Emergence of enhanced attention to fearful faces between 5 and 7 months of age

The adult brain is endowed with mechanisms subserving enhanced processing of salient emotional and social cues. Stimuli associated with threat represent one such class of cues. Previous research suggests that preferential allocation of attention to social signals of threat (i.e. a preference for fearful over happy facial expressions) emerges during the second half of the first year. The present study was designed to determine the age of onset for infants’ attentional bias for fearful faces. Allocation of attention was studied by measuring event-related potentials (ERPs) and looking times (in a visual paired comparison task) to fearful and happy faces in 5- and 7-month-old infants. In 7-month-olds, the preferential allocation of attention to fearful faces was evident in both ERPs and looking times, i.e. the negative central mid-latency ERP amplitudes were more negative, and the looking times were longer for fearful than happy faces. No such differences were observed in the 5-month-olds. It is suggested that an enhanced sensitivity to facial signals of threat emerges between 5 and 7 months of age, and it may reflect functional development of the neural mechanisms involved in processing of emotionally significant stimuli.     

常见神经心理疾病的认知电位特征

任何一个心理活动都伴有大脑神经电生理的变化,多种事件相关脑诱发电位,如P300、N400、MMN等被认为是大脑皮层活动的整合结果,与大脑复杂的认知过程有关,又称之为认知电位,可作为判断大脑高级功能的一个客观指标,用于神经精神科临床和心理学研究。因此,探讨和研究常见神经心理疾病的认知电位特征并应用到疾病的早期诊断、治疗、预后等临床工作中将具有极其重要的意义。     

阿尔茨海默病的非匹配负波的实验研究

目的非匹配负波可反映大脑皮层早期预处理的指标,探讨阿尔茨海默病(Alzheimerdisease,AD)患者非匹配负波(mismatchnegativity,MMN)的变异特征。方法应用美国NicoletSpirit脑诱发电位仪,对34例AD患者和36例健康老人的MMN作了检测。结果AD组波形不规则,MMN-Ⅰ型(延迟型)尤甚。与正常老人组相比,AD组MMN潜伏期延迟(P<0.05),本组患者P300潜伏期虽也有延长,但差异未达显著性(P>0.05)。与正常老人组比较,AD组MMN波幅以及P300波幅均同时降低,差异均有极显著性意义(均P<0.01)。结论初步认为MMN是反映AD患者认知功能的一种脑电生理检测工具。     

Spatio-temporal imaging of cortical desynchronization in migraine visual aura: a magnetoencephalography case study

OBJECTIVE: To determine cortical oscillatory changes involved in migraine visual aura using magnetoencephalography (MEG). BACKGROUND: Visual aura in the form of scintillating scotoma precedes migraine in many cases. The involvement of cortical spreading depression within striate and extra-striate cortical areas is implicated in the generation of the disturbance, but the details of its progression, the effects on cortical oscillations, and the mechanisms of aura generation are unclear. METHODS: We used MEG to directly image changes in cortical oscillatory power during an episode of scintillating scotoma in a patient who experiences aura without subsequent migraine headache. Using the synthetic aperture magnetometry method of MEG source imaging, focal changes in cortical oscillatory power were observed over a 20-minute period and visualized in coregistration with the patient's magnetic resonance image. RESULTS: Alpha band desynchronization in both the left extra-striate and temporal cortex persisted for the duration of reported visual disturbance, terminating abruptly upon disappearance of scintillations. Gamma frequency desynchronization in the left temporal lobe continued for 8 to 10 minutes following the reported end of aura. CONCLUSIONS: Observations implicate the extra-striate and temporal cortex in migraine visual aura and suggest involvement of alpha desynchronization in generation of phosphenes and gamma desynchronization in sustained inhibition of visual function.     

注意缺陷多动障碍儿童事件相关电位P300特征分析

目的:探讨注意缺陷多动障碍(ADHD)儿童事件相关电位(event related potential,ERP)P300的特点。方法:对100例ADHD患儿(研究组)[注意缺陷为主型(ADHD-I)34例、多动/冲动为主型(ADHD-HI)24例、混合型(ADHD-C)42例)]和100名正常儿童(对照组)前额区(Fz)、中央区(Cz)两个脑区的ERP P300潜伏期及波幅进行检测,比较分析研究组与对照组、ADHD各亚型及不同SNAP-Ⅳ评分分组(1.6~2.0为中度组、2.0为重度组)的P300潜伏期及波幅的差异。结果:1与对照组比较,研究组靶刺激在前额区(Fz)及中央区(Cz)P300潜伏期显著延长,波幅降低,差异具有统计学意义(P均0.01);2ADHD各亚型组间P300潜伏期与波幅差异无统计学意义(P0.05);3不同SNAP-IV评分组间,P300潜伏期与波幅差异无统计学意义(P0.05)。结论:ADHD患儿P300的潜伏期显著延长,波幅降低,提示ADHD患儿对信息加工处理的速度减慢,注意力、记忆力缺陷及认知加工能力不足。     

Electrophysiological evidence against parallel motor processing during multitasking

We combined behavioral measures with electrophysiological measures of motor activation (i.e., lateralized readiness potentials, LRPs) to disentangle the relative contribution of premotor and motor processes to multitasking interference in the prioritized processing paradigm. Specifically, we presented stimuli of two tasks (primary and background task) in each trial, but participants were instructed to perform the background task only if the primary task required no response. As expected, task performance was substantially influenced by a task probability manipulation: Background task responses were faster, psychological refractory period effects were smaller, and interference from the second task (i.e., backward compatibility effects) was larger when there was a larger probability that this task required a response. Critically, stimulus-locked and response-locked LRP analyses indicate that these behavioral effects of parallel processing were not driven by background task motor processing (e.g., motoric response activation) taking place during primary task processing. Instead, the LRP results suggest that these effects were exclusively localized during premotor stages of processing (e.g., response selection). Thus, the present results generally provide evidence for multitasking accounts allowing parallel task processing during response selection, whereas the task-specific motor responses are activated in a serial manner. One plausible account is that multiple task information sources can be processed in parallel, with sharing of limited cognitive resources depending on task relevance, but a primary and still active task goal prevents motor activation related to the goals of other tasks in order to avoid outcome conflict.     

血管性认知功能障碍神经心理及事件相关电位的研究

目的探讨非痴呆型血管性认知功能障碍(vascular cognitive impairment no dementia,VCIND)患者神经心理学及事件相关电位P300的特点。方法对64例VCIND患者(VCIND组)及42例其他疾病患者(对照组)行事件相关电位P300检查,使用简易智能状态检查量表(MMSE)、画钟测验(CDT)评定入选者认知功能状态,并进行相关分析。结果与对照组比较,VCIND组患者的CDT、MMSE评分明显降低,差异有统计学意义(P0.01),MMSE评分亚项中的时间定向、地点定向、注意/计算力、短程记忆、言语复述、阅读能力、书写能力、图形描画均明显降低,差异有统计学意义(P0.05,P0.01);P300潜伏期明显延长(P0.01),MMSE评分与P300潜伏期呈负相关(r=-0.615,P0.05)。结论事件相关电位P300检测有助于VCIND的早期诊断。     

慢性强迫游泳抑郁模型大鼠类P300电位的变化

目的探讨大鼠慢性强迫游泳抑郁模型类P300电位改变及其与行为变化的关系。方法将40只SD雄性大鼠均分为4组:强迫游泳7d模型组(S1组)、强迫游泳14d模型组(S2组)和2组对照组(C1组、C2组)。观察大鼠体质量、旷场实验和液体消耗实验等行为学指标。在麻醉状态下采用听觉oddball模式刺激诱发大鼠类P300电位,测定N1、N2、P3潜伏期和P3波幅。对大鼠类P300电位变化和行为学检测指标进行相关性分析。结果模型组大鼠与对照组相比体质量增长率降低(F=253.60,P<0.01),蔗糖水摄入率下降(F=128.38,P<0.01),旷场实验中水平得分(F=124.73,P<0.01)和垂直得分(F=41.09,P<0.01)减少,修饰次数(F=15.04,P<0.01)增加。与对照组比较,S1组和S2组P3潜伏期显著延长[S1组:(469.7±30.69)ms,S2组:(498.9±25.54)ms,C1组:(389.6±49.43)ms,C2组:(378.5±39.77)ms;F=71.534,P<0.01],P3波幅明显降低[S1组:(19.60±10.62)μV,S2组:(16.00±11.98)μ...     

首发精神分裂症患者视觉P_(300)与探索性眼动的研究

目的探讨精神分裂症视觉事件相关电位P300(VERP-P300)与探索性眼动(EEM)对首发精神分裂症患者的诊断价值。方法对40例首发精神分裂症患者(精神分裂症组)和40例正常人(对照组)分别进行VERP-P300与EEM检测,并将检测结果加以比较。结果精神分裂症组VERP-P300和EEM异常率分别为80.0%(32/40)和90.0%(36/40),二者异常的一致率为77.5%(31/40)。与对照组相比,精神分裂症组VERP-P300的潜伏期延长、波幅降低,差别有统计学意义(P<0.01);EEM检测结果中凝视点数和反应性探索评分均显著低于对照组,差别有统计学意义(P<0.01)。结论 VERP-P300和EEM检测对首发精神分裂症的辅助诊断有一定价值。