参与中文配对词语联想学习记忆的脑区和神经机制——脑功能磁共振的研究

通过脑功能磁共振技术,研究健康人参与语言的词语配对联想学习记忆任务的脑区和神经机制。对16名右利手健康志愿者进行一项词语配对联想学习记忆任务作业的同时,进行脑功能磁共振扫描。实验采用组块设计,实验任务（包括记忆编码相和记忆提取相）与对照任务（共两个相）交替进行;数据采用SPM99软件进行数据分析和脑功能区定位。结果表明：左侧额叶,特别是左侧额叶的额中下回和枕叶的18,19区在词语联想学习记忆的编码阶段中起重要作用;而左侧顶上小叶、缘上回和角回则在进行记忆提取阶段起重要作用;左侧纹状体边缘区参与了人脑词语联想学习记忆作业的编码阶段。揭示了人大脑完成语言联想学习记忆任务时,除额、顶、枕和颞叶的皮层结构参与外,还新发现有皮层下结构如纹状体参与了词语联想学习记忆。在配对词语的编码和提取阶段,激活的脑区有所变化,显示了这两个语言阶段的神经活动变化机制。     

高特质焦虑个体情绪注意偏向的脑网络研究

利用复杂网络分析方法对脑网络的拓扑结构和属性进行分析,探讨高特质焦虑个体情绪注意偏向的脑功能机制。选取高特质性焦虑(HTA)和低特质性焦虑(LTA)各15名被试,进行3种情绪面孔表情(高兴、中性和愤怒)的搜索任务,同步记录64导脑电(EEG)。对EEG数据进行同步似然分析,计算网络的整体属性参数(全局效率、聚类系数和特征路径长度)及节点属性参数(节点度)。组内统计分析显示,HTA和LTA两组被试均表现为,愤怒面孔搜索任务下额叶与颞叶节点度、聚类系数及全局效率明显大于其高兴面孔和中性面孔的值,而特征路径长度小于高兴面孔和中性面孔的值。组间统计结果表明,3种面孔搜索任务下HTA组额叶与颞叶节点度值均明显大于LTA组的值,尤其是愤怒面孔搜索任务下二组的差异更加明显(P 0.001);愤怒面孔搜索任务下,HTA组被试的节点属性参数及整体属性参数均与LTA组有显著差异,而高兴面孔和中性面孔搜索任务下,HTA组被试仅节点属性参数与LTA组有显著差异,整体属性参数无显著差异。以上结果表明,HTA个体对情绪信息(尤其是负性情绪信息)更加敏感,其神经机制可能与额、颞叶活动及脑网络信息传输能力异常增强有关。本研究从脑网络水平探讨了 HTA个体情绪认知的脑功能特点,可为焦虑症、抑郁症等精神障碍的认知功能神经机制研究提供新视角。     

阿尔茨海默病的静息态脑网络功能连接异常特征

阿尔茨海默病(AD)是严重危害中老年健康的常见神经退行性疾病,目前尚无有效的早诊办法.本文旨在从脑功能网络新视角研究AD患者脑区间功能连接异常特征,以寻求AD早诊新思路.采集了27例AD患者、20例轻度认知障碍(MCI)患者和36例正常老年人(NC)的静息态功能磁共振成像(f MRI)数据,分别构成中央执行网络(CEN)、突显网络(SN)、默认模式网络(DMN)和背侧注意网络(DAN)等4种大尺度脑功能网络并基于种子点分析方法计算网络功能连接参数,在每种脑网络下对AD、MCI患者和NC组做两两比较的双样本t检验统计学分析,得到组间网络内功能连接的显著性差异变化特征.结果表明:AD患者在CEN的右背侧楔前叶与右侧前额叶皮层、DMN的双侧内侧前额叶皮层与双侧角回及双侧后扣带回和DAN的双侧顶上小叶脑区功能连接均有显著下降,而MCI患者只在CEN的右侧后顶叶皮层脑区功能连接有所下降,两者在SN的功能连接皆无统计学意义变化.有关结果不仅印证了AD患者脑网络功能连接变异特征与其认知障碍病情变化相符,而且有望为探索MCI转化至AD的病理机制和基于脑网络功能连接分析进行AD早诊提供参考.     

经颅直流电刺激背外侧前额叶调节大学生情绪识别

目的本研究旨在考察经颅直流电刺激(Transcranial Direct Current Stimulation, tDCS)激活背外侧前额叶(Dorsolateral Prefrontal Cortex, DLPFC)能否有效调节健康大学生的情绪识别加工,并进一步比较刺激左、右侧DLPFC(l-DLPFC/r-DLPFC)的效应。方法实验采用3(tDCS刺激类型:阳极刺激l-DLPFC,阳极刺激r-DLPFC,假刺激)×3(情绪类型:快乐,愤怒,悲伤)混合设计,被试在接受tDCS刺激的同时完成情绪面孔搜索识别任务。结果 (1)与假刺激相比,阳极tDCS刺激l-DLPFC/r-DLPFC对不同情绪面孔搜索识别的影响不存在显著差异;(2)与r-DLPFC相比,tDCS阳极刺激l-DLPFC条件下情绪面孔搜索识别的反应时显著更短;(3)对快乐面孔的搜索识别正确率最高、反应时最短,愤怒面孔的正确率最低、反应时最长。结论对大学生而言,tDCS阳极刺激DLPFC对情绪识别的影响较弱;另外,与r-DLPFC相比,tDCS刺激l-DLPFC对面孔搜索识别的影响可能更强。     

视听情绪诱发的脑电信号同步性分析

为探究视听感知愉快、愤怒、悲伤、惊讶、厌恶、恐惧6种情绪时,不同脑区之间的脑电同步现象,本文设计了视听情绪诱发实验范式,利用Neuroscan 40导联脑电放大器采集脑电信号,采用AR模型以及相干平均去除基线漂移和自发脑电干扰,小波变换进行脑电特征提取,Hilbert变换获得脑电特征信号的瞬时相位,使用相位同步指数分析脑电活动的同步性.实验结果表明:Hilbert变换得到的相位同步指数能够较好地反映脑电的同步活动,为"大脑半球效价假说"提供了有效的依据.此外,在视听感知愉快情绪时,大脑皮层视觉区域占据主导作用,而感知悲伤情绪时,大脑皮层听觉区域占据主导作用.该研究可以被应用于大脑情绪认知和仿生机器人中.     

电焊噪声雨滴掩蔽作用的脑响应研究

工业噪声污染是影响工人健康和工作效率的主要环境因素之一。在传统降噪措施无法满足要求的情况下,掩蔽作用可以达到明显的主观降噪效果。为了研究声掩蔽作用对大脑皮层响应的影响,以雨滴声掩蔽电焊声作为实验声信号,收集19名健康志愿者的脑部功能磁共振(fMRI)数据。通过统计学处理分别得到噪声和掩蔽声信号刺激下受试者的脑部激活区域,并进行对比分析。研究结果发现,在接受电焊噪声原声刺激时,主要脑部激活区域为颞叶、中央后回、扣带回和额上回;在接受电焊噪声雨滴掩蔽信号刺激时,主要脑部激活区为边缘叶和枕上回。对电焊噪声雨滴掩蔽前后激活脑区的差异性分析表明,情绪处理相关的前额叶区激活更为明显。本研究提供了一种有效分析声掩蔽作用引起显著影响脑响应区域的方法,这为声掩蔽及其心理效应的评估提供了客观生理的研究思路。     

驾驶疲劳后听觉信息自动加工的ERP研究

应用事件相关电位(ERPs)研究驾驶疲劳后听觉信息自动加工的特点。采用组间对照,对照组为12名充分休息的出租车司机,实验组为15名驾驶疲劳10h的出租车司机。记录和分析听觉强度失匹配负波(mis-match negativity,MMN)。结果发现,与正常对照相比,驾驶疲劳组强度MMN潜伏期延长,波幅显著增高,且表现出左侧额区优势效应,表明驾驶疲劳后,非注意条件下对听觉信息变化的过度自动加工,对有用信息的加工不足。结论:驾驶疲劳后对于无关信息的自动加工增加,增加了驾驶危险。     

基于眼动和脑电技术的机器人情绪行为对用户交互情感的影响研究

目的探索人-机器人交互过程中用户情感的评价方法,揭示机器人情绪行为对用户交互情感的影响。方法设计音乐交互过程(正性音乐、负性音乐)和机器人情绪行为(正性情绪行为、中性情绪行为、负性情绪行为),借助主观评价、眼动追踪和脑电技术,采集19名被试在不同音乐交互过程中的主观评价指标、眼动指标和脑电指标。结果正性音乐交互过程中,机器人正性情绪行为引起的效价、唤醒度、瞳孔直径、额中线theta波相对功率、额区alpha波不对称指数显著大于中性情绪行为;而负性音乐交互过程中,机器人负性情绪行为引起的唤醒度和瞳孔直径显著大于中性情绪行为,效价和额区alpha波不对称指数显著小于中性情绪行为。结论各评价指标具有一致的结果,各指标相互结合能够有效地评价机器人音乐交互过程中用户的情感状态。评价结果表明机器人正性情绪行为(负性情绪行为)对音乐交互过程中用户正性情感(负性情感)具有增强作用,可用于进一步加强机器人音乐交互过程中用户的情感。     

基于功能性近红外光谱技术的移动地图APP用户体验评价研究

通过对比用户使用不同体验水平的移动地图APP时功能性近红外光谱（fNIRS）各项指标的差异，探索fNIRS技术评价移动地图APP用户体验水平的可能。首先，选取用户体验水平高低不同的两款移动地图APP作为实验材料，设定实验任务；之后，招募31名健康被试进行实验，记录被试者使用APP时血红蛋白浓度的变化情况。研究结果表明，被试在使用移动地图APP进行实验任务时，被试大脑前额叶皮层被激活。相较于高体验水平的移动地图APP，被试在使用低体验水平低的移动地图APP时，大脑右侧前额叶神经元激活，含氧血红蛋白（HbO）浓度会显著提升，对右脑背外侧前额叶皮层HbO浓度的检测有助于客观评价移动地图APP的用户体验水平。     

视觉刺激诱发情绪的表达抑制研究

目的研究视觉刺激诱发情绪的表达抑制对表达行为、主观体验、生理反应等系统的影响,以及表达抑制与记忆的关系。方法以32名女性为被试,采用生理和心理实验法测量被试观看电影片段的表达行为、主观体验和生理反应变化及表达抑制对记忆任务绩效的影响。结果与控制组相比,抑制组被试表情行为被抑制但仍能体验所诱发的情绪,心率变异性和皮电水平显著增加,听觉信息记忆绩效下降。结论表达抑制不对主观体验起作用但会引起交感神经激活增加,并伴有一定程度的认知代价。     

Neural substrates in secondary somatosensory area for the perception of different tactile sensations

This functional magnetic resonance imaging (fMRI) study investigated the secondary somatosensory area (SII) in humans, especially regarding the presence of distinctive spatial arrangements of neural subunits responding to different types of tactile stimuli. Ten healthy volunteers received four different sensory stimuli on the palmar side of the right hand—vibrotactile, pressure, warmth, and coolness. Based on group‐level analysis of the fMRI data, all four of the somatosensory stimuli resulted in activations in the bilateral SII and insula as well as the SI contralateral to the stimulation. The spatial distribution of neural activations corresponding to each stimulus, as examined by cortical inflation technique, revealed significant overlaps, but also showed the differences in terms of its overall topology. The local maxima of the activation within the SII, corresponding to these stimuli, manifested distinctive spatial location. These results suggest that differential networks of the SII subregions are involved in the processing of the different nature of the tactile stimuli, while sharing common regions in the parietal operculum.     

A passenger reduces sleepy driver's activation in the right prefrontal cortex: A laboratory study using near-infrared spectroscopy

The present study aimed to examine how a passenger affects the sleepiness effect (awake vs. sleepy) on an individual's prefrontal activation during a simulated driving-game task using a wireless portable near-infrared spectroscopy (NIRS) device. Participants drove from start to goal along default routes either solely (no-passenger group) or with a friend sitting beside him/her as a passenger (with-passenger group). Sleepiness level was assessed by a five-item scale questionnaire. In the no-passenger group, there were no performance and activation differences between the sleepy and awake participants. In the with-passenger group, by contrast, the sleepy participants showed more errors and lower activations in their right prefrontal cortex than the awake participants. These results suggest that a passenger has little effect on awake participants, but may weaken the sleepy participants’ vigilance and/or their cognitive abilities of action control. Practically, the present study demonstrates that NIRS may provide us a new possibility to monitor and examine the driver's mental states in the brain.     

Volumetry and topography of the human brain by magnetic resonance imaging

Software, termed Morph©, is described for the morphometric analysis of magnetic resonance images of the human brain. Algorithms for objective contrast border recognition, surface feature classification, and surface feature contour unfolding are evaluated. Intraoperator and interoperator variabilities and errors were determined to be less than 2% over a group of operators (n = 6) for the known volume of a cerebral hemisphere obtained at autopsy. Volumetric errors were measured to be ± 3% for simulated objects and less than 1% for images of phantoms. Contours of brains of normal elderly subjects (n = 6) and patients with probable Alzheimer's disease (n = 6), segmented into sulcal and gyral features to determine gyrification indices, showed concordance with literature values. Flat maps or topograms were obtained of the convoluted cortex by unfolding the segmented contours. The areas of surface features were readily obtained. The activation of the frontal eye fields (FEF) defined by functional magnetic resonance imaging (fMRI) with an oculomotor control task was mapped onto a topogram of the precentral sulcus. This software provides accurate volumetric analysis with additional topographical tools for characterizing convoluted cortical features and for presenting three‐dimensional fMRI activation patterns as two‐dimensional maps. © 2001 John Wiley & Sons, Inc. Int J Imaging Syst Technol 11, 198–208, 2000     

Diurnal variability of human operator attention disengagement and chronotype: an fMRI-based case study

The main objective of this study was to analyse diurnal variations during attention disengagement operations on a neuronal level in a group of subjects representing extreme chronotypes. The parietal lobes of the participants were scanned four times per day for activity changes using functional magnetic resonance imaging (fMRI), while the subjects performed the task at hand. The findings provide credible evidence of the existence of variability in the activity patterns and levels of the parietal lobes. The activity patterns and levels depend on both the participants’ chronotype as well as time of day. The morning type showed stronger activation of the left parietal lobe, while the evening type showed stronger activation of the right parietal lobe. There was a visible decrease in parietal lobe activity during the post-lunch dip, independent of the subjects’ chronotype. Such variability of parietal lobe activity may suggest that humans are more likely to make errors during task performance at certain times of the day as opposed to others.     

fMRI analysis of excessive binocular disparity on the human brain

The aim of this study is to evaluate brain regions related with excessive binocular disparity that may be linked to stereoscopic visual fatigue. In stereoscopic displays, excessive binocular disparity may generate blurring or double vision in the stereovision and induce unnatural oscillations in accommodation and vergence. These phenomena may lead to visual fatigue and activation (or deactivation) of human brain related with sensory and eye movement functions. A functional magnetic resonance imaging (fMRI) method is used to investigate the effect of excessive binocular disparity on human brain. Subjective assessments of visual fatigue are also conducted with the same stimuli as the fMRI experiment. Based on the subjective assessment results, participants are classified into low‐ and high‐fatigue groups. From the fMRI experiments, the high‐fatigue group showed more activation at the intraparietal sulcus (IPS) than the low‐fatigue group, when viewing an excessive disparity stimulus. The results showed that the excessive binocular disparity stimulus may induce overload to the IPS region, which is related with stereo processing and saccadic eye movement. In addition, it could be possible to use fMRI as an objective measurement method for understanding the stereoscopic visual fatigue when stimuli with excessive binocular disparity are applied.     

Stereoscopic 3D objects evoke stronger saliency for nonverbal working memory: An fMRI study

Effective working memory (WM) training is often desired to improve WM. Recent studies have suggested that WM training is more successful when participants monitor scenes in three‐dimensional (3D) environments. Although previous neuroimaging studies have examined visuospatial WM in relation to a 3D scene or object, these studies did not investigate WM using stereoscopic 3D object stimuli. We used functional magnetic resonance imaging (fMRI) to identify brain activation during an N‐back task with 3D object stimuli, and determined the difference in activation pattern between stereoscopic versus shaded 3D objects. We found that the anterior insula, ventral striatum, and posterior orbitofrontal cortex showed greater activation during the 2‐back task with stereoscopic 3D objects than with shaded 3D objects. These regions have previously been associated with a salience network.     

Group inference of default‐mode networks from functional magnetic resonance imaging data: comparison of random‐ and mixed‐effects group statistics

Default‐mode network (DMN) activity measured with functional magnetic resonance imaging (fMRI) represents dominant intrinsic neuronal activations of the human brain during rest as opposed to task periods. Previous studies have demonstrated the utility of DMNs in identifying characteristic traits such as hyperactivation and hypoactivation from group‐level fMRI data. However, these group‐level spatial patterns (SPs) were mostly based on random‐effect (RFX) statistics determined using only the intersubject variability. To reduce the potentially significant level of variability in group‐level SPs in RFX due to intrasubject variability, we were motivated to adopt a mixed‐effects (MFX) statistics that is using both intrasubject and intersubject variability. Publicly available group fMRI database during resting state was analyzed using a temporal concatenation‐based group independent component (IC) analysis, and DMN‐related ICs at the group‐level were automatically selected. The individual‐level SPs of these DMN‐related ICs were subsequently estimated using a dual‐regression approach. Using these individual‐level SPs, we evaluated the reproducibility and potential variability of the DMNs from the RFX and MFX statistics using performance measures including (1) neuronal activation levels, (2) percentages of overlap, (3) Pearson's spatial correlation coefficients, and (4) the distances between center‐of‐clusters. The resulting SPs from the MFX‐based group inference showed a significantly greater level of reproducibility than those from the RFX‐based group inference as tested in a bootstrapping framework Family‐wise error (FWE)‐corrected p < 10^?10, one‐way analysis of variance (ANOVA)). The reported findings may provide a valuable supplemental option for investigating the neuropsychiatric group‐ or condition‐dependent characteristic traits implicated in DMNs. © 2012 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 22, 121–131, 2012     

Low-frequency pulsed electromagnetic field exposure can alter neuroprocessing in humans

Extremely low-frequency magnetic fields (from DC to 300 Hz) have been shown to affect pain sensitivity in snails, rodents and humans. Here, a functional magnetic resonance imaging study demonstrates how the neuromodulation effect of these magnetic fields influences the processing of acute thermal pain in normal volunteers. Significant interactions were found between pre- and post-exposure activation between the sham and exposed groups for the ipsilateral (right) insula, anterior cingulate and bilateral hippocampus/caudate areas. These results show, for the first time, that the neuromodulation induced by exposure to low-intensity low-frequency magnetic fields can be observed in humans using functional brain imaging and that the detection mechanism for these effects may be different from those used by animals for orientation and navigation. Magnetoreception may be more common than presently thought.     

An Automated and Real-time Approach of Depression Detection from Facial Micro-expressions

Depression is a mental psychological disorder that may cause a physical disorder or lead to death. It is highly impactful on the social-economical life of a person; therefore, its effective and timely detection is needful. Despite speech and gait, facial expressions have valuable clues to depression. This study proposes a depression detection system based on facial expression analysis. Facial features have been used for depression detection using Support Vector Machine (SVM) and Convolutional Neural Network (CNN). We extracted micro-expressions using Facial Action Coding System (FACS) as Action Units (AUs) correlated with the sad, disgust, and contempt features for depression detection. A CNN-based model is also proposed in this study to auto classify depressed subjects from images or videos in real-time. Experiments have been performed on the dataset obtained from Bahawal Victoria Hospital, Bahawalpur, Pakistan, as per the patient health questionnaire depression scale (PHQ-8); for inferring the mental condition of a patient. The experiments revealed 99.9% validation accuracy on the proposed CNN model, while extracted features obtained 100% accuracy on SVM. Moreover, the results proved the superiority of the reported approach over state-of-the-art methods.