The cortical hand knob region of the brain is a knob-like segment of the precentral gyrus, projecting into the middle genu of the central sulcus. This anatomic landmark is responsible for intricate control of hand motor movements and has often been implicated in motor weakness following stroke. In some instances, damage to this area has been mistaken for peripheral causes of hand weakness. Our article aims to consolidate clinically relevant information on the cortical hand knob area in a comprehensive review to guide clinicians regarding diagnosis and treatment strategies. We conducted a systematic search within the Medline/PubMed database for reports of strokes in the cortical hand knob region. All studies were published electronically up until December 2023. The search was conducted using the keyword “hand knob”. A total of 24 reports containing 150 patients were found. The mean and median ages were 65 and 67 years, respectively. Sixty-two percent of the individuals were male. According to the TOAST criteria for the classification of the stroke, 59 individuals had a stroke due to large-artery atherosclerosis, 8 had small-vessel occlusion, 20 had cardioembolism, 25 were determined, and 38 were undetermined. The most common etiologies for stroke in the hand knob area can be attributed to large vessel occlusions, small vessel occlusions, or cardioembolism. Presentations following damage to this area can mimic ulnar, median, or radial neuropathy as well. Our comprehensive review serves as a resource for recognizing and managing stroke in the cortical hand knob area.

A Narrative Review of Stroke of Cortical Hand Knob Area

The empirical classiﬁcation of gamma-ray bursts (GRBs) into long and short GRBs based on their durations is already ﬁrmly established. This empirical classiﬁcation is generally linked to the physical classiﬁcation of GRBs originating from compact binary mergers and GRBs originating from massive star collapses, or Type I and II GRBs, with the majority of short GRBs belonging to Type I and the majority of long GRBs belonging to Type II. However, there is a signiﬁcant overlap in the duration distributions of long and short GRBs. Furthermore, some intermingled GRBs, i.e., short-duration Type II and long-duration Type I GRBs, have been reported. A multi-wavelength, multi-parameter classiﬁcation scheme of GRBs is evidently needed. In this paper, we seek to build such a classiﬁcation scheme with supervised machine learning methods, chieﬂy XGBoost. We utilize the GRB Big Table and Greiner’s GRB catalog and divide the input features into three subgroups: prompt emission, afterglow, and host galaxy. We ﬁnd that the prompt emission subgroup performs the best in distinguishing between Type I and II GRBs. We also ﬁnd the most important distinguishing feature in prompt emission to be T 90 , hardness ratio, and ﬂuence. After building the machine learning model, we apply it to the currently unclassiﬁed GRBs to predict their probabilities of being either GRB class, and we assign the most probable class of each GRB to be its possible physical class.

pdf/identifying-the-physical-origin-of-gamma-ray-bursts-with-32vrmtgp.pdf

Identifying the physical origin of gamma-ray bursts with supervised machine learning

Background Childhood hand function is considered to be one of the strongest predictors of the ability to participate in daily activities as children with cerebral palsy (CP) reach adulthood. The manual ability classification system (MACS) is currently the most widely used for grading hand function in children with CP. However, the MACS method is subjective and may be affected by the raters’ experience. Hand knob is an important control center for hand movement. Therefor this study aimed to develop and validate an objective model for hand function estimation in children with CP and visualize it as a nomogram. Methods A total of 70 Children (2–12 years old) with CP underwent magnetic resonance imaging (MRI) scanning, MACS assessment. According to MACS, children with CP were divided into mild impairment group (grade I–III) and severe impairment group (grade IV–V). Hand function prediction models based on (I) hand knob score, (II) clinical features, and (III) the combination of clinical features and hand knob score were developed and validated separately. The models were subjected to stepwise regression according to the maximum likelihood method, and the Akaike information criterion was used to select the best model. Model discrimination was assessed using receiver operating characteristic (ROC) and calibration curves. The nomogram was finally built according to the best model. Results The area under the curve (AUC) of the hand knob score model in the training set was 0.752, the clinical features model was 0.819, and the hand knob score and clinical features combined model was 0.880. The AUC of the hand knob score model in the validation set was 0.765, the clinical features model was 0.782, and the combined model was 0.894. The best model was the hand knob score-clinical features combined model, and the nomogram finally incorporated two assessment items: the hand knob score and white matter injury. The estimated probability of hand function injury degree of the combined model displayed good agreement with the actual occurrence probability. Conclusions The hand knob score-clinical features combined model can be used to preliminarily assess the degree of hand impairment in children with CP, with good calibration.

/pdf/development-and-validation-of-a-novel-model-based-on-hand-2ymj8e2y.pdf

Development and validation of a novel model based on hand knob score and white matter injury on MRI to predict hand function in children with cerebral palsy

This study was to systematically assess the occipital lobe gray and white matter volume of isolated ventriculomegaly (IVM) fetuses with MRI and to follow up the neurodevelopment of participants. MRI was used to evaluate 37 IVM fetuses and 37 control fetuses. The volume of gray and white matter in each fetal occipital gyrus was manually segmented and compared, and neurodevelopment was followed up and assessed in infancy and early childhood. Compared with the control group, the volume of gray matter in occipital lobe increased in the IVM group, and the incidence of neurodevelopmental delay increased. We tested the hypothesis that prenatal diagnosis IVM represents a biological marker for development in fetal occipital lobe. Compared with the control group, the IVM group showed differences in occipital gray matter development and had a higher risk of neurodevelopmental delay.

Volume development changes in the occipital lobe gyrus assessed by MRI in fetuses with isolated ventriculomegaly correlate with neurological development in infancy and early childhood

Abstract As an interesting subclass of gamma-ray bursts (GRBs), Type IL GRBs (such as GRB 211211A and GRB 230307A) features a long-duration prompt emission but originating from a compact binary merger. The “long duration” emission of Type IL GRBs are dominantly composed of the main burst, rather than the extended emission, differentiating them from the traditional “long-short” GRB (e.g., GRB 060614). A previous study has reported several Type IL GRBs by visual inspection of their light curves. In this work, we established a detailed criterion to identify Type IL GRBs by light curve and then systematically searched the archival Fermi/Gamma-ray Burst Monitor data with this criterion, resulting in a sample of five type IL GRBs from 2014 January 1 to 2024 January 1, i.e., GRB 230307A, GRB 211211A, GRB 200914A, GRB 200311A, and GRB 170228A. Apart from the light-curve pattern, we find that the temporal and spectral properties of these five GRBs also support this classification. Interestingly, we find that the energy ratio between extended emission and main emission is almost constant (∼0.7, with small scattering) for these GRBs, which have strong implications on the mechanism of Type IL burst. We discuss theoretical models to interpret the progenitor, central engine, and extended emission of these Type IL bursts. 

pdf/search-for-type-il-gamma-ray-bursts-criterion-results-ozf021299zoi.pdf

Search for Type IL Gamma-Ray Bursts: Criterion, Results, Verification, and Physical Implication

The central engine that powers gamma-ray bursts (GRBs), the most powerful explosions in the universe, is still not identified. Besides hyper-accreting black holes, rapidly spinning and highly magnetized neutron stars, known as millisecond magnetars, have been suggested to power both long and short GRBs. The presence of a magnetar engine following compact star mergers is of particular interest as it would provide essential constraints on the poorly understood equation of state for neutron stars. Indirect indications of a magnetar engine in these merger sources have been observed in the form of plateau features present in the X-ray afterglow light curves of some short GRBs. Additionally, some X-ray transients lacking gamma-ray bursts (GRB-less) have been identified as potential magnetar candidates originating from compact star mergers. Nevertheless, smoking gun evidence is still lacking for a magnetar engine in short GRBs, and the associated theoretical challenges have been addressed. Here we present a comprehensive analysis of the broad-band prompt emission data of a peculiar, very bright GRB 230307A. Despite its apparently long duration, the prompt emission and host galaxy properties point toward a compact star merger origin, being consistent with its association with a kilonova. More intriguingly, an extended X-ray emission component emerges as the $\gamma$-ray emission dies out, signifying the emergence of a magnetar central engine. We also identify an achromatic temporal break in the high-energy band during the prompt emission phase, which was never observed in previous bursts and reveals a narrow jet with half opening angle of approximately $3.4^\circ$.

pdf/magnetar-emergence-in-a-peculiar-gamma-ray-burst-from-a-3k2nwvxr.pdf

Magnetar emergence in a peculiar gamma-ray burst from a compact star merger

BACKGROUND AND PURPOSE: Knowledge of anatomic markers of the hand motor cortex is essential in the evaluation and treatment of motor neurologic diseases for both adults and developing populations. However, hand motor cortex variants in developing brains remain to be investigated. Our objective was to observe morphologic variants of the hand motor cortex in developing brains from neonates through childhood. MATERIALS AND METHODS: In this study, 542 participants (0∼15 years of age) were retrospectively enrolled and divided into different age groups. The hand motor cortex morphology was evaluated on the basis of 3D T1WI. Variations in hand motor cortex variants were compared among different age groups. Inter-gender and interhemispheric differences of hand motor cortex variants were also evaluated. RESULTS: Various hand motor cortex variants could be observed in developing brains, even in the neonatal period. One new morphologic shape, “immature Ω,” was found in neonates and infants. The proportion of this new shape decreased dramatically during the first year after birth, then disappeared after 1 year of age. It persisted for a longer time in the right hemisphere and in males. However, sex or hemispheric effects on the distribution of the proportion of variants were not statistically significant. Furthermore, the proportion of concordance of the bilateral hand motor cortex showed an increasing trend with age (P = .006), higher in females than males. CONCLUSIONS: Various hand motor cortex variants already existed at birth. The distribution of proportions of different variants developmentally varied during the first year after birth and became stable after 1 year of age. The concordance of the bilateral hand motor cortex could be influenced by age and sex.

http://www.ajnr.org/content/ajnr/43/2/292.full.pdf

Morphologic Variants of the Hand Motor Cortex in Developing Brains from Neonates through Childhood Assessed by MR Imaging

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Magnetar emergence in a peculiar gamma-ray burst from a compact star merger

Morphologic Variants of the Hand Motor Cortex in Developing Brains from Neonates through Childhood Assessed by MR Imaging