HRF

HRF
  • 文章类型: Journal Article
    立体定向消融放疗(SABR)越来越多地用于治疗早期非小细胞肺癌(ES-NSCLC)和肺转移。在ES-NSCLC患者中,SABR非常成功,报告的5年局部控制率约为90%。然而,由于高达90%的患者可以观察到由放射性肺损伤(RILI)引起的放射学变化,因此评估肺SABR后的局部控制可能具有挑战性.这些所谓的“良性”放射学变化随时间演变,通常无症状。已经探索了几种放射学和代谢特征来帮助区分RILI和局部复发(LR)。这些包括实体瘤的反应评估标准(RECIST),FDG-PET-CT的高危特征(HRF)和最大标准化摄取值(SUVmax)。然而,使用其中一些方法对复发的预测价值较差,特异性较低.将审查用于评估肺后SABR放射学变化的拟议新工作流程,该工作流程使用所谓的“可操作放射学特征”的存在来触发成像时间表的变化,并确定是否需要进行多学科委员会审查。此外,这项关于肺后SABR成像的重要回顾将突出当前的挑战,新的见解,在这个领域是未知的。
    Stereotactic ablative radiotherapy (SABR) is increasingly used for the treatment of early-stage non-small cell lung cancer (ES-NSCLC) and for pulmonary metastases. In patients with ES-NSCLC, SABR is highly successful with reported 5-year local control rates of approximately 90%. However, the assessment of local control following lung SABR can be challenging as radiological changes arising from radiation-induced lung injury (RILI) can be observed in up to 90% of patients. These so-called \'benign\' radiological changes evolve with time and are often asymptomatic. Several radiological and metabolic features have been explored to help distinguish RILI from local recurrences (LR). These include the Response Evaluation Criteria for Solid Tumors (RECIST), high-risk features (HRF\'s) and maximum standardized uptake value (SUVmax) on FDG-PET-CT. However, use of some of these approaches have poor predictive values and low specificity for recurrence. A proposed new workflow for the evaluation of post-lung SABR radiological changes will be reviewed which uses the presence of so-called \'actionable radiological features\' to trigger changes to imaging schedules and identifies the need for a multidisciplinary board review. Furthermore, this critical review of post-lung SABR imaging will highlight current challenges, new insights, and unknowns in this field.
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  • 文章类型: Journal Article
    背景:具有PDZ结合基序(TAZ)的转录共激活因子在大多数组织中广泛表达,并与几种转录因子相互作用以调节细胞增殖,分化,和死亡,从而影响器官发育和大小控制。然而,人们对TAZ在免疫系统中的功能及其与炎症性皮肤病的关系知之甚少,因此,我们研究了TAZ在银屑病发病机制中的作用。
    结果:有趣的是,TAZ在相关的肥大细胞中表达,特别是在溶酶体中,并与组胺释放因子(HRF)共定位。TAZ缺乏促进肥大细胞成熟并增加肥大细胞的HRF表达和分泌。TAZ缺乏症中HRF的上调不是由于转录增加,而是由于蛋白质稳定,和TAZ恢复到TAZ缺陷细胞减少HRF蛋白。有趣的是,咪喹莫特(IMQ)诱导的银屑病,其中HRF作为主要的促炎因子,在TAZKO小鼠中比在WT对照中更严重。通过IMQ处理,HRF表达和分泌增加,并且在用IMQ处理的TAZKO小鼠中更显著。
    结论:因此,由于HRF表达在TAZKO小鼠中稳定,银屑病的发病机制进展更快,提示TAZ通过调节HRF蛋白的稳定性在预防银屑病中发挥重要作用。
    BACKGROUND: Transcriptional coactivator with PDZ-biding motif (TAZ) is widely expressed in most tissues and interacts with several transcription factors to regulate cell proliferation, differentiation, and death, thereby influencing organ development and size control. However, very little is known about the function of TAZ in the immune system and its association with inflammatory skin diseases, so we investigated the role of TAZ in the pathogenesis of psoriasis.
    RESULTS: Interestingly, TAZ was expressed in mast cells associated, particularly in lysosomes, and co-localized with histamine-releasing factor (HRF). TAZ deficiency promoted mast cell maturation and increased HRF expression and secretion by mast cells. The upregulation of HRF in TAZ deficiency was not due to increased transcription but to protein stabilization, and TAZ restoration into TAZ-deficient cells reduced HRF protein. Interestingly, imiquimod (IMQ)-induced psoriasis, in which HRF serves as a major pro-inflammatory factor, was more severe in TAZ KO mice than in WT control. HRF expression and secretion were increased by IMQ treatment and were more pronounced in TAZ KO mice treated with IMQ.
    CONCLUSIONS: Thus, as HRF expression was stabilized in TAZ KO mice, psoriatic pathogenesis progressed more rapidly, indicating that TAZ plays an important role in preventing psoriasis by regulating HRF protein stability.
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  • 文章类型: Journal Article
    基于人工智能(AI)和深度学习(DL)的系统在黄斑疾病领域取得了重大进展,在检测视网膜液和评估疾病进展过程中的解剖学变化方面表现良好。这项研究旨在通过分析主要的光学相干断层扫描(OCT)生物标志物来验证AI算法,以识别和量化黄斑裂孔(MH)手术后视力恢复的预后因素。这项研究包括20例接受玻璃体切除术治疗全厚度黄斑裂孔(FTMH)的患者。FTMH的平均直径测量为285.36±97.4μm。术前最佳矫正视力(BCVA)为0.76±0.06logMAR,术后改善至0.38±0.16,具有统计学上的显著差异(p=0.001)。人工智能软件被用来评估生物标志物,如视网膜内液(IRF)和视网膜下液(SRF)的体积,外界膜(ELM)和椭球区(EZ)完整性,和视网膜高反射病灶(HRF)。AI分析显示IRF体积显著减少,术前0.08±0.12mm3到术后0.01±0.01mm3。手术后,ELM中断从79%±18%提高到34%±37%(p=0.006),而EZ中断术后从80%±22%提高到40%±36%(p=0.007)。此外,研究显示术前IRF体积与术后BCVA恢复呈负相关,提示术前液体量增加可能会阻碍视力改善.发现ELM和EZ的完整性对于术后视力改善至关重要,它们的中断对视觉恢复产生了负面影响。该研究强调了AI在量化OCT生物标志物以管理MHs和改善患者护理方面的潜力。
    Artificial intelligence (AI)- and deep learning (DL)-based systems have shown significant progress in the field of macular disorders, demonstrating high performance in detecting retinal fluid and assessing anatomical changes during disease progression. This study aimed to validate an AI algorithm for identifying and quantifying prognostic factors in visual recovery after macular hole (MH) surgery by analyzing major optical coherence tomography (OCT) biomarkers. This study included 20 patients who underwent vitrectomy for a full-thickness macular hole (FTMH). The mean diameter of the FTMH was measured at 285.36 ± 97.4 μm. The preoperative best-corrected visual acuity (BCVA) was 0.76 ± 0.06 logMAR, improving to 0.38 ± 0.16 postoperatively, with a statistically significant difference (p = 0.001). AI software was utilized to assess biomarkers, such as intraretinal fluid (IRF) and subretinal fluid (SRF) volume, external limiting membrane (ELM) and ellipsoid zone (EZ) integrity, and retinal hyperreflective foci (HRF). The AI analysis showed a significant decrease in IRF volume, from 0.08 ± 0.12 mm3 preoperatively to 0.01 ± 0.01 mm3 postoperatively. ELM interruption improved from 79% ± 18% to 34% ± 37% after surgery (p = 0.006), whereas EZ interruption improved from 80% ± 22% to 40% ± 36% (p = 0.007) postoperatively. Additionally, the study revealed a negative correlation between preoperative IRF volume and postoperative BCVA recovery, suggesting that greater preoperative fluid volumes may hinder visual improvement. The integrity of the ELM and EZ was found to be essential for postoperative visual acuity improvement, with their disruption negatively impacting visual recovery. The study highlights the potential of AI in quantifying OCT biomarkers for managing MHs and improving patient care.
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  • 文章类型: Preprint
    静息状态功能磁共振成像(rs-fMRI)是一种流行的技术,它丰富了我们对大脑和脊髓功能的理解,包括不同地区如何通信(连接)。但是功能磁共振成像是神经活动捕获血液动力学的间接测量。未测量的神经活动和测量的fMRI时间序列之间的血液动力学响应函数(HRF)接口。HRF在大脑区域和个体之间是可变的,受非神经因素调节。忽略这种HRF可变性会导致FC估计中的误差。因此,从rs-fMRI数据可靠地估计HRF至关重要。已经出现了从fMRI时间序列估计HRF的强大技术。尽管这些技术已经使用模拟和经验功能磁共振成像数据进行了非侵入性验证,使用同时电生理记录进行彻底的侵入性验证,黄金标准,一直难以捉摸。本报告通过比较来自侵入性颅内脑电图记录的HRF与根据六只癫痫大鼠同时获得的fMRI数据估计的HRF,解决了文献中的这一差距。我们发现HRF形状参数(HRF振幅,潜伏期和宽度)在地面实况和估计的HRFs之间没有显着差异(p>0.05)。在单个病理区域,HRF宽度略有差异(p=0.03)。我们的研究为HRF估计技术在直接从rs-fMRI数据可靠地无创地估计HRF的有效性提供了初步的侵入性验证。这对rs-fMRI连通性研究有显著影响,并且我们建议执行HRF反卷积以最小化HRF变异性并改善连通性估计。
    Resting-state functional MRI (rs-fMRI) is a popular technology that has enriched our understanding of brain and spinal cord functioning, including how different regions communicate (connectivity). But fMRI is an indirect measure of neural activity capturing blood hemodynamics. The hemodynamic response function (HRF) interfaces between the unmeasured neural activity and measured fMRI time series. The HRF is variable across brain regions and individuals, and is modulated by non-neural factors. Ignoring this HRF variability causes errors in FC estimates. Hence, it is crucial to reliably estimate the HRF from rs-fMRI data. Robust techniques have emerged to estimate the HRF from fMRI time series. Although such techniques have been validated non-invasively using simulated and empirical fMRI data, thorough invasive validation using simultaneous electrophysiological recordings, the gold standard, has been elusive. This report addresses this gap in the literature by comparing HRFs derived from invasive intracranial electroencephalogram recordings with HRFs estimated from simultaneously acquired fMRI data in six epileptic rats. We found that the HRF shape parameters (HRF amplitude, latency and width) were not significantly different (p>0.05) between ground truth and estimated HRFs. In the single pathological region, the HRF width was marginally significantly different (p=0.03). Our study provides preliminary invasive validation for the efficacy of the HRF estimation technique in reliably estimating the HRF non-invasively from rs-fMRI data directly. This has a notable impact on rs-fMRI connectivity studies, and we recommend that HRF deconvolution be performed to minimize HRF variability and improve connectivity estimates.
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  • 文章类型: Journal Article
    功能磁共振成像(fMRI)是神经活动的间接测量,血液动力学反应功能(HRF)将其与未测量的神经活动耦合。HRF,由几个非神经因素调节,在不同的大脑区域是可变的,个人和人口。然而,大多数人类静息状态fMRI连接研究继续假设HRF是不变的。在这篇文章中,有了先前的支持性证据,我们认为HRF变异性不能忽视,因为它严重混淆了受试者内部连通性估计和受试者之间连通性组差异.我们还讨论了其与几种疾病中HRF畸变混淆的连接障碍的临床相关性。我们提供了关于女性和男性之间HRF差异的有限数据,这导致在组水平比较中的功能连通性估计的中值误差为15.4%。我们还讨论了HRF变异性对脊髓fMRI研究的影响。需要在社区内部就HRF混淆进行更多对话,我们希望我们的文章是这个过程的催化剂。
    Functional magnetic resonance imaging (fMRI) is an indirect measure of neural activity with the hemodynamic response function (HRF) coupling it with unmeasured neural activity. The HRF, modulated by several non-neural factors, is variable across brain regions, individuals and populations. Yet, a majority of human resting-state fMRI connectivity studies continue to assume a non-variable HRF. In this article, with supportive prior evidence, we argue that HRF variability cannot be ignored as it substantially confounds within-subject connectivity estimates and between-subjects connectivity group differences. We also discuss its clinical relevance with connectivity impairments confounded by HRF aberrations in several disorders. We present limited data on HRF differences between women and men, which resulted in a 15.4% median error in functional connectivity estimates in a group-level comparison. We also discuss the implications of HRF variability for fMRI studies in the spinal cord. There is a need for more dialogue within the community on the HRF confound, and we hope that our article is a catalyst in the process.
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  • 文章类型: Journal Article
    背景:组胺释放因子(HRF)与过敏性疾病有关。我们先前在哮喘小鼠模型中显示了其致病作用。
    目的:从三个独立的人类样本(哮喘患者的血清样本,鼻病毒(RV)感染个体的鼻腔洗液和RV诱导的哮喘急性发作患者的血清样本)和一个小鼠样本,以研究哮喘和病毒诱导的哮喘急性发作中HRF功能的相关性。
    方法:通过酶联免疫吸附测定(ELISA)定量轻度/中度(MA)或重度哮喘(SA)患者和健康对照(HC)血清中的总IgE和HRF反应性IgE/IgG以及HRF。通过Western印迹分析了RV感染的BEAS-2B人支气管上皮细胞的培养基中的HRF分泌以及实验性RV感染的受试者的鼻洗液中的HRF分泌。同时对哮喘急性发作患者纵向血清样本中的HRF反应性IgE/IgG水平进行了定量。
    结果:SA的HRF反应性IgE和总IgE高于HC,而哮喘患者的HRF反应性IgG(和IgG1)较低。HC.与HRF反应性IgElow哮喘患者相比,HRF反应性IgEhigh哮喘患者在抗IgE刺激支气管肺泡灌洗(BAL)细胞后倾向于释放更多的类胰蛋白酶和前列腺素D2。RV感染诱导BEAS-2B细胞分泌HRF,和人受试者的鼻内RV感染引起鼻洗液中HRF分泌增加。哮喘患者在与RV感染相关的哮喘发作时HRF反应性IgE水平较高,与决议后相比。这种现象在没有病毒感染的哮喘发作中未见到。
    结论:重度哮喘患者的HRF反应性IgE较高。RV感染在体外和体内诱导呼吸道上皮细胞分泌HRF。这些结果表明HRF在哮喘严重程度和RV诱导的哮喘恶化中的作用。
    Histamine-releasing factor (HRF) is implicated in allergic diseases. We previously showed its pathogenic role in murine models of asthma.
    We aim to present data analysis from 3 separate human samples (sera samples from asthmatic patients, nasal washings from rhinovirus [RV]-infected individuals, and sera samples from patients with RV-induced asthma exacerbation) and 1 mouse sample to investigate correlates of HRF function in asthma and virus-induced asthma exacerbations.
    Total IgE and HRF-reactive IgE/IgG as well as HRF in sera from patients with mild/moderate asthma or severe asthma (SA) and healthy controls (HCs) were quantified by ELISA. HRF secretion in culture media from RV-infected adenovirus-12 SV40 hybrid virus transformed human bronchial epithelial cells and in nasal washings from experimentally RV-infected subjects was analyzed by Western blotting. HRF-reactive IgE/IgG levels in longitudinal serum samples from patients with asthma exacerbations were also quantified.
    HRF-reactive IgE and total IgE levels were higher in patients with SA than in HCs, whereas HRF-reactive IgG (and IgG1) level was lower in asthmatic patients versus HCs. In comparison with HRF-reactive IgElow asthmatic patients, HRF-reactive IgEhigh asthmatic patients had a tendency to release more tryptase and prostaglandin D2 on anti-IgE stimulation of bronchoalveolar lavage cells. RV infection induced HRF secretion from adenovirus-12 SV40 hybrid virus transformed bronchial epithelial cells, and intranasal RV infection of human subjects induced increased HRF secretion in nasal washes. Asthmatic patients had higher levels of HRF-reactive IgE at the time of asthma exacerbations associated with RV infection, compared with those after the resolution. This phenomenon was not seen in asthma exacerbations without viral infections.
    HRF-reactive IgE is higher in patients with SA. RV infection induces HRF secretion from respiratory epithelial cells both in vitro and in vivo. These results suggest the role of HRF in asthma severity and RV-induced asthma exacerbation.
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  • 文章类型: Journal Article
    这项研究的目的是将高血糖动物模型的谱域光学相干断层扫描(SD-OCT)扫描中观察到的小点超反射焦点(HRF)与聚焦视网膜电图(fERG)反应和视网膜标记的免疫标记相关联。使用SD-OCT对显示糖尿病性视网膜病变(DR)征象的高血糖动物模型的眼睛进行成像。使用fERG进一步评估显示点HRF的区域。将包围HRF的视网膜区域解剖并连续切开,染色并标记神经胶质原纤维酸性蛋白(GFAP)和小胶质标记(Iba-1)。在DR大鼠模型的内部核层或外部核层的所有视网膜象限中,在OCT扫描中经常看到小点HRF。与正常对照大鼠相比,HRF和邻近区域的视网膜功能降低。通过Iba-1标记检测小胶质细胞活化,并通过在小点HRF周围的离散区域观察到的Müller细胞中GFAP表达鉴定视网膜应力。在视网膜的OCT图像中看到的小点HRF与局部小胶质细胞反应相关。这项研究提供了点HRF与小胶质细胞活化相关的第一个证据,这可能使临床医生更好地评估显示HRF的进行性疾病的小胶质细胞介导的炎症成分。
    The aim of this study is to correlate small dot hyper-reflective foci (HRF) observed in spectral domain optical coherence tomography (SD-OCT) scans of an animal model of hyperglycaemia with focal electroretinography (fERG) response and immunolabelling of retinal markers. The eyes of an animal model of hyperglycaemia showing signs of diabetic retinopathy (DR) were imaged using SD-OCT. Areas showing dot HRF were further evaluated using fERG. Retinal areas enclosing the HRF were dissected and serially sectioned, stained and labelled for glial fibrillary acidic protein (GFAP) and a microglial marker (Iba-1). Small dot HRF were frequently seen in OCT scans in all retinal quadrants in the inner nuclear layer or outer nuclear layer in the DR rat model. Retinal function in the HRF and adjacent areas was reduced compared with normal control rats. Microglial activation was detected by Iba-1 labelling and retinal stress identified by GFAP expression in Müller cells observed in discrete areas around small dot HRF. Small dot HRF seen in OCT images of the retina are associated with a local microglial response. This study provides the first evidence of dot HRF correlating with microglial activation, which may allow clinicians to better evaluate the microglia-mediated inflammatory component of progressive diseases showing HRF.
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  • 文章类型: Journal Article
    已经确定翻译控制肿瘤蛋白(TCTP),也称为组胺释放因子(HRF),仅在形成二聚体(dTCTP)后才表现出与过敏反应启动相关的细胞因子样活性。通过阻止dTCTP的二聚化或以其他方式阻断其功能来抑制dTCTP的药物,也阻止过敏反应的发展,从而作为治疗过敏性疾病的潜在药物。若干证据已经证明,特异性抑制dTCTP与其推定受体或免疫球蛋白之间的相互作用的肽和抗体在过敏性炎性疾病的鼠模型中作为潜在的抗炎剂表现出显著的体内功效。这篇综述重点介绍了几种针对dTCTP的抑制剂的开发,并讨论了它们如何在几种动物模型中影响过敏性和炎症性疾病的病理生理过程,并为抗过敏药物的发现提供了新的视角。
    It has been established that translationally controlled tumor protein (TCTP), also called histamine releasing factor (HRF), exhibits cytokine-like activities associated with initiation of allergic responses only after forming dimers (dTCTP). Agents that inhibit dTCTP by preventing its dimerization or otherwise block its function, also block development of allergic reactions, thereby serving as potential drugs to treat allergic diseases. Several lines of evidence have proven that peptides and antibodies that specifically inhibit the interactions between dTCTP and either its putative receptor or immunoglobulins exhibit significant in vivo efficacy as potential anti-inflammatory agents in murine models of allergic inflammatory diseases. This review highlights the development of several inhibitors targeting dTCTP and discusses how they affect the pathophysiological processes of allergic and inflammatory diseases in several animal models and offers new perspectives on anti-allergic drug discovery.
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  • 文章类型: Journal Article
    翻译控制肿瘤蛋白(TCTP),一种存在于大多数真核生物中的高度保守的蛋白质,参与了许多生物过程。只有在炎性病症期间形成的二聚体形式的TCTP(dTCTP)表现出细胞因子样活性。因此,dTCTP被认为是过敏性疾病的治疗靶标。由于单体TCTP(mTCTP)和dTCTP具有很高的拓扑相似性,我们假设与mTCTP相互作用的小分子也会与dTCTP结合并干扰基于dTCTP的细胞过程.在这项研究中,研究了文献中列出的与mTCTP相互作用的9种化合物抑制支气管上皮细胞中细胞外dTCTP活性的能力。发现九个人中的一个,meclizine,哌嗪衍生物抗组胺药,显著降低IL-8释放并抑制NF-κB途径。通过表面等离子体共振(SPR)证实了meclizine与dTCTP的直接相互作用。此外,我们发现meclizine可以减轻卵清蛋白(OVA)诱导的小鼠气道炎症。因此,meclizine可能是一种潜在的抗过敏药物,可作为dTCTP的抑制剂。
    Translationally controlled tumor protein (TCTP), a highly conserved protein present in most eukaryotes, is involved in numerous biological processes. Only the dimeric form of TCTP (dTCTP) formed during inflammatory conditions exhibits cytokine-like activity. Therefore, dTCTP is considered as a therapeutic target for allergic diseases. Because monomeric TCTP (mTCTP) and dTCTP share a high topological similarity, we hypothesized that small molecules interacting with mTCTP would also bind to dTCTP and interfere with dTCTP-based cellular processes. In this study, nine compounds listed in the literature as interacting with mTCTP were investigated for their ability to suppress the activity of extracellular dTCTP in bronchial epithelial cells. It was found that one of the nine, meclizine, a piperazine-derivative antihistamine, significantly reduced IL-8 release and suppressed the NF-κB pathway. The direct interaction of meclizine with dTCTP was confirmed by surface plasmon resonance (SPR). Also, we found that meclizine can attenuate ovalbumin (OVA)-induced airway inflammation in mice. Therefore, meclizine might be a potential anti-allergic drug as an inhibitor for dTCTP.
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  • 文章类型: Journal Article
    观察到同侧感觉运动(iSM1)皮质对单侧任务的负BOLD反应(NBR),并被认为反映了感觉运动抑制的功能相关成分。证据表明感觉运动抑制机制随着年龄的增长而退化,以及运动能力和灵巧方面。然而,对NBR年龄相关变化的理解受到样本量相对较小的年轻人组与老年人组之间有限比较的限制。在这里,我们分析了581名健康受试者的BOLDfMRI数据集(从CamCAN存储库获得),性别平衡,从执行对视听刺激的运动响应任务的整个成人寿命中采样。我们的目的是研究感觉运动和默认模式NBR特性的大小,在衰老过程的每十年,空间范围和响应形状都会发生变化。我们观察到iSM1NBR量值在整个寿命期内呈线性下降,而对侧感觉运动(cSM1)PBR大小不变。观察到NBR的空间范围与年龄相关的减少和同侧阳性BOLD反应(PBR)的增加。这与受试者的iSM1NBR和cSM1PBR大小之间的负相关增加同时发生,反映了皮质兴奋和抑制之间平衡的变化。常规GLM分析,使用规范的血液动力学反应(HR)函数,在50岁以上的受试者中显示iSM1NBR消失。然而,反卷积分析表明,iSM1HR的形状在整个生命周期中都发生了变化,具有明显延迟的峰值时间和降低的幅度。iSM1HR幅度的最显著下降发生在年龄较大(>60岁),但HR形状和时间的首次变化早在30岁时就发生了。表明这些改变背后的单独机制的可能性。使用数据驱动的HR进行重新分析,每十年检测到老年晚期有显著的感觉运动NBR,显示在fMRI老化研究中考虑HR形态变化的重要性。这些结果可能反映了fMRI测量结果,即同侧感觉运动皮层上与年龄相关的经结肠抑制减少以及感觉运动网络中兴奋性-抑制平衡的改变。
    Ipsilateral sensorimotor (iSM1) cortex negative BOLD responses (NBR) are observed to unilateral tasks and are thought to reflect a functionally relevant component of sensorimotor inhibition. Evidence suggests that sensorimotor inhibitory mechanisms degrade with age, along with aspects of motor ability and dexterity. However, understanding of age-related changes to NBR is restricted by limited comparisons between young vs old adults groups with relatively small samples sizes. Here we analysed a BOLD fMRI dataset (obtained from the CamCAN repository) of 581 healthy subjects, gender-balanced, sampled from the whole adult lifespan performing a motor response task to an audiovisual stimulus. We aimed to investigate how sensorimotor and default-mode NBR characteristics of magnitude, spatial extent and response shape alter at every decade of the aging process. We observed a linear decrease in iSM1 NBR magnitude across the whole lifespan, whereas the contralateral sensorimotor (cSM1) PBR magnitude was unchanged. An age-related decrease in the spatial extent of NBR and an increase in the ipsilateral positive BOLD response (PBR) was observed. This occurred alongside an increasing negative correlation between subject\'s iSM1 NBR and cSM1 PBR magnitude, reflecting a change in the balance between cortical excitation and inhibition. Conventional GLM analysis, using a canonical haemodynamic response (HR) function, showed disappearance of iSM1 NBR in subjects over 50 years of age. However, a deconvolution analysis showed that the shape of the iSM1 HR altered throughout the lifespan, with significantly delayed time-to-peak and decreased magnitude. The most significant decreases in iSM1 HR magnitude occurred in older age (>60 years) but the first changes in HR shape and timing occurred as early as 30 years, suggesting the possibility of separate mechanisms underlying these alterations. Reanalysis using data-driven HRs for each decade detected significant sensorimotor NBR into late older age, showing the importance of taking changes in HR morphology into account in fMRI aging studies. These results may reflect fMRI measures of the age-related decreases in transcollosal inhibition exerted upon ipsilateral sensorimotor cortex and alterations to the excitatory-inhibitory balance in the sensorimotor network.
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