Search

A comprehensive statistical study is conducted on O+ and H+ outflows obtained from the TEAMS/FAST data during the 23rd solar cycle (1996–2007). The study investigates interhemispheric asymmetry in ionospheric outflows during local summer, winter, and equinox seasons. Data are classified into two distinct periods: the pre‐storm and geomagnetic storm phases. Numerous statistical asymmetries are identified. The findings indicate that the dayside cusp consistently demonstrates more outflow rates of O+ and H+ in the northern hemisphere than southern hemisphere during geomagnetic storms in all seasons as well as during the pre‐storm period in the summer season with the exception of H+ during summer storms. Conversely, the nightside O+ and H+ outflow rates are higher in the southern hemisphere during pre‐storm and storm periods in the summer season. Additionally, the dawnside and duskside outflow rates of O+ and H+ are predominantly stronger in the southern hemisphere. Plain Language Summary: The Earth's hemispheres receive different solar extreme ultraviolet radiation levels in different local seasons. In addition, there is a displacement between Earth's magnetic and geographic poles. Both mentioned factors cause interhemispheric asymmetries in ionospheric parameters. For the first time, this study investigates asymmetry in O+ and H+ ionospheric outflows between the northern and southern hemispheres by focusing on similar local seasons with comparable solar radiation levels. Data from the FAST/Time‐of‐flight Energy Angle Mass Spectrograph (TEAMS) instrument (1996–2007) are used for storms and pre‐storms. Hemispherical ionospheric outflows are categorized into summer, winter, and equinox and are spatially averaged in the polar regions. Findings reveal asymmetric ion outflows between hemispheres. The dayside cusp outflows are higher in the northern hemisphere than in the southern hemisphere during geomagnetic storms in all seasons except for H+ in summer. Conversely, nightside O+ and H+ outflows are more in the southern hemisphere than in the northern hemisphere during pre‐storm and storm periods in summer. Additionally, in dawnside and duskside, O+ and H+ outflows are predominantly stronger in the southern hemisphere than in the northern hemisphere. Key Points: 11‐year statistics find the northern and southern hemispheres exhibit asymmetric ion outflow even during similar local seasonsDuring storms, the cusp dayside exhibits higher O+ and H+ outflow rates in the northern hemisphere compared to the southern hemisphereThe dawnside and duskside O+ and H+ outflow rates are stronger in the southern hemisphere than in the northern hemisphere [ABSTRACT FROM AUTHOR]

Enlarged perivascular spaces (EPVS) are increasingly recognized as an MRI detectable feature of neuroinflammatory processes and age-related neurodegenerative changes. Understanding perivascular characteristics in healthy individuals is crucial for their applicability as a reference for pathological changes. Limited data exists on the EPVS load and interhemispheric asymmetry in distribution among young healthy subjects. Despite the known impact of hydration on brain morphometric studies, blood plasma osmolality's effect on EPVS remains unexplored.This study investigated the influence of age, total intracranial volume (TIV), and blood plasma osmolality on EPVS characteristics in 59 healthy adults, each undergoing MRI and osmolality assessment twice within 14.8 months (mean ± 4 months). EPVS analysis was conducted in the centrum semiovale using high-resolution automated segmentation, followed by an optimization algorithm to enhance EPVS segmentation accuracy. Linear Mixed Effects model was used for the statistical analysis, which unveiled significant inter-individual variability in EPVS load and inter-hemispheric asymmetry. EPVS volume increased with age, higher TIV and lower blood plasma osmolality levels. Our findings offer valuable insights into EPVS characteristics among the healthy population, establishing a foundation to further explore age-related and pathological changes.

Abstract A comprehensive statistical study is conducted on O+ and H+ outflows obtained from the TEAMS/FAST data during the 23rd solar cycle (1996–2007). The study investigates interhemispheric asymmetry in ionospheric outflows during local summer, winter, and equinox seasons. Data are classified into two distinct periods: the pre‐storm and geomagnetic storm phases. Numerous statistical asymmetries are identified. The findings indicate that the dayside cusp consistently demonstrates more outflow rates of O+ and H+ in the northern hemisphere than southern hemisphere during geomagnetic storms in all seasons as well as during the pre‐storm period in the summer season with the exception of H+ during summer storms. Conversely, the nightside O+ and H+ outflow rates are higher in the southern hemisphere during pre‐storm and storm periods in the summer season. Additionally, the dawnside and duskside outflow rates of O+ and H+ are predominantly stronger in the southern hemisphere.

The solar wind and its embedded magnetic field, the interplanetary magnetic field (IMF) together with magnetic reconnection power the large-scale plasma and magnetic flux circulation in the Earth's magnetosphere-ionosphere system. This circulation is termed as convection and its strength is controlled by the north-south IMF component (IMF Bz). In recent years, an interest has arisen to investigate the lesser-known role of the dusk-dawn component (IMF By) in convection. It has been previously known though that prevailing nonzero IMF By can cause plasma flow asymmetries in the high-latitude ionosphere, but how the magnetospheric flows, for instance, in the magnetotail plasma sheet are affected, remains to be investigated. In this article, we introduce the recent progress and the latest achievements in the research of the influence of IMF By on tail plasma sheet convection. The research progress has been rapid and it has revealed that both fast and slow convection are affected in a manner that is in accordance with the asymmetries observed in the ionospheric convection. The results indicate the significance of the IMF B[sub y] component on magnetospheric convection and they represent a major advance in the field of solar wind-magnetosphere coupling. [ABSTRACT FROM AUTHOR]

The purpose of the study was a theoretical review of the problem of interhemispheric asymmetry and lateral preferences in children with intellectual disabilities. Data analysis from numerous studies in neuropsychology have allowed a new view of the possibility of developing compensatory mechanisms for various disorders of higher mental functions with specific features of the lateral organization profile types of motor and sensory functions that play a basic role in the mental development of children with disabilities. The analysis of the presented scientific approaches and factual studies allow to state the presence of hidden contradictions in the issues of determining correlations of interhemispheric asymmetry in impaired development. The review of the literature presented in this paper proves the presence of qualitative peculiarities of the organization of movements in brain of schoolchildren with intellectual disabilities. At the same time, the theoretical analysis revealed a lack of consensus on the influence of lateral preferences in the difficulties encountered, which determines the relevance and necessity of further search for opportunities to use neuropsychological data and the individual lateral preferences in the development of movement skills.

The solar wind and its embedded magnetic field, the interplanetary magnetic field (IMF) together with magnetic reconnection power the large-scale plasma and magnetic flux circulation in the Earth’s magnetosphere-ionosphere system. This circulation is termed as convection and its strength is controlled by the north-south IMF component (IMF Bz). In recent years, an interest has arisen to investigate the lesser-known role of the dusk-dawn component (IMF By) in convection. It has been previously known though that prevailing nonzero IMF By can cause plasma flow asymmetries in the high-latitude ionosphere, but how the magnetospheric flows, for instance, in the magnetotail plasma sheet are affected, remains to be investigated. In this article, we introduce the recent progress and the latest achievements in the research of the influence of IMF By on tail plasma sheet convection. The research progress has been rapid and it has revealed that both fast and slow convection are affected in a manner that is in accordance with the asymmetries observed in the ionospheric convection. The results indicate the significance of the IMF By component on magnetospheric convection and they represent a major advance in the field of solar wind-magnetosphere coupling.

Objectives. To quantify genome-wide DNA methylation in the olfactory bulbs, frontoparietal and occipital areas, and cerebellum in male Wistar rats in normal conditions and in a model of incomplete cerebral ischemia caused by permanent bilateral occlusion of the common carotid arteries. Materials and methods. The study was performed on 23 male Wistar rats, which were divided into sham operation and cerebral ischemia groups. Genome-wide DNA methylation levels at CCGG sites were determined by methyl-sensitive restriction using endonucleases MspI and HpaII, followed by densitometric analysis of electropherograms in ImageJ software. Results and conclusions. Incomplete cerebral ischemia produced 56.3% (95% CI 33.2–76.90) mortality on day 7. Surviving rats of the cerebral ischemia group, as compared with animals of the sham operation group, displayed marked neurological deficit, which was accompanied by changes in the genome-wide DNA methylation level in the nervous tissue of brain structures (p < 0.05). Incomplete cerebral ischemia in male Wistar rats was characterized by interhemispheric asymmetry in the severity and direction of the epigenomic reactions of nervous tissue in both ischemic and non-ischemic areas of the brain. It is likely that these dynamics of changes in the genome-wide DNA methylation status of nervous tissue are responsible for imparting plasticity to neuronal function during ischemic injury. [ABSTRACT FROM AUTHOR]

An interhemispheric asymmetry of thermospheric Oxygen (O) to Nitrogen (N2) column density ratio (∑O/N2) variations was observed by the Global‐scale Observations of the Limb and Disk (GOLD) during the 3–5 November 2021 geomagnetic storm. ∑O/N2 depletion is more equatorward in the local morning than in the local afternoon in the northern hemisphere (NH), while more equatorward in the local afternoon than the local morning in the southern hemisphere (SH). The Thermosphere Ionosphere Electrodynamics General Circulation Model simulations reproduced the observed ∑O/N2 asymmetry. The impacts of interplanetary magnetic field (IMF) east‐west component (By) on the interhemispheric asymmetry of ∑O/N2 depletion was investigated. Comparisons of simulation results with and without real By show that the dominant positive IMF By results in the Joule heating maximum occurring in the local afternoon of NH and local morning in the SH during the storm initial phase, which generates the corresponding ∑O/N2 changes. Additionally, the IMF By during this storm are more crucial in the SH than in the NH. Without By, equatorward penetration of the ∑O/N2 depletion in GOLD Field of View are almost same in the SH. However, in the NH, there is still more equatorward depletion in the local morning than the local afternoon without By. Key Points: Global‐scale Observations of the Limb and Disk (GOLD) observed an interhemispheric asymmetry of ∑O/N2 depletion during the storm on 4 November 2021, and was reproduced by modelDominant positive interplanetary magnetic field By enhances magnitude of depletions in both hemispheres compared with the ones without ByWithout By, equatorward penetration of the ∑O/N2 depletion in GOLD Field of View are almost same in the southern hemisphere [ABSTRACT FROM AUTHOR]

The article deals with the influence of systematic physical training and sport on the concentration of attention and interhemispheric asymmetry in the students of the higher education educational institution aged 19–20 years. The review of the literature corresponding to the research issue is given. The Amatuni test was used for the practical physiological study. On the basis of the study the author has made conclusions about the impact of physical education and sports on the mental activity of students.

Using the total electron content (TEC) observations from GPS, and simulations from the Thermosphere Ionosphere Electrodynamic General Circulation Model (TIEGCM), this work investigates the large-scale traveling ionospheric disturbances (LSTIDs) and the possible involved drivers during the geomagnetic storm on January 14-15, 2022. Based on the term analysis of O+ continuity equation in TIEGCM, it is found that the traveling atmospheric disturbances in equatorward winds are responsible for the LSTIDs, with minor contributions from plasma drifts owing to the prompt penetration electric field. A strong interhemispheric asymmetry of the LSTIDs is observed, which might be attributed to both the equatorward wind disturbances and background plasma. The stronger wind (plasma) disturbances occurs in the winter hemisphere than that in the summer hemisphere. The maximum magnitude of LSTIDs in electron density disturbances occurs at ∼250 and ∼270 km in the northern and southern hemispheres, respectively, owing to both the thermospheric equatorward winds and background plasma. An interesting phenomenon that tail-like LSTIDs occur at the dip equator and low latitudes might be related to the eruption of the Tonga volcano, but it is not well reproduced in TIEGCM that deserves further exploration in a future study.

The purpose of the study was a theoretical review of the problem of interhemispheric asymmetry and lateral preferences in children with intellectual disabilities. Data analysis from numerous studies in neuropsychology have allowed a new view of the possibility of developing compensatory mechanisms for various disorders of higher mental functions with specific features of the lateral organization profile types of motor and sensory functions that play a basic role in the mental development of children with disabilities. The analysis of the presented scientific approaches and factual studies allow to state the presence of hidden contradictions in the issues of determining correlations of interhemispheric asymmetry in impaired development. The review of the literature presented in this paper proves the presence of qualitative peculiarities of the organization of movements in brain of schoolchildren with intellectual disabilities. At the same time, the theoretical analysis revealed a lack of consensus on the influence of lateral preferences in the difficulties encountered, which determines the relevance and necessity of further search for opportunities to use neuropsychological data and the individual lateral preferences in the development of movement skills. [ABSTRACT FROM AUTHOR]

Background. The neuropsychological approach suggests that differences in cognitive processes are associated with the variability of combinations of signs of partial dominance of certain brain structures, manifested in the form of individual laterality profiles. However, the problem of identifying and studying the relationship between interhemispheric asymmetry and cognitive functions in adolescents with a high level of intelligence remains not fully resolved, which determines the relevance of this study.The aim of the research was to describe the relationship between the type of profile of interhemispheric asymmetry with the characteristics of cognitive functions in adolescents with average and high levels of intelligence.Materials and methods. The sample included 52 people aged 12–15 years: 26 adolescents with high level intelligence (main group), 26 adolescents with an average level of intelligence (control group). The following research methods were used: Wechsler test (WISC-IV), method for studying the profile of interhemispheric asymmetry (Khomskaya E.D., Efimova I.V.); method “Correction test” by B. Bourdon; method ”Story on a given topic”.Results. The majority of adolescents with a high level of intelligence revealed the severity of right-lateral features, which were traced in the manual, auditory and visual spheres of sensorimotor asymmetry. At the same time, the severity of right-lateral and ambilateral features is accompanied by more pronounced indicators of the development of cognitive functions. Adolescents with the type of profile of interhemispheric asymmetry “Left-handed” were characterized by an insufficient level of attention stability and a reduced ability for detailed speech utterance, regardless of the level of intelligence.Conclusions. The data obtained show that the peculiarity of individual profiles of interhemispheric asymmetry determines the uneven development of a number of mental functions in adolescence and the different readiness of brain mechanisms to support various cognitive processes. We assume that the results of the work will expand the understanding of the role of interhemispheric asymmetry of the brain in the organization of cognitive functions in adolescents with a high level of intelligence.

The work is devoted to one of the most relevant problems of ophthalmology and neurophysiology which is the study of interhemispheric interactions in children with ophthalmopathology.The purpose of this work is to study lateral phenotypes in children with ophthalmopathology.Patients and methods. 374 6–15 years old children were observed: 1) 160 children with non-paralytic strabismus; 2) 111 children with organic pathology of the retina and the optic nerve; 3) 103 children of the control group (without ophthalmopathology). The lateral phenotype (LP) was determined according to the scheme “dominant hand — dominant ear — dominant eye”.Results. Different LP ratios were obtained in the examined groups of children (p < 0.001). The ratio of right-handers / left-handers / ambidextrous children was most uniform in the group of children with non-paralytic strabismus (43,8 / 22,5 / 33,7 %). In the group of children with organic ophthalmopathology it was “shifted” to the right-hand side (65,8 / 10,8 / 23,4 %). In the control group the number of left-handers was minimal, and the number of ambidextrous was maximal (51,4 / 3,9 / 44,7).Conclusion. It was found that children with organic ophthalmopathology are characterized by the most pronounced predominance of right-sided LP, and children with non-paralytic strabismus are characterized by a relatively uniform distribution of right-sided, left-sided and symmetrical LP. The identified features may reflect increased left-hemispheric activity in children with organic ophthalmopathology and adaptivecompensatory increase in right-hemispheric activity in children with non-paralytic strabismus.

Observations of interhemispheric asymmetry in the cusp region due to the interplanetary magnetic field (IMF) By component have been performed for years, but those observations typically are not simultaneous in both hemispheres and represent an average picture. Simultaneous instantaneous observations in both hemispheres are rare. We have combined four sets of magnetometers in Antarctica to produce equivalent ionospheric currents and current amplitudes at 10 s resolution using the spherical elementary current systems technique. These Antarctica spherical elementary currents are roughly conjugate to the northern hemisphere spherical elementary currents derived over Greenland and North America. We examined five intervals with large interplanetary magnetic field By positive and negative and demonstrate that the equivalent current pattern in opposite hemispheres are asymmetric with respect to one another during IMF By positive with the cusp throat opening towards the dusk in the northern hemisphere and towards the dawn in the southern hemisphere. This configuration reverses for interplanetary magnetic field By negative. In one of these events we examine the rotation of the equivalent currents in real time in the northern hemisphere. We also compare these results with virtual magnetometer predictions from the Space Weather Modeling Framework. Simultaneous spherical elementary currents observations in both hemispheres are important because they allow us to observe the evolution of the cusp throat during changing solar wind and interplanetary magnetic field conditions. Key Points: We show the instantaneous equivalent ionospheric current orientation in the cusp for positive and negative IMF ByWe demonstrate that this pattern is reversed in opposite hemispheresMagnetically conjugate spherical elementary currents provide an opportunity to observe the high temporal variation in the cusp region [ABSTRACT FROM AUTHOR]

Introduction. In neuropsychological practice the dichotic listening task has been widely used for more than 50 years as a valid test for determining the laterality of auditory speech asymmetry. Theoretical analysis. Most of the studies of the dichotic listening task in aphasia are characterized by small sample groups, a wide demographic features of them, lack attention to the type and aphasia severity, a size of local brain damage as well. Without taking into account these important factors it is difficult to answer to some questions: 1. whether the vector of auditory speech asymmetry is determined by the age, type and aphasia severity; 2. whether the laterality of auditory speech asymmetry affects the dynamics of aphasia recovery. The aim of the study: the connection between quantitative parameters of the dichotic listening task and the dynamics of aphasia regression. Empirical analysis. Material. The study involved patients (N = 109) with traumatic and post-stroke efferent motor (50.7 ± 10.1 years) and acoustic mnestic (54.4 ± 8.2 years) aphasia of mild and moderate severity of speech disorders. Methods. Kimura’s dichotic listening task modified by B. S. Kotik; the quantitative assessment of speech in aphasia L. S. Tsvetkova, T. V. Akhutina, N. M. Pylaeva. The speech assessment was carried out twice: before and after a 6-week course of speech rehabilitation. Results. Between efferent motor and acoustic mnestic aphasia groups the difference in the laterality of ear superiority was revealed. The efferent motor aphasia group shows the ambidextrous pattern in auditory perception. The dichotic listening task efficiency increases with a burst of the left ear productivity and vice versa with the right ear. The acoustic mnestic aphasia group presents a pronounced effect of the right ear suppression. Its productivity is significantly lower than the productivity of the left ear and the same indicator of the efferent motor aphasia group. The effectiveness of the dichotic listening task in the acoustic mnestic aphasia group does not exhibit a correlation with the parameters of productivity of the right or left ear. The aphasia groups vary in the dynamics of aphasia regression. In the acoustic mnestic aphasia group, this dynamics was 2.5 times higher than in the efferent motor aphasia group. Conclusion. The right hemisphere laterality in auditory speech perception correlates positively with the dynamics of aphasia regression. Further research should find an answer to the question of the constellations of significant factors and their hierarchical relationships that could determine the positive dynamics of recovery of aphasic disorders.

Field‐aligned distributions of H+ with energy less than 100 eV in the magnetosphere originate from the ionosphere through ionospheric outflow. Recently, a statistical interhemispheric asymmetry in this ion outflow was reported. In this study, we investigate a case study of asymmetric field‐aligned distributions (E < 100 eV) resulting from asymmetric outflow observed on 13 August 2019 by the Hot Plasma Composition Analyzer onboard the Magnetospheric Multiscale mission. During the reported event, the average phase space density in the parallel direction (pitch angle < 45°) is about 4.7 times higher than in the anti‐parallel direction (pitch angle > 135°), indicating greater outflow from the southern hemisphere. In this event, electron precipitation fluxes are also asymmetric between hemispheres, with more electrons traveling to the southern hemisphere than to the northern hemisphere. Global MHD simulation results (SWMF/BAT‐S‐RUS available from the CCMC) confirm that several ionospheric parameters (joule heating, convection velocities, and energy fluxes of precipitating electrons) are more enhanced in the southern hemisphere. We suggest that these interhemispheric asymmetries might cause a stronger outflow from the southern hemisphere than from the northern hemisphere, to produce the observed asymmetric field‐aligned distributions for the low‐energy H+. Key Points: Low‐energy (E < 100 eV) H+ field‐aligned distributions are asymmetric in the outer magnetosphereConditions in the southern hemisphere ionosphere are favorable and result in asymmetric outflowThe observed low‐energy H+ pitch‐angle distributions are consistent with asymmetric outflow as the cause [ABSTRACT FROM AUTHOR]

Attachment theory suggests that interindividual differences in attachment security versus insecurity (anxiety and avoidance) contribute to the ways in which people perceive social emotional signals, particularly from the human face. Among different facial features, eye gaze conveys crucial information for social interaction, with a straight gaze triggering different cognitive and emotional processes as compared to an averted gaze. It remains unknown, however, how interindividual differences in attachment associate with early face encoding in the context of a straight versus averted gaze. Using electroencephalography (EEG) and recording event-related potentials (ERPs), specifically the N170 component, the present study (N = 50 healthy adults) measured how the characteristics of attachment anxiety and avoidance relate to the encoding of faces with respect to gaze direction and head orientation. Our findings reveal a significant relationship between gaze direction (irrespective of head orientation) and attachment anxiety on the interhemispheric (i.e. right) asymmetry of the N170 and thus provide evidence for an association between attachment anxiety and eye gaze processing during early visual face encoding. [ABSTRACT FROM AUTHOR]

• Blood plasma osmolality inversely correlates with EPVS volume in the healthy population. • EPVS volume increases with age even in the relatively young people. • There is substantial inter-individual variability in EPVS load. • EPVS distribution exhibits individual asymmetry across hemispheres. Enlarged perivascular spaces (EPVS) are increasingly recognized as an MRI detectable feature of neuroinflammatory processes and age-related neurodegenerative changes. Understanding perivascular characteristics in healthy individuals is crucial for their applicability as a reference for pathological changes. Limited data exists on the EPVS load and interhemispheric asymmetry in distribution among young healthy subjects. Despite the known impact of hydration on brain morphometric studies, blood plasma osmolality's effect on EPVS remains unexplored. This study investigated the influence of age, total intracranial volume (TIV), and blood plasma osmolality on EPVS characteristics in 59 healthy adults, each undergoing MRI and osmolality assessment twice within 14.8 months (mean ± 4 months). EPVS analysis was conducted in the centrum semiovale using high-resolution automated segmentation, followed by an optimization algorithm to enhance EPVS segmentation accuracy. Linear Mixed Effects model was used for the statistical analysis, which unveiled significant inter-individual variability in EPVS load and inter-hemispheric asymmetry. EPVS volume increased with age, higher TIV and lower blood plasma osmolality levels. Our findings offer valuable insights into EPVS characteristics among the healthy population, establishing a foundation to further explore age-related and pathological changes. [ABSTRACT FROM AUTHOR]

Purpose. To study the dynamics of interhemispheric interactions in children with friendly strabismus as a result of functional treatment. Material and methods. The study included 135 children aged 6 to 8 (average 6.8±0.1) years with convergent non-paralytic operated strabismus in combination with hypermetropic refraction and 96 children of the same age in the control group (average 7.1±0.1 years) without ophthalmic pathology. In children with strabismus, the leading hand and dominant eye were determined before and after functional treatment. Characteristics of spatial perception were evaluated by copying of complex geometric shapes which were Taylor’s (right-handed) and Ray-Osterritz’s (left-handed). Results. After functional treatment in the group of children with non-paralytic strabismus, along with improved binocular functions and improved performance of the Taylor and Ray-Osterritz tests, there was an increase in the number of ambidextrous children and a significant decrease in the number of left-handers (p

With an ageing of population and a splurging epidemic of diabetes mellitus (DM), the prevalence of complications associated with pathology of the central nervous system are expected to increase, which in the future may have serious consequences for public health. It is known that one of the main manifestations of brain damage in type 1 diabetes is cognitive impairment, which is possibly associated with the peculiarities of vascularization and interhemispheric asymmetry, which requires in-depth analysis using modern neuroimaging methods. The aim of the study is to assess the symmetry of structural, metabolic and neurovascularization changes in the brain in patients with type 1 diabetes and cognitive impairment. The study included 120 patients with type 1 diabetes aged 18 to 45 years suffering from cognitive impairment, and 30 people without cognitive decline and the control group (n=30) healthy people without diabetes. Neuropsychological testing included the Montreal Cognitive Dysfunction Assessment Scale (MoCA test). For neuroimaging methods, standard magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), contrast and non-contrast-enhanced perfusion were used. Statistical processing was carried out using the SPSS Statistic 2020 software. In patients with type 1 diabetes with cognitive impairment, as manifested by impaired memory and/or attention, perfusion imaging revealed the presence of brain asymmetry zones. Standard MRI allowed to demonstrate changes in the white, gray matter and hippocampus in the right hemisphere. The results obtained were refined taking into account the topical localization, so during the perfusion study, regions with asymmetric blood flow were identified - namely, the white matter of the frontal lobe and the gray matter in the occipital lobe. Spectroscopy of the brain revealed that it was in these areas of the brain that the most significant metabolic disorders were noted – in the form of significantly altered ratio of N-acetylaspartate (NAA)/ choline (Cho) on the left, along with the asymmetry in phosphocreatine level (Cr 2) on the right. In conclusion, early preclinical predictive diagnostics with the use of modern neuroimaging methods allows for timely detection of impaired vascularization and brain metabolism in this group of patients, However, decreased perfusion in the region within the region of frontal lobe white matter and temporal lobe grey matter, and hippocampal cell metabolism by spectra should be highlighted among the parameters Cr right and NAA/ Cho left. [ABSTRACT FROM AUTHOR]

Polar electrodynamics is largely controlled by solar wind and magnetospheric forcing. Different conditions can make plasma convection and magnetic field disturbances asymmetric between hemispheres. So far, these asymmetries have been studied in isolation. We present an explanation of how they are linked via displacements of magnetic field line footpoints between hemispheres, under the assumption of ideal magnetohydrodynamics. This displacement has so far been studied only on a point by point basis; here we generalize the concept to a 2D displacement vector field. We estimate displacement fields from average patterns of ionospheric convection using the Weimer et al. (J. Geophys. Res., 2005a, 110, A05306) model. These estimates confirm that the influence of the interplanetary magnetic field extends deep into the magnetosphere, as predicted by models and in-situ observations. Contrary to predictions, the displacement associated with dipole tilt appears uniform across the nightside, and it exceeds the effect of IMF By. While more research is needed to confirm these specific findings, our results demonstrate how ionospheric observations can be used to infer magnetospheric morphology, and that the displacement field is a critical component for understanding geospace as a coupled two-hemisphere system. [ABSTRACT FROM AUTHOR]

With an ageing of population and a splurging epidemic of diabetes mellitus (DM), the prevalence of complications associated with pathology of the central nervous system are expected to increase, which in the future may have serious consequences for public health. It is known that one of the main manifestations of brain damage in type 1 diabetes is cognitive impairment, which is possibly associated with the peculiarities of vascularization and interhemispheric asymmetry, which requires in-depth analysis using modern neuroimaging methods. The aim of the study is to assess the symmetry of structural, metabolic and neurovascularization changes in the brain in patients with type 1 diabetes and cognitive impairment. The study included 120 patients with type 1 diabetes aged 18 to 45 years suffering from cognitive impairment, and 30 people without cognitive decline and the control group (n=30) healthy people without diabetes. Neuropsychological testing included the Montreal Cognitive Dysfunction Assessment Scale (MoCA test). For neuroimaging methods, standard magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), contrast and non-contrast-enhanced perfusion were used. Statistical processing was carried out using the SPSS Statistic 2020 software. In patients with type 1 diabetes with cognitive impairment, as manifested by impaired memory and/or attention, perfusion imaging revealed the presence of brain asymmetry zones. Standard MRI allowed to demonstrate changes in the white, gray matter and hippocampus in the right hemisphere. The results obtained were refined taking into account the topical localization, so during the perfusion study, regions with asymmetric blood flow were identified - namely, the white matter of the frontal lobe and the gray matter in the occipital lobe. Spectroscopy of the brain revealed that it was in these areas of the brain that the most significant metabolic disorders were noted – in the form of significantly altered ratio of N-acetylaspartate (NAA)/choline (Cho) on the left, along with the asymmetry in phosphocreatine level (Cr 2) on the right. In conclusion, early preclinical predictive diagnostics with the use of modern neuroimaging methods allows for timely detection of impaired vascularization and brain metabolism in this group of patients, However, decreased perfusion in the region within the region of frontal lobe white matter and temporal lobe grey matter, and hippocampal cell metabolism by spectra should be highlighted among the parameters Cr right and NAA/Cho left.

Polar electrodynamics is largely controlled by solar wind and magnetospheric forcing. Different conditions can make plasma convection and magnetic field disturbances asymmetric between hemispheres. So far, these asymmetries have been studied in isolation. We present an explanation of how they are linked via displacements of magnetic field line footpoints between hemispheres, under the assumption of ideal magnetohydrodynamics. This displacement has so far been studied only on a point by point basis; here we generalize the concept to a 2D displacement vector field. We estimate displacement fields from average patterns of ionospheric convection using the Weimer et al. (J. Geophys. Res., 2005a, 110, A05306) model. These estimates confirm that the influence of the interplanetary magnetic field extends deep into the magnetosphere, as predicted by models and in-situ observations. Contrary to predictions, the displacement associated with dipole tilt appears uniform across the nightside, and it exceeds the effect of IMF By. While more research is needed to confirm these specific findings, our results demonstrate how ionospheric observations can be used to infer magnetospheric morphology, and that the displacement field is a critical component for understanding geospace as a coupled two-hemisphere system.

The previous study has indicated that the interplanetary magnetic field (IMF) By and solar wind flow speed (Vsw) have crucial effects on the cusp auroral intensity in the Northern Hemisphere. However, it is not clear how these factors influence the cusp aurora in the Southern Hemisphere. Using DMSP/SUSSI observations from 2004 to 2017 during non‐storm periods, we compared the factors affecting the intensity of cusp aurora between the Northern and Southern Hemispheres by dividing the observations into weak‐ and intense‐emission events. We found that the auroral intensity in the southern cusp: (a) has a positive correlation with solar wind power input, (b) is statistically weak under southward IMF conditions, and (c) is critically controlled by the IMF By and Vsw. These results are essentially consistent with those obtained in the Northern Hemisphere. However, the IMF By effect shows apparent interhemispheric asymmetry, that is, the IMF By effect reaches the maximum at 2 nT in the Northern Hemisphere, but at −2 nT in the Southern Hemisphere. Further analysis shows that the 2‐nT deviations disappear after dividing all events by season and the IMF By distributions of intense‐emission events show clear seasonal difference. Based on these results, we suggest that the dependence of the cusp auroral intensity on the IMF By is not only controlled by −Vsw × By field, but also affected by season. Plain Language Summary: As one of the most important regions in the magnetosphere, the polar cusp is the direct entry of the solar wind particles entering the Earth. The cusp aurora is produced by the interaction of the solar wind particles and the neutral particles in the upper atmosphere. Therefore, the intensity of the cusp aurora is significantly influenced by solar wind power input. According to previous research, solar wind power input can be well measured by the solar wind speed, the interplanetary field magnitude, and the IMF direction together, and the dependence of the cusp auroral intensity on these factors has also been widely investigated. A recent work statistically analyzed the occurrence conditions, that is, the solar wind and IMF conditions, for "auroral midday gap" observed above the Northern Hemisphere. It revealed that the IMF By component is vital in enhancing the auroral emissions near the cusp. However, whether these factors have the same effects in the Southern Hemisphere is still unclear. In this study, we made an interhemispheric comparison of the interplanetary factors affecting the cusp auroral intensity. Some new results were obtained, and they are important for fully understanding the cusp aurora. Key Points: Among factors deciding solar wind power input, the IMF By is confirmed to critically control cusp auroral intensity in both hemispheresThe dependence of the cusp aurora on the IMF By shows clear interhemispheric asymmetry and seasonal differenceThe interhemispheric asymmetry of the IMF By effect is affected by both the −Vsw × By electric field and the season [ABSTRACT FROM AUTHOR]

Cortical asymmetry is one of the fundamental but not fully understood feature of the brain. Special attention in modern research is paid to manual asymmetry, studied using biomechanical and neurophysiological analysis. To determine the kinematic differences between the dominant and non-dominant hands in healthy volunteers when performing a simple functional automated task-oriented movement. The study included 10 healthy volunteers aged 24 to 42 years, 4 women, 6 men. Biomechanical assessment was carried out using the video motion analysis system "Biosoft-3D." As a movement paradigm was chosen reaching, grasping a glass from the table and drinking imitation, performed alternately with the right (dominant) and left (non-dominant) hand. Tatistically significant differences of angles and angular velocities were observed on short segments of the trajectory of movement in the shoulder and wrist joints. The analysis of the angular velocity variability showed that the variability in the left hand was significantly higher than in the right (p < 0.05). The data obtained allow us to conclude that, in general, the movements of the right (dominant) and left (non-dominant) hand when performing a task-oriented movement differ only during short parts of movement and have a non-linear character. [ABSTRACT FROM AUTHOR]

Justification. Mental retardation is a persistent decrease in human cognitive activity against the background of organic damage to the central nervous system. Neurophysiological diagnostics, in particular electroencephalography (EEG), most adequately reflects the morpho-functional state of the central nervous system, which is the basis of the mechanisms of mental activity, and the originality of the bioelectrical activity of the brain can be considered as the main indicator that determines a decrease in the level of intellectual development and, thereby, characterizes this state. This provision actualizes the search for highly informative indicators of the originality of the bioelectrical activity of the brain in children with intellectual disabilities. Purspose. With the use of periodometric analysis investigate EEG’s indicators and interhemispheric asymmetry of rhythms amplitudes in MR patients. Materials and methods. The EEG was recorded in a state of calm wakefulness with closed eyes with Neuron-Spectrum-2 electroencephalograph. Differences in indicators were tracked using the calculation of the coefficient of compliance (CC), EEG functional asymmetry coefficients in amplitude were determined, too. Results. It was revealed that in MR patients the amplitudes of the rhythms were greater than in healthy subjects. The greatest increase was determined in theta rhythm in the anterior temporal and posterior temporal leads in the left hemispheres. Duration indices in the delta, theta and alpha ranges of the EEG in mental retardation compared with the control group were increased, and the indices of the duration of beta rhythms - decreased. When analyzing FMPA in MR persons it turned out that in right-handers the negativeness of FMPA indices increased, and in left-handers there was an increase in the positivity of FMPA indices. Conclusions 1. With mental retardation, the amplitudes of the rhythms were greater than in healthy people. The greatest increase was determined in theta rhythm in the anterior temporal and posterior temporal leads in the left hemispheres. 2. The indices of duration in the delta, theta and alpha ranges of the EEG of MR subjects were increased, and the indices of the duration of beta rhythms – decreased. 3. When analyzing FMPA in MR persons, it turned out that in right-handers the negativeness of FMPA indices increased, and in left-handers there was an increase in the positivity of FMPA indices.

The GPS observation data measured at GXUN (22.84°N, 108.33°E, MLAT ~ 12.14°N) and BAKO (6.49°S, 106.84°E, MLAT ~ 17.18°S) stations from 2006 to 2015 are utilized to make a comparative study of the northern and southern equatorial ionization anomaly (EIA) crests in the East-Asian sector. The intensity of northern EIA crest is similar to that of southern EIA crest during the solar minimum years, while during the solar maximum years, the intensity of northern EIA crest is a little stronger than that of southern EIA crest except in summer season of northern hemisphere. The geomagnetic latitude (MLAT) of northern EIA crest shows a weak semiannual variation with the highest in equinoctial months and the lowest in solistical months, but the MLAT of southern EIA crest shows a clear annual variation with the highest in summer season of southern hemisphere and the lowest in winter season of southern hemisphere, which is particularly obvious during the solar minimum years. The intensities of northern and southern EIA crests have good correlation, which is independent of the solar activity, but the correlation coefficients of MLAT between northern and southern EIA crests increase with the solar activity. A comprehensive analysis of the previous studies and our results indicate that the intensity, MLAT, and interhemispheric asymmetry of EIA crest are mainly dominated by photochemical process, equatorial fountain effect, and neutral wind, respectively. [ABSTRACT FROM AUTHOR]

Abstract Background The purpose of this review is to provide a comprehensive overview of the findings of clinical electrophysiology studies aimed to investigate changes in information processing of migraine with aura patients. Main body Abnormalities in alpha rhythm power and symmetry, the presence of slowing, and increased information flow in a wide range of frequency bands often characterize the spontaneous EEG activity of MA. Higher grand-average cortical response amplitudes, an increased interhemispheric response asymmetry, and lack of amplitude habituation were less consistently demonstrated in response to any kind of sensory stimulation in MA patients. Studies with single-pulse and repetitive transcranial magnetic stimulation (TMS) have reported abnormal cortical responsivity manifesting as greater motor evoked potential (MEP) amplitude, lower threshold for phosphenes production, and paradoxical effects in response to both depressing or enhancing repetitive TMS methodologies. Studies of the trigeminal system in MA are sparse and the few available showed lack of blink reflex habituation and abnormal findings on SFEMG reflecting subclinical, probably inherited, dysfunctions of neuromuscular transmission. The limited studies that were able to investigate patients during the aura revealed suppression of evoked potentials, desynchronization in extrastriate areas and in the temporal lobe, and large variations in direct current potentials with magnetoelectroencephalography. Contrary to what has been observed in the most common forms of migraine, patients with familial hemiplegic migraine show greater habituation in response to visual and trigeminal stimuli, as well as a higher motor threshold and a lower MEP amplitude than healthy subjects. Conclusion Since most of the electrophysiological abnormalities mentioned above were more frequently present and had a greater amplitude in migraine with aura than in migraine without aura, neurophysiological techniques have been shown to be of great help in the search for the pathophysiological basis of migraine aura.

Here we analyze the impact of projected climate change on plankton ecology in all major ocean biomes over the 21st century, using a multidecade (1880–2090) experiment conducted with the Community Climate System Model (CCSM-3.1) coupled ocean-atmosphere-land-sea ice model. The climate response differs fundamentally in the Northern and Southern Hemispheres for diatom and small phytoplankton biomass and consequently for total biomass, primary, and export production. Increasing vertical stratification in the Northern Hemisphere oceans decreases the nutrient supply to the ocean surface. Resulting decreases in diatom and small phytoplankton biomass together with a relative shift from diatoms to small phytoplankton in the Northern Hemisphere result in decreases in the total primary and export production and export ratio, and a shift to a more oligotrophic, more efficiently recycled, lower biomass euphotic layer. By contrast, temperature and stratification increases are smaller in the Southern compared to the Northern Hemisphere. Additionally, a southward shift and increase in strength of the Southern Ocean westerlies act against increasing temperature and freshwater fluxes to destratify the water-column. The wind-driven, poleward shift in the Southern Ocean subpolar-subtropical boundary results in a poleward shift and increase in the frontal diatom bloom. This boundary shift, localized increases in iron supply, and the direct impact of warming temperatures on phytoplankton growth result in diatom increases in the Southern Hemisphere. An increase in diatoms and decrease in small phytoplankton partly compensate such that while total production and the efficiency of organic matter export to the deep ocean increase, total Southern Hemisphere biomass does not change substantially. The impact of ecological shifts on the global carbon cycle is complex and varies across ecological biomes, with Northern and Southern Hemisphere effects on the biological production and export partially compensating. The net result of climate change is a small Northern Hemisphere-driven decrease in total primary production and efficiency of organic matter export to the deep ocean.

Patients suffering from manganese encephalopathy, which develops while taking surrogate drugs, suffer from pronounced subcortical pseudobulbar syndrome, pyramidal insufficiency and a complex of autonomic disorders. The most pronounced of them are disorders of motor functions. The work is devoted to the study of the bioelectrical activity of the brain of patients with manganese encephalopathy in order to develop an EEG-criterion for diagnosing this disease. The subjects underwent EEG recording using a 16-channel electroencephalograph "NeuroCom standart" (KhAI-Medika, Ukraine) in accordance with the international recording system "10-20". The following were analyzed: the power of the signals of the main rhythms of the background EEG, the relative characteristics of the power of the signals of the main EEG rhythms – the activation coefficient of the cortex, the activation coefficient of the sub cortex, the indices of interhemispheric asymmetries in terms of the power of bioelectric signals in bilaterally synchronous points of the head. It was found that in patients with manganese encephalopathy both the cortical activation coefficients and the sub cortex activation coefficients had values that can be observed in patients with аnother diseases. In turn, such indicators as interhemispheric asymmetry in the power of signals of individual rhythms and interhemispheric asymmetry in the total power of signals at bilaterally synchronous points of the head in patients with manganese encephalopathy had values that significantly differed from those in patients with other types of pathology. So, with indicators of 16-18 interhemispheric asymmetries in healthy people and 9-25 in patients in coma, in patients with manganese encephalopathy, it was observed: in one patient – 12 interhemispheric asymmetries, in the other of the patients – 9, 7, 3 and 2 interhemispheric asymmetries in signal power of individual rhythms at bilaterally synchronous points of the head. The reason for such a pronounced smoothing of interhemispheric asymmetries in patients with manganese encephalopathy, obviously, may be those destructive changes in the subcortical parts of the GM that are present in this group of patients. [ABSTRACT FROM AUTHOR]

Emotional decoding and automatic identification of major depressive disorder (MDD) are helpful for the timely diagnosis of the disease. Electroencephalography (EEG) is sensitive to changes in the functional state of the human brain, showing its potential to help doctors diagnose MDD. In this paper, an approach for identifying MDD by fusing interhemispheric asymmetry and cross-correlation with EEG signals is proposed and tested on 32 subjects [16 patients with MDD and 16 healthy controls (HCs)]. First, the structural features and connectivity features of the θ-, α-, and β-frequency bands are extracted on the preprocessed and segmented EEG signals. Second, the structural feature matrix of the θ-, α-, and β-frequency bands are added to and subtracted from the connectivity feature matrix to obtain mixed features. Finally, the structural features, connectivity features, and the mixed features are fed to three classifiers to select suitable features for the classification, and it is found that our mode achieves the best classification results using the mixed features. The results are also compared with those from some state-of-the-art methods, and we achieved an accuracy of 94.13%, a sensitivity of 95.74%, a specificity of 93.52%, and an F1-score (f1) of 95.62% on the data from Beijing Anding Hospital, Capital Medical University. The study could be generalized to develop a system that may be helpful in clinical purposes.

We undertook this observational study among 435 patients (365 men and 70 women) who were divided into 3 groups based on the severity of the brain damage (clinical features and results of neuropsychological assessment, magnetic resonance imaging, electroenchephalography, transcortical Doppler): 1. Patients with alcohol dependence syndrome F10.2х) without comorbid psychiatric disorders; 2. Patients with alcohol dependence syndrome F10.2х) and mild comorbid organic brain disorder F06.7x; 3. Patients with alcohol dependence syndrome F10.2х) and moderate comorbid organic brain disorder (F06.7x). We assessed the severity of emotional disorders, alexithymia and interhemispheric asymmetry and compared these features between the groups. We found that the severity of the organic brain damage play important role in the association between the interhemispheric asymmetry and the severity of emotional disorders and alexithymia in patients with alcohol dependence. The complex analysis of the data shown that left-handedness and a functional asymmetry toward the left are the protective factors for the emotional disorders and alexithymia in the group of patients without organic brain disorder. Moreover, right-sided cerebral deficiency and a functional asymmetry toward the right are associated with higher risk of the emotional disorders in patients with alcohol dependence.

The magnetogram inversion technique (MIT), developed at ISTP SB RAS more than forty years ago, has been used until recently only in the Northern Hemisphere. In recent years, MIT has been improved and extended to make instantaneous calculations of 2D distributions of electric fields, horizontal and field-aligned currents in two polar ionospheres. The calculations were carried out based on one-minute ground-based geomagnetic measurements from the worldwide network of stations in both hemispheres (SuperMAG). In this paper, this extended technique is used in the approximation of uniform ionospheric conductance and is applied for the first time to calculations of equivalent and field-aligned currents in two hemispheres through the example of the August 17, 2001 geomagnetic storm. We have obtained the main and essential result: the advanced MIT-ISTP can calculate large-scale distributions of ionospheric convection and FACs in the Northern (N) and Southern (S) polar ionospheres with a high degree of expected hemispheric similarity between these distributions. Using the said event as an example, we have established that the equivalent and field-aligned currents obtained with the advanced technique exhibit the expected dynamics of auroral electrojets and polar caps in two hemispheres. Hall current intensities in polar caps and auroral electrojets, calculated from the equivalent current function, change fairly synchronously in the N and S hemispheres throughout the magnetic storm. Both (westward and eastward) electrojets of the N hemisphere are markedly more intense than respective electrojets of the S hemisphere, and the Hall current in the north polar cap is almost twice as intense as that in the south one. This interhemispheric asymmetry is likely to be due to seasonal conductance variations, which is implicitly contained in the current function. From FAC distributions we determine auroral oval boundaries and calculate magnetic fluxes through the polar caps in the N and S hemispheres. These magnetic fluxes coincide with an accuracy of about 5% and change almost synchronously during the magnetic storm. In the N hemisphere, the magnetic flux in the dawn polar cap is more intense that that in the dusk one, and vice versa in the S hemisphere. These asymmetries (dawn–dusk and interhemispheric) in the polar caps are consistent with the theory of reconnection for IMF By>0 and with satellite images of auroral ovals; both of these asymmetries decrease during the substorm expansion phase.

In this study we use the CHAMP wind observations from 2002 to 2004 to investigate features of mid-latitude thermospheric winds at low and high geomagnetic activity levels. The winds are observed between the geomagnetic latitudes 40–50° north or south within an altitude range of 370–450 Km and averaged longitudinally. The low geomagnetic activity level wind generally leads eastward in both hemispheres for all the seasons. Maximum westward speeds going above 100 m/s are observed at all levels of geomagnetic activity. Most investigations on F-region parameters assume the equinoxes are fundamentally the same. A first time separation of Equinox season using CHAMP winds reveals equinoctial asymmetric behavior of the wind speed at the two levels considered. Interhemispheric asymmetry in neutral wind behaviour is clearly evident in the solstice seasons with local winds considered in each of the hemispheres. This is consistent with asymmetry in the amount of solar illumination received in each of the hemispheres and differences in the magnetic field strength at magnetically conjugate regions. [ABSTRACT FROM AUTHOR]

Anthropogenic aerosols, concentrated largely in the Northern Hemisphere, not only affect the local climate but also induce pronounced changes in atmospheric circulation that extend into the Southern Hemisphere (SH). In coupled historical single‐forcing simulations, aerosol forcing induces a deceleration of both the subpolar jet (SPJ) and the subtropical jet (STJ) in SH in austral winter. Atmospheric general circulation model experiments indicate that the STJ is weakened by an interhemisphere gradient in the zonal mean sea surface temperature (SST) and an anomalous cross‐equatorial Hadley circulation, while the SPJ response shares similar feedbacks with the greenhouse gas forcing. Specifically, atmospheric eddy adjustments are important for the SPJ change. The atmospheric response unique to anthropogenic aerosol forcing (e.g., cross‐equatorial Hadley cell and the weakened SH STJ) can be exploited for climate change attribution. Plain Language Summary: Anthropogenic increase in aerosol concentrations in the Northern Hemisphere caused not only severe local air pollution but also atmospheric circulation changes as far away as in the Southern Hemisphere. Climatologically, the Southern Hemisphere westerlies show significant seasonal variation; the subtropical jet dominates the upper troposphere during austral winter but diminishes in austral summer. In contrast, the subpolar jet is zonally symmetric and strong in austral summer, but it weakens and exists only over the South Pacific in austral winter. The present study examines austral winter Southern Hemisphere subpolar and subtropical jet responses to historical aerosol forcing over the past century in climate model simulations. Results show that the subpolar and subtropical jets both weaken with little shift in latitudinal position. By reflecting the solar irradiation, the aerosols reduce the sea surface temperature more in the Northern than the Southern Hemisphere. We demonstrate that the hemispheric contrast in the sea surface temperature change induces an anomalous interhemispheric overturning circulation that slows the subtropical jet. Greenhouse gas forcing also influences the Southern Hemisphere westerlies, but with distinct spatial patterns and mechanisms compared to anthropogenic aerosols. Key Points: The Southern Hemisphere atmospheric circulation change is identified in response to anthropogenic aerosol forcingThe aerosol forcing weakens the subtropical jet and strengthens the subpolar jet due to the interhemisphere asymmetric SST responseThe spatially uniform cooling effect of aerosols induces a subpolar and subtropical jet change similar to the GHG effect with sign reversed [ABSTRACT FROM AUTHOR]

Emotional decoding and automatic identification of major depressive disorder (MDD) are helpful for the timely diagnosis of the disease. Electroencephalography (EEG) is sensitive to changes in the functional state of the human brain, showing its potential to help doctors diagnose MDD. In this paper, an approach for identifying MDD by fusing interhemispheric asymmetry and cross-correlation with EEG signals is proposed and tested on 32 subjects [16 patients with MDD and 16 healthy controls (HCs)]. First, the structural features and connectivity features of the θ-, α-, and β-frequency bands are extracted on the preprocessed and segmented EEG signals. Second, the structural feature matrix of the θ-, α-, and β-frequency bands are added to and subtracted from the connectivity feature matrix to obtain mixed features. Finally, the structural features, connectivity features, and the mixed features are fed to three classifiers to select suitable features for the classification, and it is found that our mode achieves the best classification results using the mixed features. The results are also compared with those from some state-of-the-art methods, and we achieved an accuracy of 94.13%, a sensitivity of 95.74%, a specificity of 93.52%, and an F1-score (f1) of 95.62% on the data from Beijing Anding Hospital, Capital Medical University. The study could be generalized to develop a system that may be helpful in clinical purposes. [ABSTRACT FROM AUTHOR]

Objective: To compare the interhemispheric asymmetry of the motor cortex excitability of chronic stroke patients with healthy and to observe if the magnitude of this asymmetry is associated to sensory-motor impairment and stroke chronicity. Methods: This cross-sectional study was performed with chronic stroke and aged and sex-matched healthy individuals. The interhemispheric asymmetry index was calculated by the difference of rest motor threshold (rMT) of the brain hemispheres. The rMT was assessed by transcranial magnetic stimulation over the cortical representation of the first dorsal interosseous muscle. To investigate the relationship of the asymmetry with sensory-motor impairment and injury chronicity, the stroke patients were grouped according to the level of sensory-motor impairment (mild/moderate, moderate/severe, and severe) and different chronicity stages (> 3–12, 13–24, 25–60, and > 60 months since stroke). Results: Fifty-six chronic stroke and twenty-six healthy were included. We found higher interhemispheric asymmetry in stroke patients (mean, 27.1 ± 20.9) compared to healthy (mean, 4.9 ± 4.7). The asymmetry was higher in patients with moderate/severe (mean, 35.4 ± 20.4) and severe (mean, 32.9 ± 22.7) impairment. No difference was found between patients with mild/moderate impairment (mean, 15.5 ± 12.5) and healthy. There were no differences of the interhemispheric asymmetry between patients with different times since stroke (> 3–12, mean, 32 ± 18.1; > 13–24, mean, 20.7 ± 16.2; > 25–60, mean, 29.6 ± 18.1; > 60 months, mean, 25.9 ± 17.5). Conclusion: Stroke patients showed higher interhemispheric asymmetry of the motor cortex excitability when compared to healthy, and the magnitude of this asymmetry seems to be correlated with the severity of sensory-motor impairment, but not with stroke chronicity. Significance: Higher interhemispheric asymmetry was found in stroke patients with greatest sensory-motor impairment. [ABSTRACT FROM AUTHOR]

Simultaneous eastward and westward traveling surges were observed at Tjörnes, Iceland, and Syowa station, Antarctica, respectively. Several remarkable differences were identified. (1) The position of the initial bright spot was shifted by 1.7 to 2.3 MLT between both hemispheres. (2) The surges differ in traveling speed between the eastward traveling surge (6.5 km s−1) and the westward traveling surge (1.3 km s−1). (3) The Arase satellite was located on a geomagnetic field line connecting both ground stations and observed a significant excess in westward component of the magnetic field, which is consistent with the large shifts of the initial bright spots in both hemispheres. (4) The background Hall current flows eastward (Northern Hemisphere) and westward (Southern Hemisphere). The observed north‐south asymmetry of the traveling surges suggests that the ionosphere can play an essential role in controlling the fundamental spatiotemporal development of auroras in both hemispheres. Plain Language Summary: Occasionally, the aurora suddenly brightens in local areas of the Northern and Southern Hemispheres, causing explosive and widespread phenomena. At this time, it is known that a part of the aurora travels toward east or west from the point of the explosion; however, the formation mechanism of this traveling aurora is unknown. Recently, this traveling aurora has been reproduced by computer simulation, and it has been shown that the direction of its traveling is determined by the state of the ionosphere rather than by the projected motion of the source region in the magnetosphere. In this paper, we observed traveling auroras with two identical high‐speed cameras installed in the Northern and Southern Hemispheres simultaneously and clarified for the first time that the state of the ionosphere determines the direction of the traveling aurora. Understanding the mechanism of such connection between the space and the Earth is important for predicting the space environment required for various human activities and technologies using the space. Key Points: An auroral breakup was captured simultaneously by ground‐based all‐sky cameras at magnetically conjugate stations in both hemispheresThe auroral surge evolved asymmetrically regarding the longitudinal direction in both hemispheresThe surge evolved in the direction of the ionospheric Hall current, which is consistent with the expectation from a global simulation [ABSTRACT FROM AUTHOR]

Processing of acoustic space in the human auditory system implicates the interaction of the left and right hemispheres of the brain. In this study, we investigated the influence of the position and motion direction of sound stimuli on the amplitude and latency of N1, P2, MMN, and P3a components of auditory evoked potentials in the left and right brain hemispheres. The data suggest that functional asymmetry of the N1P2 complex and difference waveforms can be described as weak contralateral dominance. Deviants moving from the lateral positions evoked later P3a components than those moving from the midline, which is consistent with the concept of higher localization accuracy in the frontal part of the acoustic space. The motion direction affected the MMN and P3a latency: the centrifugal deviants produced earlier MMN and P3a responses than the centripetal deviants. This could result from a stronger orienting reaction caused by stimuli moving from the center towards the periphery as compared with the opposite direction. [ABSTRACT FROM AUTHOR]

Interplanetary (IP) shocks drive magnetosphere‐ionosphere (MI) current systems that in turn are associated with ground magnetic perturbations. Recent work has shown that IP shock impact angle plays a significant role in controlling the subsequent geomagnetic activity and magnetic perturbations; for example, highly inclined shocks drive asymmetric MI responses due to interhemispherical asymmetric magnetospheric compressions, while almost head‐on shocks drive more symmetric MI responses. However, there are few observations confirming that inclined shocks drive such asymmetries in the high‐latitude ground magnetic response. We use data from a chain of Antarctic magnetometers, combined with magnetically conjugate stations on the west coast of Greenland, to test these model predictions (Oliveira & Raeder, 2015, https://doi.org/10.1002/2015JA021147; Oliveira, 2017, https://doi.org/10.1007/s13538-016-0472-x). We calculate the time derivative of the magnetic field (∂B/∂t) in each hemisphere separately. Next, we examine the ratio of Northern to Southern Hemisphere ∂B/∂t intensities and the time differences between the maximum ∂B/∂t immediately following the impact of IP shocks. We order these results according to shock impact angles obtained from a recently published database with over 500 events and discuss how shock impact angles affect north‐south hemisphere asymmetries in the ground magnetic response. We find that the hemisphere the shock strikes first usually has (1) the first response in ∂B/∂t and (2) the most intense response in ∂B/∂t. Additionally, we show that highly inclined shocks can generate high‐latitude ground magnetic responses that differ significantly from predictions based on models that assume symmetric driving conditions. Key Points: High latitude interhemispheric comparisons are performed to study asymmetries in ground magnetic perturbations caused by shock inclinationsThe hemisphere the shock strikes first usually has (1) the first response in ∂B/∂t and (2) the most intense response in ∂B/∂tImpact angles are an important parameter controlling the timing and intensity of the ground magnetic response to interplanetary shocks [ABSTRACT FROM AUTHOR]

Brain-computer interfaces (BCIs), based on motor imagery, are increasingly used in neurorehabilitation. However, some people cannot control BCI, predictors of this are the features of brain activity and personality traits. It is not known whether the success of BCI control is related to interhemispheric asymmetry. The study was conducted on 44 BCI-naive subjects and included one BCI session, EEG-analysis, 16PF Cattell Questionnaire, estimation of latent left-handedness, and of subjective complexity of real and imagery movements. The success of brain states recognition during imagination of left hand (LH) movement compared to the rest is higher in reserved, practical, skeptical, and not very sociable individuals. Extraversion, liveliness, and dominance are significant for the imagination of right hand (RH) movements in “pure” right-handers, and sensitivity in latent left-handers. Subjective complexity of real LH and of imagery RH movements correlates with the success of brain states recognition in the imagination of movement of LH compared to RH and depends on the level of handedness. Thus, the level of handedness is the factor influencing the success of BCI control. The data are supposed to be connected with hemispheric differences in motor control, lateralization of dopamine, and may be important for rehabilitation of patients after a stroke.

In this study we use high‐quality convection data from the Electron Drift Instrument on board Cluster to investigate how near‐Earth tail activity affects the average convection pattern in the magnetotail lobes when the interplanetary magnetic field has a dominating east‐west (By) component. Two different proxies have been used to represent different levels of reconnection in the near‐Earth tail: The value of the AL index and the substorm phases identified by the Substorm Onsets and Phases from Indices of the Electrojet algorithm. We find that the convection changes from a dominantly YGSM direction, but opposite in the two hemispheres, to a flow oriented more toward the plasma sheet, as the north‐south component of the convection increases when reconnection enhances in the near Earth tail. This result is consistent with recent observations of the convection in the ionosphere, which suggest that the nightside convection pattern becomes more north‐south symmetric when tail reconnection increases. This is also supported by simultaneous auroral observations from the two hemispheres, which shows that conjugate auroral features become more symmetric during substorm expansion phase. The reduced asymmetry implies that the asymmetric pressure balance in the lobes is altered during periods with strong reconnection in the near‐Earth tail. Key Points: Average lobe convection when IMF By≠0 is more north‐south aligned for high |AL| compared to low |AL|Average lobe convection when IMF By≠0 is more north‐south aligned during substorms compared to nonsubstorm intervalsThe more north‐south aligned convection implies that enhanced near‐Earth tail reconnection alters the average lobe convection [ABSTRACT FROM AUTHOR]

The present study investigates the dependence of the local auroral electrojet (AEJ) intensity on solar illumination by statistically examining northward geomagnetic disturbances in the auroral zone in terms of the solar zenith angle χ. It is found that on the dayside, both westward and eastward electrojets (WEJ and EEJ) are more intense for smaller χ, suggesting that the solar extreme ultraviolet‐induced conductance is the dominant factor for the AEJ intensity. On the nightside, in contrast, the χ dependence of the AEJ intensity, if sorted solely by the magnetic local time, apparently depends on the station longitude and hemisphere. However, if additionally sorted by the dipole tilt angle ψ, a consistent pattern emerges. That is, although χ and ψ are correlated, the solar zenith angle and dipole tilt angle have physically different effects on the AEJ intensity. The nightside AEJ, especially the WEJ, tends to be more intense for smaller |ψ|. Moreover, whereas the WEJ is statistically more intense when the ionosphere is dark, the EEJ is more intense when it is sunlit. The preference of the WEJ for the dark ionosphere prevails widely in magnetic local time from premidnight to dawn, and therefore, it cannot be attributed to the previously proposed processes of the preferred monoenergetic or broadband auroral precipitation in the dark ionosphere. Instead, it may be explained, at least morphologically, in terms of the conductance enhancement due to the diffuse auroral precipitation, which is also prevalent from premidnight to dawn and is more intense in the dark hemisphere. Key Points: The nightside westward electrojet (WEJ) is more intense when the ionosphere is dark, and the eastward electrojet (EEJ) when it is sunlitBoth WEJ and EEJ are more intense when the dipole tilt is smaller, and this effect is comparable to the effect of solar illuminationThe preference of the WEJ intensity for the dark ionosphere likely reflects that of diffuse e‐ precipitation and ionospheric conductance [ABSTRACT FROM AUTHOR]

The review presents the current understanding of interhemispheric asymmetry of the human brain activity, recorded by electrophysiological and hemodynamic methods using various sound features. Along with the anatomical differences which may exist between the auditory cortices of the left and right brain hemispheres, the authors consider how lateralization of auditory responses depends on the parameters of sound stimulation and what patterns of interhemispheric asymmetry can be found in auditory evoked potentials (AEP) elicited during spatial processing of sound stimuli. [ABSTRACT FROM AUTHOR]

The westward quasi‐6‐day planetary wave (Q6DW) with zonal wave number 1 is a prominent oscillation in the mesosphere and lower thermosphere region, which causes significant variabilities in the ionosphere through E region wind dynamo. In this paper, the neutral wind observations from the Thermosphere Ionosphere and Mesosphere Electric Dynamics Doppler Imager experiment, the kinetic temperature observations from the Sounding of the Atmosphere using Broadband Emission Radiometry instrument, and the total electron content (TEC) maps from globally distributed Global Positioning System (GPS) receivers during 2003–2017 are utilized to statistically study the Q6DW in both the neutral atmosphere and the ionosphere. Our statistical results show that (1) the Q6DW is most likely to occur during May and September, exhibiting a quasi‐semiannual oscillation. (2) The periods of the Q6DW show two statistical crests at ~6 and ~7 days separately. (3) The ionospheric oscillations due to the Q6DW are positively related to both the 10.7‐cm solar flux index and the neutral wave amplitudes in the mesosphere and lower thermosphere region. The stronger oscillations in TEC under higher solar activity conditions are due to the larger ionization rate and thus larger background TEC. A stronger Q6DW results in stronger wind dynamos in the E region, which leads to stronger F region responses indirectly. (4) The interhemispheric asymmetries of the ionospheric responses to Q6DW show weak negative correlations with both solar activities and neutral wave perturbations, the mechanism of which needs our further investigation. Key Points: The Q6DW in both neutral atmosphere and its modulations on the ionosphere during 2003–2017 are statistically investigatedThe Q6DWs are most likely to occur during May and September with periods at ~6 and 7 days, separatelyBoth the absolute ionospheric responses and their interhemispheric asymmetries are related to solar activities and neutral wave amplitudes [ABSTRACT FROM AUTHOR]

The von Economo neurons (VEN) are characterized by a large soma, spindle-like soma, with little dendritic arborization at both, the basal and apical poles. In humans, VENs have been described in the entorhinal cortex, the hippocampal formation, the anterior cingulate cortex, the rostral portion of the insula and the dorsomedial Brodmann’s area 9 (BA9). These cortical regions have been associated with cognitive functions such as social interactions, intuition and emotional processing. Previous studies that searched for the presence of these cells in the lateral frontal poles yielded negative results. The presence of VENs in other cortical areas on the medial surface of the human prefrontal cortex which share both a common functional network and similar laminar organization, led us to examine its presence in the medial portion of the frontal pole. In the present study, we used tissue samples from five postmortem subjects taken from the polar portion of BA10, on the medial surface of both hemispheres. We found VENs in the human medial BA10, although they are very scarce and dispersed. We also observed crests and walls of the gyrus to quantitatively assess: (A) interhemispheric asymmetries, (B) the VENs/pyramidal ratio, (C) the area of the soma of VENs and (D) the difference in soma area between VENs and pyramidal and fusiform cells. We found that VENs are at least seven times more abundant on the right hemisphere and at least 2.5 times more abundant in the crest than in the walls of the gyrus. The soma size of VENs in the medial frontopolar cortex is larger than that of pyramidal and fusiform cells of layer VI, and their size is larger in the walls than in the crests. Our finding might be a contribution to the understanding of the role of these neurons in the functional networks in which all the areas in which they have been found are linked. However, the particularities of VENs in the frontal pole, as their size and quantity, may also lead us to interpret the findings in the light of other positions such as van Essen’s theory of tension-based brain morphogenesis.