scholarly journals The restless brain: how intrinsic activity organizes brain function

2015 ◽  
Vol 370 (1668) ◽  
pp. 20140172 ◽  
Author(s):  
Marcus E. Raichle

Traditionally studies of brain function have focused on task-evoked responses. By their very nature such experiments tacitly encourage a reflexive view of brain function. While such an approach has been remarkably productive at all levels of neuroscience, it ignores the alternative possibility that brain functions are mainly intrinsic and ongoing, involving information processing for interpreting, responding to and predicting environmental demands. I suggest that the latter view best captures the essence of brain function, a position that accords well with the allocation of the brain's energy resources, its limited access to sensory information and a dynamic, intrinsic functional organization. The nature of this intrinsic activity, which exhibits a surprising level of organization with dimensions of both space and time, is revealed in the ongoing activity of the brain and its metabolism. As we look to the future, understanding the nature of this intrinsic activity will require integrating knowledge from cognitive and systems neuroscience with cellular and molecular neuroscience where ion channels, receptors, components of signal transduction and metabolic pathways are all in a constant state of flux. The reward for doing so will be a much better understanding of human behaviour in health and disease.

2001 ◽  
Vol 24 (5) ◽  
pp. 823-824 ◽  
Author(s):  
Márk Molnár

We discuss whether low-dimensional chaos and even nonlinear processes can be traced in the electrical activity of the brain. Experimental data show that the dimensional complexity of the EEG decreases during event-related potentials associated with cognitive effort. This probably represents increased nonlinear cooperation between different neural systems during sensory information processing.


2020 ◽  
Author(s):  
Sreejan Kumar ◽  
Cameron T. Ellis ◽  
Thomas O’Connell ◽  
Marvin M Chun ◽  
Nicholas B. Turk-Browne

AbstractThe extent to which brain functions are localized or distributed is a foundational question in neuroscience. In the human brain, common fMRI methods such as cluster correction, atlas parcellation, and anatomical searchlight are biased by design toward finding localized representations. Here we introduce the functional searchlight approach as an alternative to anatomical searchlight analysis, the most commonly used exploratory multivariate fMRI technique. Functional searchlight removes any anatomical bias by grouping voxels based only on functional similarity and ignoring anatomical proximity. We report evidence that visual and auditory features from deep neural networks and semantic features from a natural language processing model are more widely distributed across the brain than previously acknowledged. This approach provides a new way to evaluate and constrain computational models with brain activity and pushes our understanding of human brain function further along the spectrum from strict modularity toward distributed representation.


2010 ◽  
Vol 12 (4) ◽  
pp. 463-470 ◽  

Continuing to discover how the brain works is one of the great challenges ahead of us. Although understanding the brain anatomy and its functional organization provided a first and indispensable foundation, it became clear that a static view was insufficient. To understand the complexity of neuronal communication, it is necessary to examine the chemical nature of the neurotransmission and, using the example of the acetylcholine receptors, follow the different layers of networks that can be distinguished. The natural alkaloid nicotine contained in tobacco leaves acts as an agonist with a subclass of acetylcholine receptors, and provides an interesting tool to approach brain functions. Analysis of the nicotinic acetylcholine receptors, which are ligand gated channels, revealed that these receptors are expressed at different critical locations on the neurons including the synaptic boutons, neurites, cell bodies, and even on the axons. These receptors can modulate the activity at the microcircuit synaptic level, in the cell processing of information, and, by acting on the velocity of action potential, the synchrony of communication between brain areas. These actions at multiple levels of brain organization provide an example of the complexity of brain neurocircuitry and an illustration of the relevance of this knowledge for psychiatry.


EMJ Neurology ◽  
2020 ◽  
pp. 68-79
Author(s):  
Varruchi Sharma ◽  
Atul Sankhyan ◽  
Anshika Varshney ◽  
Renuka Choudhary ◽  
Anil K. Sharma

It has been suggested that an intricate communication link exists between the gut microbiota and the brain and its ability to modulate behaviour of an individual governing homeostasis. Metabolic activity of the microbiota is considered to be relatively constant in healthy individuals, despite differences in the composition of microbiota. The metabolites produced by gut microbiota and their homeostatic balance is often perturbed as a result of neurological complications. Therefore, it is of paramount importance to explore the link between gut microbiota and brain function and behaviour through neural, endocrine, and immune pathways. This current review focusses on the impact of altered gut microbiota on brain functions and how microbiome modulation by use of probiotics, prebiotics, and synbiotics might prove beneficial in the prevention and/or treatment of neurological disorders. It is important to carefully understand the complex mechanisms underlying the gut–brain axis so as to use the gut microbiota as a therapeutic intervention strategy for neurological disorders.


Author(s):  
Jack M. Gorman

This book makes complicated concepts and findings in modern neuroscience accessible to anyone with an interest in how the brain works. It explains in detail how every experience we have from the moment we are conceived changes our brains. Finally, it advances the idea that psychotherapy is a type of life experience that alters brain function and corrects aberrant brain connections. The chapters explore what makes our brains different from our nearest genetic neighbors; how life’s experiences affect the way genes in the brain are expressed and neurons connect with each other; why connections between different parts of the brain are important in both health and disease; what happens in the brains of animals and humans in the face of sudden fear, in depression, or when falling in love; and how medications and psychotherapies work. The book is based on cutting-edge research in neuroscience, psychiatry, and psychology and includes references to the scientific literature. Written by an author who studied human behavior and brain function for three decades, it is presented in a highly accessible manner, full of personal anecdotes and observations, and it touches on many of the controversies in contemporary mental health practice.


e-Neuroforum ◽  
2015 ◽  
Vol 21 (3) ◽  
Author(s):  
Daniela C. Dieterich ◽  
Moritz J. Rossner

AbstractNeuronal as well as glial cells contribute to higher order brain functions. Many observations show that neurons and glial cells are not only physically highly intermingled but are physiologically tightly connected and mutually depend at various levels on each other. Moreover, macroglia classes like astrocytes, NG2 cells and oligodendrocytes are not at all homogenous cell populations but do possess a markedly heterogeneity in various aspects similar to neurons. The diversity of differences in morphology, functionality and, cellular activity has been acknowledged recently and will be integrated into a concept of brain function that pictures a neural rather than a puristical neuronal world. With the recent progress in “omic” technologies, an unbiased and exploratory approach toward an enhanced understanding of glial heterogeneity has become possible. Here, we provide an overview on current technical transcriptomic and proteomic approaches used to dissect glial heterogeneity of the brain.


2016 ◽  
Vol 12 (3) ◽  
Author(s):  
Piotr Prokopowicz ◽  
Dariusz Mikołajewski

AbstractResearch on the computational models of the brain constitutes an important part of the current challenges within computational neuroscience. The current results are not satisfying. Despite the continuous efforts of scientists and clinicians, it is hard to fully explain all the mechanisms of a brain function. Computational models of the brain based on fuzzy logic, including ordered fuzzy numbers, may constitute another breakthrough in the aforementioned area, offering a completing position to the current state of the art. The aim of this paper is to assess the extent to which possible opportunities concerning computational brain models based on fuzzy logic techniques may be exploited both in the area of theoretical and experimental computational neuroscience and in clinical applications, including our own concept. The proposed approach can open a family of novel methods for a more effective and (neuro)biologically reliable brain simulation based on fuzzy logic techniques useful in both basic sciences and applied sciences.


Neuroforum ◽  
2018 ◽  
Vol 24 (2) ◽  
pp. A73-A84
Author(s):  
Martin Heine ◽  
Arthur Bikbaev

Abstract A detailed analysis of synapses as connecting elements between neurons is of central importance to understand the brain’s cognitive performance and its constraints. Nowadays, state-of-the-art optical methods make possible to localize individual molecules in a living cell. In particular, the dynamics of molecular composition can be evaluated in smallest neuronal compartments, such as pre- and postsynaptic membrane. The monitoring of the distribution of receptors, ion channels, and adhesion molecules over time revealed their continuous stochastic motion. This is surprising, since the synapses are considered as accumulation sites anchoring these molecules. The direct manipulation of the lateral dynamics of glutamate receptors, in combination with classical electrophysiological approaches, demonstrated that such molecular dynamics is necessary for the induction of synaptic plasticity and, in turn, is influenced by synaptic activity. Therefore, the molecular dynamics requires further studies in the context of the brain function in health and disease.


2020 ◽  
Vol 13 ◽  
Author(s):  
Davide Martino Coda ◽  
Johannes Gräff

Over the last two decades, the explosion of experimental, computational, and high-throughput technologies has led to critical insights into how the brain functions in health and disease. It has become increasingly clear that the vast majority of brain activities result from the complex entanglement of genetic factors, epigenetic changes, and environmental stimuli, which, when altered, can lead to neurodegenerative and neuropsychiatric disorders. Nevertheless, a complete understanding of the molecular mechanisms underlying neuronal activities and higher-order cognitive processes continues to elude neuroscientists. Here, we provide a concise overview of how the interaction between the environment and genetic as well as epigenetic mechanisms shapes complex neuronal processes such as learning, memory, and synaptic plasticity. We then consider how this interaction contributes to the development of neurodegenerative and psychiatric disorders, and how it can be modeled to predict phenotypic variability and disease risk. Finally, we outline new frontiers in neurogenetic and neuroepigenetic research and highlight the challenges these fields will face in their quest to decipher the molecular mechanisms governing brain functioning.


Antioxidants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1035
Author(s):  
Natalia Cichon ◽  
Joanna Saluk-Bijak ◽  
Leslaw Gorniak ◽  
Lukasz Przyslo ◽  
Michal Bijak

Neuroplasticity is a complex physiological process occurring in the brain for its entire life. However, it is of particular importance in the case of central nervous system (CNS) disorders. Neurological recovery largely depends on the ability to reestablish the structural and functional organization of neurovascular networks, which must be pharmacologically supported. For this reason, new forms of therapy are constantly being sought. Including adjuvant therapies in standard treatment may support the enhancement of repair processes and restore impaired brain functions. The common hallmark of nerve tissue damage is increased by oxidative stress and inflammation. Thus, the studies on flavonoids with strong antioxidant and anti-inflammatory properties as a potential application in neuro intervention have been carried out for a long time. However, recent results have revealed another important property of these compounds in CNS therapy. Flavonoids possess neuroprotective activity, and promote synaptogenesis and neurogenesis, by, among other means, inhibiting oxidative stress and neuroinflammation. This paper presents an overview of the latest knowledge on the impact of flavonoids on the plasticity processes of the brain, taking into account the molecular basis of their activity.


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