Photoacoustic treatment mitigates cognitive dysfunction in a model of sleep-wake rhythm disturbance

Sleep-wake rhythm disturbances,which are characterized by abnormal sleep timing or duration,are associated with cognitive dysfunction.Photoacoustic treatments including light and sound stimulation have been found to be effective in modulating sleep patterns and improving cognitive behavior in abnormal sleep-wake pattern experiments.In this study,we examined whether light and sound interventions could reduce sleep-wake pattern disturbances and memory deficits in a sleep rhythm disturbance model.We established a model of sleep rhythm disturbance in C57 BL/6 J mice via a sleep deprivation method involving manual cage tapping,cage jostling,and nest disturbance.We used a Mini Mitter radio transmitter device to monitor motor activity in the mice and fear conditioning tests to assess cognitive function.Our results indicated that an intervention in which the mice were exposed to blue light(40-Hz flickering frequency)for 1 hour during their subjective daytime significantly improved the 24-hour-acrophase shift and reduced the degree of memory deficit induced by sleep deprivation.However,interventions in which the mice were exposed to a 40-Hz blue light at offset time or subjective night time points,as well as 2 Hz-blue light at 3 intervention time points(subjective day time,subjective night time,and offset time points),had no positive effects on circadian rhythm shift or memory deficits.Additionally,a 2000-Hz sound intervention during subjective day time attenuated the24-hour-acrophase shift and memory decline,while 440-Hz and 4000-Hz sounds had no effect on circadian rhythms.Overall,these results demonstrate that photoacoustic treatment effectively corrected abnormal sleep-wake patterns and cognitive dysfunction associated with sleep-deprivation-induced disturbances in sleep-wake rhythm.All animal experiments were approved by the Experimental Animal Ethics Committee of Drum Tower Hospital Affiliated to the Medical College of Nanjing University,China(approval No.20171102)on November20,2017.     

Adverse effects of semicircular circle angles variation on Epley repositioning procedure: a study on reconstruction of Micro-CT images 3D

Abstract

Background: For patients with posterior semicircular canal (PSC) BPPV, Epley re-position maneuver and some improvement methods are the most efficient treatment methods. But there were still 9.43% patients who were not benefit from Epley re-position maneuver.

Objective: To measure the angles of semicircular canals and evaluate its effect on Epley maneuver.

Methods: Fifteen skull specimens, containing 30 temporal bone specimens were included. After Micro-CT scanning, 3D reconstruction was loaded with the CT image. The angles between each semicircular canal and each standard skull plane were measured. Furthermore, the angles’ effect on Epley maneuver was evaluated according to the three-dimension (3D) model.

Results: Angles of PSC plane: Frankfurt plane was 71.54?±?6.51, sagittal plane was 53.77?±?5.36°, and the coronal plane was 43.33?±?3.56°. Angles between PSC and the sagittal plane of skulls had an adverse effect on Epley maneuver, when it was less than 45°.

Conclusion: 1. Variation could be found in angles between the semicircular canals and the standard planes of skulls, which meant variation of semicircular canals’ location existing in skulls. 2. The variation of angles between PSC and sagittal plane could have an adverse effect on the Epley maneuver when the angle was less than 45°, which may cause the Epley maneuver to be invalid.     

CD200 maintains the region-specific phenotype of microglia in the midbrain and its role in Parkinson's disease

Microglia are a specialized population of tissue macrophages in the mammalian brain. Microglial phenotype is tightly regulated by local environmental factors, although little is known about these factors and their region-preferred roles in regulating local neuroinflammatory responses. We hypothesized that microglia in different brain regions respond differently to neuroinflammatory stimulation and that CD200, an anti-inflammatory protein mainly originated from neurons, acts as a local cue inhibiting microglia activation in the midbrain. We utilized a CD200-deficient mouse line to analyze the phenotypic role of CD200 in the regulation of normal neuron–microglia homeostasis in the midbrain and in the dopaminergic degeneration in an α-synuclein overexpression model of PD. We found that systemic administration of an endotoxin lipopolysaccharide induced a region-preferred change in CD200 expression in the midbrain. Similarly, CD200^−/− mice showed a regional preference in an enhancement of microglia activation and baseline inflammatory levels in the midbrain and dopamine neuron loss in the substantia nigra (SN). In a mouse model of Parkinson's disease (PD) induced by rAAV-hSYN injection into the SN, CD200^−/− mice showed more dopamine neuron loss in the SN than wild type mice. Activation of CD200 receptors with a CD200 fusion protein alleviated the neuroinflammation and neuronal death in the SN of PD mice. These findings demonstrate that CD200 is essential for the midbrain homeostasis and acts as a critical local regulator in controlling microglial properties related to the PD pathogenesis.     

以姿势平衡障碍为突出表现的家族性致死性失眠一例并文献复习

目的报道1例以姿势平衡障碍为突出表现的家族性致死性失眠(fatal familial insomnia,FFI)患者的临床表现和基因特点。方法分析1例以姿势平衡障碍、重复语言为突出表现,曾疑诊为进行性核上性麻痹(progressive supranuclear palsy,PSP)的FFI患者的临床特征、影像学特点、脑电图及多导睡眠监测等资料,并对患者血标本进行朊蛋白PRNP基因检测。结果本例患者为39岁女性,症状逐渐进展,主要表现为姿势平衡障碍、语速快、重复语言,快速进展的认知障碍,伴睡眠相关呼吸暂停、吸气性喘鸣,同时有血压高、出汗多、心动过速、呼吸不规律等自主神经症状。结合患者PRNP基因检测结果为D178N/129M型,最终诊断为FFI。结论吸气性喘鸣或"牛吼声"在FFI的诊断中有提示意义。姿势平衡障碍在FFI临床症状谱中相对罕见,129位氨基酸等位基因多态性为Met/Met纯合子的FFI患者早期以姿势不稳,向后倾倒为主要临床表现的FFI病例,国内鲜有报道。     

基于弥散张量成像技术的双相障碍患者脑白质纤维束异常分析

目的探讨抑郁期双相障碍患者脑白质纤维束的变化。方法选取42例未用药双相障碍抑郁期患者(患者组)和年龄、性别及右利手与之相匹配的59名对照者(对照组)进行DTI检查,根据约翰霍普金斯大学人类白质纤维束图谱,将大脑白质组织分割为20条公认存在的粗大纤维束,应用PANDA软件计算每个被试者每条白质纤维束的4项平均弥散属性,采用非参数置换检验比较2组在20条白质纤维束上弥散指标的差异,将差异有统计学意义的脑白质纤维束弥散指标与临床指标进行Pearson相关分析。结果患者组左侧钩束各向异性分数(fractional anisotropy,FA)值低于对照组(0.40±0.01与0.41±0.01,P=0.001);胼胝体辐射线额部FA值低于对照组(0.36±0.02与0.38±0.02,P<0.001);左侧钩束径向弥散率(radial diffusivity,RD)值高于对照组(6.57×10^-4±2.41×10^-5与6.40×10^-4±2.42×10^-5,P=0.0017)。Pearson相关分析显示,2组弥散指标差异有统计学意义的白质纤维束与临床指标之间均无相关性。结论抑郁期双相障碍患者钩束及胼胝体辐射线额部存在脑白质完整性破坏。     

The effect of jet lag on the human brain: A neuroimaging study

Jet lag is commonly experienced when travelers cross multiple time zones, leaving the wake–sleep cycle and intrinsic biological “clocks” out of synchrony with the current environment. The effect of jet lag on intrinsic cortical function remains unclear. Twenty‐two healthy individuals experiencing west‐to‐east jet lag flight were recruited. Brain structural and functional magnetic resonance studies, as well as psychological and neurohormonal tests, were carried out when participants returned from travel over six time zones and 50 days later when their jet lag symptoms had resolved. During jet lag, the functional brain network exhibited a small‐world topology that was shifted toward regularity. Alterations during jet lag relative to recovery included decreased basal ganglia‐thalamocortical network connections and increased functional connectivity between the medial temporal lobe subsystem and medial visual cortex. The lower melatonin and higher thyroid hormone levels during jet lag showed the same trend as brain activity in the right lingual gyrus. Although there was no significant difference between cortisol measurements during and after jet lag, cortisol levels were associated with temporal lobe activity in the jet lag condition. Brain and neuroendocrine changes during jet lag were related to jet lag symptoms. Further prospective studies are needed to explore the time course over which jet lag acts on the human brain.     

Demyelinating processes in aging and stroke in the central nervous system and the prospect of treatment strategy

Demyelination occurs in response to brain injury and is observed in many neurodegenerative diseases. Myelin is synthesized from oligodendrocytes in the central nervous system, and oligodendrocyte death‐induced demyelination is one of the mechanisms involved in white matter damage after stroke and neurodegeneration. Oligodendrocyte precursor cells (OPCs) exist in the brain of normal adults, and their differentiation into mature oligodendrocytes play a central role in remyelination. Although the differentiation and maturity of OPCs drive endogenous efforts for remyelination, the failure of axons to remyelinate is still the biggest obstacle to brain repair after injury or diseases. In recent years, studies have made attempts to promote remyelination after brain injury and disease, but its cellular or molecular mechanism is not yet fully understood. In this review, we discuss recent studies examining the demyelination process and potential therapeutic strategies for remyelination in aging and stroke. Based on our current understanding of the cellular and molecular mechanisms underlying remyelination, we hypothesize that myelin and oligodendrocytes are viable therapeutic targets to mitigate brain injury and to treat demyelinating‐related neurodegeneration diseases.