Traumatic axonal injury is a progressive process evoked by shear forces on the brain, gradually evolving from focal axonal alteration and cumulating in neural disconnection. Clinical classifiers and conventional neuro...Traumatic axonal injury is a progressive process evoked by shear forces on the brain, gradually evolving from focal axonal alteration and cumulating in neural disconnection. Clinical classifiers and conventional neuroimaging are limited in traumatic axonal injury detection, outcome prediction, and treatment guidance. Diffusion weighted imaging is an advanced magnetic resonance imaging (MRI) technique that is sensitive to the movement of water molecules, providing additional information on the micro-structural arrangement of tissue. Quantitative analysis of diffusion metrics can aid in the localization of axonal injury and/or de(dys)myelination caused by trauma. Diffusion MRI tractography is an extension of diffusion weighted imaging, and can provide additional information about white matter pathways and the integrity of brain neural networks. Both techniques are able to detect the early micro-structural changes caused by Traumatic Brain Injury (TBI), and can be used to increase understanding of the mechanisms of brain plasticity in recovery after brain injury and possibly optimize treatment planning of patients with Traumatic Brain Injury. This review focuses on the theoretical basis and applied advanced techniques of diffusion weighted imaging, their limitations and applications, and future directions in the application to TBI.展开更多
This study aimed to understand the differences in clinical,epidemiological,and laboratory features between the new coronavirus disease 2019(COVID-2019)and influenza A in children.Data of 23 hospitalized children with ...This study aimed to understand the differences in clinical,epidemiological,and laboratory features between the new coronavirus disease 2019(COVID-2019)and influenza A in children.Data of 23 hospitalized children with COVID-19(9 boys,5.7±3.8 years old)were compared with age-and sexmatched 69 hospitalized and 69 outpatient children with influenza A from a hospital in China.展开更多
Transcranial electrical stimulation （TCES） is effective in treating many conditions, but it has not been possible to accurately forecast current density within the complex anatomy of a given subject＇s head. We soug...Transcranial electrical stimulation （TCES） is effective in treating many conditions, but it has not been possible to accurately forecast current density within the complex anatomy of a given subject＇s head. We sought to predict and verify TCES current densities and determine the variability of these current distributions in patient-specific models based on magnetic resonance imaging （MRI） data. Two experiments were performed. The first experiment estimated conductivity from MRIs and compared the current density results against actual measurements from the scalp surface of 3 subjects. In the second experiment, virtual electrodes were placed on the scalps of 18 subjects to model simulated current densities with 2 mA of virtually applied stimulation. This procedure was repeated for 4 electrode locations. Current densities were then calculated for 75 brain regions. Comparison of modeled and measured external current in experiment 1 yielded a correlation of r = .93. In experiment 2, modeled individual differences were greatest near the electrodes （ten-fold differences were common）, but simulated current was found in all regions of the brain. Sites that were distant from the electrodes （e.g. hypothalamus） typically showed two- fold individual differences. MRI-based modeling can effectively predict current densities in individual brains. Significant variation occurs between subjects with the same applied electrode configuration. Individualized MRI- based modeling should be considered in place of the 10-20 system when accurate TCES is needed.展开更多
Impairments in using eye gaze to establish joint attention and to comprehend the mental states and intentions of other people are striking features of autism. Here, using event-related functional MRI (fMRI), we show t...Impairments in using eye gaze to establish joint attention and to comprehend the mental states and intentions of other people are striking features of autism. Here, using event-related functional MRI (fMRI), we show that in autism, brain regions involved in gaze processing, i ncluding the superior temporal sulcus (STS) region, are not sensitive to intenti ons conveyed by observed gaze shifts. On congruent trials, subjects watched as a virtual actor looked towards a checkerboard that appeared in her visual field, confirming the subject’s expectation regarding what the actor ‘ought to do’in this context. On incongruent trials, she looked towards empty space, violating the subject’s expectation. Consistent with a prior report from our laboratory t hat used this task in neurologically normal subjects, ‘errors’(incongruent tri als) evoked more activity in the STS and other brain regions linked to social co gnition, indicating a strong effect of intention in typically developing subject s (n=9). The same brain regions were activated during observation of gaze shifts in subjects with autism (n=10), but did not differentiate congruent and incongr uent trials, indicating that activity in these regions was not modulated by the context of the perceived gaze shift. These results demonstrate a difference in t he response of brain regions underlying eye gaze processing in autism. We conclu de that lack of modulation of the STS region by gaze shifts that convey differen t intentions contributes to the eye gaze processing deficits associated with aut ism.展开更多
文摘Traumatic axonal injury is a progressive process evoked by shear forces on the brain, gradually evolving from focal axonal alteration and cumulating in neural disconnection. Clinical classifiers and conventional neuroimaging are limited in traumatic axonal injury detection, outcome prediction, and treatment guidance. Diffusion weighted imaging is an advanced magnetic resonance imaging (MRI) technique that is sensitive to the movement of water molecules, providing additional information on the micro-structural arrangement of tissue. Quantitative analysis of diffusion metrics can aid in the localization of axonal injury and/or de(dys)myelination caused by trauma. Diffusion MRI tractography is an extension of diffusion weighted imaging, and can provide additional information about white matter pathways and the integrity of brain neural networks. Both techniques are able to detect the early micro-structural changes caused by Traumatic Brain Injury (TBI), and can be used to increase understanding of the mechanisms of brain plasticity in recovery after brain injury and possibly optimize treatment planning of patients with Traumatic Brain Injury. This review focuses on the theoretical basis and applied advanced techniques of diffusion weighted imaging, their limitations and applications, and future directions in the application to TBI.
文摘This study aimed to understand the differences in clinical,epidemiological,and laboratory features between the new coronavirus disease 2019(COVID-2019)and influenza A in children.Data of 23 hospitalized children with COVID-19(9 boys,5.7±3.8 years old)were compared with age-and sexmatched 69 hospitalized and 69 outpatient children with influenza A from a hospital in China.
基金supported by the Sutter Institute for Medical Researchthe Aaken Research Institute
文摘Transcranial electrical stimulation （TCES） is effective in treating many conditions, but it has not been possible to accurately forecast current density within the complex anatomy of a given subject＇s head. We sought to predict and verify TCES current densities and determine the variability of these current distributions in patient-specific models based on magnetic resonance imaging （MRI） data. Two experiments were performed. The first experiment estimated conductivity from MRIs and compared the current density results against actual measurements from the scalp surface of 3 subjects. In the second experiment, virtual electrodes were placed on the scalps of 18 subjects to model simulated current densities with 2 mA of virtually applied stimulation. This procedure was repeated for 4 electrode locations. Current densities were then calculated for 75 brain regions. Comparison of modeled and measured external current in experiment 1 yielded a correlation of r = .93. In experiment 2, modeled individual differences were greatest near the electrodes （ten-fold differences were common）, but simulated current was found in all regions of the brain. Sites that were distant from the electrodes （e.g. hypothalamus） typically showed two- fold individual differences. MRI-based modeling can effectively predict current densities in individual brains. Significant variation occurs between subjects with the same applied electrode configuration. Individualized MRI- based modeling should be considered in place of the 10-20 system when accurate TCES is needed.
文摘Impairments in using eye gaze to establish joint attention and to comprehend the mental states and intentions of other people are striking features of autism. Here, using event-related functional MRI (fMRI), we show that in autism, brain regions involved in gaze processing, i ncluding the superior temporal sulcus (STS) region, are not sensitive to intenti ons conveyed by observed gaze shifts. On congruent trials, subjects watched as a virtual actor looked towards a checkerboard that appeared in her visual field, confirming the subject’s expectation regarding what the actor ‘ought to do’in this context. On incongruent trials, she looked towards empty space, violating the subject’s expectation. Consistent with a prior report from our laboratory t hat used this task in neurologically normal subjects, ‘errors’(incongruent tri als) evoked more activity in the STS and other brain regions linked to social co gnition, indicating a strong effect of intention in typically developing subject s (n=9). The same brain regions were activated during observation of gaze shifts in subjects with autism (n=10), but did not differentiate congruent and incongr uent trials, indicating that activity in these regions was not modulated by the context of the perceived gaze shift. These results demonstrate a difference in t he response of brain regions underlying eye gaze processing in autism. We conclu de that lack of modulation of the STS region by gaze shifts that convey differen t intentions contributes to the eye gaze processing deficits associated with aut ism.
