Atherosclerosis and aortic aneurysms are prevalent aortic disorders. Significantly, atherosclerosis frequently impacts the common carotid artery (CA), whereas aortic aneurysms typically involve the abdominal aorta (AA), indicating possible heterogeneity between CA and AA with an ambiguous underlying mechanism. Sphingolipids, a crucial branch of lipid metabolism, has increasingly garnered attention in vascular diseases by influencing the phenotypic regulation of vascular smooth muscle cells (VSMCs). Nevertheless, whether sphingolipids play a role in the heterogeneity between CA and AA and in disease susceptibility remains uncertain. Public transcriptomics were employed to clarify the distinctions in contractility and calcification of VSMCs in relation to the vulnerability of human AA and CA to aortic aneurysms and atherosclerosis, respectively. Bulk RNA-seq revealed transcriptomic variances in the biology of VSMCs between AA and CA from rats. Primary VSMCs from AA (AASMC) and CA (CASMC) were isolated for further validation. The specific variations in sphingolipid metabolism (comprising 8 classes of sphingolipids with 169 species) between AA and CA from rats were further characterized using UPLC–QTOF-MS-based lipidomics. Most sphingolipids, except sphingomyelin, were significantly elevated in CA compared to AA. Ceramides were the major contributor to these differences, which was further confirmed by in situ immunofluorescence of AA and CA from rats and healthy humans. The differential expression of genes involved in ceramide biosynthesis (Cers1-4), transport (Cert1), and metabolic processes (Smpd1, Sgpp1, Sphk2, and Sgms1/2), along with variations in subcellular organelles in VSMCs, contributed to the heterogeneity of sphingolipid metabolism between AA and CA. The effects of ceramides on VSMC biology were subsequently assessed using primary VSMCs. Specifically, AASMC exhibited greater contractility and lower susceptibility to calcification compared to CASMC. Exogenous ceramides heightened the susceptibility to calcification in both CASMC and AASMC, whereas the inhibition of ceramide synthases engendered an opposing consequence. Notably, in CA from patients with atherosclerosis but not AA from aortic aneurysms, the activation of sphingolipid metabolism (including ceramides) was positively correlated with calcification and negatively correlated with the regulatory processes of VSMC contraction. Furthermore, the ceramide metabolism was activated along with calcification in CA, which corresponded with the accumulation of ceramide in atherosclerotic plaques of human. In this study, we identified ceramides, a major class of sphingolipid metabolites, as a promising determinant in unequal biology and susceptibility to calcification of CA and AA. Our results reveal the previously unappreciated role of sphingolipid metabolism, particularly ceramides, in regional vascular pathology. These findings provide novel insights that inform our understanding of disease mechanisms and highlight potential ways for future therapeutic exploration. Sphingolipids' role in vascular heterogeneity between common carotid artery (CA) and abdominal aorta (AA) have been elucidated through a comprehensive approach involving public transcriptomics, RNA sequencing, and lipidomics. Ceramides, key in sphingolipid metabolism, modulate contractility and calcification differences in vascular smooth muscle cells (VSMCs) between CA and AA.

ABSTRACTIntroductionMultitasking during flights leads to a high mental workload, which is detrimental for maintaining task performance. Electroencephalography (EEG) power spectral analysis based on frequency‐band oscillations and microstate analysis based on global brain network activation can be used to evaluate mental workload. This study explored the effects of a high mental workload during simulated flight multitasking on EEG frequency‐band power and microstate parameters.MethodsThirty‐six participants performed multitasking with low and high mental workloads after 4 consecutive days of training. Two levels of mental workload were set by varying the number of subtasks. EEG signals were acquired during the task. Power spectral and microstate analyses were performed on the EEG. The indices of four frequency bands (delta, theta, alpha, and beta) and four microstate classes (A–D) were calculated, changes in the frequency‐band power and microstate parameters under different mental workloads were compared, and the relationships between the two types of EEG indices were analyzed.ResultsThe theta‐, alpha‐, and beta‐band powers were higher under the high than under the low mental workload condition. Compared with the low mental workload condition, the high mental workload condition had a lower global explained variance and time parameters of microstate B but higher time parameters of microstate D. Less frequent transitions between microstates A and B and more frequent transitions between microstates C and D were observed during high mental workload conditions. The time parameters of microstate B were positively correlated with the delta‐, theta‐, and beta‐band powers, whereas the duration of microstate C was negatively correlated with the beta‐band power.ConclusionEEG frequency‐band power and microstate parameters can be used to detect a high mental workload. Power spectral analyses based on frequency‐band oscillations and microstate analyses based on global brain network activation were not completely isolated during multitasking.

Real or simulated microgravity induces a senescence-like modification of carotid artery in both human and animal observations, with the mechanisms not fully elucidated. Here, we aim to elucidate the role of sterol regulatory element-binding protein 1 (SREBP1, encoded by Srebf1) mediated lipogenesis in the process. Pharmacological activation of SREBP1 directly triggers senescence-like transformation in vascular smooth muscle cells (VSMC), while silencing Srebf1 exerts an opposite effect. Mechanistically, SREBP1-mediated lipogenesis upregulates acetyl-CoA pool to increase histone acetylation, modifying the chromatin accessibility which limiting recruitment of SRF/myocardin complexes to CArG boxes of contractile genes and opening the chromatin accessibility of aging genes. Srebf1 knockdown and local delivery of lentivirus or AAV-mediated VSMC specific expressing sh-Srebf1 significantly attenuates the senescence-like transformation of VSMC both in vitro and in vivo. Our findings reveal a previously unrecognized feature of SREBP1-mediated lipogenesis in vascular biology and SM-induced carotid artery remodeling. Microgravity triggers carotid artery aging via SREBP1. This lipid regulator remodels chromatin by boosting acetyl-CoA, silencing contractile genes while activating aging pathways. Targeting SREBP1 blocks senescence, revealing a therapeutic strategy for spaceflight-associated vascular remodeling.

为探讨飞行多任务脑力负荷对听觉失匹配负波(MMN)的影响,比较MMN在不同脑力负荷下的变化.24名男性受试者完成低、中、高负荷模拟飞行多任务,采用可模拟飞行目标追踪、仪表监视、突发事件处理的多任务作为任务模型.每项任务完成后填写NASA-TLX量表,任务过程中采集受试者脑电信号.采用Oddball范式下的听觉刺激诱发MMN,比较其在不同脑力负荷任务下的变化.结果表明:随着多任务脑力负荷的增加,任务绩效下降且NASA-TLX评分升高(P<0.05).3种脑力负荷下MMN均表现为额中央优势,波峰在150～200 ms之间.随着脑力负荷的升高,MMN的波幅升高(P<0.05),但MMN的潜伏期无明显变化(P>0.05).模拟飞行多任务的脑力负荷主要体现在认知负荷上,MMN波幅的升高可反映其脑力负荷的升高.

Background Soldiers are often exposed to high-intensity noise produced by military weapons and equipment during activities, and the incidence of noise-induced hearing loss (NIHL) in many arms is high. Oxidative stress has a significant role in the pathogenesis of NIHL, and research has confirmed that ginsenoside Rd (GSRd) suppresses oxidative stress. Therefore, we hypothesized that GSRd may attenuate NIHL and cochlear hair cell loss, induced by military aviation noise stimulation, through the Sirtuin1/proliferator-activated receptor-gamma coactivator 1α (SIRT1/PGC-1α) signaling pathway. Methods Forty-eight male guinea pigs were randomly divided into four groups: control, noise stimulation, GSRd, and glycerol. The experimental groups received military helicopter noise stimulation at 115 dB (A) for 4 h daily for five consecutive days. Hair cell damage was evaluated by using inner ear basilar membrane preparation and scanning electron microscopy. Terminal dUTP nick end labeling and immunofluorescence staining were conducted. Changes in the SIRT1/PGC-1α signaling pathway and other apoptosis-related markers in the cochleae, as well as oxidative stress parameters were used as readouts. Results Loss of outer hair cells, more disordered cilia, prominent apoptosis, and elevated free radical levels were observed in the experimental groups. GSRd treatment markedly improved morphological changes and apoptosis through decreasing Bcl-2 associated X protein (Bax) expression and increasing Bcl-2 expression. In addition, GSRd upregulated superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels, decreased malondialdehyde (MDA) levels, and enhanced the activity of SIRT1 and PGC-1α messenger ribonucleic acid and protein expression. Conclusion GSRd can improve structural and functional damage to the cochleae caused by noise. The underlying mechanisms may be associated with the SIRT1/PGC-1α signaling pathway.

BACKGROUND:Pilots must process multiple streams of information simultaneously. Mental workload is one of the main issues in man-machine interactive mode when dealing with multiple tasks. This study aimed to combine functional near-infrared spectroscopy (fNIRS) and electrocardiogram (ECG) to detect changes in mental workload during multitasking in a simulated flight. METHODS:Twenty-six participants performed three multitasking tasks at different mental workload levels. These mental workload levels were set by varying the number of subtasks. fNIRS and ECG signals were recorded during tasks. Participants filled in the national aeronautics and space administration task load index (NASA-TLX) scale after each task. The effects of mental workload on scores of NASA-TLX, performance of tasks, heart rate (HR), heart rate variability (HRV), and the prefrontal cortex (PFC) activation were analyzed. RESULTS:Compared to multitasking in lower mental workload conditions, participants exhibited higher scores of NASA-TLX, HR, and PFC activation when multitasking in high mental workload conditions. Their performance was worse during the high mental workload multitasking condition, as evidenced by the higher average tracking distance, smaller number of response times, and longer response time of the meter. The standard deviation of the RR intervals (SDNN) was negatively correlated with subjective mental workload in the low task load condition and PFC activation was positively correlated with HR and subjective mental workload in the medium task load condition. CONCLUSION:HR and PFC activation can be used to detect changes in mental workload during simulated flight multitasking tasks.

为探讨脑电微状态用于测量飞行活动脑力负荷的可行性,比较4类脑电微状态参数在不同脑力负荷下的变化.12名男性受试者依次完成高、低负荷的模拟飞行多任务,采用模拟飞行目标追踪、仪表监视、突发事件处理的多任务作为任务模型.每项任务完成后填写NASA-TLX量表,任务过程中采集受试者脑电信号.采用聚类方法分析脑电微状态,提取反映认知活动的A、B、C、D4类脑电微状态时间参数,比较其在不同脑力负荷任务下的变化.结果表明:与低负荷任务相比,高负荷任务下的NASA-TLX评分升高且任务绩效降低(P<0.05);高负荷任务下的微状态A和微状态C的持续时间、微状态C的覆盖率以及微状态A和微状态C之间的转移概率降低(P<0.05),而微状态D的频率和覆盖率以及微状态A和微状态C之间的转移概率升高(P<0.05).高脑力负荷可导致微状态A和微状态C的参数降低而微状态B和微状态D的参数升高,微状态参数对脑力负荷的变化具有一定的敏感性.

Background: A continuous flight task load can induce fatigue and lead to changes in electroencephalography (EEG). EEG microstates can reflect the activities of large-scale neural networks during mental fatigue. This exploratory experiment explored the effects of mental fatigue induced by continuous simulated flight multi-tasking on EEG microstate indices.Methods: Twenty-four participants performed continuous 2-hour aircraft piloting simulation while EEG were recorded. The Stanford sleepiness scale (SSS) and critical flicker fusion frequency (CFF) were measured before and after the task. Microstate analysis was applied to EEG. Four microstate classes (A-D) were identified during the pre-task, post-task, beginning, and end phases. The effects of mental fatigue were analyzed.Results: Compared with the pre-task, the post-task had a higher global explained variance (GEV) and time pa-rameters of class C but lower occurrence and coverage of class D. The end had a higher GEV but lower duration and coverage of class D than at the beginning. After 2 h of multitasking, the transition probability between A and D, and between B and D decreased but between A and C increased. Subjective fatigue scores were negatively correlated with occurrence and coverage of class D. Task performance was negatively correlated with duration and coverage of class C but positively correlated with duration and occurrence of class B.Conclusion: Time parameters and transition probability of EEG microstates can detect mental fatigue induced by continuous aircraft piloting simulation. The global brain network activation of mental fatigue can be detected by EEG microstates that can evaluate flight fatigue.

Objective To analyze the risk factors inducing hyperuricemia (HUA) in helicopter pilots and put forward the corresponding intervention measures. Methods A total of 190 male helicopter pilots, aged 20-50 years and with more than 100 hours of flight time, were recruited from April to October 2020 in a flight brigade. A self-designed questionnaire was used, by which the basic information of subjects were collected including eating habits, physical exercise, smoking and drinking, exposure to noise and vibration at work, mood, disease, work performance, sleep status, genetic factors, and so on. At the same time, 28 SPF grade 6-week-old male C57BL/6J mice were randomly divided into 7 groups (4 each): control group, noise group, noise + vitamin C (Vit C) group, noise + multivitamin (Multi Vit) group, noise + hyperbaric oxygen (HBO) group, noise + HBO + Vit C group, and noise + HBO + Multi Vit group. After continuous intervention for 7 days, Multiskan Ascent was used to detect the uric acid (UA) level in mice sera. Results Finally, 186 subjects, aged 22-50 years and with (1378±569) hours of flight time, were included in present study. Of whom 17 (9.14%) were self-reported with HUA (HUA group) and 169 (9.14%) were with normal uric acid (NUA group). No significant difference existed between the two groups in age, height, body mass index and the proportion of hyperglycemia. The proportions of hyperlipidemia and fatty liver were significantly higher in HUA group (17.6% and 29.4%, respectively) than those in NUA group (4.7% and 10.1%, respectively) with statistically significant difference (P 0.05) in the other 8 dimensions. Noise and vibration exposure were closely related to the occurrence of HUA. Among them, strong noise and long daily exposure, great influence on emotion, the poor effect and low use frequency of protective measures would significantly increase the risk of HUA; Long daily exposure and great influence on emotion of vibration would also increase the risk of HUA. Compared with the control group, the serum UA level in noise group increased significantly [(38.710±10.201) μmol/L vs. (191.935±9.542) μmol/L] with significant difference (P 0.05). Conclusions HUA in helicopter pilots is related to noise and vibration exposure in working environment. Hyperbaric oxygen and dietary vitamin supplementation can effectively reduce the increase of serum uric acid level caused by noise exposure. DOI: 10.11855/j.issn.0577-7402.2021.02.08

目的 研究某新型运输机(简称A)和已列装运输机(简称B)飞行人员本场及长航时飞行作业负荷特点规律,为制定相关的航卫保障措施提供参考依据.方法 采用自认劳累负荷量表(RPE)、斯坦福嗜睡感量表(SSS)、NASA任务负荷指数(NASA-TLX)结合心率监测及心率变异性分析的方法,以32名两型运输机飞行人员(A13人,B19人)为研究对象,于飞行前、中、后开展主观负荷程度、生理参数的变化情况分析比较,探讨两型运输机飞行人员的作业负荷变化特点.结果 飞行后,两型运输机飞行人员RPE、SSS评分增加非常显著(P<0.01),着陆阶段NASA-TLX评分非常显著高于其他飞行阶段(P＜0.01).飞行中,A型运输机飞行人员心率变异性指标RMSSD、VLF、HFnorm显著低于B型运输机飞行人员(P＜0.05),LFnorm、LF/HF非常显著高于B型运输机飞行人员(P＜0.01),A型运输机飞行人员各心率值显著高于B型运输机飞行人员(P＜0.05).不同飞行阶段中,着陆阶段飞行人员VLF、TP显著高于起飞阶段(P＜0.05),巡航阶段各心率值显著低于起飞、着陆阶段(P＜0.05).结论 两型运输机飞行人员的作业负荷具有共性,精神紧张度在巡航阶段均减轻,着陆阶段均增加;但A型运输机飞行人员心率、交感神经张力、精神紧张度均高于B型,提示现阶段A型运输机飞行人员的作业负荷强度高于B型运输机飞行人员.

脑力负荷生理测量在工效学中有着广泛的研究和应用.脑力劳动中的信息加工过程会引发神经系统的活动,神经系统的活动可引起相应生理指标的改变,从而间接反映脑力负荷的变化.本文首先重点介绍了认知负荷理论和信息加工模型来阐述信息加工与脑力负荷的关系.基于信息加工模型,进一步介绍了选择性注意的信息加工方式和加工控制对脑力负荷的影响,最后对脑功能成像方法结合信息加工理论和模型测量脑力负荷进行了展望.

Aims: Weightlessness exposure conduces to substantial vascular remodeling, mechanisms behind which remain unclear. Acid sphingomyelinase (ASM) catalyzed ceramide (Cer) generation accounts for multiple vascular disorders, so the role of it in adjustment of cerebral artery (CA) and small mesenteric artery (MA) was investigated in simulated weightless rats. Main methods: Rats were hindlimb unloaded tail suspended (HU) to simulate the effect of weightlessness. Arterial morphology was examined by hematoxylin-eosin staining. Cer abundance was measured by immunohistochemistry. Western blotting was used to detect protein content. Apoptosis was detected by transferase-mediated dUTP nick end labeling. Key findings: During 4 weeks of tail suspension, intima-media thickness (IMT) and media cross section area (CSA) were increased gradually in CA but decreased gradually in MA (P < 0.05). Correspondingly, the apoptosis and proliferation of vascular smooth muscle cells were reduced and enhanced respectively in CA (P < 0.05), while promoted and restrained in MA (P < 0.05). As compared to control, both ASM protein expression and Cer content were lowered in CA and elevated in MA of HU rats (P < 0.05). Permeable Cer incubation reversed the change of apoptosis and proliferation in CA of HU rats, while ASM inhibition recapitulated it in control rats. On the contrary, ASM inhibitors restored the alteration of apoptosis and proliferation in MA of HU. Significance: The results suggest that by controlling the balance between apoptosis and proliferation, ASM/Cer exerts an important role in structural adaptation of CA and MA to simulated weightlessness.

Noise exposure relates to various pathological disorders including liver damage, preventive measures of which are being demanded. Hyperbaric oxygen treatment (HBOT), as a non-invasive procedure, exerts convincing therapeutic potency on multiple liver diseases. The efficacy of HBOT in mitigating noise induced liver damage (NILD) and associated mechanisms would be elucidated here. Mice were subject to broad band noise (20-20k Hz, 90-110 dB) for 5 days by 3 hours/day. HBOT with 2.5 atmosphere absolute (ata) was employed before noise exposure. Morphology of liver tissue was examined by hematoxylin-eosin (HE) staining. Oil Red O (ORO), transferase-mediated dUTP nick end labelling (TUNEL) test and western blot were utilized to detect lipid accumulation, apoptotic cells and protein expression, respectively. Ceramide (Cer) level was assayed by immunohistochemistry (IHC) analysis. With noise exposure, conspicuous structural derangement and lipid deposition occurred in liver tissue of mice, which was alleviated significantly by the application of HBOT. Meanwhile, HBOT reduced the proportion of apoptotic hepatocytes, restraining the superoxide production in noise exposed mice. In view of underlying mechanisms, noise enhanced the acid sphingomyelinase (ASM) protein expression and the Cer generation in liver tissue of mice which was reversed substantially by HBOT. Altogether, HBOT ameliorates the structural and functional derangement of liver by neutralizing the ASM/Cer pathway in noise exposed mice.

目的 比较5种量表在飞行活动中的脑力负荷测量适用性,筛选最适用于测量飞行活动主观脑力负荷的量表.方法 27名飞行员受试者每人完成1次起落航线飞行训练,训练后根据飞行过程起飞阶段、平飞巡航阶段以及降落阶段的实际体会,分别填写NASA任务负荷指数(NASA-TLX)量表、主观负荷评价技术(SWAT)量表、修正的库柏-哈柏(MCH)量表、工作负荷描述(WP)量表和多资源问卷(MRQ).比较并分析5种量表在测量不同飞行阶段主观脑力负荷的敏感性、诊断性和可接受性.结果 敏感性方面,NASA-TLX量表最高,WP量表次之,MRQ量表最低;诊断性方面,NASA-TLX量表在脑力负荷分类诊断中具有优势,而WP量表在信息加工过程不同脑力资源的使用情况诊断中具有优势;可接受性方面,MRQ量表可接受性差,表现为量表填写时间长和理解难度大.结论 NASA-TLX量表具有很好的敏感性和诊断性,可作为飞行活动脑力负荷主观测量的首选.WP量表能从信息加工过程中不同脑力资源的使用情况进行诊断,可与NASA-TLX量表相结合测量飞行活动的脑力负荷.

脑力负荷是工效学中的重要概念,脑力负荷测量在工效学中有着广泛的研究.任务绩效用于脑力负荷的测量有着科学的理论基础和实际的应用.本文首先重点介绍了耶基斯-多德森定律、"倒U形"模型以及剩余资源理论来阐述脑力负荷与任务需求、任务绩效的关系.基于上述理论基础,进一步介绍了任务绩效在脑力负荷测量中的应用方法 并分析了其优势和缺陷,最后总结了任务绩效应更多地与其他脑力负荷指标相结合来综合测量脑力负荷,并用于进一步探索脑力负荷测量的建模方法 .

Free radicals and oxidative stress play an important role in the pathogenesis of noise-induced hearing loss (NIHL). Some ginseng monomers showed certain therapeutic effects in NIHL by scavenging free radicals. Therefore, we hypothesized that ginsenoside Rd (GSRd) may exert neuroprotective effects after noise-induced auditory system damage through a mechanism involving the SIRT1/PGC-1α signaling pathway. Forty-eight guinea pigs were randomly divided into four equal groups (normal control group, noise group, experimental group that received GSRd dissolved in glycerin through an intraperitoneal injection at a dose of 30 mg/kg body weight from 5 days before noise exposure until the end of the noise exposure period, and experimental control group). Hearing levels were examined by auditory brainstem response (ABR) and distortion product otoacoustic emission (DPOAE). Hematoxylin–eosin and Nissl staining were used to examine neuron morphology. RT-qPCR and western blotting analysis were used to examine SIRT1/PGC-1α signaling and apoptosis-related genes, including Bax and Bcl-2, in the auditory cortex. Bax and Bcl-2 expression was assessed via immunohistochemistry analysis. Superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione peroxidase (GSH-Px) levels were determined using a commercial testing kit. Noise exposure was found to up-regulate ABR threshold and down-regulate DPOAE amplitudes, with prominent morphologic changes and apoptosis of the auditory cortex neurons (p < 0.01). GSRd treatment restored hearing loss and remarkably alleviated morphological changes or apoptosis (p < 0.01), concomitantly increasing Bcl-2 expression and decreasing Bax expression (p < 0.05). Moreover, GSRd increased SOD and GSH-Px levels and decreased MDA levels, which alleviated oxidative stress damage and activated SIRT1/PGC-1α signaling pathway. Taken together, our findings suggest that GSRd ameliorates auditory cortex injury associated with military aviation NIHL by activating the SIRT1/PGC-1α signaling pathway, which can be an attractive pharmacological target for the development of novel drugs for NIHL treatment.

Military flying labor hygiene is a discipline that focuses on influences of special flight environment and labor condition on human body and related prevent measures,with the core of flight fatigue.Health information and technique training can help flight surgeons to enhance professional competency and improve the prevention and recovery of military flying fatigue.The course construction of teaching system in this study included survey of demand,arrangement of content,identification of strategy,determination of evaluation,and feedback of results.Meanwhile,the textbook compilation,cultivation of teaching team and construction of laboratory were also needed.After a 4-year practice,a formal teaching system has been established and its teaching effectiveness has basically fulfilled the professional requirement for flight surgeons.

Noise-induced hearing loss (NIHL) relates closely to auditory cortex (AC) injury, so countermeasures aiming at the AC recovery would be of benefit. In this work, the effect of hyperbaric oxygen treatment on NIHL was elucidated, which was imposed on mice before (HBOP), during (HBOD) or after (HBOA) noise exposure. Morphology of neurons was assayed by hematoxylin-eosin or Nissl staining. Ceramide (Cer) level was measured through immunohistochemistry analysis. Apoptotic neurons were counted using transferase-mediated dUTP nick end labeling (TUNEL) staining. We demonstrated that the intense, broad band noise raised the threshold of auditory brainstem response, evoked neuronal degeneration or apoptosis and triggered the Cer accumulation in AC, all of which were restored significantly by HBOP, but not HBOD or HBOA. Cer over-generation reversed the advantages of HBOP significantly, while its curtailment recapitulated the effect. Next, noise exposure raised the superoxide or malondialdehyde (MDA) production which was blocked by HBOP or Cer repression. Oxidative control not only attenuated the hearing loss or neurodegeneration but, in turn, reduced the Cer formation significantly. In summary, mutual regulation between Cer and oxidative stress underlies the HBOP's curative effect on hearing loss and neuronal damage in noise-exposed mice.

目的 研究不同强度某型军用直升机噪声刺激下,豚鼠听性脑干反应(A BR)及畸变产物耳声发射(DPOAE)的变化特点.方法 35只雄性豚鼠随机分为5组:对照组,95 dB(A)组,105 dB(A)组,115 dB(A)组和120dB(A)组.对照组不给予噪声刺激,其余4组给予相应强度噪声刺激,每天4h,共刺激5d.采用ABR、DPOAE对豚鼠噪声刺激前后听力进行测试.结果 随着噪声刺激强度增加,豚鼠ABR阈值升高,80 dB处Ⅲ波潜伏期延长,DPOAE幅值下降.95 dB(A)和105 dB(A)组豚鼠听力约在噪声刺激后3～5 d逐渐恢复,115 dB(A)组豚鼠大约在5～7 d听力逐渐恢复,120dB(A)噪声刺激后7d豚鼠听力仍未恢复正常.结论 随着噪声刺激强度的增加,豚鼠听力损伤加重,听力恢复的时程延长,恢复的可能性减低.军用直升机噪声暴露对豚鼠听力损伤具有明显的损伤剂量依赖性和恢复时间依赖性.

目的 观察不同脑力负荷状态下失匹配负波振幅变化情况.方法 对28名被试采用5个难度等级的数字N-back任务建立梯度脑力负荷状态模型,并同步采集脑电信号,采用非任务相关听觉刺激oddball范式引出失匹配负波并测量平均振幅.任务结束后使用任务负荷量表NASA-TLX评价被试主观脑力负荷状态,并分析Fz电极处MMN振幅随脑力负荷状态变化情况.结果 因采集脑电信号质量不佳剔除4名被试数据,分析24名被试数据,结果显示随着N-back任务难度增加,被试完成任务的正确率逐渐下降、反应时逐渐升高(P<0.05),NASA-TLX得分逐渐升高(P<0.05).成功提取各任务中被试MMN波形,测量其振幅随任务难度等级增加而降低(P<0.05).结论 使用数字N-back任务成功建立梯度脑力负荷状态模型,在此模型中,脑力负荷水平越高,测得MMN振幅越低.