And Skills ◽  
Vagal Nerve Stimulator ◽  
Neurological Conditions ◽  
The Brain

Neurosurgery describes the surgical treatment and management of various disease processes that target the brain, spinal cord, and peripheral nervous system. The specialty is wide and varied as increasing numbers of neurological conditions can now be improved following neurosurgery; for example, some types of epilepsy respond to the insertion of a vagal nerve stimulator, Parkinson’s disease symptoms can be diminished with a deep brain stimulator, and intractable back pain may be improved following spinal surgery. Practitioners must be equipped with the knowledge and skills to care for these patients and meet their immediate and long-term needs.

Psychiatric neurosurgery

2018 ◽  
pp. 135-184
Author(s):  
Walter Glannon
Keyword(s):  
Clinical Trials ◽  
Deep Brain Stimulation ◽  
Brain Stimulation ◽  
Neural Circuits ◽  
Therapeutic Potential ◽  
Genetic Material ◽  
Research Subjects ◽  
Ethical Justification ◽  
The Brain ◽  
Deep Brain

This chapter discusses functional neurosurgery designed to modulate dysfunctional neural circuits mediating sensorimotor, cognitive, emotional, and volitional capacities. The chapter assesses the comparative benefits and risks of neural ablation and deep brain stimulation as the two most invasive forms of neuromodulation. It discusses the question of whether individuals with a severe or moderately severe psychiatric disorder have enough cognitive and emotional capacity to weigh reasons for and against ablation or deep brain stimulation and give informed consent to undergo it. The chapter also discusses the obligations of investigators conducting these trials to research subjects. In addition, it examines the medical and ethical justification for a sham control arm in psychiatric neurosurgery clinical trials. It considers the therapeutic potential of optogenetics as a novel form of neuromodulation. The fact that this technique manipulates both genetic material and neural circuits and has been tested only in animal models makes it unclear what its benefit–risk ratio would be. The chapter concludes with a brief discussion of the potential of neuromodulation to stimulate endogenous repair and growth mechanisms in the brain.

Capturing the Forest but Missing the Trees: Microstates Inadequate for Characterizing Shorter-Scale EEG Dynamics

2019 ◽  
Vol 31 (11) ◽  
pp. 2177-2211 ◽  
Author(s):  
Saurabh Bhaskar Shaw ◽  
Kiret Dhindsa ◽  
James P. Reilly ◽  
Suzanna Becker
Keyword(s):  
Systems Analysis ◽  
Temporal Dynamics ◽  
Field Potential ◽  
Stable States ◽  
Dynamical Systems Analysis ◽  
Eeg Data ◽  
Show Evidence ◽  
Winner Takes All ◽  
Microstate Analysis ◽  
The Brain

The brain is known to be active even when not performing any overt cognitive tasks, and often it engages in involuntary mind wandering. This resting state has been extensively characterized in terms of fMRI-derived brain networks. However, an alternate method has recently gained popularity: EEG microstate analysis. Proponents of microstates postulate that the brain discontinuously switches between four quasi-stable states defined by specific EEG scalp topologies at peaks in the global field potential (GFP). These microstates are thought to be “atoms of thought,” involved with visual, auditory, salience, and attention processing. However, this method makes some major assumptions by excluding EEG data outside the GFP peaks and then clustering the EEG scalp topologies at the GFP peaks, assuming that only one microstate is active at any given time. This study explores the evidence surrounding these assumptions by studying the temporal dynamics of microstates and its clustering space using tools from dynamical systems analysis, fractal, and chaos theory to highlight the shortcomings in microstate analysis. The results show evidence of complex and chaotic EEG dynamics outside the GFP peaks, which is being missed by microstate analysis. Furthermore, the winner-takes-all approach of only one microstate being active at a time is found to be inadequate since the dynamic EEG scalp topology does not always resemble that of the assigned microstate, and there is competition among the different microstate classes. Finally, clustering space analysis shows that the four microstates do not cluster into four distinct and separable clusters. Taken collectively, these results show that the discontinuous description of EEG microstates is inadequate when looking at nonstationary short-scale EEG dynamics.

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