Cerebral Hemispheres Research Articles

Roles of the Default Mode Network in Different Aspects of Self-representation When Remembering Social Autobiographical Memories.

Autobiographical memory (AM) is episodic memory for personally experienced events, in which self-representation is more important than that in laboratory-based memory. Theoretically, self-representation in a social context is categorized as the interpersonal self (IS) referred to in a social interaction with a person or the social-valued self (SS) based on the reputation of the self in the surrounding society. Although functional neuroimaging studies have demonstrated the involvement of the default mode network (DMN) in self-representation, little is known about how the DMN subsystems contribute differentially to IS-related and SS-related AMs. To elucidate this issue, we used fMRI to scan healthy young adults during the recollection of AMs. We performed multivariate pattern analysis (MVPA) and assessed functional connectivity in the DMN subsystems: the midline core, medial temporal lobe (MTL), and dorsomedial pFC (dmPFC) subsystems. The study yielded two main sets of findings. First, MVPA revealed that all DMN subsystems showed significant classification accuracy between IS-related and nonsocial-self-related AMs, and IS-related functional connectivity of the midline core regions with the retrosplenial cortex of the MTL subsystem and the dmPFC of the dmPFC subsystem was significant. Second, MVPA significantly distinguished between SS-related and nonsocial-self-related AMs in the midline core and dmPFC subsystems but not in the MTL subsystem, and SS-related functional connectivity with the midline core regions was significant in the temporal pole and TPJ of the dmPFC subsystem. Thus, dissociable neural mechanisms in the DMN could contribute to different aspects of self-representation in social AMs.

Localized anaplastic lymphoma kinase-positive histiocytosis in a cerebellar hemisphere with long-term treatment: illustrative case.

Anaplastic lymphoma kinase (ALK)-positive histiocytosis (ALK-H) is an emerging entity in the category of histiocytic neoplasms that was first reported as a multisystemic disease in three infants in 2008. The clinicopathological spectrum of ALK-H has been expanded to include localized disorders in specific organs, but the features of this subtype are not well known. The authors report a case of ALK-H localized in the central nervous system that was difficult to treat and review the relevant literature. The authors reviewed archival histiocytic tumors at their institute and found a pediatric case of ALK-H localized in a cerebellar hemisphere that had previously been reported as histiocytic sarcoma. Chemotherapy (approximately 1 year), additional surgery, and conventional chemotherapy (approximately 2.5 years) led to clinical remission, and maintenance chemotherapy was continued (approximately 1.5 years). Three years after completing treatment, a high-grade glioma was found in a cerebral hemisphere, and the patient died of the glioma 2 years later. Although the prognosis of ALK-H is generally good according to prior cases, the authors' case required long-term conventional chemotherapy, suggesting the tumor displayed aggressive characteristics. Early administration of ALK inhibitors may be necessary.

Effects of GLP1 receptor analogues in obesity with neurodevelopmental disorder: case report of a patient with holoprosencephaly.

Holoprosencephaly is an anomaly in the division of the prosencephalon into cerebral hemispheres during the second month of gestation. Patients can present with early-onset obesity favoured by the cognitive impairment. We present a case of a 24 year-old woman with holoprosencephaly and class III obesity who was treated by 2.4 mg/week SEMAGLUTIDE. Her body weight decreased from 115.3 to 94.3 kg after one-year (18% of total body weight loss). In addition, she presented a marked reduction in self- and hetero-aggressive behaviour when exposed to the sight of food. The treatment was well tolerated, with the exception of a few vomiting when eating palatable food too quickly. GLP1-RAs may be interesting for obesity treatment in the context of neurodevelopmental disorders. They appear to reduce compulsive eating and aggressive behaviour, particularly in relation to exposure to food, and lead to weight loss similar to that seen in people without neurodevelopmental disorders.

The neural mechanism of communication between graduate students and advisers in different adviser-advisee relationships

Communication is crucial in constructing the relationship between students and advisers, ultimately bridging interpersonal interactions. Only a few studies however explore the communication between postgraduate students and advisers. To fill the gaps in the empirical researches, this study uses functional near-infrared spectroscopy (FNIRS) techniques to explore the neurophysiology differences in brain activation of postgraduates with different adviser-advise relationships during simulated communication with their advisers. Results showed significant differences in the activation of the prefrontal cortex between high-quality and the low-quality students during simulating and when communicating with advisers, specifically in the Broca's areas, the frontal pole, and the orbitofrontal and dorsolateral prefrontal cortices. This further elucidated the complex cognitive process of communication between graduate students and advisers.

Activation of the Frontal Pole Using Children’s Video Games: Support for Children’s Well-being

Effective support intended to promote children’s well-being has gained scholarly attention worldwide. Well-being is composed of complex elements. Of these elements, the promotion of executive function, which coordinates cognitive activities, via an effective method is important. Regarding the frontal pole in the anterior part of the prefrontal cortex, scholars presume that it is involved in advanced abilities, such as metacognition, and is essential for well-being. In today’s digital society, video games are appealing to children. Thus, a possibility exists that children can achieve certain aspects of well-being, such as a sense of achievement, perseverance, and happiness, by playing video games. In this regard, evidence that video games can be used to activate the prefrontal cortex is accumulating. In light of this discussion, this study hypothesizes that playing video games may affect the frontal pole and analyzes the brain activation of the frontal pole using video games compared with a mental abacus activity. The results demonstrate that playing through an educational game called Big Brain Academy: Brain vs. Brain exhibited more activation potential than mental abacus in many points.

A case report of neonatal incontinentia pigmenti complicated by severe cerebrovascular lesions in one of the male monozygotic twins

BackgroundThis article reports a case of neonatal incontinentia pigmenti onset in only one male monozygotic twin with characteristic skin lesions after birth followed by severe cerebrovascular lesions.Case presentationA male infant, the first of monozygotic twins, was born with multiple yellow pustules all over his body, repeated new herpes at different sites during the course of the disease, aggravated by fusion, warty crusts, and hyperpigmentation; biopsy pathology suggested eosinophilic spongiform edema of the skin. Peripheral blood eosinophils were significantly elevated, and brain magnetic resonance imaging revealed diffuse multiple cystic and lamellar abnormal signal areas in the left frontal and parietal lobes. On day 30, the infant showed neurological symptoms, such as poor response and apnea, and an emergency cranial computed tomography scan revealed abnormal changes in the left cerebral hemisphere and bilateral cerebellum. After admission, he was given a potassium permanganate bath and topical mupirocin for 1 month, and the skin abnormalities improved. He was treated with mechanical ventilation and vasoactive drugs for 2 days after the cerebrovascular accident, and died the same day after the parents chose hospice care. No deletion variants or point mutations were detected in subsequent genetic tests, and chromosomal copy number variation tests revealed different degrees of chimeric duplications and deletions in different regions of chromosomes Y and 3. The parents were healthy, and his twin brother had normal growth and development with no abnormalities at multiple follow-up visits.ConclusionNeonatal incontinentia pigmenti in only one male monozygotic twin is extremely rare and the genetic diagnosis is challenging. Awareness of the combined cerebrovascular lesions needs to be enhanced, and potential prevention and treatment methods need to be explored to improve the prognosis.

Analysis of functional connectivity changes in attention networks and default mode networks in patients with depression and insomnia.

Major Depressive Disorder (MDD) and Insomnia Disorder (ID) are prevalent psychiatric conditions often occurring concurrently, leading to substantial impairment in daily functioning. Understanding the neurobiological underpinnings of these disorders and their comorbidity is crucial for developing effective interventions. This study aims to analyze changes in functional connectivity within attention networks and default mode networks in patients with depression and insomnia. The functional connectivity alterations in individuals with MDD, ID, comorbid MDD and insomnia (iMDD), and healthy controls (HC) were assessed from a cohort of 174 participants. They underwent rs-fMRI scans, demographic assessments, and scale evaluations for depression and sleep quality. Functional connectivity analysis was conducted using region-of-interest (ROI) and whole-brain methods. The MDD and iMDD groups exhibited higher Hamilton Depression Scale (HAMD) scores compared to HC and ID groups (P < 0.001). Both ID and MDD groups displayed enhanced connectivity between the left and right orbital frontal cortex compared to HC (P < 0.05), while the iMDD group showed reduced connectivity compared to HC and ID groups (P < 0.05). In the left insula, reduced connectivity with the right medial superior frontal gyrus was observed across patient groups compared to HC (P < 0.05), with the iMDD group showing increased connectivity compared to MDD (P < 0.05). Moreover, alterations in functional connectivity between the left thalamus and left temporal pole were found in iMDD compared to HC and MDD (P < 0.05). Correlation analyses revealed associations between abnormal connectivity and symptom severity in MDD and ID groups. Our findings demonstrate distinct patterns of altered functional connectivity in individuals with MDD, ID, and iMDD compared to healthy controls. These findings contribute to a better understanding of the pathophysiology of depression and insomnia, which could be used as a reference for the diagnosis and treatments of these patients.

Grey matter volume reduction in the frontotemporal cortex associated with persistent verbal auditory hallucinations in Chinese patients with chronic schizophrenia: Insights from a 3 T magnetic resonance imaging study

BackgroundPersistent auditory verbal hallucinations (pAVHs) are a fundamental manifestation of schizophrenia (SCZ), yet the exact connection between pAVHs and brain structure remains contentious. This study aims to explore the potential correlation between pAVHs and alterations in grey matter volume (GMV) within specific brain regions among individuals diagnosed with SCZ. Methods76 SCZ patients with pAVHs (pAVH group), 57 SCZ patients without AVHs (non-AVH group), and 83 healthy controls (HC group) were investigated using 3 T magnetic resonance imaging. The P3 hallucination item of the Positive and Negative Syndrome Scale was used to assess the severity of pAVHs. Voxel-based morphometry was used to analyze the GMV profile between the three groups. ResultsCompared to the non-AVH and HC groups, the pAVH group exhibited extensive reduction in GMV within the frontotemporal cortex. Conversely, no significant difference in GMV was observed between the non-AVH and HC groups. The severity of pAVHs showed a negative correlation with GMV in several regions, including the right fusiform, right inferior temporal, right medial orbitofrontal, right superior frontal, and right temporal pole (p = 0.0036, Bonferroni correction). Stepwise linear regression analysis revealed that GMV in the right temporal pole (β = −0.29, p = 0.001) and right fusiform (β = −0.21, p = 0.01) were significantly associated with the severity of pAVHs. ConclusionsWidespread reduction in GMV is observed within the frontotemporal cortex, particularly involving the right temporal pole and right fusiform, which potentially contribute to the pathogenesis of pAVHs in individuals with chronic SCZ.

Idiosyncratic patterns of interhemispheric connectivity in the face and scene networks of the human brain

Abstract Neuroimaging studies have revealed a network of regions in both hemispheres of the human brain that respond selectively to faces. Neural models of face processing have typically focused on functional connectivity between regions in the same hemisphere (intrahemispheric), with a particular bias toward the right hemisphere. Here, we explored the role of interhemispheric connectivity using fMRI. We used three datasets to compare functional connectivity, as shown by correlations between the time-courses of neural activity of face regions during different natural viewing paradigms. We found higher correlations of neural activity between corresponding interhemispheric regions (e.g., rFFA–lFFA) than between intrahemispheric regions (e.g., rFFA–rOFA), indicating a bias towards higher interhemispheric than intrahemispheric connectivity. A similar interhemispheric bias was evident in scene-selective regions. In contrast, we did not find an interhemispheric bias in early visual regions (V1–V3), where intrahemispheric connectivity between corresponding regions was generally higher than interhemispheric connectivity. Next, we asked whether the higher interhemispheric connectivity in the face and scene networks between corresponding regions was consistent across participants. We found that the interhemispheric bias was significantly attenuated when we compared the time-course of response across participants. This shows that interhemispheric bias in connectivity between corresponding regions in the face and scene networks is specific to the individual. These findings raise the possibility that idiosyncratic variation in interhemispheric connectivity may explain individual differences in perception.

Daily quetiapine after severe TBI improves learning and memory.

Traumatic brain injury (TBI) induces cognitive deficits driven by neuroinflammation and cerebral edema. The commonly used atypical antipsychotic, quetiapine (QTP), has been recently shown to improve post-TBI outcomes. We hypothesized that QTP would thereby improve animal learning and memory 2 weeks after severe TBI. CD1 male mice (n = 35) underwent severe TBI (controlled cortical impact, injury, I) or sham craniotomy (S), followed by BID saline (P, placebo) or QTP (10 or 20 mg/kg, IP) for 2 weeks. Animals underwent Morris Water Maze (MWM) exercises to gauge spatial learning and memory. The distance and time required for swimming animals to reach the platform area (Zone 5, Z5) located in quadrant 1 (Zone 1, Z1) was calculated from digital video recordings analyzed using Ethovision software. Animal bodyweights were recorded daily and on day 14, injured cerebral hemispheres were procured for edema determination (wet-to-dry ratio). Intergroup differences were evaluated with ANOVA/Bonferroni correction (p < 0.05). On day 14, animal weight loss recovery was lowest in I + P compared to I + QTP20 and I + QTP10 (p ≤ 0.01 for either). Cerebral edema was greatest in I + P, and only significantly decreased in I + QTP20 (p < 0.05). Both QTP doses similarly improved spatial learning by significantly reducing latency time and travel distance to target zones (p < 0.05). In probe memory trials, only I + QTP20 and not I + QTP10 significantly favored animal reaching or crossing into target zones (p < 0.05). Post-TBI QTP reduces brain edema and improves spatial learning and memory with a potential dose dependence impact benefiting memory up to 14 days. These data suggest an unanticipated QTP benefit following brain injury that should be specifically explored.

Brain Connectomics Improve the Prediction of High-Risk Depression Profiles in the First Year following Breast Cancer Diagnosis

Background. Prediction of high-risk depression trajectories in the first year following breast cancer diagnosis with fMRI-related brain connectomics is unclear. Methods. The Be Resilient to Breast Cancer (BRBC) study is a multicenter trial in which 189/232 participants (81.5%) completed baseline resting-state functional magnetic resonance imaging (rs-fMRI) and four sequential assessments of depression (T0-T3). The latent growth mixture model (LGMM) was utilized to differentiate depression profiles (high vs. low risk) and was followed by multivoxel pattern analysis (MVPA) to recognize distinct brain connectivity patterns. The incremental value of brain connectomics in the prediction model was also estimated. Results. Four depression profiles were recognized and classified into high-risk (delayed and chronic, 14.8% and 12.7%) and low-risk (resilient and recovery, 50.3% and 22.2%). Frontal medial cortex and frontal pole were identified as two important brain areas against the high-risk profile outcome. The prediction model achieved 16.82-76.21% in NRI and 12.63-50.74% in IDI when brain connectomics were included. Conclusion. Brain connectomics can optimize the prediction against high-risk depression profiles in the first year since breast cancer diagnoses.

Cortical grey matter volume differences in children with developmental coordination disorder compared to typically developing children

IntroductionThe cause of Developmental Coordination Disorder (DCD) is unknown, but neuroimaging evidence suggests that DCD may be related to altered brain development. Children with DCD show less structural and functional connectivity compared to typically developing (TD) children, but few studies have examined cortical volume in children with DCD. The purpose of this study was to investigate cortical grey matter volume using voxel-based morphometry (VBM) in children with DCD compared to TD children.MethodsThis cross-sectional study was part of a larger randomized-controlled trial (ClinicalTrials.gov ID: NCT02597751) that involved various MRI scans of children with/without DCD. This paper focuses on the anatomical scans, performing VBM of cortical grey matter volume in 30 children with DCD and 12 TD children. Preprocessing and VBM data analysis were conducted using the Computational Anatomy Tool Box-12 and a study-specific brain template. Differences between DCD and TD groups were assessed using a one-way ANOVA, controlling for total intracranial volume. Regression analyses examined if motor and/or attentional difficulties predicted grey matter volume. We used threshold-free cluster enhancement (5,000 permutations) and set an alpha level of 0.05. Due to the small sample size, we did not correct for multiple comparisons.ResultsCompared to the TD group, children with DCD had significantly greater grey matter in the left superior frontal gyrus. Lower motor scores (meaning greater impairment) were related to greater grey matter volume in left superior frontal gyrus, frontal pole, and right middle frontal gyrus. Greater grey matter volume was also significantly correlated with higher scores on the Conners 3 ADHD Index in the left superior frontal gyrus, superior parietal lobe, and precuneus. These results indicate that greater grey matter volume in these regions is associated with poorer motor and attentional skills.DiscussionGreater grey matter volume in the left superior frontal gyrus in children with DCD may be a result of delayed or absent healthy cortical thinning, potentially due to altered synaptic pruning as seen in other neurodevelopmental disorders. These findings provide further support for the hypothesis that DCD is related to altered brain development.

3D Models as a Source for Neuroanatomy Education: A Stepwise White Matter Dissection Using 3D Images and Photogrammetry Scans.

White matter dissection (WMD) involves isolating bundles of myelinated axons in the brain and serves to gain insights into brain function and neural mechanisms underlying neurological disorders. While effective, cadaveric brain dissections pose certain challenges mainly due to availability of resources. Technological advancements, such as photogrammetry, have the potential to overcome these limitations by creating detailed three-dimensional (3D) models for immersive learning experiences in neuroanatomy. This study aimed to provide a detailed step-by-step WMD captured using two-dimensional (2D) images and 3D models (via photogrammetry) to serve as a comprehensive guide for studying white matter tracts of the brain. One formalin-fixed brain specimen was utilized to perform the WMD. The brain was divided in a sagittal plane and both cerebral hemispheres were stored in a freezer at -20°C for 10 days, then thawed under running water at room temperature. Micro-instruments under an operating microscope were used to perform a systematic lateral-to-medial and medial-to-lateral dissection, while 2D images were captured and 3D models were created through photogrammetry during each stage of the dissection. Dissection was performed with comprehensive examination of the location, main landmarks, connections, and functions of the white matter tracts of the brain. Furthermore, high-quality 3D models of the dissections were created and housed on SketchFab®, allowing for accessible and free of charge viewing for educational and research purposes. Our comprehensive dissection and 3D models have the potential to increase understanding of the intricate white matter anatomy and could provide an accessible platform for the teaching of neuroanatomy.

Insights on cognitive reorganization after hemispherectomy in Rasmussen's encephalitis. Anarrative review.

Rasmussen's encephalitis is a rare neurological pathology affecting one cerebral hemisphere, therefore, posing unique challenges. Patients may undergo hemispherectomy, a surgical procedure after which cognitive development occurs in the isolated contralateral hemisphere. This rare situation provides an excellent opportunity to evaluate brain plasticity and cognitive recovery at a hemispheric level. This literature review synthesizes the existing body of research on cognitive recovery following hemispherectomy in Rasmussen patients, considering cognitive domains and modulatory factors that influence cognitive outcomes. While language function has traditionally been the focus of postoperative assessments, there is a growing acknowledgment of the need to broaden the scopeof language investigation in interaction with other cognitive domains and to consider cognitive scaffolding in development and recovery. By synthesizing findings reported in the literature, we delineate how language functions may find support from the right hemisphere after left hemispherectomy, but also how, beyond language, global cognitive functioning is affected. We highlight the critical influence of several factors on postoperative cognitive outcomes, including the timing of hemispherectomy and the baseline preoperative cognitive status, pointing to early surgical intervention as predictive of better cognitive outcomes. However, further specific studies are needed to confirm this correlation. This review aims to emphasize a better understanding of mechanisms underlying hemispheric specialization and plasticity in humans, which are particularly important for both clinical and research advancements. Thisnarrative review underscores the needfor an integrative approach based on cognitive scaffolding to provide a comprehensive understanding of mechanisms underlying the reorganization in Rasmussen patients after hemispherectomy.

An fMRI-based investigation of the effects of odors on the functional connectivity network underlying the working memory.

In the human brain, the regions responsible for emotion processing, motivation, and memory are heavily influenced by olfaction, whose neural pathway is directly exposed to the outer world. In this study, we used fMRI to examine how different olfactory conditions might affect the functional connectivity circuit underlying working memory in the brain. To this end, 30 adults (aged 20-35), 13 males and 17 females, with high educational levels were chosen. Participants were screened for potential olfactory issues before undergoing the Sniffin' sticks test, which was part of the inclusion criteria. Before imaging, each participant was given the required level of training and was then asked to complete four olfactory tests involving pleasant and unpleasant odors, air, and null stimulation. The results of Seed-based analysis suggested a function connection between the inferior parietal region and the left frontal pole region upon olfactory stimulation with vanilla scent in contrast to null stimulation in this comparison, ROI-based analysis revealed an inverse synchronous among the entorhinal cortex, orbitofrontal cortex, and dorsolateral prefrontal cortex (dlPFC). Both dlPFC and hippocampus were involved in olfactory discrimination between two different stimulants. Our findings indicate the presence of inverse correlations between several regions associated with olfaction and working memory, with pleasant scents leaving a stronger impact on the working memory-related areas, particularly the inferior parietal region.

A comprehensive review on role of magnetic resonance imaging in the precise measurement of corpus callosum

Magnetic Resonance Imaging (MRI) has emerged as a powerful and non-invasive imaging technique, playing a pivotal role in neuroimaging research and clinical diagnosis. This comprehensive review explores the significance of MRI in the precise measurement of the corpus callosum, a key structure connecting the two hemispheres of the brain. The corpus callosum plays a crucial role in inter hemispheric communication and is implicated in various neurological and psychiatric disorders. The review begins by elucidating the anatomy and functions of the corpus callosum, emphasizing its importance in facilitating seamless communication between the cerebral hemispheres. Subsequently, the paper delves into the historical evolution of MRI techniques and how advancements have enhanced the visualization and measurement capabilities of the corpus callosum. A detailed examination of various MRI modalities, including structural MRI, diffusion tensor imaging (DTI), and functional MRI, is presented in the context of corpus callosum analysis. Structural MRI provides high-resolution images for accurate morphological assessments, while DTI offers insights into white matter microstructure and fiber tractography, allowing for a more comprehensive understanding of the corpus callosum's integrity. The review also highlights the role of MRI in investigating alterations in the corpus callosum associated with neurological disorders such as multiple sclerosis, epilepsy, and neurodevelopmental disorders. Additionally, the paper explores how functional MRI contributes to understanding the functional connectivity and inter hemispheric interactions mediated by the corpus callosum. Challenges and limitations in the measurement of the corpus callosum using MRI are discussed, including methodological considerations, image artifacts, and potential sources of variability. The review concludes by outlining future directions in corpus callosum imaging research, including the integration of advanced imaging techniques, artificial intelligence, and large-scale multi-center studies to enhance the precision and reliability of measurements.In summary, this comprehensive review underscores the pivotal role of MRI in advancing our understanding of the corpus callosum, providing valuable insights into both normal brain function and pathological conditions. The continual evolution of MRI techniques holds promise for further refining the assessment of the corpus callosum, ultimately contributing to improved diagnostic accuracy and therapeutic interventions in neurological and psychiatric disorders.

Treatment of ornithine transcarbamylase deficiency in a child with glyceryl phenylbutyrate

Glyceryl phenylbutyrate (GPB) serves as a long-term management medication for Ornithine transcarbamylase deficiency (OTCD), effectively controlling hyperammonemia, but there is a lack of experience in using this medicine in China. This article retrospectively analyzes the case of a child diagnosed with OTCD at Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, including a review of related literature. After diagnosis, the patient was treated with GPB, followed by efficacy follow-up and pharmacological monitoring. The 6-year and 6-month-old male patient exhibited poor speech development, disobedience, temper tantrums, and aggressive behavior. Blood ammonia levels peaked at 327 μmol/L; urine organic acid analysis indicated elevated uracil levels; cranial MRI showed extensive abnormal signals in both cerebral hemispheres. Genetic testing revealed de novo mutation in the OTC gene (c.241T>C, p.S81P). Blood ammonia levels were approximately 43, 80, and 56 μmol/L at 1, 2, and 3 months after starting GPB treatment, respectively. During treatment, blood ammonia was well-controlled without drug-related adverse effects. The patient showed improvement in developmental delays, obedience, temperament, and absence of aggressive behavior.

Research on electrical capacitance tomography (ECT) detection of cerebral hemorrhage based on symmetrical cancellation method

Currently, there is an urgent need for a fast and portable intracerebral hemorrhage (ICH) detection technology for pre-hospital emergency scenarios. Owing to the disproportionately elevated permittivity of blood compared to other brain tissues, Electrical Capacitance Tomography (ECT) offers a viable modality for mapping the spatial distribution of permittivity within the brain, thus facilitating the imaging-based identification of ICH. Currently, ECT is confined to time-differential imaging due to limited sensitivity, and this methodology requires non-hemorrhagic measurements for comparison, data that are frequently inaccessible in clinical contexts. To overcome this limitation, in accordance with the natural bilateral symmetry of the cerebral hemispheres, a symmetrical cancellation scheme is introduced. In this method, electrodes are uniformly arrayed around the cranial periphery and strategically positioned in a symmetrical manner relative to the sagittal suture. Subsequently, the measured capacitances for each electrode pair are subtracted from those of their symmetrical counterparts aligned with the sagittal suture. As a result, this process isolates the capacitance attributable solely to hemorrhagic events within a given hemisphere, permitting the absolute imaging of ICH. To assess the feasibility of this method, simulation and empirical imaging were conducted respectively on a numerical hemorrhage model and three physical models (a water-wrapped hemorrhage model, an isolated porcine fat-wrapped hemorrhage model, and an isolated porcine brain tissue-wrapped hemorrhage model). Traditional absolute imaging, time-differential imaging and symmetrical cancellation imaging were performed on all models. The results substantiate that the proposed imaging modality is capable of obtaining absolute imaging of ICH. But a mirrored artifact, symmetrical to the site of the actual hemorrhage image appeared in each of the imaging results. This mirror artifact was characterized by identical dimensions and an inverted pixel-value schema, an intrinsic consequence of the symmetrical cancellation imaging algorithm. The real image of hemorrhage can be ascertained through pre-judgment with the symptoms of the patient. Additionally, the quality of this imaging is seriously dependent on the precise alignment between the electrodes and the sagittal suture of the brain; even a minor deviation in symmetry could introduce excessive noises. Thus, the complicated operational procedures remain as challenges for practical application.

Temporal multiplexing of perception and memory codes in IT cortex

A central assumption of neuroscience is that long-term memories are represented by the same brain areas that encode sensory stimuli1. Neurons in inferotemporal (IT) cortex represent the sensory percept of visual objects using a distributed axis code2–4. Whether and how the same IT neural population represents the long-term memory of visual objects remains unclear. Here we examined how familiar faces are encoded in the IT anterior medial face patch (AM), perirhinal face patch (PR) and temporal pole face patch (TP). In AM and PR we observed that the encoding axis for familiar faces is rotated relative to that for unfamiliar faces at long latency; in TP this memory-related rotation was much weaker. Contrary to previous claims, the relative response magnitude to familiar versus unfamiliar faces was not a stable indicator of familiarity in any patch5–11. The mechanism underlying the memory-related axis change is likely intrinsic to IT cortex, because inactivation of PR did not affect axis change dynamics in AM. Overall, our results suggest that memories of familiar faces are represented in AM and perirhinal cortex by a distinct long-latency code, explaining how the same cell population can encode both the percept and memory of faces.

Malformations of the Cerebral Commissures

AbstractMalformations of the cerebral commissures are abnormalities involving the structures which connect the brain hemispheres. The main cerebral commissures are the anterior commissure, the hippocampal commissure, and the corpus callosum, which is the largest and best known of the three and connects the neocortex of the two cerebral hemispheres. Commissures of more reduced extension are the posterior commissure and the habenular commissure. They derive embryologically from the same structure, the commensurate plate. Any interference in the embryological development of the brain commissures may cause an anomaly of all the three commissures or of a single commissure, as well as any combination of anomalies of each of them.Each of these three commissural traits may be absent, isolated, or in combination. The abnormality of the commissures, in addition, can be complete or partial, with dysplasia of the meninges, with multicystic dysplasia of the interhemispheric meninges, in the context of Aicardi syndrome or with the presence of interhemispheric lipomas.The complete agenesis of the commissures (“classic” form) is the most common form and encompasses more than a third of the cases. In complete agenesis, by definition, both the corpus callosum and the hippocampal commissure are totally absent.Anomalies of the commissural structures associated with dysplasia of the meninges include the agenesis of the corpus callosum with interhemispheric cysts (a complex spectrum of clinical and neuroradiological conditions characterized by the associated presence of an interhemispheric cyst formed by communicating cavities) and the agenesis of commissures with interhemispheric lipomas that are usually located in the subarachnoid space.Genes responsible for axonal migration to the commissural plate and those responsible for crossing and connections with the neurons of the contralateral hemisphere are multiple, so that malformations of the cerebral commissure/corpus callosum can be found in numerous malformative syndromes with other multiple associated abnormalities.