Interhemispheric Asymmetry Research Articles

Персональная динамика отношения максимумов спектральных плотностей мощности альфа/дельта ритмов пациентов для оценки времени начала развития отсроченной церебральной ишемии после субарахноидального кровоизлияния

To assess the time of onset of delayed cerebral ischemia after subarachnoid hemorrhage, an approach based on personal dynamics of the ratio of the maximums of spectral densities of alpha/delta electroencephalogram rhythms in the data of long-term electroencephalographic monitoring was proposed and tested on clinical data. In contrast to the currently accepted estimation of the index based on alpha (8–13 Hz) and delta (1–4 Hz) frequency ranges averaged over the frequency ranges of rhythm powers. The proposed method is based on the calculation of the ratio of the maxima of the spectral power density in the frequency bands of alpha and delta rhythms using the calculation of Fourier spectra with a Hamming window of 3 hours. It is shown that the dynamics of the index of the ratio of maxima of spectral power densities of alpha/delta rhythms reflects the dependence of the development of delayed cerebral ischemia on a steady decrease in the index ten times more than in control patients. The results reflecting the interhemispheric asymmetry of the dynamics of the ratio of the maxima of spectral densities of alpha/delta rhythm power in patients with diagnosed delayed ischemia are presented.

Функциональная межполушарная асимметрия и нейрокогнитивное развитие у детей и подростков

<p>Many neuropsychologists believe that left-handed individuals are more likely to experience developmental disorders. In addition, non-coinciding lateralization of analyzers (cross-laterality) is also considered as a possible factor in dysontogenesis. However, in recent years it has been demonstrated that functional interhemispheric asymmetry (FIA) has minimal impact on intelligence and quality of life. This study aims to measure the contribution of manual and visual asymmetries to the overall level of neurocognitive development (ND) in children and adolescents. A total of 922 individuals were studied, including 594 boys and 328 girls aged 4–17 years, who underwent neuropsychological diagnostics. The scale of general level of development from the psychometric battery “Multifactorial Investigation of Neuropsychological Development” was used. The measurement of seven FIA indicators was carried out by observing subjects and assessing the performance on five techniques for lateral signs. No significant influence on ND was found for FIA and cross-lateralization. In some age groups, lateral signs were associated with ND, but this association was not stable. Additionally, it was shown that the results of techniques for lateral signs are inconsistent with each other.</p>

Asymmetry of the Frontal Aslant Tract and Development of Supplementary Motor Area Syndrome.

Background/Objectives: The purpose of this study was to investigate preoperative interhemispheric differences of the FAT in relation to the onset of postoperative SMA syndrome. Methods: This was a single-center retrospective analysis of patients who underwent surgical resection of diffuse gliomas involving the SMA between 2018 and 2022. Inclusion criteria were availability of preoperative and postoperative Magnetic Resonance Imaging, no previous surgery, and no neurological deficits at presentation. Diffusion-weighted data were processed by spherical deconvolution (SD) and diffusion tensor imaging tractography algorithms, and TrackVis was used to dissect the FAT of both hemispheres. The FAT data were analyzed for correlation with postoperative SMA syndrome onset. Results:N = 25 cases were included in the study, among which n = 23 had preoperative bilaterally identifiable FAT by SD. N = 12 developed an SMA syndrome, 6 demonstrated a motor-only syndrome, 4 had a verbal-only syndrome, and 2 had mixed verbal and motor features. The SMA syndrome incidence was significantly more frequent in lower-grade gliomas (p = 0.005). On the tumor side, the FAT identified by SD was smaller than the contralateral (mean volume 6.53 cm3 and 13.33 cm3, respectively, p < 0.001). In the 6 cases that developed a verbal SMA syndrome, a normalized FAT volume asymmetry (FAT-VA) demonstrated an asymmetry shifted towards the non-dominant side (mean FAT-VA = -0.68), while the cases with no postoperative verbal impairment had opposite asymmetry towards the dominant side (mean FAT-VA = 0.42, p = 0.010). Conclusions: Preoperative interhemispheric FAT volume asymmetry estimated according to functional dominance can predict postoperative onset of verbal SMA syndrome, with proportionally smaller FAT on the affected dominant hemisphere.

Interhemispheric Asymmetry in the High-Latitude Neutral Density Variations During the 13-14 March 2022 Storm.

During the second recovery phase of the 13-14 March 2022 storm, intense high-latitude neutral mass density spikes are detected by satellites at ∼500km in both hemispheres. These density spikes, accurately modeled by the Global Ionospheric Thermosphere Model (GITM), are identified as high-latitude neutral mass density anomalies (HDAs). The GITM simulation indicates that these HDAs, which extends over the polar region, are important features in high-latitude neutral density. Furthermore, GITM reveals that these HDAs are manifestations of transpolar traveling atmospheric disturbances triggered on the dawn side. Moreover, GITM also reveals significant interhemispheric asymmetries (IHAs) in the magnitude, propagation speed, and propagation direction of HDAs, which are linked to the IHAs in the distribution and magnitude of Joule heating deposited as well as the thermospheric background conditions. This study presents a dynamic perspective on the IHA of storm-time high-latitude neutral density variations that is particularly helpful to the proper interpretation of satellite observations.

Mid-holocene changes in the global ITCZ: meridional structure and land–sea rainfall differences

Changes in the global and annual Intertropical Convergence Zone (ITCZ) during the mid-Holocene are quantified in this study, using simulations from the Paleoclimate Modelling Intercomparison Project Phase 4. We find an ensemble mean northward migration of ITCZ position by 0.2∘\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^\\circ $$\\end{document}, 0.3∘\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^\\circ $$\\end{document}, and 0.8∘\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^\\circ $$\\end{document} using three different metrics, which is consistent with proxy evidence of a slight (within one degree) northward shift during the mid-Holocene. The width of the ITCZ exhibits no changes during this period, while the strength has a minor weakening by 0.9% and 0.6% based on precipitation and streamfunction metrics, respectively. Moreover, there is an ensemble mean increase in northern-to-southern hemisphere precipitation (4.6%) and ω\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\omega $$\\end{document} ratio indices (12%) during the mid-Holocene, suggesting a more uneven and right-skewed meridional structure of the ITCZ with a greater asymmetry. Additionally, the moisture budget analysis indicates the eddy flux term and dynamic term primarily enhance the inter-hemispheric asymmetry of precipitation and poleward migration of both the northern and the southern rain belts within the ITCZ. Further investigation reveals that the northward migration of annual rainfall within the ITCZ predominantly occurs over terrestrial regions, which therefore dominate the change towards more asymmetric structure of the zonally averaged ITCZ. Moisture budgets for land and ocean separately indicate that the land-sea difference in the annual rainfall changes is primarily due to different changes in evaporation.

Combining Temperature and Precipitation to Constrain the Aerosol Contribution to Observed Climate Change

Abstract Using the past to improve future predictions requires an understanding and quantification of the individual climate contributions to the observed climate change by aerosols and greenhouse gases (GHGs), which is hindered by large uncertainties in aerosol forcings and responses across climate models. To estimate historical aerosol responses, we apply detection and attribution methods to attribute a joint change in temperature and precipitation to forcings by combining signals of observed changes in tropical wet and dry regions, the interhemispheric temperature asymmetry, global mean temperature (GMT), and global mean land precipitation (GMLP). Fingerprints representing the climate response to aerosols (AERs) and the remaining external forcings (noAER; mostly GHG) are derived from large ensembles of historical single- and ALL-forcing simulations from three models in phase 6 of the Coupled Model Intercomparison Project and selected using a perfect model study. Results from an imperfect model study and a hydrological sensitivity analysis support combining our choice of temperature and precipitation fingerprints into a joint study. We find that diagnostics including temperature and precipitation slightly better constrain the noAER signal than diagnostics based purely on temperature or GMT-only and allow for the attribution of AER cooling (even when GMT is not included in the fingerprint). These results are robust across fingerprints from different climate models. Estimated contributions for AER and noAER agree with other published estimates including those from the most recent IPCC report. Finally, we attribute the best estimate of 0.46 K ([−0.86, −0.05] K) of aerosol-induced cooling and 1.63 K ([1.26, 2.00] K) of noAER warming in 2010–19 relative to 1850–1900 using the combined signals of GMT and GMLP. Significance Statement Aerosols are small liquid or solid airborne particles. They are predominantly the secondary result of emissions of aerosol precursor gases emitted via industrial or natural processes. While greenhouse gases warm the climate, aerosols can have a cooling effect on the climate system, thus offsetting some of the greenhouse gas–related warming. We expect greenhouse gas concentrations in the atmosphere to continue to increase, while aerosol concentrations are likely going to decline due to their impacts on human health. Our study uses observed temperature and precipitation changes to quantify how much aerosols have offset warming from past greenhouse gas emissions. This can help constrain future predictions of global warming.

Support vector machine classification of patients with depression based on resting-state electroencephalography.

Depression is one of the most common mental disorders. Although depression is typically diagnosed by identifying specific symptoms and through history, no recognized standard for depression diagnosis exists. This assures the development of objective diagnostic tools for depression. We investigated the differences in the resting-state electroencephalograms (EEGs) of patients with depression and healthy controls (HCs) to distinguish patients from HCs by using a support vector machine (SVM) classifier with the following two feature selection approaches: t test and receiver operating characteristic analysis. We used the EEG data from the Patient Repository of EEG Data + Computational Tools; this study included 21 patients with depressive disorder (MDD) and 21 HCs. The relative frequency power, alpha interhemispheric asymmetry, left-right coherence, strength, clustering coefficient (CC), shortest path length, sample entropy (SampEn), multiscale entropy (MSE), and detrended fluctuation analysis (DFA) data were extracted to determine candidate EEG features associated with depression. With the t-test selection, the SVM classifier demonstrated the highest performance with the accuracy, sensitivity, and specificity of 96.66%, 95.93%, and 97.550% for the eye-open condition and 91.33%, 90.59%, and 91.81% for the eye-closed condition, respectively. For comparisons of features in the 2 selection approaches, the most influential features were relative frequency power and left-right coherence. Using this information to distinguish patients with MDD from HC subjects with the SVM classifier resulted in a mean accuracy over 90%. Although this result may not be robust enough for clinical applications, further exploration is necessary given the simplicity, objectivity, and efficiency of the classifier.

Enlarged brain perivascular spaces correlate with blood plasma osmolality in the healthy population: A longitudinal study

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.

Progression of hippocampal subfield atrophy and asymmetry in Alzheimer's disease.

Alzheimer's disease (AD) affects the hippocampus during its progression, but the specific observable changes of hippocampal subfields during disease progression remain poorly understood. In this study, we employed an event-based model (EBM) to determine the sequence of occurrence of hippocampal subfield atrophy in mild cognitive impairment (MCI) and AD cohorts. Subjects (207) were included: 86 MCI, 53 AD, and 68 healthy controls from the Alzheimer's Disease Neuroimaging Initiative (ADNI). Participants underwent structural magnetic resonance imaging (MRI) scans to analyse the hippocampal subfields. We assigned each patient to a specific EBM stage, based on the number of their abnormal subfields. A combination of 2-year follow-up MRI scans were applied to demonstrate the longitudinal consistency and utility of the model's staging system. The model estimated that the earliest atrophy occurs in the hippocampal fissure, then spreading to other subregions in both MCI and AD. We identified a marked divergence between the sequences of left and right hippocampal subfields atrophy, so inter-hemispheric asymmetry pattern was further analysed. The sequence of asymmetry index (AI) increases beginning in the molecular and granule cell layers of the dentate gyrus (GC-ML-DG), cornus ammonis (CA) 4, and the molecular layer (ML). Longitudinal analysis confirms the efficacy of the model. In addition, the model stages were significantly correlated with patients' memory scores (p < .05). Collectively, we used a data-driven method to provide new insight into AD hippocampal progression. The present model could aid in understanding of the disease stages, as well as tracking memory decline.

Influence of functional brain asymmetry on coordination stability of children with intellectual disabilities

Introduction. Coordination stability is expressed in psychomotor control of motor activity by the human nervous system and in postural balance as a consequence of cortical-subcortical regulatory processes. With mental retardation, there is a violation of the integrative activity of the higher parts of the brain, a violation of the synthesis and analysis of afferent information of all mental and motor functions, and a violation of spatio-temporal interactions. It is relevant to determine the lateralization of psychomotor processes in people with intellectual disabilities as one of the predictors of understanding the relationship between motor asymmetries in the context of the mechanisms of initiation and further regulation of motor actions.The objective was to determine the nature of lateralization of psychomotor processes in children with intellectual disabilities and to identify the degree of influence on coordination stability.Methods and materials. The study involved 40 children aged 14–15 years, who were divided into 2 groups: 20 children with mild mental retardation and 20 normotypical children from a secondary school. Identification of the individual profile of functional interhemispheric asymmetry included passing 7 tests to determine the functional asymmetry of the arms and 6 tests to determine the functional asymmetry of the legs. Also 2 tests for coordination stability.Results. In normotypical schoolchildren, right-sided lateralization predominates, which indicates the dominance of the left hemisphere. In schoolchildren with mental retardation, the coefficient of manual asymmetry revealed left-sided lateralization. These features are expressed, among other things, in motor manifestations; the regulation of motor actions in some cases is uncoordinated.Conclusions. There is no specific algorithm for psychomotor control that can be observed in normotypical schoolchildren; motor skills, as well as bilateral body coordination, have reduced development.

Кластеризация эпилептиформных разрядов в индивидуальной диагностике ранней стадии отсроченной церебральной ишемии

To detect the onset of delayed cerebral ischemia after aneurysmal hemorrhage in the subarachnoid space, a clinical data method for detecting clusters of epileptiform discharges in the data of long-term electroencephalographic monitoring of patients was proposed and tested. It is based on the identification of distributions of epileptiform discharges that are continuous in time and exceed the adaptive threshold and have a clearly expressed interhemispheric asymmetry.

The first-night effect of sleep occurs over nonconsecutive nights in unfamiliar and familiar environments.

The first night in an unfamiliar environment is marked by reduced sleep quality and changes in sleep architecture. This so-called first-night effect (FNE) is well established for two consecutive nights and lays the foundation for including an adaptation night in sleep research to counteract FNEs. However, adaptation nights rarely happen immediately before experimental nights, which raises the question of how sleep adapts over nonconsecutive nights. Furthermore, it is yet unclear, how environmental familiarity and hemispheric asymmetry of slow-wave sleep (SWS) contribute to the explanation of FNEs. To address this gap, 45 healthy participants spent two weekly separated nights in the sleep laboratory. In a separate study, we investigated the influence of environmental familiarity on 30 participants who spent two nonconsecutive nights in the sleep laboratory and two nights at home. Sleep was recorded by polysomnography. Results of both studies show that FNEs also occur in nonconsecutive nights, particularly affecting wake after sleep onset, sleep onset latency, and total sleep time. Sleep disturbances in the first night happen in both familiar and unfamiliar environments. The degree of asymmetric SWS was not correlated with the FNE but rather tended to vary over the course of several nights. Our findings suggest that nonconsecutive adaptation nights are effective in controlling for FNEs, justifying the current practice in basic sleep research. Further research should focus on trait- and fluctuating state-like components explaining interhemispheric asymmetries.

Sleep apnea evokes right hemisphere dominance and psychological disorders: An exploratory study

BackgroundObstructive sleep apnea (OSA) is considered one of the major causes of sleep disorders and psychological disorders in individuals. Brain asymmetry (BA) demonstrates individual hemispheric activity and psychological disorders. This study aimed to explore the characteristics of BA and psychology in OSA. MethodsEnrolment of patients for sleep assessment at the Sleep Medicine Center. Clinical characteristics, handedness, and psychological scales were prospectively collected from subjects. Subsequently, EEG power in alpha, beta, and theta bilaterally was calculated for the rest and sleep phases. ResultsA total of 152 OSA and 21 non-OSA subjects were included in the study. In the frontal, central and occipital regions, OSA exhibited increased interhemispheric asymmetry with increasing apnea-hypopnea index (AHI) during rest and sleep. Simultaneously, the results showed that greater activity in the right hemisphere was positively associated with anxiety and extraversion, while inversely with positive and lie scale. In addition, the results show that OSA contributes to abnormal BA fluctuations during sleep. ConclusionsOur results suggest that sleep disorders associated with apnea-hypopnea and arousal may contribute to increased BA during sleep. Such changes may persist into wakefulness with psychological traits.

Journal Club: Prehospital Detection of Large Vessel Occlusion Stroke With Electroencephalography: Results of the ELECTRA-STROKE Study.

The ELECTRA-STROKE study investigated the potential of EEG for prehospital triage of patients with ischemic stroke due to large vessel occlusion (LVO), in which fast triage to stroke centers for endovascular treatment is crucial. The study was conducted in 4 phases, and this Journal Club article focuses on the fourth phase in the prehospital setting with suspected stroke patients. An EEG cap with dry electrodes was used to measure brain activity. The main focus was on the diagnostic accuracy of the theta/alpha ratio, which yielded an area under the receiver operator characteristic curve (AUC) of 0.80. Secondary endpoints, particularly the Brain Symmetry Index (a quantified EEG interhemispheric cortical power asymmetry index) in the delta frequency band, showed an AUC of 0.91. Despite the convenient study design and user-friendly EEG device, limitations include a single-arm design, a relatively small sample size, and exclusions due to data quality issues. The usefulness of EEG in the detection of neuronal changes based on brain ischemia was highlighted, but uncertainties remain regarding its use in certain patient groups. The improvements in the Brain Symmetry Index from phase 3 to 4 of the study indicate the potential for further refinement and investigation of combined methods to improve diagnostic accuracy. The study provides insight into the role of EEG in prehospital stroke detection, recognizing both the strengths and limitations. Overall, the study contributes to understanding the promise of EEG in optimizing LVO stroke triage and urges further refinement and exploration of complementary diagnostic approaches.

Interhemispheric Asymmetry in the Seasonal Ionospheric Outflow

AbstractA 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.

Predictors of clozapine efficacy in treatment-resistant schizophrenia: A cross-sectional analysis of sociodemographic, clinical, biochemical, and electrophysiological EEG changes

Abstract Context: Although neuroleptics are available for treating schizophrenia, patient compliance with treatment remains a major hurdle. Such patients turn into treatment-resistant schizophrenia (TRS) where clozapine can be prescribed, but it causes severe side effects. Many markers can predict favorable responses to clozapine therapy. Aims: To assess sociodemographic, clinical, electrophysiological, and biochemical parameters among TRS patients and to evaluate the difference between TRS patients with and without response to clozapine. Settings and Design: A prospective observational study was carried out for a period of 2 years from October 31, 2020, to November 1, 2022, in the Psychiatry Department of a Tertiary Care Hospital in Eastern Odisha. Materials and Methods: All patients visiting the Psychiatry Department of a tertiary care hospital, diagnosed with International Classification of Diseases schizophrenia were screened for TRS as per modified Kane’s criteria. The assessed parameters were compared using the Brief Psychiatry Rating Scale, the Positive and Negative Syndrome Scale of Schizophrenia, and Clinical Global Impressions scale. Statistical Analysis Used: Data were compiled and analyzed using IBM corporation’s Statistical Package for the Social Sciences (SPSS) software version 27. Results: Thirty-one eligible patients consented to the study, with 21 (67.7%) females and 10 (32.3%) males. Maximum, 17 (54.8%), belonged to 18–35 years of age. The biochemical parameters, fasting blood sugar (FBS), and triglycerides (TGs) had mean values of 94.56 (±6.6) mg/dL and 157 (±9.8) mg/dL, respectively. Gross electroencephalogram abnormalities were seen in 3 (10%) cases. Conclusions: The female gender, higher education, and a shorter duration of untreated psychosis predicted a better outcome. The patients showing good responses had higher trends in FBS and TGs at follow-up. Clozapine was associated with increased electrophysiological intra- and interhemispheric asymmetry.

The relationship between individual characteristics of interhemispheric asymmetry and cognitive style “impulsivity/reflectivity”

The article at the theoretical and empirical levels discusses the peculiarities of the relationship between functional asymmetries of the cerebral hemispheres of younger schoolchildren with the cognitive style « impulsivity-reflexivity. The main approaches to studying this issue in domestic and foreign studies are characterized, a conclusion is made about the relevance of its consideration. The study used the device Activacyometer-6 (Yu.A.Tsygareli) and the technique “Choosing a paired figure” (J.Kagan). The study made it possible to establish and clarify the existence of differences in the processing of information by the left and right hemispheres of the brain, as well as to confirm the existence of a certain connection between the functional asymmetry of the hemispheres with such manifestations of cognitive style as “impulsivity – reflexivity” In particular, it is given that the existence of individual differences (5% level is significant) in the speed of decision-making leads to the fact that children, who are characterized by left-sided hemispheric organization, have “reflexive” signs, make decisions slowly, are prone to analytical means of categorization, are more attentive to individual details, better control their behavior, use more productive means of solving problems and perform tasks with the least number of errors. On the contrary, children who have right-sided asymmetry demonstrate a thematic means of categorization, they are characterized by manifestations of impulsivity, they are less attentive, hyperactive in their actions, give very quick answers, most often focusing on the influence of momentary emotions. The investigation led to the conclusion that in certain conditions of uncertainty, when it is necessary to make the right choice from a number of alternatives, impulsive subjects made their choice quickly, without careful study of alternative options. In turn, reflective subjects, on the contrary, made their decisions on the basis of careful study of all. Pros and cons, while using more productive ways to solve problems.

Search for approaches to transcranial neuromodulation in patients with post-stroke hemiparesis in real clinical practice

BACKGROUND: To increase the efficiency of motor recovery after a stroke in routine clinical practice, the search for selective biomarkers that determine the choice of the optimal strategy for noninvasive neuromodulation of the brain remains relevant. The study of interhemispheric interaction patterns can hypothetically help in determining the correct conceptual model of neuromodulation. AIM: To determine variants of interhemispheric interaction based on a correlation analysis of motor cortex excitability in patients with poststroke hemiparesis stratified by the degree of motor deficit. MATERIALS AND METHODS: This retrospective observational study involved 185 people (men, 56.2%; women, 43.8%) aged 19–88 years with verified poststroke hemiparesis and 40 healthy volunteers (men, 55.0%; women, 45.0%) aged 20–85 years. The patients underwent diagnostic transcranial magnetic stimulation in the projection of the cortical representation of m. abductor pollicis brevis and m. tibialis anterior of both brain hemispheres. The excitability level of the motor cortex and its interhemispheric asymmetry were recorded, and correlation analysis in subgroups stratified by the degree of paresis was performed. RESULTS: No interhemispheric correlation of resting motor thresholds (rMT) was found in patients with a level of muscle strength for the “hand” segment of 0–2 points (р 0.05). In the remaining subgroups, positive interhemispheric correlations of the rMT were noted (p 0.02). A positive correlation of the rMT of the damaged brain hemisphere and interhemispheric asymmetry of the motor cortex excitability for all degrees of paresis was observed when evaluating the cortical representation of the upper limb muscles. A negative correlation between the rMT of the unaffected brain hemisphere and interhemispheric asymmetry was detected for all degrees of motor deficit of the “foot” segment (p 0.02). CONCLUSION: The study did not confirm the concept of interhemispheric competition of the studied functional activity of the brain. Three authentic variants of interhemispheric interaction were identified: unidirectional hemispheric interaction with predominant reactivity of the affected hemisphere, unidirectional hemispheric interaction with predominant reactivity of the unaffected hemisphere, and functional interhemispheric dissociation. The results indicate the need to rethink some approaches to transcranial neuromodulation strategies in the analyzed cohort.

The Relationship between Immunological and Psychopathological Characteristics in Patients with Focal Epilepsy Depending on the Interhemispheric Asymmetry Profile

The Relationship between Immunological and Psychopathological Characteristics in Patients with Focal Epilepsy Depending on the Interhemispheric Asymmetry Profile

North Atlantic Warming Hole Modulates Interhemispheric Asymmetry of Future Temperature and Precipitation

AbstractThe observed cooling in the subpolar North Atlantic, known as the warming hole, is receiving much attention because of its relationship with the climate sensitivity in the Earth System Models (ESMs). However, the impact of its future projection on the global climate remains unclear due to large uncertainties. Here, we show that the future warming hole changes will affect the interhemispheric asymmetry of temperature and precipitation by modulating the Northern Hemisphere (NH) warming. Models with a weaker warming hole in the future project stronger NH warming by injecting more non‐radiative fluxes to the atmosphere. This leads to an asymmetric warming contrast between the two hemispheres, resulting in a meridional shift of the Inter‐Tropical Convergence Zone and more precipitation increases in the NH. Our study implies that the future warming hole controls the interhemispheric heat exchanges and associated changes in the global temperature and precipitation, suggesting that its improved simulation is essential.