Left Hemisphere Research Articles

Genetically supported causality between brain structural connectome and sleep duration in children: a two-sample Mendelian randomization study.

Certain structural brain connections have been confirmed to influence sleep duration in children. However, the causal relationships between all brain regions and children's sleep duration remain unclear. A two-sample Mendelian randomization analysis was conducted using data from genome-wide association studies (GWAS) to examine the relationships between 206 structural connections and sleep duration in children. Sensitivity analyses were employed to validate the findings and assess the robustness of the causal inferences. Stronger connectivity from the left hemisphere (LH) control network to the accumbens (β = -0.15, 95% CI = [-0.30, -2.88E-03], P = 0.05) and from the LH somatomotor network to the LH default network (β = -0.18, 95% CI = [-0.34, -0.03], P = 0.02) in white-matter structural connectivity (SC) were associated with shorter sleep durations. Conversely, increased white-matter SC from the LH dorsal attention network to the thalamus (β = 0.14, 95% CI = [8.45E-04, 0.27], P = 0.05), from the right hemisphere (RH) control network to the thalamus (β = 0.10, 95% CI = [0.01, 0.19], P = 0.03), from the RH default network to the thalamus (β = 0.08, 95% CI = [4.53E-03, 0.16], P = 0.04), from the RH limbic network to the thalamus (β = 0.15, 95% CI = [0.05, 0.26], P = 3.77E-03), and from the RH somatomotor network to the thalamus (β = 0.20, 95% CI = [0.07, 0.32], P = 1.63E-03) correlated with longer sleep durations in children. Two-sample Mendelian randomization provides novel insights into the relationships between brain regions and sleep duration in children. Our findings demonstrate a causal relationship between specific brain areas and sleep duration.Significance Statement 1. Innovative Approach: Employed two-sample Mendelian randomization to explore causal relationships between brain structural connectivity and sleep duration in children, leveraging genetic variants as instrumental variables.2. Comprehensive Data Analysis: Utilized data from genome-wide association studies (GWAS) to assess 206 structural connections, supported by extensive sensitivity analyses to confirm the robustness of the findings.3. Implications for Pediatric Health: Findings suggest that specific brain connectivity patterns can significantly impact sleep duration, providing insights for targeted interventions to improve sleep in children.

The role of cognitive load on interlimb differences in motor coordination in older adults.

While the dominant hand has been shown to have performance advantages over the nondominant hand, these interlimb differences have found to be dependent on task and biomechanical demands. The dynamic dominance hypothesis suggests that the left hemisphere is specialized for the control of intersegmental dynamics while the nondominant right hemisphere is specialized for postural control, in right-handers. In a real-world scenario, however, cognitive challenges might be expected to modulate these specialized behaviors. Therefore, we hypothesized that with increased cognitive load, lateralized motor control processes would become even more asymmetrical. We recruited 16 right-handed older adults (11 females, 5 males; 65.88 years ± 1.99 SEM) to perform 170 trials of a unilateral reaching task with each of their hands on the Kinereach system. In each trial, participants rapidly committed to memory a set of pictorial instructions before identifying and reaching for the correct object on a screen. The complexity of the task increased over the course of the experiment. Our results demonstrated higher reaction times in the right compared to left hand (p = 0.0004). Movements became increasingly curved and erroneous with cognitive load, but interlimb differences in movement quality were absent. We found higher joint cocontraction in the right compared to left arm (p < 0.05), but these differences were unaffected by cognitive load. Hence, with the addition of a cognitive load, we observed asymmetries in reaction time but not in joint coordination or movement quality. This highlights the role of cognitive load in modulating limb/hemisphere specializations for control processes.

Pattern Separation Involves Regions Beyond the Hippocampus in Non-demented elderly Individuals: a 7T Object Lure Task fMRI Study

Abstract Investigating the mechanism of differentiating similar representations, known as pattern separation, has primarily focused on the hippocampus. The roles of cortical regions and their interaction with the hippocampus remain largely unclear. In this study, we address this topic by analyzing whole-brain, high-resolution mnemonic similarity task (MST) fMRI data collected with a 7-Tesla MR scanner. Structural and functional MRI data were acquired from 55 non-demented elderly subjects. During the encoding phase of the MST task, participants responded with “indoor” or “outdoor” to 66 everyday objects. In the recognition phase, participants were asked to make “same” / “similar” / “new” judgements about objects that were either the same as previously seen objects (targets), similar but different from previously seen objects (lures), or new objects (foils). A general linear model was conducted on hippocampal regions of interest (ROIs) and at the whole-brain level with five conditions, including “new” response to foils (foil), “same” response to targets (hit), correct “similar” response to lure (lure correct rejection, LureCR), false “same” response to lure (lure false alarm, LureFA), and one condition for all others. The activity difference when lures were identified as “similar” compared to “same” (LureCR versus LureFA) was used to assess if a region is involved in pattern separation. An association analysis was conducted to test if lure discrimination performance was correlated with activity difference of hippocampal ROIs between LureCR and LureFA, as well as age. Task-based functional connectivity between hippocampal ROIs and other regions involved in pattern separation was examined. In the hippocampal ROI analysis, left anterior CA3/DG showed greater activity in LureCR condition compared to LureFA. All other hippocampal ROIs did not show differential activity. Better lure discrimination performance was associated with larger activity difference between LureCR and LureFA at left anterior CA3/DG and right anterior subiculum. In the whole-brain analyses, regions in the frontoparietal network (FPN) consistently showed increased activity in the Hit, LureCR and LureFA conditions, and the activity was right-lateralized for Hit and LureFA conditions but bilateral for LureCR condition. Eleven clusters, mainly located in the left hemisphere, were identified to show significant activity difference between LureCR and LureFA condition, including left FPN, middle temporal lobe and subcortical regions. In summary, with the whole-brain high-resolution MST fMRI data, regions exhibiting the pattern separation signature were found to be lateralized to the left hemisphere in elderly participants. The left and right FPN are suggested to have distinct functional roles in the MST. The right FPN contributes to retrieving previously viewed same or similar objects, while the left FPN is preferentially involved in pattern separation. Furthermore, the pattern separation process might require the coordinated effort of FPN and hippocampus, with their interaction potentially mediated by subcortical regions.

Autopsy of an unknown dead person to find out cause of death- A massive cerebrovascular accident (CVA)

Introduction: Intracerebral haemorrhage (ICH) is one of the lethal and most debilitating type of stroke affecting more than 1 million people globally every year. Most common cause of ICH is hypertension and responsible for about 70% of all ICH. Case report: Sealed dead body of 45 years old unknown male brought for autopsy to find out the cause of death. Patient was admitted to district hospital with unconscious state. Status of vital at time of admission was 210/110. Autopsy finding: No external injury was present on the body. No internal injury or abnormality seen on opening neck, chest and abdomen.Facial bone intact. No abnormality detected at scalp, cranial bone and meninges. External surface of brain was normal and intact. Brain was soft and congested. On sectioning of cerebral hemisphere huge hematoma of size 6.0×4.5 cm was present in deep left cerebral hemisphere. Conclusion: Hypertension is one of the most important risk factors for ICH. ICH is a medical emergency with high chances of morbidity as well as mortality. Advancement in early diagnosis and neurocritical care have improved and increased the survival.

The hypointense pulvinar sign on susceptibility weighed magnetic resonance imaging: A visual biomarker for iron deposition in epilepsy

Objective Our study aimed to investigate potential alterations in iron deposition within pulvinar, using susceptibility weighted imaging (SWI) MRI in epilepsy patients through a biomarker termed the “hypointense pulvinar sign.” Methods A full-text radiological information system search of radiological reports was performed for the term “epilepsy” between 2014 and 2022. Only patients with the diagnosis of epilepsy were included. SWI was assessed by two readers recording lateralization of an asymmetrically more hypointense pulvinar. Cohen’s kappa for inter-rater reliability was calculated. Fisher’s exact test was performed to assess for significance between groups. Results Our epilepsy cohort comprised 105 patients with following diagnoses: 45 intra-axial tumor, 13 meningioma, 13 MRI negative, 12 encephalomalacia, seven siderosis, six cavernoma, five arteriovenous malformation, two acute demyelinating encephalomyelitis, one tuberous sclerosis, one giant aneurysm. The hypointense pulvinar sign was correct in 44% of cases. Notably, right hemispheric lesions exhibited a significantly higher proportion of correct hypointense pulvinar signs compared to the left hemisphere (46% vs 24%; p = 0.044). Inter-rater reliability was substantial at 0.62 ( p &lt; 0.001). Only two of 21 (10%) of healthy controls demonstrated a hypointense pulvinar sign, which was significantly different from the epilepsy cohort ( p &lt; 0.01). Conclusions The hypointense pulvinar sign has proven to be a reproducible, simple to use biomarker for iron deposition in epilepsy which could be considered for inclusion into multimodal precision medicine models.

Investigating the Effectiveness of Neuropsychological Rehabilitation on Stroke Patients

Objectives: This study aimed to investigate neuropsychological rehabilitation’s effectiveness on stroke patients’ cognitive status. Methods: This quasi-experimental study examined 22 adults with ischemic stroke of the left hemisphere (with an average age of 64.31 years) before and after the intervention. The patients had fluent aphasia (10 people) and non-fluent aphasia (12 people), along with cognitive disorders such as memory or attention disorder. Medical examination and para-clinical diagnosis of magnetic resonance imaging (MRI) with different causes, along with the Persian diagnostic aphasia battery bedside version (P-DAB-AQ1, 2016), were conducted. The severity of language disorder and type of aphasia were investigated using the Persian diagnostic aphasia battery (P-DAB-1) and Persian picture naming battery tests. Also, the mini-mental state examination (MMSE) test checked the cognitive dimensions. Verb network strengthening therapy, treatment of underlying forms, Persian verb, and sentence production protocol, and semantic feature analysis (SFA) for patients were also used. Results: Findings show that the participants’ average aphasia quotient (AQ1) score increased from 74.80 to 80.12, and the average MMSE score increased from 17 to 22.59. The main variables do not follow a normal distribution (P&lt;0.05), but the difference between scores before and after the intervention follows a normal distribution (P&lt;0.05). Both the AQ1 and MMSE variables significantly differ before and after the intervention, according to the Wilcoxon test. The non-fluent aphasia group has a higher increase in MMSE scores than the fluent aphasia group. Discussion: Neuropsychological rehabilitation interventions can effectively improve AQ1 and MMSE. In addition, further research on neuropsychological rehabilitation interventions with two intervention and control groups and the treatment methods used during this study can be suggested for the treatment of stroke patients.

Foreign Accent Syndrome: insights from Neuroimaging and Pathophysiological mechanisms.

Foreign Accent Syndrome (FAS) is a rare and complex speech disorder characterized by the sudden emergence of a foreign accent, typically following neurological events such as strokes, traumatic brain injuries, or neurodegenerative diseases. This comprehensive review explores the pathophysiology, neuroimaging findings, and prevalence of FAS. Neuroimaging studies, including MRI and fMRI, reveal significant brain reorganization predominantly in the left hemisphere, involving regions such as the superior temporal gyrus and medial frontal structures. Functional connectivity disruptions and the phenomenon of dynamic diaschisis are discussed as potential mechanisms. Additionally, the review addresses the psychogenic aspects of FAS, highlighting the role of psychological factors and functional neurological disorders. The high comorbidity of FAS with other conditions underscores the need for a multidisciplinary diagnostic and therapeutic approach. This paper aims to enhance the understanding of FAS and contribute to the development of effective treatment strategies for this unique speech disorder.

Modelling pathological spread through the structural connectome in the frontotemporal dementia clinical spectrum.

The ability to predict the pathology spreading in patients with frontotemporal dementia (FTD) is crucial for early diagnosis and targeted interventions. This study examined the relationship between network vulnerability and longitudinal atrophy progression in FTD patients, using Network Diffusion Model (NDM) of pathology spread. Thirty behavioural-variant FTD (bvFTD), 13 semantic-variant primary progressive aphasia (svPPA), 14 nonfluent-variant PPA (nfvPPA) and 12 semantic behavioral variant FTD (sbvFTD) patients underwent longitudinal T1-weighted MRI. Fifty young controls (YC) (20-31 years) underwent multi-shell diffusion MRI scan. NDM was developed to model FTD pathology progression as a spreading process from a seed through the healthy structural connectome, using connectivity measures from fractional anisotropy (FA) and intra-cellular volume fraction (ICVF) in YC. Four disease epicenters were initially identified from the peaks of atrophy of each FTD variant: left insula (bvFTD), left temporal pole (svPPA), right temporal pole (sbvFTD) and left supplementary motor area (nfvPPA). Pearson's correlations were calculated between NDM-predicted atrophy in YC and the observed longitudinal atrophy in FTD patients over a follow-up of 24 months. The NDM was then run for all the 220 brain seeds to verify whether the four epicenters were among those that yielded the highest correlation. Using NDM, predictive maps in YC showed pathology progression from the peaks of atrophy in svPPA, nfvPPA, and sbvFTD over 24-months. svPPA exhibited early involvement of left temporal and occipital lobes, progressing to extensive left hemisphere impairment. nfvPPA and sbvFTD similarly spread bilaterally to frontal, sensorimotor, and temporal regions, with sbvFTD additionally affecting the right hemisphere. Moreover, the NDM-predicted atrophy of each region was positively correlated to longitudinal real atrophy, with a greater effect in svPPA and sbvFTD. In bvFTD, the model starting from the left insula (the peak of atrophy) demonstrated a highly left-lateralized pattern, with pathology spreading to frontal, sensorimotor, temporal, and basal ganglia regions, with minimal extension to the contralateral hemisphere by 24 months. However, unlike the atrophy peaks observed in the other three phenotypes, the left insula did not show the strongest correlation between the estimated and actual atrophy. Instead, the bilateral superior frontal gyrus emerged as optimal seeds for modelling atrophy spread, showing the highest correlation ranking in both hemispheres. Overall, NDM applied on ICVF connectome yielded higher correlations relative to NDM applied on FA maps. The NDM implementation using cross-sectional structural connectome is a valuable tool to predict atrophy patterns and pathology spreading in FTD clinical variants.

When the brain says “No!”: An MRI study on the neural correlates of resistance to immoral orders.

Abstract Milgram's studies explored psychological and contextual factors influencing (dis)obedience to immoral orders, but the mechanisms preventing individuals from being coerced into causing pain to others remained largely unknown. Our fMRI study investigated the neural correlates of disobedience to such orders, focusing on three phases of the decision-making process: order processing (pre-decision), action (decision), and outcome and effect processing (post-decision). Within these phases we targeted three socio-cognitive (cognitive conflict, sense of agency— SoA, and theory of mind— ToM) and two socio-affective (empathy and guilt) processes. Our findings revealed that participants who engaged the angular gyrus and temporo-parietal junction, particularly in the left hemisphere, as well as median prefrontal areas before obeying the command to send a shock — possibly to mitigate cognitive conflict between self and other and to enhance their SoA — were more likely to disobey the experimenter’s instructions to administer a shock to a victim. Additionally, we found involvement of social brain regions during the post-decision phase (encompassing ToM, empathy, and guilt areas), especially in response to shock events, to process the victim’s pain. Higher activity in these regions when obeying orders was associated with a higher rate of prosocial disobedience. This study sheds light on the mechanisms that lead individuals to resist immoral actions under authoritative pressure in an experimental context.

Patterns and Predictors of Orbitofrontal Sulcogyral Morphology in a Non-Clinical Population

Abstract Frequencies of orbitofrontal cortex (OFC) sulcogyral patterns in populations, with less common patterns identified at higher rates among those with psychopathology. Previous work has assumed demographic characteristics have no influence on OFC sulcogyral patterns. However, the influence of sociodemographic and health-related characteristics on OFC patterns within a neurotypical population has not been formally evaluated. We used structural brain magnetic resonance imaging (MRI) from a cohort from the Human Connectome Project (HCP) with existing OFC sulcogyral characterizations (n=238); none of the participants had psychiatric diagnoses. We evaluated distributions of participant demographics (i.e., age), socioeconomic factors (i.e., employment), and health history related factors (i.e., smoking history) by OFC sulcogyral pattern within each hemisphere. We then used logistic regression to estimate the odds of OFC sulcogyral pattern by participant characteristics. Distributions of study sample characteristics did not vary substantially by OFC sulcogyral pattern type within either hemisphere. Findings from logistic regression analyses suggest no association between OFC sulcogyral pattern and any of the demographic or socioeconomic characteristics. Two health history-related characteristics, body mass index (BMI) and smoking history, were associated with increased odds of having specific OFC pattern types. For example, individuals with obesity had a 2.65 increased odds (95% CI: 1.17, 6.65) of having OFC sulcogyral pattern Type II, III, or IV, compared to Type I in the left hemisphere with normal BMIs. We did not observe substantial influence of demographic or socioeconomic characteristics on OFC sulcogyral patterns. These results confirm assumptions made in previous work that demographic and socioeconomic characteristics do not seem to impact OFC patterns. We do show some evidence for an influence of health history related factors (obesity and smoking history); future work should evaluate whether these and other phenotypic risk factors interact to modify the relationship between psychiatric diagnoses and OFC sulcogyral patterns.

MONITORING MUSICAL DEVELOPMENTOF CHILDREN OF THE THIRD YEAR OF LIFE,TAKING INTO ACCOUNT HOLISTIC THINKING

The article discusses the concept of functional asymmetry of the child’s cerebral hemispheres and the universal developmental paradigm. The universal developmental paradigm means that the characteristic of the world in which we exist is its duality, its division into right and left, light and dark, good and evil... It is thinking, as a function of the human mind, that can be considered the essence of man - a fundamentally intelligent being, and therefore thinking, since thinking is a system-forming factor of man as a living system, and at the same time a necessary and sufficient factor of his being as a rational being, as a species of Homo sapiens. Therefore, the main developmental goal of education should be considered the development of thinking in pupils. Preschool children's brains are used to remembering everything as it is - in a variety of colors, smells, sounds, and other factors. During reproduction, an image-model is created in the right hemisphere, and a verbal definition corresponding to the image is created in the left hemisphere. As a result, perception is not erased, it gives rise to brilliant poems, books, paintings, discoveries. This is unlimited and natural for him. During learning, in most cases, either the left or the right hemisphere of the brain is loaded, while the opposite remains unused. Experimentally, using K. Pearson’s criterion, it was confirmed that the musical development of a child of the third year of life will be more effective and qualitative if the holistic thinking of the two hemispheres of the child's brain is involved. Holistic thinking is the combined work of the two cerebral hemispheres, relying on all channels of information perception. Of course, the tasks of developing preschool children’s personality will be successfully solved if music lessons include consideration of the main issues of factual material. In this case, the music teacher varies the methods of study and forms of work. We propose conditions for individual and personal development of the child, namely, within the framework of the program, thematic planning, conducting classes, games, matinees, etc. the music teacher should have didactic material that changes the type and form of presentation of educational material, and the child has the freedom to choose the task (the same task should provide the possibility of its implementation through an image, word, scheme, modelling, musical accompaniment, movement, etc.), that is, to promote the integration of the right and left types of being in learning and development. Activities that involve two hemispheres of the preschoolers' brain simultaneously will be more effective.

СТАТИСТИЧНІ МЕТОДИ У ПРОВЕДЕННІ ПЕДАГОГІЧНИХ ДОСЛІДЖЕНЬ (ПРИКЛАДНИЙ АСПЕКТ)

The article discusses the concept of functional asymmetry of the child’s cerebral hemispheres and the universal developmental paradigm. The universal developmental paradigm means that the characteristic of the world in which we exist is its duality, its division into right and left, light and dark, good and evil. It is thinking, as a function of the human mind, that can be considered the essence of man - a fundamentally intelligent being, and therefore thinking, since thinking is a system-forming factor of man as a living system, and at the same time a necessary and sufficient factor of his being as a rational being, as a species of Homo sapiens. Therefore, the main developmental goal of education should be considered the development of thinking in pupils. Preschool children's brains are used to remembering everything as it is - in a variety of colours, smells, sounds, and other factors. During reproduction, an image-model is created in the right hemisphere, and a verbal definition corresponding to the image is created in the left hemisphere. As a result, perception is not erased, it gives rise to brilliant poems, books, paintings, discoveries. This is unlimited and natural for him. During learning, in most cases, either the left or the right hemisphere of the brain is loaded, while the opposite remains unused. Experimentally, using K. Pearson’s criterion, it was confirmed that the musical development of a child of the third year of life will be more effective and qualitative if the holistic thinking of the two hemispheres of the child's brain is involved. Holistic thinking is the combined work of the two cerebral hemispheres, relying on all channels of information perception. Of course, the tasks of developing preschool children’s personality will be successfully solved if music lessons include consideration of the main issues of factual material. In this case, the music teacher varies the methods of study and forms of work. We propose conditions for individual and personal development of the child, namely, within the framework of the programme, thematic planning, conducting classes, games, matinees, etc. the music teacher should have didactic material that changes the type and form of presentation of educational material, and the child has the freedom to choose the task (the same task should provide the possibility of its implementation through an image, word, scheme, modelling, musical accompaniment, movement, etc.), that is, to promote the integration of the right and left types of being in learning and development. Activities that involve two hemispheres of the preschoolers’ brain simultaneously will be more effective.

MRI-Negative Temporal Lobe Epilepsy: A Study of Brain Structure in Adults Using Surface-Based Morphological Features.

This research aimed to delve into the cortical morphological transformations in patients with magnetic resonance imaging (MRI)-negative temporal lobe epilepsy (TLE-N), seeking to uncover the neuroimaging mechanisms behind these changes. A total of 29 individuals diagnosed with TLE-N and 30 healthy control participants matched by age and sex were selected for the study. Using the surface-based morphometry (SBM) technique, the study analyzed the three-dimensional-T1-weighted MRI scans of the participants' brains. Various cortical structure characteristics, such as thickness, surface area, volume, curvature, and sulcal depth, among other parameters, were measured. When compared with the healthy control group, the TLE-N patients exhibited increased insular cortex thickness in both brain hemispheres. Additionally, there was a notable reduction in the curvature of the piriform cortex (PC) and the insular granular complex within the right hemisphere. In the left hemisphere, the volume of the secondary sensory cortex (OP1/SII) and the third visual area was significantly reduced in the TLE-N group. However, no significant differences were found between the groups regarding cortical surface area and sulcal depth (p < 0.025 for all, corrected by threshold-free cluster enhancement). The study's initial findings suggest subtle morphological changes in the cerebral cortex of TLE-N patients. The SBM technique proved effective in identifying brain regions impacted by epileptic activity. Understanding the microstructural morphology of the cerebral cortex offers insights into the pathophysiological mechanisms underlying TLE.

Neurometabolic Profile in Obese Patients: A Cerebral Multi-Voxel Magnetic Resonance Spectroscopy Study.

Background and Objectives: Obesity-related chronic inflammation may lead to neuroinflammation and neurodegeneration. This study aimed to evaluate the neurometabolic profile of obese patients using cerebral multivoxel magnetic resonance spectroscopy (mvMRS) and assess correlations between brain metabolites and obesity markers, including body mass index (BMI), waist circumference, waist-hip ratio, body fat percentage, and indicators of metabolic syndrome (e.g., triglycerides, HDL cholesterol, fasting blood glucose, insulin, and insulin resistance index (HOMA-IR)). Materials and Methods: This prospective study involved 100 participants, stratified into two groups: 50 obese individuals (BMI ≥ 30 kg/m2) and 50 controls (18.5 ≤ BMI < 25 kg/m2). Anthropometric measurements, body fat percentage, and biochemical markers were evaluated. All subjects underwent long- and short-echo mvMRS analysis of the frontal and parietal supracallosal subcortical and deep white matter, as well as the cingulate gyrus, analyzing NAA/Cr, Cho/Cr, and mI/Cr ratios, along with absolute concentrations of NAA and Cho. Results: Obese participants exhibited significantly decreased NAA/Cr and Cho/Cr ratios in the deep white matter of the right cerebral hemisphere (p < 0.001), while absolute concentrations of NAA and Cho did not differ significantly between groups (p > 0.05). NAA levels showed negative correlations with more reliable obesity parameters (waist circumference and waist-to-hip ratio) but not with BMI, particularly in the deep frontal white matter and dorsal anterior cingulate gyrus of the left cerebral hemisphere. Notably, insulin demonstrated a significant negative impact on NAA (ρ = -0.409 and ρ = -0.410; p < 0.01) and Cho levels (ρ = -0.403 and ρ = -0.392; p < 0.01) at these locations in obese individuals. Conclusions: Central obesity and hyperinsulinemia negatively affect specific brain regions associated with cognitive and emotional processing, while BMI is not a reliable parameter for assessing brain metabolism.

Is an earlier onset of focal epilepsy associated with atypical language lateralization? A systematic review, meta-analysis and new data.

Right and bilateral language representation is common in focal epilepsy, possibly reflecting the influence of epileptogenic lesions and/or seizure activity in the left hemisphere. Atypical language lateralization is assumed to be more likely in cases of early seizure onset, due to greater language plasticity in childhood. However, evidence for this association is mixed, with most research based on small samples and heterogenous cohorts. In this preregistered meta-analysis we examined the association between age at seizure onset and fMRI-derived language lateralization in individuals with focal epilepsy. The pooled effect size demonstrated a correlation between an earlier onset and rightward language lateralization in the total sample (r=0.1, p=.005, k=58, n=1240), with no difference in the correlation between left and right hemisphere epilepsy samples (Q=62.03, p=.302). In exploratory analyses of the individual participant data (n=1157), we demonstrated strong evidence that a logarithmic model fits the data better than a linear (BF=350) or categorical model with 6 years of age as a cut-off (BF=36). These findings indicate that there is a small but significant relationship between age at seizure onset and language lateralization. The relationship was consistent with theories of language plasticity proposing an exponential decline in plasticity over early childhood. However, given that this effect was subtle and only found in larger sample sizes, an early age at seizure onset would not serve as a good indicator of atypical language lateralization on the individual patient level.

Associations between ADHD symptoms, executive function and frontal EEG in college students

Introduction This study aims to assess whether electroencephalogram (EEG) spectral power change scores (e.g. task spectral power subtracted from resting state spectral power) across three different frequency bands, alpha (8–12 Hz), theta (4–7 Hz), and beta (13–30 Hz), predicts self-reported attention-deficit hyperactivity disorder (ADHD) symptoms using the Adult ADHD Self-Report Scale (ASRS) over and above self-reported executive function (EF) abilities using the Behavior Rating Inventory of Executive Function (BRIEF-A) Global Executive Composite (GEC) T-scores for adults. Methods Data were collected at a rural, mid-sized southeastern university (N = 52) and participants received course credit for participation. Participants self-reported ADHD symptoms and EF abilities before completing eyes open resting state and the attention network test (ANT), a common flanker task that measures ability to orient attention, stay alert, and resolve conflict (i.e. distractor arrows) while recording EEG spectral power at electrodes F3 and F4. Bivariate correlations determine associations between EEG measures and self-reported ADHD symptoms and EF abilities. Linear regressions were used to assess whether EEG change scores were predictive of ADHD symptoms over and above EF abilities. Results High correlation coefficients were found only when comparing the ASRS and BRIEF-A GEC T-scores (r = .822, p <.001). Regression analyses produced significant results indicating EEG spectral change scores were predictive of ADHD symptoms, over and above GEC T-Scores, for the alpha band but not the theta and beta bands. Additionally, we found an inverse relationship when comparing change scores in the alpha band across the right (F4) and left (F3) hemispheres supporting the theory of frontal asymmetry for individuals with increased ADHD symptoms. Conclusion This study is the first to assess the predictive ability of EEG spectral power change scores in predicting ADHD symptoms, which are not solely explained by deficits in executive control. Past research has indicated significant differences when comparing task and resting state spectral power indicating change scores might have some utility in measuring cognitive load, specifically in the alpha band, which has been associated with inhibition, working memory, and anticipation of stimuli. Further research should be conducted to assess the utility change scores might have in providing an objective measure related to a clinical population with ADHD.

Asymmetry of Directed Brain Connectivity at Birth in Low-Risk Full-Term Newborns.

Functional connectivity hubs were previously identified at the source level in low-risk full-term newborns by high-density electroencephalography (HD-EEG). However, the directionality of information flow among hubs remains unclear. The aim of this study was to study the directionality of information flow among source level hubs in low-risk full-term newborns using HD-EEG. A retrospective analysis of HD-EEG collected from a prospective study. Subjects included 112 low-risk full-term (37-41 weeks' gestation) newborns born in a large delivery center and studied within 72 hours of life by HD-EEG. The directionality of information flow between hubs at the source level was quantified using the partial directed coherence in the delta frequency band. Descriptive statistics were used to identify the maximum and minimum information flow. Differences in information flow between cerebral hemispheres were assessed using Student t-test. There was higher information flow from the left hemisphere to the right hemisphere hubs (p < 0.05, t-statistic = 2). The brainstem had the highest information inflow and lowest outflow among all the hubs. The left putamen received the lowest information, and the right pallidum had the highest information outflow to other hubs. In low-risk full-term newborns, there is a significant information flow asymmetry already present, with left hemisphere dominance at birth. The relationship between these findings and the more prevalent left hemisphere dominance observed in full-term newborns, particularly in relation to language, warrants further study.

Empowering Data Sharing in Neuroscience: A Deep Learning De-identification Method for Pediatric Brain MRIs.

Privacy concerns, such as identifiable facial features within brain scans, have hindered the availability of pediatric neuroimaging datasets for research. Consequently, pediatric neuroscience research lags adult counterparts, particularly in rare disease and under-represented populations. The removal of face regions (image defacing) can mitigate this, however existing defacing tools often fail with pediatric cases and diverse image types, leaving a critical gap in data accessibility. Given recent NIH data sharing mandates, novel solutions are a critical need. To develop an AI-powered tool for automatic defacing of pediatric brain MRIs, deep learning methodologies (nnU-Net) were employed using a large, diverse multi-institutional dataset of clinical radiology images. This included multi-parametric MRIs (T1w, T1w-contrast enhanced, T2w, T2w-FLAIR) with 976 total images from 208 brain tumor patients (Children's Brain Tumor Network, CBTN) and 36 clinical control patients (Scans with Limited Imaging Pathology, SLIP) ranging in age from 7 days to 21 years old. Face and ear removal accuracy for withheld testing data was the primary measure of model performance. Potential influences of defacing on downstream research usage were evaluated with standard image processing and AI-based pipelines. Group-level statistical trends were compared between original (non-defaced) and defaced images. Across image types, the model had high accuracy for removing face regions (mean accuracy, 98%; N=98 subjects/392 images), with lower performance for removal of ears (73%). Analysis of global and regional brain measures (SLIP cohort) showed minimal differences between original and defaced outputs (mean r S=0.93, all p < 0.0001). AI-generated whole brain and tumor volumes (CBTN cohort) and temporalis muscle metrics (volume, cross-sectional area, centile scores; SLIP cohort) were not significantly affected by image defacing (all r S>0.9, p<0.0001). The defacing model demonstrates efficacy in removing facial regions across multiple MRI types and exhibits minimal impact on downstream research usage. A software package with the trained model is freely provided for wider use and further development (pediatric-auto-defacer; https://github.com/d3b-center/pediatric-auto-defacer-public). By offering a solution tailored to pediatric cases and multiple MRI sequences, this defacing tool will expedite research efforts and promote broader adoption of data sharing practices within the neuroscience community. AI = artificial intelligence; CBTN = Children's Brain Tumor Network; CSA = cross-sectional area; SLIP = Scans with Limited Imaging Pathology; TMT = temporalis muscle thickness; NIH = National Institute of Health; LH = left hemisphere; RH = right hemisphere.

The repeatability of behavioural laterality during nest building in zebra finches

Cerebral laterality is a widespread phenomenon across animals and refers to the specialization of the left and right hemispheres of the brain for perceptual, cognitive and behavioural tasks. Behavioural laterality occurs in several contexts, including foraging, mate selection, predator detection and tool manufacture. Behavioural laterality during nest building, however, has rarely been addressed. We conducted two experiments to examine (1) whether behavioural laterality occurs during nest building, (2) whether laterality correlates with nest-building speed, (3) whether laterality during nest building is repeatable, and (4) whether nest-building experience influences laterality. In Experiment 1, we scored individual laterality indices for 58 zebra finch (Taeniopygia guttata) males, the nest-building sex in this species, based on which eye he used to view then select the first 25 pieces of nest material. We calculated correlations between laterality strength and nest-building duration. In Experiment 2, to test the repeatability of laterality during nest building, we measured laterality for 20 males across five nests built by each male. Individuals varied both in the direction and the strength of behavioural laterality of material selection during nest building. Overall, however, males were not consistent in their laterality across the five nests. We found no correlation between laterality strength and nest-building duration in either experiment. Finally, we found evidence for building experience influencing the behavioural laterality of individuals: more building experience results in more predictable behavioural laterality during nest-material selection.

Hemispheric asymmetry for global-local processing: Effects of stimulus category and ageing.

Hemispheric asymmetry has been reported for global-local processing in young and older adults, with global processing specialised in the right hemisphere (RH-global specialisation) and local processing specialised in the left hemisphere (LH-local specialisation). Questions persist regarding the extent to which hemispheric asymmetry is influenced by stimulus category (verbal stimuli processed in the left hemisphere; visuospatial stimuli processed in the right hemisphere). Some evidence suggests stimulus category does not influence hemispheric asymmetry (stimulus-independent account) while other evidence suggests it does (stimulus-dependent account). In older adults, there is evidence of a local-processing advantage, believed to result from slower and less accurate performance in right-hemisphere compared to left-hemisphere functioning-the right-hemisphere ageing hypothesis. We examined hemispheric asymmetry for global-local processing in young and older participants with three hierarchical figures (letters, verbalisable objects, and nonverbalisable shapes), in a within-subjects design using a divided-attention paradigm and unilateral presentation. Our findings for letters and verbalisable objects support the stimulus-independent account-young and older participants demonstrated RH-global specialisation and LH-local specialisation regardless of stimulus category. In older participants, we also found a local-processing advantage for all three stimulus categories-an advantage best explained as faster and more accurate performance in local processing regardless of the visual field of stimulus presentation. Overall, we found hemispheric asymmetry for global-local processing in both young and older adults, and differences in global processing between young and older adults. Future investigation is suggested for the hemispheric asymmetry found in global-local processing of nonverbalisable shapes, and the mechanisms underlying age-related changes in global processing.