Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 165, March 1977

This bibliography lists 198 reports, articles, and other documents introduced into the NASA scientific and technical information system in February 1977

Аналіз електроенцефалограм людини, отриманих під час емоційних стимулів

Об’єктом розгляду є електрична активність головного мозку людини. Предмет роботи – методи аналізу електроенцефалограм під час дії різноманітних стимулів. Метою роботи є вивчення природи виникнення електричних сигналів мозку, методи їх реєстрації та аналізу для дослідження реакції на візуальні емоційнонавантажені стимули. У першому розділі описуються загальні поняття про природу виникнення електричного сигналу мозку людини, а також нейрофізіологічні ознаки присутності різних частотних складових сигналу за певних станів людини. У другому розділі наведено принципи реєстрації сигналів електроенцефалограми (ЕЕГ) та описано пристрої, що здатні це виконувати. Також розглянуто опис основної системи накладання сенсорів (електродів) на голову людини. В кінці розділу наведено приклад компактного 8-канального енцефалографа власної розробки, що здатен реєструвати сигнали ЕЕГ та передавати їх по бездротовому зв’язку на мобільні прилади (смартфон, планшет). Третій розділ описує основні математичні методи аналізу ЕЕГ сигналів. Основними є методи спектрального та вейвлет-аналізу та аналіз детрендових коливань, за допомогою яких можна отримати детальне представлення про роботу мозку, шляхом виявлення різноманітних патернів в частотних діапазонах. У четвертому розділі описується практичне застосування методів спектрального та Detrended Moving Average аналізів на експериментальній базі даних ЕЕГ для 48 здорових волонтерів, запис ЕЕГ для яких проводився під час демонстрації певних емоційнонавантажених візуальних стимулів. Також в цьому розділі наведені результати виконаного аналізу разом з їх нейрофізіологічним тлумаченням.An important place in the study of brain activity is occupied by the study of its electrical potentials. Electroencephalography (EEG) is a method of graphical recording of brain biopotentials, which allows analyzing its physiological maturity and condition, the presence of focal lesions, general brain disorders and their nature. It consists of recording and analyzing the total bioelectric activity of the brain — an electroencephalogram (EEG). EEG can be taken from the scalp, from the surface of the brain, as well as from deep brain structures. As a rule, an electroencephalogram is understood as a surface recording, that is, made from the intact head surface. EEG is most often used to diagnose epilepsy, which causes EEG disorders. It is also used to diagnose sleep disorders, deep anesthesia, coma, encephalopathy, and brain death. EEG was used as the main method for diagnosing tumors, stroke, and other focal brain diseases, but when it became possible to obtain high-resolution anatomical images using magnetic resonance imaging (MRI) and computed tomography (CT) techniques, the use of EEG declined. Despite its limited resolution, the EEG continues to be a valuable tool for research and diagnosis. The object of consideration is the electrical activity of the human brain. The subject of the work is methods of analyzing electroencephalograms during the action of various stimuli. The aim of the work is to study the nature of the occurrence of electrical signals of the brain, methods of their registration and analysis to study the response to visual emotional stimuli. The first chapter describes general concepts about the nature of the occurrence of an electrical signal in the human brain, as well as neurophysiological signs of the presence of various frequency components of the signal in certain human states. The second chapter describes the principles of recording electroencephalogram signals and describes devices that can perform this. The description of the main system for applying sensors (electrodes) to the human head is also considered. At the end of the section, an example of a compact 8-channel encephalograph of our own design is given, which is able to register EEG signals and transmit them wirelessly to mobile devices (smartphone, tablet). The third section describes the basic mathematical methods for analyzing EEG signals. The main methods are spectral and wavelet analysis and detrended oscillation analysis, which can be used to get a detailed picture of brain function by identifying various patterns in frequency ranges. The fourth section describes the practical application of spectral and Detrended Moving Average analysis methods on an experimental EEG database. Here, initially the EEG records were made for 48 healthy volunteers whose EEG recording was performed while demonstrating certain emotionally loaded visual stimuli. Stimuli were selected from the International Affective Pictures System (IAPS) based on their average emotional valence values. In order to assess the induced changes of the brain’s electrical activity, the EEG-bands were subdivided in a following way: 1 [3.5, 5.8], 2 [5.9, 7.4], 1 [7.5, 9.4], 2 [9.5, 10.7], 3 [10.8, 13.5], 1 [13.6, 25], 2 [25.1, 40] Hz. As a result, Power Spectral Density (PSD) were visualized as a map on the schematic figure of the head used to render the statistical significance test, demonstrating that variations in powers for our signals were caused by non-identical forms of visual effect rather than being an accident. These details were also shown in the heads charts. The study of changes in power spectrum density showed neurodynamics triggered by visual stimulation experience. However, when comparing PSD values obtained during the presentation of the first and second neutral series, it was discovered that when processing neutral images followed by negative stimuli, a well-defined activation focus developed in the left parietal region of the cortex in the 2 subband. The DMA algorithm revealed statistically important variations in the left temporal and frontal regions of the cortex, which were marked by more pronounced activation during the perception of neutral faces in the presence of positive images. This may be the start of a new path of improved inner focus and meaningful emotional experiences. As a result, the sex-related aspects of the emotional valence effect on neutral face perception were discovered by analyzing EEG-based brain neurodynamics in the mechanism in perception in human faces of various modalities. The stimulation of two large cognitive networks in the brain: mental or theta-network and cognitive beta- network, was the key distinction

Neurofeedback Therapy for Enhancing Visual Attention: State-of-the-Art and Challenges

We have witnessed a rapid development of brain-computer interfaces (BCIs) linking the brain to external devices. BCIs can be utilized to treat neurological conditions and even to augment brain functions. BCIs offer a promising treatment for mental disorders, including disorders of attention. Here we review the current state of the art and challenges of attention-based BCIs, with a focus on visual attention. Attention-based BCIs utilize electroencephalograms (EEGs) or other recording techniques to generate neurofeedback, which patients use to improve their attention, a complex cognitive function. Although progress has been made in the studies of neural mechanisms of attention, extraction of attention-related neural signals needed for BCI operations is a difficult problem. To attain good BCI performance, it is important to select the features of neural activity that represent attentional signals. BCI decoding of attention-related activity may be hindered by the presence of different neural signals. Therefore, BCI accuracy can be improved by signal processing algorithms that dissociate signals of interest from irrelevant activities. Notwithstanding recent progress, optimal processing of attentional neural signals remains a fundamental challenge for the development of efficient therapies for disorders of attention

Sleep, Wakefulness, Dreams and Memory

Sleep-wakefulness cycle mechanisms shown in central neural activity change

USSR Space Life Sciences Digest

Research in exobiology, life sciences technology, space biology, and space medicine and physiology, primarily using data gathered on the Salyut 6 orbital space station, is reported. Methods for predicting, diagnosing, and preventing the effects of weightlessness are discussed. Psychological factors are discussed. The effects of space flight on plants and animals are reported. Bioinstrumentation advances are noted

Role of water in physics of blood and cerebrospinal fluid

Known physical mechanisms of temperature dependence anomalies of water properties were used to explain the regularities in temperature dependence (TDs) of dynamic, electrical and optical characteristics of biological systems. The dynamics of hydrogen bonds in bulk and hydrated water affected the activation energies TDs of ion currents of voltage-dependent channels that regulate signaling and trophic bonds in the neuropil of the cortical parenchyma. The physics of minimizing the TD of the isobaric heat capacity of water made it possible to explain the stabilization and functional optimization of the thermodynamics of eyeball fluids at 34.5 C and the human brain during sleep at 36.5 C. At these temperatures, the thermoreceptors of the cornea and the cells of the ganglionic layer of the retina, through connections with the suprachiasmatic nucleus and the pineal gland, switch the circadian rhythm from daytime to nighttime. The phylogenesis of the circadian rhythm was reflected in the dependence of the duration of the nighttime sleep of mammals on the diameter of the eyeball and the mass of the pineal gland. The activity of all the nerves of the eyeball led to the division of the nocturnal brain metabolism into NREM and REM phases. These phases correspond to two modes of the glymphatic system - electrochemical and dynamic. The first is responsible for the relaxation processes of synaptic plasticity and chemical neutralization of toxins with the participation of water and melatonin. Rapid eye movement and an increase in cerebral blood flow in the second mode increase water exchange in the parenchyma and flush out toxins into the venous system. Electrophysics of clearance and conductivity of ionic and water channels of membranes of blood vessels and astrocytes modulate oscillations of polarization potentials of water dipole domains in parietal plasma layers of arterioles and capillaries

Aerospace Medicine and Biology: A continuing bibliography with indexes, supplement 142

This bibliography lists 256 reports, articles, and other documents introduced into the NASA scientific and technical information system in May 1975 for aerospace medicine and biology

Aerospace medicine and biology: A continuing bibliography with indexes, supplement 128, May 1974

This special bibliography lists 282 reports, articles, and other documents introduced into the NASA scientific and technical information system in April 1974