scholarly journals Spectral and Spatial Characteristics of the Activity of Brain Structures, Participating in the Perception and Production of Speech

2019 ◽  
Vol 14 (2) ◽  
pp. 705-719
Author(s):  
N.M. Pankratova ◽  
M.A Polikarpov ◽  
E.F. Tarasov ◽  
S.D. Rykunov ◽  
M.N. Ustinin
Keyword(s):  
Speech Perception ◽  
Experimental Approach ◽  
Brain Activity ◽  
Brain Structures ◽  
Spectral Features ◽  
Spatial Characteristics ◽  
Spatial Features ◽  
Magnetic Encephalography ◽  
Speech Research ◽  
The Brain

Spectral and spatial characteristics of the encephalograms, registered while speech perception and production, are considered. Systematical bibliographical review is presented, including the articles studying the speech sources spectra and their location in the brain. Encephalography is selected as a basic experimental approach. Advantages of the magnetic encephalography, experimental difficulties and possible artifacts are noted. It is concluded that brain speech activity possesses a great variety of spectral and spatial features. The method of functional tomography based on magnetic encephalography data is proposed to quantitatively analyze this activity in detail. The method makes it possible to extract and precisely localize in space various spectral features of the brain activity studied in experiments on speech research.

scholarly journals Consciousness, decision making, and volition: freedom beyond chance and necessity

2021 ◽  
Author(s):  
Hans Liljenström
Keyword(s):  
Decision Making ◽  
Free Will ◽  
Brain Activity ◽  
Brain Structures ◽  
Complex Process ◽  
Neural Information ◽  
Neural Information Processing ◽  
Stochastic Population Model ◽  
The Brain

AbstractWhat is the role of consciousness in volition and decision-making? Are our actions fully determined by brain activity preceding our decisions to act, or can consciousness instead affect the brain activity leading to action? This has been much debated in philosophy, but also in science since the famous experiments by Libet in the 1980s, where the current most common interpretation is that conscious free will is an illusion. It seems that the brain knows, up to several seconds in advance what “you” decide to do. These studies have, however, been criticized, and alternative interpretations of the experiments can be given, some of which are discussed in this paper. In an attempt to elucidate the processes involved in decision-making (DM), as an essential part of volition, we have developed a computational model of relevant brain structures and their neurodynamics. While DM is a complex process, we have particularly focused on the amygdala and orbitofrontal cortex (OFC) for its emotional, and the lateral prefrontal cortex (LPFC) for its cognitive aspects. In this paper, we present a stochastic population model representing the neural information processing of DM. Simulation results seem to confirm the notion that if decisions have to be made fast, emotional processes and aspects dominate, while rational processes are more time consuming and may result in a delayed decision. Finally, some limitations of current science and computational modeling will be discussed, hinting at a future development of science, where consciousness and free will may add to chance and necessity as explanation for what happens in the world.

scholarly journals Estimation of the Directions of Alpha Rhythm Elementary Sources Using the Method of Human Brain Functional Tomography Based On the Magnetic Encephalography Data

2018 ◽  
Vol 13 (2) ◽  
pp. 426-436 ◽  
Author(s):  
M.N. Ustinin ◽  
S.D. Rykunov ◽  
A.I. Boyko ◽  
O.A. Maslova ◽  
K.D. Walton ◽  
...  
Keyword(s):  
Inverse Problem ◽  
Time Series ◽  
Human Brain ◽  
Alpha Rhythm ◽  
Brain Activity ◽  
Problem Solution ◽  
New York University ◽  
Magnetic Encephalography ◽  
The Brain ◽  
Calculation Grid

New method for the magnetic encephalography data analysis was proposed. The method transforms multichannel time series into the spatial structure of the human brain activity. In this paper we further develop this method to determine the dominant direction of the electrical sources of brain activity at each node of the calculation grid. We have considered the experimental data, obtained with three 275-channel magnetic encephalographs in New York University, McGill University and Montreal University. The human alpha rhythm phenomenon was selected as a model object. Magnetic encephalograms of the brain spontaneous activity were registered for 5-7 minutes in magnetically shielded room. Detailed multichannel spectra were obtained by the Fourier transform of the whole time series. For all spectral components, the inverse problem was solved in elementary current dipole model and the functional structure of the brain activity was calculated in the frequency band 8-12 Hz. In order to estimate the local activity direction, at the each node of calculation grid the vector of the inverse problem solution was selected, having the maximal spectral power. So, the 3D-map of the brain activity vector field was produced – the directional functional tomogram. Such maps were generated for 15 subjects and some common patterns were revealed in the directions of the alpha rhythm elementary sources. The proposed method can be used to study the local properties of the brain activity in any spectral band and in any brain compartment.

scholarly journals CHANGES OF THE LOCAL FUNCTIONAL BRAIN ACTIVITY ASSOCIATED WITH SPEECH DISORDERS IN CHILDREN WITH EPILEPSY AND DEVELOPMENTAL DELAY (PET STUDY)

2019 ◽  
pp. 39-43
Author(s):  
Yu. G. Khomenko ◽  
G. V. Kataeva ◽  
V. I. Kolomiec
Keyword(s):  
Cerebral Metabolism ◽  
Brain Activity ◽  
Brain Structures ◽  
Speech Disorders ◽  
Speech Development ◽  
Metabolism Rate ◽  
Local Functional ◽  
Left And Right ◽  
Functional Brain Activity ◽  
The Brain

PET study of cerebral glucose metabolism was performed in 73 children with epilepsy and mental retardation. Expressive speech disorders were associated with decrease of cerebral metabolism rate of glucose (CMRglu) in the upper frontal gyrus, caudate nucleus and thalamus of the left and right hemispheres. In the group with combined expressive and impressive speech disorders the significant CMRglu reduction in the middle temporal and supramarginal gyrus of the left hemisphere was observed. The obtained results confirm that the brain structures associated with the executive functions and complex association processes have a great significance in the speech development.

scholarly journals Study of Attention Deficit and Hyperactivity Disorder Using the Method of Functional Tomography Based On Magnetic Encephalography Data

2019 ◽  
Vol 14 (2) ◽  
pp. 517-532
Author(s):  
M.N. Ustinin ◽  
S.D. Rykunov ◽  
A.I. Boyko ◽  
O.A. Maslova ◽  
N.M. Pankratova
Keyword(s):  
Time Series ◽  
Frequency Band ◽  
Attention Deficit ◽  
Brain Activity ◽  
Current Dipole ◽  
Hyperactivity Disorder ◽  
Psychic Disorders ◽  
Magnetic Encephalography ◽  
Delta Rhythm ◽  
The Brain

New method for the magnetic encephalography data analysis was proposed, making it possible to transform multichannel time series into the spatial structure of the human brain activity. In this paper we applied this method to the analysis of magnetic encephalograms, obtained from subjects with attention deficit and hyperactivity disorder. We have considered the experimental data, obtained with 275-channel magnetic encephalographs in McGill University and Montreal University. Magnetic encephalograms of the brain spontaneous activity were registered for 5 minutes in magnetically shielded room. Detailed multichannel spectra were obtained by the Fourier transform of the whole time series. For all spectral components, the inverse problem was solved in elementary current dipole model and the functional structure of the brain activity was calculated in the broad frequency band 0.3-50 Hz. It was found that frequency band relations are different in different experiments. We proposed to use these relations by the summary electric power produced by the sources in selected frequency band. The delta rhythm in frequency band 0.3 to 4 Hz was studied in detail. It was found, that many delta rhythm dipoles were localized outside the brain, and their spectrum consists of the heartbeat harmonics. It was concluded that in experiments considered, the delta rhythm represents the vascular activity of the head. To study the spatial distribution of all rhythms from theta to gamma the partial spectra of the brain divisions were calculated. The partial spectrum includes all frequencies produced by the dipole sources located in the region of brain selected at the magnetic resonance image. The method can be further applied to study encephalograms in various psychic disorders.

Word Learning in 6-Month-Olds: Fast Encoding–Weak Retention

2011 ◽  
Vol 23 (11) ◽  
pp. 3228-3240 ◽  
Author(s):  
Manuela Friedrich ◽  
Angela D. Friederici
Keyword(s):  
Semantic Memory ◽  
Word Learning ◽  
Declarative Memory ◽  
Brain Activity ◽  
Brain Structures ◽  
Memory Formation ◽  
Fast Encoding ◽  
Frequent Exposure ◽  
The Brain ◽  
Lexical Mapping

There has been general consensus that initial word learning during early infancy is a slow and time-consuming process that requires very frequent exposure, whereas later in development, infants are able to quickly learn a novel word for a novel meaning. From the perspective of memory maturation, this shift in behavioral development might represent a shift from slow procedural to fast declarative memory formation. Alternatively, it might be caused by the maturation of specific brain structures within the declarative memory system that may support lexical mapping from the very first. Here, we used the neurophysiological method of ERPs to watch the brain activity of 6-month-old infants, when repeatedly presented with object–word pairs in a cross-modal learning paradigm. We report first evidence that infants as young as 6 months are able to associate objects and words after only very few exposures. A memory test 1 day later showed that infants did not fully forget this newly acquired knowledge, although the ERP effects indicated it to be less stable than immediately after encoding. The combined results suggest that already at 6 months the encoding process of word learning is based on fast declarative memory formation, but limitations in the consolidation of declarative memory diminish the long lasting effect in lexical-semantic memory at that age.

scholarly journals A Comprehensive Review on Brain-Computer Interface Controlled Movements

2019 ◽  
Vol 5 (6) ◽  
pp. 3
Author(s):  
Kulsheet Kaur Virdi ◽  
Satish Pawar
Keyword(s):  
Brain Activity ◽  
Brain Computer Interface ◽  
Low Cost ◽  
Neuromuscular Disorders ◽  
Research Work ◽  
Brain Structures ◽  
Computer Interface ◽  
Body Parts ◽  
Machine Interface ◽  
The Brain

A brain-computer interface (BCI), also referred to as a mind-machine interface (MMI) or a brain-machine interface (BMI), provides a non-muscular channel of communication between the human brain and a computer system. With the advancements in low-cost electronics and computer interface equipment, as well as the need to serve people suffering from disabilities of neuromuscular disorders, a new field of research has emerged by understanding different functions of the brain. The electroencephalogram (EEG) is an electrical activity generated by brain structures and recorded from the scalp surface through electrodes. Researchers primarily rely on EEG to characterize the brain activity, because it can be recorded noninvasively by using portable equipment. The EEG or the brain activity can be used in real time to control external devices via a complete BCI system. For these applications there is need of such machine learning application which can be efficiently applied on these EEG signals. The aim of this research is review different research work in the field of brain computer interface related to body parts movements.

scholarly journals Brain activity during moral judgement of action

2020 ◽  
Vol 9 (2) ◽  
pp. 67-81
Author(s):  
K.R. Arutyunova ◽  
I.M. Sozinova ◽  
Yu.I. Alexandrov
Keyword(s):  
Brain Activity ◽  
Age Groups ◽  
Brain Structures ◽  
Interdisciplinary Studies ◽  
Moral Judgement ◽  
Individual Development ◽  
Functional Systems ◽  
History Of ◽  
Neurophysiological Mechanisms ◽  
The Brain

Interdisciplinary studies of cognitive and neurophysiological mechanisms of moral judgement often combine tools borrowed from philosophy, psychology and neuroscience. In this work, we review the studies of brain activity during moral judgement at different stages of individual development. Generally, it has been shown that moral judgement is accompanied by activations in brain areas related to emotion and social cognition; and these activations may vary across individuals of different age groups. We discuss these data from the positions of the system-evolutionary theory and compare our view with the domain-general approach to cognitive processes and brain activity underlying moral judgement. We suggest that moral judgement, as part of individual behaviour, is supported by activity of functional systems formed at different stages of individual development; therefore brain activity during moral judgement is accounted for by the specificity of distribution of neural elements of functional systems across the brain structures, which is determined by the history of an individual’s interactions with the environment.

scholarly journals Study of the Perception of Written Speech Using Functional Tomography Based On Electroencephalography Data

2021 ◽  
Vol 16 (1) ◽  
pp. 1-14
Author(s):  
M.N. Ustinin ◽  
S.D. Rykunov ◽  
A.I. Boyko ◽  
E.F. Tarasov ◽  
I.V. Zhuravlev ◽  
...  
Keyword(s):  
Brain Activity ◽  
Three Dimensional ◽  
Single Layer ◽  
Separate Experiment ◽  
Current Dipole ◽  
Spatial Characteristics ◽  
Spectral Components ◽  
The Brain ◽  
Emotional Rating ◽  
Written Speech

The spectral and spatial characteristics of the electroencephalograms recorded during the perception of written speech were studied. For the experimental study, four groups were formed, each containing 100 words: words with a positive emotional rating, words with a negative emotional rating, words with concrete meanings, and words with abstract meanings. A separate experiment was conducted for each group with the subjects. Words were represented by white text on a black background, each word was presented for 1000 ms, after the presentation of the stimulus there was a pause of 500 ms. Brain activity was recorded using an electroencephalograph with 19 leads, arranged according to the 10–20 scheme. For detailed quantitative analysis of this activity, method of functional tomography of the brain, based on electroencephalography data, was used. This method is based on the Fourier transform of multichannel encephalographic data and the localization of individual spectral components. The method makes it possible to single out and stably localize in space various spectral features of the brain activity studied in experiments on speech research. The frequency band from 8 to 30 Hz was analyzed; for all spectral components in this band, the inverse problem was solved in the approximation of an equivalent current dipole in a single-layer spherical conductor, without any restrictions on the position of the source. As a result, three-dimensional maps of activity were built - the functional structures of the brain. The presentation of these functional structures on magnetic resonance imaging allows one to study the frequency and spatial characteristics of responses to various speech stimuli.

scholarly journals Stereoelectroencephalography for continuous two-dimensional cursor control in a brain-machine interface

2013 ◽  
Vol 34 (6) ◽  
pp. E3 ◽  
Author(s):  
Sumeet Vadera ◽  
Amar R. Marathe ◽  
Jorge Gonzalez-Martinez ◽  
Dawn M. Taylor
Keyword(s):  
Brain Activity ◽  
Intractable Epilepsy ◽  
Brain Structures ◽  
Brain Machine Interface ◽  
Cursor Control ◽  
Spectral Changes ◽  
Power Spectral ◽  
Machine Interface ◽  
The Brain ◽  
Epilepsy Monitoring

Stereoelectroencephalography (SEEG) is becoming more prevalent as a planning tool for surgical treatment of intractable epilepsy. Stereoelectroencephalography uses long, thin, cylindrical “depth” electrodes containing multiple recording contacts along each electrode's length. Each lead is inserted into the brain percutaneously. The advantage of SEEG is that the electrodes can easily target deeper brain structures that are inaccessible with subdural grid electrodes, and SEEG does not require a craniotomy. Brain-machine interface (BMI) research is also becoming more common in the Epilepsy Monitoring Unit. A brain-machine interface decodes a person's desired movement or action from the recorded brain activity and then uses the decoded brain activity to control an assistive device in real time. Although BMIs are primarily being developed for use by severely paralyzed individuals, epilepsy patients undergoing invasive brain monitoring provide an opportunity to test the effectiveness of different invasive recording electrodes for use in BMI systems. This study investigated the ability to use SEEG electrodes for control of 2D cursor velocity in a BMI. Two patients who were undergoing SEEG for intractable epilepsy participated in this study. Participants were instructed to wiggle or rest the hand contralateral to their SEEG electrodes to control the horizontal velocity of a cursor on a screen. Simultaneously they were instructed to wiggle or rest their feet to control the vertical component of cursor velocity. The BMI system was designed to detect power spectral changes associated with hand and foot activity and translate those spectral changes into horizontal and vertical cursor movements in real time. During testing, participants used their decoded SEEG signals to move the brain-controlled cursor to radial targets that appeared on the screen. Although power spectral information from 28 to 32 electrode contacts were used for cursor control during the experiment, post hoc analysis indicated that better control may have been possible using only a single SEEG depth electrode containing multiple recording contacts in both hand and foot cortical areas. These results suggest that the advantages of using SEEG for epilepsy monitoring may also apply to using SEEG electrodes in BMI systems. Specifically, SEEG electrodes can target deeper brain structures, such as foot motor cortex, and both hand and foot areas can be targeted with a single SEEG electrode implanted percutaneously. Therefore, SEEG electrodes may be an attractive option for simple BMI systems that use power spectral modulation in hand and foot cortex for independent control of 2 degrees of freedom.

scholarly journals Largest-scale dissociation of brain activity at propofol-induced loss of consciousness

SLEEP ◽  
2020 ◽  
Author(s):  
Jesus Pujol ◽  
Laura Blanco-Hinojo ◽  
Lluís Gallart ◽  
Luís Moltó ◽  
Gerard Martínez-Vilavella ◽  
...  
Keyword(s):  
Functional Mri ◽  
Brain Activity ◽  
Brain Structures ◽  
Functional Condition ◽  
Brain Network ◽  
Sleep Cycle ◽  
Loss Of Consciousness ◽  
Self Awareness ◽  
Subcortical Structures ◽  
The Brain

Abstract The brain is a functional unit made up of multi-level connected elements showing a pattern of synchronized activity that varies in different states. The wake-sleep cycle is a major variation of brain functional condition that is ultimately regulated by subcortical arousal- and sleep-promoting cell groups. We analyzed the evolution of functional MRI signal in the whole cortex and in a deep region including most sleep- and wake-regulating subcortical nuclei at loss of consciousness induced by the hypnotic agent propofol. Optimal data were obtained in 21 of the 30 healthy participants examined. A dynamic analysis of functional MRI time courses on a time-scale of seconds was conducted to characterize consciousness transition, and functional connectivity maps were generated to detail the anatomy of structures showing different dynamics. Inside the magnet, loss of consciousness was marked by the participants ceasing to move their hands. We observed activity synchronization after loss of consciousness within both the cerebral cortex and subcortical structures. However, the evolution of functional MRI signal was dissociated, showing a transient reduction of global cortico-subcortical coupling that was restored during the unconscious state. An exception to cortico-subcortical decoupling was a brain network related to self-awareness (i.e., the default mode network) that remained connected to subcortical brain structures. Propofol-induced unconsciousness is thus characterized by an initial, transitory dissociated synchronization at the largest scale of brain activity. Such cortico-subcortical decoupling and subsequent re-coupling may allow the brain to detach from waking activity and reorganize into a functionally distinct state.

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