事件相关电位与精神科常用药物

事件相关电位(event related potentials,ERP)是一种特殊的诱发电位,其不只包括由外界刺激诱发出的神经系统电位的变化,还包括伴随的各种生理活动,如认知和运动等神经系统的电位变化,包括P1、N1、P2(外源性成分),N2、P3(P300、内源性成分),N400、CNV、MMN、ERN、PN等.是继脑电图和肌电图之后的临床神经电生理的第三大进展,被称为"窥测精神之窗".     

尿毒症患者认知障碍与事件相关电位

自20世纪发现脑电图(electroencephalography,EEG)以来,随着人类对脑电活动研究的不断深入,逐渐形成、发展了事件相关电位(eventrelated potentials,ERP)。ERP即人注意到某客体并对其进行高级认知加工时,通过平均叠加在头皮上记录下来的电位。ERP反映人对一个事件认知过程中大脑的神经电生理的改变,因此也有人将其     

P50诱发反应在脑外伤后认知受损评估中的应用

认知功能受损是各种脑外伤( TBI)最常见的神经精神后遗症之一。回顾应用P50 诱发反应(ERP) 进行TBI后认知功能损害评估等研究,阐述了TBI后认知功能损害的胆碱能假说及其与听觉门控受损的相关性,讨论受损听觉门控通道的神经生理特征及其与P50ERP的关系,以及P50ERP的记录原则,并总结TBI后持续认知功能障碍患者P50ERP的研究进展,最后提出临床应用P50ERP研究、评估及治疗TBI后认知功能障碍的可能性。     

老年患者全髋关节置换术前后事件相关电位变化的研究

目的：初步探讨老年患者全髋关节置换术前后事件相关电位（ERP）的变化。方法：选择无认知功能障碍临床症状、拟于全身麻醉下行全髋关节置换手术的老年患者30例,在手术前1d和手术后3d用ERP仪进行ERP的P300和N400刺激模式测定。手术前1d测得P3b（P300亚组成分）波幅下降低于3．0μV、潜伏期延长超过550ms的患者被设为阳性组,其余患者被设为阴性组。结果：阳性组患者术后P3b、N400潜伏期较术前明显延长,P3b、N400波幅及词条匹配率较术前明显降低（P均〈0．01）。阳性组患者手术前后各项指标与阴性组手术前后比较差异均有统计学意义（P均〈0．01）。结论：术前ERP的P3b波幅有下降和潜伏期延长的患者,术后认知障碍会进一步加重;ERP可能可作为老年患者全髋关节置换术后早期认知功能改变的量化指标.     

闭合性颅脑外伤患者事件相关电位的检测

对64例闭合性颅脑外伤患者分别采用视觉（图像）、听觉刺激诱发事件相关电位（ERP），其P3波潜伏期较正常对照组明显延长（P＜0．001）。ERP中P3波潜伏期、波幅与患者的病情严重程度密切相关（P＜0．001）。其中31例患者进行了ERP复测。两次P3波潜伏期有极显著的差异（P＜0．001）。结果提示，ERP可作为观察颅脑外伤患者脑认知功能损害程度及其恢复程度的一种客观指标。     

帕金森病短时记忆障碍的事件相关电位研究

目的 :评价不同刺激序列诱发的事件相关电位 (ERP)对非痴呆帕金森病 (ND PD)短时记忆 (STM )障碍的诊断价值。方法 :应用经典Oddball序列、Sternberg序列分别对 2 4例ND PD患者 (患者组 )和 30例健康受试者 (对照组 )进行ERP检查。结果 :Oddball序列下 ,两组P30 0潜伏期、波幅均无明显差异 (P >0 .0 5 ) ;Sternberg序列下 ,患者组P5 6 0波幅 ( 16 .6± 5 .2 μV)较对照组 ( 2 8.5± 4.4μV)显著降低 ( P <0 .0 5 ) ,前者波幅与记忆商值呈正相关 (r =0 .6 8,P <0 .0 5 ) ,患者组 10例出现N6 80波均存在STM障碍。结论 :Sternberg序列诱发的ERP ,P5 6 0波幅的降低和N 6 80波的出现对STM障碍的诊断有一定的临床价值     

卒中后抑郁患者事件相关电位与单胺类神经递质水平相关性研究

目的探讨卒中后抑郁患者事件相关电位(event-related potential,ERP)与单胺类神经递质的关系。方法测定48例卒中后抑郁患者(PSD组)和46例体检健康者(对照组)ERP和血浆单胺类神经递质水平,并进行比较分析。结果 PSD组ERP测定异常率为91.7%,ERP中N2及P3波潜伏期较对照组延长,P3波幅较对照组降低(P<0.01);PSD组去甲肾上腺素、多巴胺和5-羟色胺水平较对照降低(P<0.01);PSD组ERP成分中P3波潜伏期与去甲肾上腺素、多巴胺和5-羟色胺水平呈负相关(P<0.05),P3波幅与去甲肾上腺素、多巴胺和5-羟色胺水平呈正相关(P<0.05)。结论卒中后抑郁患者存在血浆单胺类神经递质水平降低与认知障碍,且二者相互影响,ERP和血浆单胺类神经递质水平测定可作为卒中后抑郁患者临床诊治的判定指标。     

正常人不同刺激野ERP及其法医学价值研究

目的研究正常人不同刺激野电生理反应及头皮分布,进一步探讨不同视野缺损时视觉信息处理的特征与差别。方法本研究分别对30名正常视功能被试进行不同刺激野刺激,同时记录其脑电反应。结果事件相关电位（ERP）早期成分显示：与上视野缺损相比,下视野缺损引起广泛脑区N1和枕颞部P1潜伏期显著延长;此外,上视野缺损较下视野缺损诱发出较小P1,而N1振幅表现为上下视野间相似。ERP晚期成分显示：与下视野缺损对比,上视野缺损引起广泛脑区N2和左半球中央顶区P3潜伏期显著延长,以及较小N2,而P3振幅在上下视野间无差异。结论ERP结果提示,下视野缺损主要引起ERP早期成分P1和N1潜伏期的延长,而上视野缺损主要引起ERP晚期成分N2和P3潜伏期的延长,以及P1和N2振幅的降低。     

老年性痴呆患者事件相关电位P300和多导睡眠图对照研究

目的：探讨老年性痴呆患者事件相关电位（ERP）和多导睡眠图（PSG）之间的关系。方法：对36例临床诊断的老年性痴呆患者及35例年龄匹配的健康人进行对照研究,所有受试者均进行ERP和PSG测试。结果：研究组中ERP测定的异常率为94．4％（34／36）,ERP中N2、P3波潜伏期较对照组延长,P3波幅降低,其差异具有显著性意义（P〈0．01）,PSG测定睡眠潜伏期延长、觉醒次数和S1阶段增多、总睡眠时间、深睡眠（S3＋S4）、快眼动睡眠时间和睡眠纺锤波指数减少、睡眠效率降低与对照组比较差异有显著性意义（P〈0．01）。ERP成分中P3波潜伏期P3波幅与PSG测定中睡眠潜伏期、觉醒次数、总睡眠时间、深睡眠、快眼动睡眠时间、睡眠效率及纺锤波指数等指标存在显著的相关性（P〈0．01）。结论：老年性痴呆患者存在明显的认知功能减退和睡眠质量下降。ERP和PSG可以作为老年性痴呆患者早期诊断的辅助指标。     

体感诱发电位和改良脑出血量表在脑出血患者肢体运动功能预测中的应用

Objective To evaluate the extremity function of patients with intracerebral hemorrhage (ICH)using short-latency somatosensory evoked potentials (SEPs) and a modified intracerebral hemorrhage (MICH) scale.Methods On admission, SEP was applied in the examination of 61 patients with ICH. P40 latency and the amplitude of posterior tibial nerve potentials in both the healthy and affected extremities were measured. Abnormalities were classified based on the margin of lower extremity SEP latency and the main waveform changes. MICH was measured simultaneously to prepare a prognosis. The modified Rankin scale (MRS) score was assessed 3 months after the attack as well.Results Compared with the healthy side, there were significant differences in posterior tibial nerve P40 latency and amplitude on the affected side among patients with ICH. P40 latency and MRS scores on the affected side 3 months after the attack were positively correlated. On the unaffected side, P40 amplitude and the MRS score 3 months after the attack were negatively correlated. The MICH score on admission and the MRS score 3 months after the attack were positively correlated. Based on MRS scores (MRS≥4 indicating a poor prognosis), the predictive sensitivities for a poor prognosis of SEP and the MICH scale in patients with ICH were 80.77% and 84.61% respectively, while the specificities were 62.68% and 88.57% respectively, and the accordance rates were 70.5% and 86.9% respectively. Conclusions SEP and the MICH scale are closely correlated with the prognosis for extremity function in patients with ICH.The combination of SEP with the MICH scale might be helpful in predicting the prognosis of the patients with ICH.     

Dissociable medial frontal negativities from a common monitoring system for self- and externally caused failure of goal achievement

Goal-directed behavior requires the ability to adapt performance strategies based on the attribution of unintended outcomes to internal or external causes. Using event-related brain potentials, the present research compared neural activity following self-generated errors induced by a flanker task and following externally generated errors induced by supposed “technical malfunctions”. Errors and malfunctions were associated with temporally dissociable ERP components, the short-latency error-related negativity (ERN) and the longer-latency feedback-related negativity (FRN), respectively. Independent component analysis (ICA) was applied to compare the underlying neural components of ERN and FRN. ICA results revealed that the FRN is attributable to the neural sources of the ERN, suggesting that the two components share a source network. Furthermore, single-trial amplitudes of ERN and FRN were specifically related to the implementation of error correction and malfunction compensation: the stronger the failure signal, the more efficient was remedial behavior. Together the results demonstrate that internally and externally generated unintended action outcomes engage a common monitoring mechanism that manifests in two temporally distinct ERP components and induces similar compensatory processes. The temporal dissociation of the ERP components might provide the basis for further processes of outcome attribution underlying action selection and changes in performance strategy. In line with recent neuroimaging findings, ERN and FRN appear to reflect the use of different sources of information about action outcome to update action value.     

Cortical lateralization during verb generation: a combined ERP and fMRI study

Lateralization of scalp-recorded event-related potentials (ERPs) and functional MRI (fMRI) activation was investigated using a verb generation task in 10 healthy right-handed adults. ERPs showed an early transient positivity in the left inferior temporal region (500-1250 ms) following auditory presentation of the stimulus noun. A sustained slow cortical negativity of later onset (1250-3000 ms) was then recorded, most pronounced over left inferior frontal regions. fMRI data were in agreement with both ERP effects, showing left lateralized activation in inferior and superior temporal as well as inferior frontal cortices. Lateralized ERP effects occurred during the verb generation task but not during passive word listening or during word- and nonword repetition. Thus, ERPs and fMRI provided convergent evidence regarding language lateralization, with ERPs revealing the temporal sequence of posterior to anterior cortical activation during semantic retrieval.     

Ventral striatal and medial prefrontal BOLD activation is correlated with reward-related electrocortical activity: a combined ERP and fMRI study

Functional magnetic resonance imaging (fMRI) research suggests that the ventral striatum (VS)/nucleus accumbens, medial prefrontal cortex (mPFC), and broader mesocorticolimbic dopamine system mediate aspects of reward processing from expectation of reward to pleasantness experienced upon reward attainment. In parallel, research utilizing event-related potentials (ERP) indicates that the feedback negativity (FN) is sensitive to reward vs. non-reward feedback and outcome expectation. The FN has been source localized to the mPFC and dorsal striatum, and converging evidence suggests that the FN reflects reward processing in the mesocorticolimbic system. However, the extent to which ERP and fMRI measures of reward processing are correlated has yet to be explored within the same individuals. The primary aim of the current study was to examine the convergence between fMRI (i.e., VS and mPFC) and ERP (i.e., FN) measures of reward processing in forty-two participants who completed counterbalanced fMRI and ERP sessions while performing the same monetary gambling task. For the Win>Loss comparison, fMRI activation in the mesocorticolimbic reward circuit including the VS and mPFC was positively correlated with the FN. Here, we demonstrate that monetary gains activate the VS, mPFC, caudate, amygdala, and orbital frontal cortex, enhance the FN ERP component within 300 ms post feedback, and that these measures are related. Thus, fMRI and ERP measures provide complementary information about mesocorticolimbic activity during reward processing, which may be useful in assessing pathological reward sensitivity.     

The effect of visuospatial attentional load on the processing of irrelevant acoustic distractors

This work investigated the role of cognitive control functions in selective attention when task-relevant and -irrelevant stimuli come from different sensory modalities. We parametrically manipulated the load of an attentive tracking task and investigated its effect on irrelevant acoustic change-related processing. While subjects were performing the visual attentive tracking task, event-related potentials (ERPs) were recorded for frequent standard tones and rare deviant tones presented as auditory distractors. The deviant tones elicited two change-related ERP components: the mismatch negativity (MMN) and the P3a. The amplitude of the MMN, which indexes the early detection of irregular changes, increased with increasing attentional load, whereas the subsequent P3a component, which indicates the involuntary orienting of attention to deviants, was significant only in the lowest load condition. These findings suggest that active exclusion of the early detection process of irrelevant acoustic changes depends on available resources of cognitive control, whereas the late involuntary orienting of attention to deviants can be passively suppressed by high demand on central attentional resources. The present study thus reveals opposing visual attentional load effects at different temporal and functional stages in the rejection of deviant auditory distractors and provides a new perspective on the resolution of the long-standing early versus late attention selection debate.     

Three stages of facial expression processing: ERP study with rapid serial visual presentation

Electrophysiological correlates of the processing facial expressions were investigated in subjects performing the rapid serial visual presentation (RSVP) task. The peak latencies of the event-related potential (ERP) components P1, vertex positive potential (VPP), and N170 were 165, 240, and 240 ms, respectively. The early anterior N100 and posterior P1 amplitudes elicited by fearful faces were larger than those elicited by happy or neutral faces, a finding which is consistent with the presence of a ‘negativity bias.’ The amplitude of the anterior VPP was larger when subjects were processing fearful and happy faces than when they were processing neutral faces; it was similar in response to fearful and happy faces. The late N300 and P300 not only distinguished emotional faces from neutral faces but also differentiated between fearful and happy expressions in lag2. The amplitudes of the N100, VPP, N170, N300, and P300 components and the latency of the P1 component were modulated by attentional resources. Deficient attentional resources resulted in decreased amplitude and increased latency of ERP components. In light of these results, we present a hypothetical model involving three stages of facial expression processing.     

Olfactory and trigeminal event-related potentials in migraine

BACKGROUND: Trigeminal/neuronal hyperexcitability and spreading depression activating the trigemino-vascular system are discussed in migraine-pathophysiology. This study investigated trigeminal and olfactory event-related potentials in migraineurs. METHODS: Nasal chemosensitivity was assessed in 19 female migraineurs with or without aura > 72 h before or after an attack and in 19 healthy females employing event-related cortical potentials (ERPs) after specific trigeminal stimulation of nasal nociceptors with short pulses of CO2, and specific olfactory stimulation with H2S. Odour thresholds and odour identification performance were also tested. RESULTS: Migraineurs exhibited greater responses to trigeminal stimulation, indicated by significantly larger ERP amplitudes N1. In contrast, olfactory ERP amplitudes P1N1 were significantly smaller in migraineurs. A leave-one-out classification procedure on the basis of these two parameters assigned 76.3% cases correctly. The olfactory ERP amplitude discriminated better between groups than trigeminal ERPs (71.1 vs. 68.4% correct classification). CONCLUSIONS: Our data suggest trigeminal hyperexcitability in migraineurs. A general increase of nasal chemosensitivity is not supported because of smaller olfactory ERP amplitudes in migraineurs. Olfactory ERPs discriminate better than trigeminal ERPs between migraineurs and controls, emphasizing the significance of the olfactory system in migraine.     

Simultaneous ERP and fMRI of the auditory cortex in a passive oddball paradigm

Infrequent occurrences of a deviant sound within a sequence of repetitive standard sounds elicit the automatic mismatch negativity (MMN) event-related potential (ERP). The main MMN generators are located in the superior temporal cortex, but their number, precise location, and temporal sequence of activation remain unclear. In this study, ERP and functional magnetic resonance imaging (fMRI) data were obtained simultaneously during a passive frequency oddball paradigm. There were three conditions, a STANDARD, a SMALL deviant, and a LARGE deviant. A clustered image acquisition technique was applied to prevent contamination of the fMRI data by the acoustic noise of the scanner and to limit contamination of the electroencephalogram (EEG) by the gradient-switching artifact. The ERP data were used to identify areas in which the blood oxygenation (BOLD) signal varied with the magnitude of the negativity in each condition. A significant ERP MMN was obtained, with larger peaks to LARGE deviants and with frontocentral scalp distribution, consistent with the MMN reported outside the magnetic field. This result validates the experimental procedures for simultaneous ERP/fMRI of the auditory cortex. Main foci of increased BOLD signal were observed in the right superior temporal gyrus [STG; Brodmann area (BA) 22] and right superior temporal plane (STP; BA 41 and 42). The imaging results provide new information supporting the idea that generators in the right lateral aspect of the STG are implicated in processes of frequency deviant detection, in addition to generators in the right and left STP.     

Maturation of luminance- and motion-defined form perception beyond adolescence: a combined ERP and fMRI study

Abilities to discriminate forms defined by motion continue to develop throughout childhood. To investigate late development of the visual motion system, we measured brain activity with event-related EEG potentials (ERPs) and functional magnetic resonance imaging (fMRI) in groups of adolescents (15-17 years) and adults (20-30 years) during a visual form discrimination task--with forms being either defined by motion or luminance contrast. We further explored whether possible developmental changes varied with the degree of motion coherence reflecting maturation specific to global motion processing. Both the fMRI activation patterns and ERP topographies were very similar between adolescents and adults, suggesting that the basic visual networks for processing motion and form are established by the age of 15-17. The ERP response to luminance- and motion-defined forms was dominated by a posterior negativity (N1: 120-270 ms). The N1 of the motion contrast was delayed in adolescents, whereas the N1 of the static condition did not differ between groups. Since the motion-evoked N1 is thought to arise in the middle temporal area MT/V5, our results indicate that visual motion processing in MT continues to get faster, becoming still more efficient during late development. Neither the ERP nor the fMRI results revealed maturation effects specific to motion coherence. This indicates that the specific mechanisms to process global dot motion are already mature in adolescence. The present findings support the view that static perception matures earlier than dynamic perception, and that these visual systems have different developmental courses.     

Combined event-related fMRI and intracerebral ERP study of an auditory oddball task

Event-related fMRI (efMRI) has been repeatedly used to seek the neural sources of endogenous event-related potentials (ERP). However, significant discrepancies exist between the efMRI data and the results of previously published intracranial ERP studies of oddball task. To evaluate the capacity of efMRI to define the sources of the P3 component of ERP within the human brain, both efMRI and intracerebral ERP recordings were performed in eight patients with intractable epilepsy (five males and three females) during their preoperative invasive video-EEG monitoring. An identical auditory oddball task with frequent and target stimuli was completed in two sessions. A total of 606 intracerebral sites were electrophysiologically investigated by means of depth electrodes. In accordance with the finding of multiple intracerebral generators of P3 potential, the target stimuli evoked MRI signal increase in multiple brain regions. However, regions with evident hemodynamic and electrophysiological responses overlapped only partially. P3 generators were always found within hemodynamic-active sites, if these sites were investigated by means of depth electrodes. On the other hand, unequivocal local sources of P3 potential were apparently also located outside the regions with a significant hemodynamic response (typically in mesiotemporal regions). Both methods should thus be viewed as mutually complementary in investigations of the spatial distribution of cortical and subcortical activation during oddball task.