为研究情绪重评时的大脑皮层源活动,针对情绪重评实验范式下采集的15例健康人同步EEG-fMRI数据,首先提出一种新颖的基于偶极子特征优化的融合源定位方法:根据fMRI加权最小范数估计源定位结果,采用20 ms EEG滑动时间窗,提取每个时窗内的...为研究情绪重评时的大脑皮层源活动,针对情绪重评实验范式下采集的15例健康人同步EEG-fMRI数据,首先提出一种新颖的基于偶极子特征优化的融合源定位方法:根据fMRI加权最小范数估计源定位结果,采用20 ms EEG滑动时间窗,提取每个时窗内的偶极子空间融合特征,将其作为动态融合先验进行加权最小范数估计溯源;随后将该结果与fMRI加权最小范数估计源定位结果进行情绪重评机制上的对比;最后采用样本熵进行脑电源复杂度分析。实验结果表明,该方法可以在高时间和空间分辨率下,有效地追踪情绪重评任务下大脑皮层上的脑电源动态并识别出相关脑区。情绪重评过程中,随着后枕顶叶晚期正电位的出现,显著活跃脑区从左顶叶下部、右侧额中回下部、左侧脑岛转移到右侧颞上回和左外侧枕叶,最后在晚期正电位慢波阶段激活了右侧梭状回、右侧额中回下部和右侧扣带回峡部(P<0.05)。通过脑电源样本熵的计算,提取出被试在接受不同情绪刺激后1500 ms内的显著脑区(P<0.05):情绪响应的活跃脑区为左外侧枕叶(负性:0.688±0.124,中性:0.590±0.126);情绪重评的活跃脑区为右侧额中回下部(负性重评:0.814±0.114,负性:0.736±0.123);情绪重评的抑制脑区为右侧颞上回(负性:0.642±0.152,负性重评:0.546±0.090)。这些结果为情绪重评相关的皮层脑电源定位研究提供了脑区参考。展开更多
Background: Mild traumatic brain injury (mTBI) is one of the most common forms of cerebral pathology in young people and disorders involve dysfunctions in cognitive and motor spheres. We would like to examine the stru...Background: Mild traumatic brain injury (mTBI) is one of the most common forms of cerebral pathology in young people and disorders involve dysfunctions in cognitive and motor spheres. We would like to examine the structural and functional alterations of the brain in patients with mTBI while performing hand movements. Methods: Twenty healthy right-handed subjects (age 25.1 ± 3.9) and 10 patients (age 27.9 ± 7.3) with mTBI without hemiparesis participated in the study using functional magnetic resonance imaging (fMRI) and electroencephalography (EEG). FMRI and EEG reactions were analysed during right- and left-hand movements. Results: It was shown that fMRI reactive changes have a larger inter-individual variability of activation during left-hand movements in comparison with right-hand ones in healthy subjects. The TBI patients demonstrated an increase of a diffuse component of fMRI reactive changes compared to healthy people. A greater number of the brain structures was involved, mainly at the subcortical level, mostly in the left hemisphere during right-hand movement. EEG study demonstrated coherence changes for the slow (delta) frequency bands in the left hemisphere, while performing both hand movements. In healthy persons, EEG coherence changes were observed in the fast (alhpa2) frequency band predominantly in contralateral hemispheres, while performing hand movements. Conclusion: So, fMRI and EEG studies revealed the most expressed pathological reactive changes in the left hemisphere and the brain cortical structures during right-hand movements in patients after mTBI. These data allowed us to propose that the younger brain structures were the most sensitive to mTBI.展开更多
The combination of electroencephalogram (EEG) and functional magnetic resonance imaging(fMRI) is a very attractive aim in neuroscience in order to achieve both high temporal and spatial resolution for the non-invasive...The combination of electroencephalogram (EEG) and functional magnetic resonance imaging(fMRI) is a very attractive aim in neuroscience in order to achieve both high temporal and spatial resolution for the non-invasive study of cognitive brain function. In this paper, we record simultaneous EEG-fMRI of the same subject in emotional processing experiment in order to explore the characteristics of different emotional picture processing, and try to find the difference of the subjects' brain hemisphere while viewing different valence emotional pictures. The late positive potential(LPP) is a reliable electrophysiological index of emotional perception in humans. According to the analysis results, the slow-wave LPP and visual cortical blood oxygen level-dependent (BOLD) signals are both modulated by the rated intensity of picture arousal. The amplitude of the LPP correlate significantly with BOLD intensity in visual cortex, amygdala, temporal area, prefrontal and central areas across picture contents.展开更多
Objective: To characterise flash visual evoked potentials(FVEPs) in 20 patient s with Creutzfeldt-Jacob disease (CJD),and assess the relationships between spo ntaneous EEG patterns and the responses to individual stim...Objective: To characterise flash visual evoked potentials(FVEPs) in 20 patient s with Creutzfeldt-Jacob disease (CJD),and assess the relationships between spo ntaneous EEG patterns and the responses to individual stimuli. Methods: We analy sed the shape and time course of periodic sharp wave complexes(PSWCs) and respon ses to 1 Hz flashes. In nine patients, we applied an algorithm based on an autor egressive model with exogenous input (ARX) to estimate responses to individual r andom flashes and their interaction with PSWCs. Results:The FVEPs included P1 an d N1 components in all patients, and the P2 peak in 18. Eight patients showed gi ant FVEPs (N1-P2 > 60 V), all of whom had an MM polymorphism in codon129 of the prion protein gene; in seven cases, the presence of giant FVEPs correlated with a prominent and almost continuous periodic EEG pattern. Giant N1-P2 abnormally spread on the anterior scalp regions, and had a different waveform distribution from that of the PSWCs. In five patients with a normal or slightly enlarged ave rage N1-P2 amplitude, single sweep (ARX) analysis revealed a period of relative refractoriness following individual PSWCs. In four patients with‘giant’FVEPs, the individual responses occurred regardless of the interval between the stimul us and previous PSWC, but their amplitude had an inverse relationship with the i nterval length.Conclusions: Giant responses to flash stimuli are a common findin g in CJD patients (40%of our cases). Single sweep ARX analysis showed that PSWC s were followed by a period of partial refractoriness, which prevented most of t he individual responses to flashes, but not giant FVEPs. The association between prominent spontaneous paroxysms and giant FVEPs suggests that both are due to a common hyperexcitable change favouring neuronal synchronisation. Significance: Our data contribute to clarifying the debated problem of the occurrence of giant FVEPs in CJD and their relationships with the spontaneous periodic EEG pattern.展开更多
脑电(Electroencephalography,EEG)和功能磁共振(Functional magnetic resonance imaging,fMRI)技术的结合,可以实现两者优势的互补,获得更加合理的源定位结果。本文报道的是一种将fMRI先验信息结合到脑电源定位中的新方法。在该方法中...脑电(Electroencephalography,EEG)和功能磁共振(Functional magnetic resonance imaging,fMRI)技术的结合,可以实现两者优势的互补,获得更加合理的源定位结果。本文报道的是一种将fMRI先验信息结合到脑电源定位中的新方法。在该方法中,先利用SPM方法计算获得fMRI的统计映射参数,然后将基于计算获得的统计参数构造的权矩阵结合到FOCUSS的迭代过程中,对脑电的反演提供具有fMRI先验空间位置信息的约束,提高脑电的源空间定位精度,从而获得更加合理的定位结果。通过对一形状知觉实验fMRI和脑电数据的结合定位分析,结果初步证实了改进方法能获得和生理更加一致的结果。展开更多
文摘为研究情绪重评时的大脑皮层源活动,针对情绪重评实验范式下采集的15例健康人同步EEG-fMRI数据,首先提出一种新颖的基于偶极子特征优化的融合源定位方法:根据fMRI加权最小范数估计源定位结果,采用20 ms EEG滑动时间窗,提取每个时窗内的偶极子空间融合特征,将其作为动态融合先验进行加权最小范数估计溯源;随后将该结果与fMRI加权最小范数估计源定位结果进行情绪重评机制上的对比;最后采用样本熵进行脑电源复杂度分析。实验结果表明,该方法可以在高时间和空间分辨率下,有效地追踪情绪重评任务下大脑皮层上的脑电源动态并识别出相关脑区。情绪重评过程中,随着后枕顶叶晚期正电位的出现,显著活跃脑区从左顶叶下部、右侧额中回下部、左侧脑岛转移到右侧颞上回和左外侧枕叶,最后在晚期正电位慢波阶段激活了右侧梭状回、右侧额中回下部和右侧扣带回峡部(P<0.05)。通过脑电源样本熵的计算,提取出被试在接受不同情绪刺激后1500 ms内的显著脑区(P<0.05):情绪响应的活跃脑区为左外侧枕叶(负性:0.688±0.124,中性:0.590±0.126);情绪重评的活跃脑区为右侧额中回下部(负性重评:0.814±0.114,负性:0.736±0.123);情绪重评的抑制脑区为右侧颞上回(负性:0.642±0.152,负性重评:0.546±0.090)。这些结果为情绪重评相关的皮层脑电源定位研究提供了脑区参考。
文摘Background: Mild traumatic brain injury (mTBI) is one of the most common forms of cerebral pathology in young people and disorders involve dysfunctions in cognitive and motor spheres. We would like to examine the structural and functional alterations of the brain in patients with mTBI while performing hand movements. Methods: Twenty healthy right-handed subjects (age 25.1 ± 3.9) and 10 patients (age 27.9 ± 7.3) with mTBI without hemiparesis participated in the study using functional magnetic resonance imaging (fMRI) and electroencephalography (EEG). FMRI and EEG reactions were analysed during right- and left-hand movements. Results: It was shown that fMRI reactive changes have a larger inter-individual variability of activation during left-hand movements in comparison with right-hand ones in healthy subjects. The TBI patients demonstrated an increase of a diffuse component of fMRI reactive changes compared to healthy people. A greater number of the brain structures was involved, mainly at the subcortical level, mostly in the left hemisphere during right-hand movement. EEG study demonstrated coherence changes for the slow (delta) frequency bands in the left hemisphere, while performing both hand movements. In healthy persons, EEG coherence changes were observed in the fast (alhpa2) frequency band predominantly in contralateral hemispheres, while performing hand movements. Conclusion: So, fMRI and EEG studies revealed the most expressed pathological reactive changes in the left hemisphere and the brain cortical structures during right-hand movements in patients after mTBI. These data allowed us to propose that the younger brain structures were the most sensitive to mTBI.
基金The Open Project of the State Key Laboratory of Robotics and System at Harbin Institute of Technologygrant number:SKLRS-2010-2D-09,SKLRS-2010-MS-10+5 种基金National Natural Science Foundation of Chinagrant number:61201096Natural Science Foundation of Changzhou Citygrant number:CJ20110023Changzhou High-tech Reasearch Key Laboratory Projectgrant number:CM20123006
文摘The combination of electroencephalogram (EEG) and functional magnetic resonance imaging(fMRI) is a very attractive aim in neuroscience in order to achieve both high temporal and spatial resolution for the non-invasive study of cognitive brain function. In this paper, we record simultaneous EEG-fMRI of the same subject in emotional processing experiment in order to explore the characteristics of different emotional picture processing, and try to find the difference of the subjects' brain hemisphere while viewing different valence emotional pictures. The late positive potential(LPP) is a reliable electrophysiological index of emotional perception in humans. According to the analysis results, the slow-wave LPP and visual cortical blood oxygen level-dependent (BOLD) signals are both modulated by the rated intensity of picture arousal. The amplitude of the LPP correlate significantly with BOLD intensity in visual cortex, amygdala, temporal area, prefrontal and central areas across picture contents.
文摘Objective: To characterise flash visual evoked potentials(FVEPs) in 20 patient s with Creutzfeldt-Jacob disease (CJD),and assess the relationships between spo ntaneous EEG patterns and the responses to individual stimuli. Methods: We analy sed the shape and time course of periodic sharp wave complexes(PSWCs) and respon ses to 1 Hz flashes. In nine patients, we applied an algorithm based on an autor egressive model with exogenous input (ARX) to estimate responses to individual r andom flashes and their interaction with PSWCs. Results:The FVEPs included P1 an d N1 components in all patients, and the P2 peak in 18. Eight patients showed gi ant FVEPs (N1-P2 > 60 V), all of whom had an MM polymorphism in codon129 of the prion protein gene; in seven cases, the presence of giant FVEPs correlated with a prominent and almost continuous periodic EEG pattern. Giant N1-P2 abnormally spread on the anterior scalp regions, and had a different waveform distribution from that of the PSWCs. In five patients with a normal or slightly enlarged ave rage N1-P2 amplitude, single sweep (ARX) analysis revealed a period of relative refractoriness following individual PSWCs. In four patients with‘giant’FVEPs, the individual responses occurred regardless of the interval between the stimul us and previous PSWC, but their amplitude had an inverse relationship with the i nterval length.Conclusions: Giant responses to flash stimuli are a common findin g in CJD patients (40%of our cases). Single sweep ARX analysis showed that PSWC s were followed by a period of partial refractoriness, which prevented most of t he individual responses to flashes, but not giant FVEPs. The association between prominent spontaneous paroxysms and giant FVEPs suggests that both are due to a common hyperexcitable change favouring neuronal synchronisation. Significance: Our data contribute to clarifying the debated problem of the occurrence of giant FVEPs in CJD and their relationships with the spontaneous periodic EEG pattern.
文摘脑电(Electroencephalography,EEG)和功能磁共振(Functional magnetic resonance imaging,fMRI)技术的结合,可以实现两者优势的互补,获得更加合理的源定位结果。本文报道的是一种将fMRI先验信息结合到脑电源定位中的新方法。在该方法中,先利用SPM方法计算获得fMRI的统计映射参数,然后将基于计算获得的统计参数构造的权矩阵结合到FOCUSS的迭代过程中,对脑电的反演提供具有fMRI先验空间位置信息的约束,提高脑电的源空间定位精度,从而获得更加合理的定位结果。通过对一形状知觉实验fMRI和脑电数据的结合定位分析,结果初步证实了改进方法能获得和生理更加一致的结果。
