scholarly journals The dynamics of neural activation variables

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Hendrik Reimann ◽  
Jonas Lins ◽  
Gregor Schöner
Keyword(s):  
Detailed Analysis ◽  
Building Blocks ◽  
Cognitive Robotics ◽  
Neural Activation ◽  
Nervous Systems ◽  
And Behavior ◽  
Elementary Building

AbstractThis paper presents a comprehensive and detailed analysis of the elementary building blocks of neurally inspired architectures for cognitive robotics. It provides a brief outline of the fundamental principles by which biological nervous systems link to the environment in terms of perception, cognition, and behavior. We describe a class of dynamic neural activation variable based on these principles. We show that these dynamic neurons have the appropriate stability properties.Adding even simple connections between a small number of nodes is sufficient to constitute systems that make important decisions. Going through these mechanisms in detail, this paper should facilitate the design of neurally inspired architectures for behavior generation in robotic agents.

Brains as Engines of Association

2019 ◽  
Author(s):  
Dale Purves
Keyword(s):  
Neural Systems ◽  
Neural Function ◽  
Trial And Error ◽  
Nervous Systems ◽  
The Past ◽  
Sensing Systems ◽  
Lifetime Experience ◽  
Survival And Reproduction ◽  
Pros And Cons ◽  
And Behavior

Brains as Engines of Association seeks an operating principle of the human brain and is divided into four parts. The first part (“What Nervous Systems Do for Animals”) is intended to set the stage for understanding the emergence of neural systems as promoting what all organisms must accomplish: survival and reproduction. The second part (“Neural Systems as Engines of Association”) lays out the general argument that biological sensing systems face a daunting problem: they cannot measure the parameters of the world in the way physical instruments can. As a result, nervous systems must make and update associations (synaptic connections) on the basis of empirical success or failure over both evolutionary and individual time. The third part (“Evidence that Neural Systems Operate Empirically”) reviews evidence accumulated over the past 20 years that supports this interpretation in vision and audition, the sensory systems that have been most studied from this or any other perspective. Finally, the fourth part (“Alternative Concepts of Neural Function”) considers the pros and cons of other interpretations of how brains operate. The overarching theme is that the nervous systems of humans and every other animal operate on the basis associations between stimuli and behavior made by trial and error over species and lifetime experience.

scholarly journals Fundamental functional differences between gyri and sulci: implications for brain function, cognition, and behavior

2021 ◽  
Vol 1 (1) ◽  
pp. 23-41
Author(s):  
Xi Jiang ◽  
Tuo Zhang ◽  
Shu Zhang ◽  
Keith M Kendrick ◽  
Tianming Liu
Keyword(s):  
Brain Function ◽  
Cell Biology ◽  
Functional Anatomy ◽  
Building Blocks ◽  
Functional Differentiation ◽  
Cortical Folding ◽  
Brain Functions ◽  
Functional Relationships ◽  
Structural Architecture ◽  
And Behavior

Abstract Folding of the cerebral cortex is a prominent characteristic of mammalian brains. Alterations or deficits in cortical folding are strongly correlated with abnormal brain function, cognition, and behavior. Therefore, a precise mapping between the anatomy and function of the brain is critical to our understanding of the mechanisms of brain structural architecture in both health and diseases. Gyri and sulci, the standard nomenclature for cortical anatomy, serve as building blocks to make up complex folding patterns, providing a window to decipher cortical anatomy and its relation with brain functions. Huge efforts have been devoted to this research topic from a variety of disciplines including genetics, cell biology, anatomy, neuroimaging, and neurology, as well as involving computational approaches based on machine learning and artificial intelligence algorithms. However, despite increasing progress, our understanding of the functional anatomy of gyro-sulcal patterns is still in its infancy. In this review, we present the current state of this field and provide our perspectives of the methodologies and conclusions concerning functional differentiation between gyri and sulci, as well as the supporting information from genetic, cell biology, and brain structure research. In particular, we will further present a proposed framework for attempting to interpret the dynamic mechanisms of the functional interplay between gyri and sulci. Hopefully, this review will provide a comprehensive summary of anatomo-functional relationships in the cortical gyro-sulcal system together with a consideration of how these contribute to brain function, cognition, and behavior, as well as to mental disorders.

scholarly journals Similarities between extreme events in the solar-terrestrial system by means of nonextensivity

2011 ◽  
Vol 18 (5) ◽  
pp. 563-572 ◽  
Author(s):  
G. Balasis ◽  
C. Papadimitriou ◽  
I. A. Daglis ◽  
A. Anastasiadis ◽  
I. Sandberg ◽  
...  
Keyword(s):  
Extreme Events ◽  
Solar Flares ◽  
Particle Physics ◽  
Building Blocks ◽  
Magnetic Storms ◽  
Earthquake Dynamics ◽  
Magnitude Distribution ◽  
Terrestrial System ◽  
Universal Principles ◽  
Elementary Building

Abstract. The dynamics of complex systems are founded on universal principles that can be used to describe disparate problems ranging from particle physics to economies of societies. A corollary is that transferring ideas and results from investigators in hitherto disparate areas will cross-fertilize and lead to important new results. In this contribution, we investigate the existence of a universal behavior, if any, in solar flares, magnetic storms, earthquakes and pre-seismic electromagnetic (EM) emissions, extending the work recently published by Balasis et al. (2011a). A common characteristic in the dynamics of the above-mentioned phenomena is that their energy release is basically fragmentary, i.e. the associated events are being composed of elementary building blocks. By analogy with earthquakes, the magnitude of the magnetic storms, solar flares and pre-seismic EM emissions can be appropriately defined. Then the key question we can ask in the frame of complexity is whether the magnitude distribution of earthquakes, magnetic storms, solar flares and pre-fracture EM emissions obeys the same law. We show that these apparently different extreme events, which occur in the solar-terrestrial system, follow the same energy distribution function. The latter was originally derived for earthquake dynamics in the framework of nonextensive Tsallis statistics.

scholarly journals Connectivity matters – ultrafast isomerization dynamics of bisazobenzene photoswitches

2016 ◽  
Vol 18 (22) ◽  
pp. 14795-14804 ◽  
Author(s):  
Chavdar Slavov ◽  
Chong Yang ◽  
Luca Schweighauser ◽  
Chokri Boumrifak ◽  
Andreas Dreuw ◽  
...  
Keyword(s):  
Building Blocks ◽  
Ultrafast Dynamics ◽  
Elementary Building

We have investigated the ultrafast dynamics of o-, m- and p-bisazobenzenes, which represent elementary building blocks for photoswitchable multiazobenzene nanostructures.

scholarly journals Selective enhancement of object representations through multisensory integration

2019 ◽  
Author(s):  
David A. Tovar ◽  
Micah M. Murray ◽  
Mark T. Wallace
Keyword(s):  
Multisensory Integration ◽  
Sensory Information ◽  
Stimulus Presentation ◽  
Building Blocks ◽  
Object Representations ◽  
The Individual ◽  
And Behavior ◽  
Living Objects ◽  
Selective Enhancement ◽  
The Brain

AbstractObjects are the fundamental building blocks of how we create a representation of the external world. One major distinction amongst objects is between those that are animate versus inanimate. Many objects are specified by more than a single sense, yet the nature by which multisensory objects are represented by the brain remains poorly understood. Using representational similarity analysis of human EEG signals, we show enhanced encoding of audiovisual objects when compared to their corresponding visual and auditory objects. Surprisingly, we discovered the often-found processing advantages for animate objects was not evident in a multisensory context due to greater neural enhancement of inanimate objects—the more weakly encoded objects under unisensory conditions. Further analysis showed that the selective enhancement of inanimate audiovisual objects corresponded with an increase in shared representations across brain areas, suggesting that neural enhancement was mediated by multisensory integration. Moreover, a distance-to-bound analysis provided critical links between neural findings and behavior. Improvements in neural decoding at the individual exemplar level for audiovisual inanimate objects predicted reaction time differences between multisensory and unisensory presentations during a go/no-go animate categorization task. Interestingly, links between neural activity and behavioral measures were most prominent 100 to 200ms and 350 to 500ms after stimulus presentation, corresponding to time periods associated with sensory evidence accumulation and decision-making, respectively. Collectively, these findings provide key insights into a fundamental process the brain uses to maximize information it captures across sensory systems to perform object recognition.Significance StatementOur world is filled with an ever-changing milieu of sensory information that we are able to seamlessly transform into meaningful perceptual experience. We accomplish this feat by combining different features from our senses to construct objects. However, despite the fact that our senses do not work in isolation but rather in concert with each other, little is known about how the brain combines the senses together to form object representations. Here, we used EEG and machine learning to study how the brain processes auditory, visual, and audiovisual objects. Surprisingly, we found that non-living objects, the objects which were more difficult to process with one sense alone, benefited the most from engaging multiple senses.

Hierarchical nanomechanics of vimentin alpha helical coiled-coil proteins

2006 ◽  
Vol 978 ◽  
Author(s):  
Theodor Ackbarow ◽  
Markus J. Buehler
Keyword(s):  
Atomistic Simulation ◽  
Coiled Coil ◽  
Building Blocks ◽  
Tensile Tests ◽  
Coiled Coils ◽  
Atomistic Modeling ◽  
Alpha Helices ◽  
Hierarchical Assembly ◽  
Leading Role ◽  
Elementary Building

AbstractCoiled-coil alpha-helical dimers are the elementary building blocks of intermediate filaments (IFs), an important component of the cell's cytoskeleton. Therefore, IFs play a leading role in the mechanical integrity of the cells. Here we use atomistic simulation to carry out tensile tests on coiled-coils as well as on single alpha-helices of the 2B segment of the vimentin dimer that has been shown to control the large-deformation behavior of cells. We compare the characteristic force-strain curves of both structures and suggest explanations for the differences on this fundamental level of hierarchical assembly. We further systematically explore the strain rate dependence of the mechanical properties of the vimentin coiled-coil protein. We develop a simple continuum model capable of reproducing the atomistic modeling results. The model enables us to extrapolate to much lower deformation rates approaching those used in experiment.

Model Reduction in Structural Analysis Using a Multiresolution Analysis

2002 ◽  
Author(s):  
Sudarsanam Chellappa ◽  
Alejandro R. Diaz
Keyword(s):  
Multiresolution Analysis ◽  
Building Blocks ◽  
Structural Systems ◽  
Fine Scale ◽  
Design Problems ◽  
Elastic Systems ◽  
Principal Application ◽  
Complex Structural ◽  
Scale Properties ◽  
And Behavior

A method is presented to reduce the size of models used in analysis of elastic systems. The reduction is accomplished using a multiresolution analysis applied to elasticity operators to average fine scale properties and behavior while limiting loss of information. In discretized form, the method results in smaller matrices that can be used as building blocks to construct larger systems. The principal application envisioned is in design problems involving complex structural systems, such as crash-worthiness design, where very intensive computations demand computational efficiency.

Are We Ready to investigate Cognitive Function of Fetal Brain? The Role of Advanced Four-dimensional Sonography

2016 ◽  
Vol 10 (2) ◽  
pp. 116-124 ◽  
Author(s):  
Aida Salihagic Kadic ◽  
Lara Spalldi Barisic
Keyword(s):  
Cognitive Function ◽  
Cognitive Functions ◽  
Fetal Brain ◽  
Building Blocks ◽  
Time Lapse ◽  
Functional Development ◽  
4D Ultrasound ◽  
And Behavior

ABATRACT Human brain is fascinating organ in so many ways. Some of its cognitive functions, such as ability to learn, memorize, think, percept different sensations, such as pain, to have emotion, process audio-visual inputs, and to coordinate reaction and movements have been subjects of studies for many years. Yet, till recently, we could only make assumptions about prenatal activities, interactions and its construction of complex structures in the time frame of antenatal life. With the prenatal assessment (sonoembryology, neurosonoembryology, KANET test, etc.) by latest advanced HDlive, Silhouette and Flow 3D/4D imaging there is possibility to follow in continuity normal structural and functional development from the early beginnings of “life” and on the other hand consider what might be different (not necessarily abnormal) and deviate from normal development and behavior. On this way, we are able to supplement knowledge of fundamental building blocks of development of fetal cognitive functions, to pay more attention and follow up fetuses at higher risk and finally find some of the possible origins of cognitive dysfunctions which may manifest in childhood or later in life.82 With the introduction of different 3D/4D ultrasound modes we have ability to observe all of this in vivo while emerging, and make “time-lapse” of fetal neurodevelopment and behavior in correlation to its cognitive functional development How to cite this article Kurjak A, Spalldi Barisic L, Stanojevic M, Salihagic Kadic A, Porovic S. Are We Ready to investigate Cognitive Function of Fetal Brain? The Role of Advanced Fourdimensional Sonography. Donald School J Ultrasound Obstet Gynecol 2016;10(2):116-124.

Elementary Building Blocks of Self-Assembled Peptide Nanotubes

2010 ◽  
Vol 132 (44) ◽  
pp. 15632-15636 ◽  
Author(s):  
Nadav Amdursky ◽  
Michel Molotskii ◽  
Ehud Gazit ◽  
Gil Rosenman
Keyword(s):  
Building Blocks ◽  
Peptide Nanotubes ◽  
Self Assembled ◽  
Elementary Building

scholarly journals Inferring cortical function in the mouse visual system through large-scale systems neuroscience

2016 ◽  
Vol 113 (27) ◽  
pp. 7337-7344 ◽  
Author(s):  
Michael Hawrylycz ◽  
Costas Anastassiou ◽  
Anton Arkhipov ◽  
Jim Berg ◽  
Michael Buice ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Large Scale ◽  
Model Organism ◽  
Building Blocks ◽  
Mammalian Brain ◽  
Cortical Function ◽  
Scientific Mission ◽  
Large Populations ◽  
Cell Type Specific ◽  
And Behavior

The scientific mission of the Project MindScope is to understand neocortex, the part of the mammalian brain that gives rise to perception, memory, intelligence, and consciousness. We seek to quantitatively evaluate the hypothesis that neocortex is a relatively homogeneous tissue, with smaller functional modules that perform a common computational function replicated across regions. We here focus on the mouse as a mammalian model organism with genetics, physiology, and behavior that can be readily studied and manipulated in the laboratory. We seek to describe the operation of cortical circuitry at the computational level by comprehensively cataloging and characterizing its cellular building blocks along with their dynamics and their cell type-specific connectivities. The project is also building large-scale experimental platforms (i.e., brain observatories) to record the activity of large populations of cortical neurons in behaving mice subject to visual stimuli. A primary goal is to understand the series of operations from visual input in the retina to behavior by observing and modeling the physical transformations of signals in the corticothalamic system. We here focus on the contribution that computer modeling and theory make to this long-term effort.

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