scholarly journals Memory entrainment by visually evoked theta-gamma coupling

2017 ◽  
Author(s):  
Moritz Köster ◽  
Ulla Martens ◽  
Thomas Gruber
Keyword(s):  
Human Brain ◽  
Visual Stimulation ◽  
Internal Representation ◽  
Human Memory ◽  
Integral Function ◽  
Gamma Activity ◽  
Theta Frequency ◽  
Entrainment Effect ◽  
Individual Alpha Frequency

AbstractIt is an integral function of the human brain to sample novel information from the environment and to update the internal representation of the external world. The formation of new memories is assumed to be orchestrated by neuronal oscillations, the rhythmic synchronization of neuronal activity within and across cell assemblies. Specifically, successful encoding of novel information is associated with increased theta oscillations (3-8Hz) and theta coupled gamma activity (40-120Hz), and a decrease in alpha oscillations (8-12Hz). However, given the correlative nature of neurophysiological recordings, the causal role of neuronal rhythms in human memory encoding is still unclear. Here, we experimentally enhance the formation of novel memories by a visual brain stimulation at an individually adjusted theta frequency, in contrast to the stimulation at an individual alpha frequency. Critically, the memory entrainment effect by the theta stimulation was not explained by theta power per se, but was driven by visually evoked theta-gamma coupling in wide spread cortical networks. These findings provide first evidence for a functional role of the theta rhythm and the theta-gamma neuronal code in human episodic memory. Yet more strikingly, the entrainment of mnemonic network mechanisms by a simplistic visual stimulation technique provides a proof of concept that internal rhythms align with visual pacemakers, which can entrain complex cognitive functions in the wake human brain.

Virtual Reality—Virtual Brain: Questioning Reality

Leonardo ◽  
2018 ◽  
Vol 51 (5) ◽  
pp. 453-459 ◽  
Author(s):  
Teresa Wennberg
Keyword(s):  
Virtual Reality ◽  
Human Brain ◽  
Cognitive Processes ◽  
Human Memory ◽  
Computer Memory ◽  
Brain Functions ◽  
Multimedia Art ◽  
Individual Human

The author’s multimedia art is inspired by memory and cognitive processes. This paper discusses certain human brain functions, including a reflection on the evolution from individual human memory to collective computer memory and the role of the artist in this vital change.

Role of structural plasticity in the human brain for multisensory compensation following unilateral peripheral vestibular lesion

2008 ◽  
Vol 35 (S 01) ◽  
Author(s):  
C Helmchen ◽  
J Klinkenstein ◽  
T Sander ◽  
J Gliemroth ◽  
B Machner ◽  
...  
Keyword(s):  
Human Brain ◽  
Structural Plasticity ◽  
Vestibular Lesion

scholarly journals A Superfluid Perspective on Neutron Star Dynamics

Universe ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 17
Author(s):  
Nils Andersson
Keyword(s):  
Neutron Star ◽  
Degrees Of Freedom ◽  
Temperature Scale ◽  
Fluid System ◽  
Fluid Core ◽  
State Of Matter ◽  
Entrainment Effect ◽  
Neutron Component ◽  
The Impact

As mature neutron stars are cold (on the relevant temperature scale), one has to carefully consider the state of matter in their interior. The outer kilometre or so is expected to freeze to form an elastic crust of increasingly neutron-rich nuclei, coexisting with a superfluid neutron component, while the star’s fluid core contains a mixed superfluid/superconductor. The dynamics of the star depend heavily on the parameters associated with the different phases. The presence of superfluidity brings new degrees of freedom—in essence we are dealing with a complex multi-fluid system—and additional features: bulk rotation is supported by a dense array of quantised vortices, which introduce dissipation via mutual friction, and the motion of the superfluid is affected by the so-called entrainment effect. This brief survey provides an introduction to—along with a commentary on our current understanding of—these dynamical aspects, paying particular attention to the role of entrainment, and outlines the impact of superfluidity on neutron-star seismology.

The role of the anterior nuclei of the thalamus in human memory processing

2021 ◽  
Author(s):  
Catherine M. Sweeney-Reed ◽  
Lars Buentjen ◽  
Jürgen Voges ◽  
Friedhelm C. Schmitt ◽  
Tino Zaehle ◽  
...  
Keyword(s):  
Human Memory ◽  
Memory Processing

scholarly journals The Right Hemisphere Is Responsible for the Greatest Differences in Human Brain Response to High-Arousing Emotional versus Neutral Stimuli: A MEG Study

2021 ◽  
Vol 11 (8) ◽  
pp. 960
Author(s):  
Mina Kheirkhah ◽  
Philipp Baumbach ◽  
Lutz Leistritz ◽  
Otto W. Witte ◽  
Martin Walter ◽  
...  
Keyword(s):  
Human Brain ◽  
Right Hemisphere ◽  
Emotional Stimuli ◽  
Brain Response ◽  
Whole Brain ◽  
Brain Responses ◽  
Cortical Regions ◽  
The Right ◽  
Healthy Participants

Studies investigating human brain response to emotional stimuli—particularly high-arousing versus neutral stimuli—have obtained inconsistent results. The present study was the first to combine magnetoencephalography (MEG) with the bootstrapping method to examine the whole brain and identify the cortical regions involved in this differential response. Seventeen healthy participants (11 females, aged 19 to 33 years; mean age, 26.9 years) were presented with high-arousing emotional (pleasant and unpleasant) and neutral pictures, and their brain responses were measured using MEG. When random resampling bootstrapping was performed for each participant, the greatest differences between high-arousing emotional and neutral stimuli during M300 (270–320 ms) were found to occur in the right temporo-parietal region. This finding was observed in response to both pleasant and unpleasant stimuli. The results, which may be more robust than previous studies because of bootstrapping and examination of the whole brain, reinforce the essential role of the right hemisphere in emotion processing.

Repetition Suppression of Induced Gamma Activity Predicts Enhanced Orienting toward a Novel Stimulus in 6-month-old Infants

2008 ◽  
Vol 20 (12) ◽  
pp. 2137-2152 ◽  
Author(s):  
Kelly A. Snyder ◽  
Andreas Keil
Keyword(s):  
Visual Processing ◽  
Novelty Detection ◽  
Neural Mechanisms ◽  
Human Infant ◽  
Gamma Activity ◽  
Repeated Stimulus ◽  
Repetition Suppression ◽  
The Face ◽  
Over 40 Years

Habituation refers to a decline in orienting or responding to a repeated stimulus, and can be inferred to reflect learning about the properties of the repeated stimulus when followed by increased orienting to a novel stimulus (i.e., novelty detection). Habituation and novelty detection paradigms have been used for over 40 years to study perceptual and mnemonic processes in the human infant, yet important questions remain about the nature of these processes in infants. The aim of the present study was to examine the neural mechanisms underlying habituation and novelty detection in infants. Specifically, we investigated changes in induced alpha, beta, and gamma activity in 6-month-old infants during repeated presentations of either a face or an object, and examined whether these changes predicted behavioral responses to novelty at test. We found that induced gamma activity over occipital scalp regions decreased with stimulus repetition in the face condition but not in the toy condition, and that greater decreases in the gamma band were associated with enhanced orienting to a novel face at test. The pattern and topography of these findings are consistent with observations of repetition suppression in the occipital–temporal visual processing pathway, and suggest that encoding in infant habituation paradigms may reflect a form of perceptual learning. Implications for the role of repetition suppression in infant habituation and novelty detection are discussed with respect to a biased competition model of visual attention.

The human brain: Chairman’s introduction

1981 ◽  
Vol 292 (1057) ◽  
pp. 151-153
Keyword(s):  
Human Brain ◽  
Cultural Evolution ◽  
Positive Feedback ◽  
Time Scale ◽  
Biological Evolution ◽  
Internal Models ◽  
Adaptive Behaviour ◽  
Myelin Sheaths ◽  
The Brain

Much has been said at the symposium about the pre-eminent role of the brain in the continuing emergence of man. Tobias has spoken of its explosive enlargement during the last 1 Ma, and how much of its enlargement in individual ontogeny is postnatal. We are born before our brains are fully grown and ‘wired up ’. During our long adolescence we build up internal models of the outside world and of the relations of parts of our bodies to it and to one another. Neurons that are present at birth spread their dendrites and project axons which acquire their myelin sheaths, and establish innumerable contacts with other neurons, over the years. New connections are formed; genetically endowed ones are stamped in or blanked off. People born without arms may grow up to use their toes in skills that are normally manual. Tobias, Darlington and others have stressed the enormous survival value of adaptive behaviour and the ‘positive feedback’ relation between biological and cultural evolution. The latter, the unique product of the unprecedentedly rapid biological evolution of big brains, advances on a time scale unknown to biological evolution.

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