Auditory P300 event-related potential in tobacco smokers

The aim of this study was to elucidate the chronic effects of tobacco smoking on the P300, a neurophysiological index of cognitive function. Prospective study participants were recruited from a family medicine polyclinic. We selected 32 right-handed smokers who had smoked more than 15 cigarettes per day, by inhalation, for more than 2 years. The control population consisted of 32 right-handed, age-matched healthy individuals who had never smoked. Event-related potentials (ERPs) were recorded with the auditory “oddball” two-tone discrimination task. The data from the central (Cz) and frontal (Fz) electrodes were analyzed. The P300 and N1 amplitudes at Fz were lower in the study population compared to the control group. The early component of ERP, the measure of mental speed (N1) latency at Fz was prolonged in the study group compared to the controls, possibly because early cognitive processes such as sensory input or initial encoding of sensory information were delayed in this group. For those who smoke, a decreased N1 amplitude might indicate delayed information processing and possibly short-term memory disturbance. Thus, chronic tobacco smoking may produce prefrontal cognitive dysfunction.     

P300 event-related brain potential and personality in depression.

P300 is an event-related brain potential (ERP) particularly interesting to the study of cognitive processes in normal subjects and in psychopathology. P300 has been applied in depression with controversial results. A major source for these controversial results could result from the diversity of depressed patients included in the different studies. Supporting this assumption, impulsivity, blunted affect, suicidal behavior and psychotic features significantly influence P300 amplitude. However, no data are available on the possible influences of the personality of depressed patients on P300. Since personality is related to P300 in normal subjects, the aim of the present study is to investigate the relationship between ERPs (P200, N200, and P300) and the Temperament and Character Inventory (TCI) in 54 depressed patients. The main results of the study concern the absence of major correlations between personality dimensions as assessed by the TCI and ERP parameters among depressed patients. Only weak partial positive correlations relate N200 latency with harm avoidance, and P300 amplitude (Pz) with the self-directedness dimension. N200 amplitude is also negatively correlated to persistence. However, the preliminary nature of the presented results with respect to the weak statistical significance should be underlined.     

The P300 wave of the human event-related potential.

The P300 wave is a positive deflection in the human event-related potential. It is most commonly elicited in an "oddball" paradigm when a subject detects an occasional "target" stimulus in a regular train of standard stimuli. The P300 wave only occurs if the subject is actively engaged in the task of detecting the targets. Its amplitude varies with the improbability of the targets. Its latency varies with the difficulty of discriminating the target stimulus from the standard stimuli. A typical peak latency when a young adult subject makes a simple discrimination is 300 ms. In patients with decreased cognitive ability, the P300 is smaller and later than in age-matched normal subjects. The intracerebral origin of the P300 wave is not known and its role in cognition not clearly understood. The P300 may have multiple intracerebral generators, with the hippocampus and various association areas of the neocortex all contributing to the scalp-recorded potential. The P300 wave may represent the transfer of information to consciousness, a process that involves many different regions of the brain.     

Cerebrovascular accident alters P300 event-related potential characteristics

P300 event-related potentials to counted (target) and uncounted (background) visual stimuli were recorded from subjects who had sustained either a right or a left middle cerebral artery cerebrovascular accident (CVA) and from appropriate normal control subjects. Subjects were asked to count target stimuli and to ignore non-target stimuli. Standard measurements of the amplitude and latency of P300 components as well as intercorrelations among P300 wave forms from 3 brain regions (Fz, Cz, Pz) were collected. Amplitudes of N1-P2 and N2-P3 components as well as overall amplitude of the ERP wave form were reliably reduced by a CVA, but component latencies were not significantly affected. The amplitude reduction associated with a CVA cannot be simply interpreted as evidence for reduced cognitive efficiency because overall amplitudes and intercorrelations between brain regions of CVA patients were reduced for both counted and uncounted stimuli. The intercorrelations between brain regions were particularly reduced if the CVA was localized in the right hemisphere. For CVA patients, reduced component amplitudes may reflect decreased cortical intercommunication associated with damage to subcortical brain structures.     

P300 event-related potential in epileptic children and adolescents

P300 is a manifestation of activity in a limited capacity system "whose use in the service of different tasks is under relative control by instruction". It is accepted as an objective correlate of mental processing involved in the allocation of attentional resources when immediate memory is engaged. The aim of this study was to evaluate cognitive function in epileptic children and adolescents. We applied the "auditory oddball" paradigm to elicit event-related potentials (ERPs) according to the IFCN recommendation standards. ERPs were studied in fifteen patients with generalized epileptic seizures at matched age (8-18 years) (mean 13.8 +/- 2.4 y). 50 neurologically normal children were used as a control group. ERP were averaged with a Multiliner (Toennies, Germany) equipment. The method included two different tones for frequent and for rare stimuli generated at random. The tones were presented binaurally through headphones. ERPs were recorded at Fz, Cz and Pz according to the International 10-20 system. ERPs for target and non-target stimuli were averaged separately. The major positive peak between 250 and 500 ms for the rare tones was regarded as the cognitive evoked potential (P300). Latency values were obtained from the intersection of extrapolated lines from the ascending and descending slopes of each peak. The latencies of the N1, P2, N2 and P300 waves were determined for each subject, as well as peak to peak amplitudes of N1-P2, P2-N2, N2-P300. Auditory event related potential may be helpful procedures used in objective evaluation of cognitive function in patients with epilepsy.     

P300 event-related potential and serotonin-1A activity in depression.

The identification of the brain structures and neurotransmitters responsible for the generation and/or modulation of P300 could lead to important clinical implications. Since serotonin disturbances seem to play a critical role in depression, the aim of the study was to assess the possible relationships between the P300 event-related brain potential and serotonergic activity in depression. The study was conducted among 45 major depressive inpatients, and serotonergic activity was assessed by prolactin (PRL) response to flesinoxan (a 5-HT1A agonist). Results showed a significant negative correlation between P300 amplitude and PRL response to flesinoxan (r = -0.40, P = 0.007 at Cz; r = -0.47, P = 0.001 at Pz). In contrast, both P300 latency and reaction time were not related to endocrine response. This study supports a role for serotonin-1A in the neurobiological modulation of P300 amplitude.     

Cerebral networks linked to the event-related potential P300

P300 is an event-related potential that is elicited by an oddball paradigm. In several neuropsychiatric diseases, differences in latencies and amplitude compared to healthy subjects have been reported. Because of its clinical significance, several investigations have tried to elucidate the intracranial origins of the P300 component. In the present study we could demonstrate a network of P300 generators. Investigated were 15 healthy subjects with an acoustical oddball paradigm within a fMRI block design, which enabled us to exclude attention or acoustical processing effects. The inferior and middle frontal, superior temporal, lower parietal cortex, the insula and the anterior cingulum were significantly activated symmetrical in both hemispheres.     

老年期抑郁症患者事件相关电位P300特征

目的：探讨有无自杀行为的老年期抑郁症患者认知功能的事件相关电位P300特征。方法：对60例老年期抑郁症患者（有自杀行为者20例,无自杀行为者40例）及60例性别、年龄匹配的正常老年人为对照,进行听觉诱发的事件相关电位P300检测。同时应用汉密尔顿抑郁量表（HAND）及老年认知功能量表（SECF）分别评价抑郁症组抑郁情绪及认知功能。结果：抑郁症组与对照组相比,P2、N2、P3潜伏期明显延长,P2、P3波幅明显降低;有自杀行为组N2、P3波幅比无自杀行为组明显降低。抑郁症组HAMD总分与P300各指标无相关,SECF总分与N2、P2、P3潜伏期显著负相关。结论：P300对老年期抑郁症患者早期认知功能损害评定具有一定价值,有、无自杀行为的老年期抑郁症患者认知功能损害不同。     

P300 event-related potential amplitude and impulsivity in cocaine-dependent subjects

Previous studies report reduced amplitude of the P300 event-related potential in cocaine-dependent individuals. Cocaine dependence is also associated with increased impulsivity, possibly due to deficits in cognitive function that are associated with reduced P300 amplitude. In the current study, the relationship between cocaine dependence, impulsivity, and P300 amplitude were examined. An auditory oddball event-related potential task along with self-report (Barratt Impulsiveness Scale version 11) and behavioral laboratory (Immediate and Delayed Memory Task) measures of impulsivity were assessed in healthy controls (n = 14) and subjects who met DSM-IV criteria for current cocaine dependence (n = 17). P300 amplitude was reduced and self-reported and behavioral laboratory impulsivity scores were elevated among the cocaine-dependent group compared to controls. There was a positive correlation between the questionnaire and behavioral laboratory measures of impulsivity, and a negative correlation between impulsivity measures and P300 amplitude. The correlation between self-reported impulsivity scores and P300 amplitude remained after taking into account the number of childhood conduct disorder symptoms. This study supports the hypothesis that the basic neurophysiology responsible for the P300 amplitude in cocaine-dependent individuals is associated with impulsivity independent of a history of childhood conduct disorder symptoms.     

精神分裂症患者事件相关电位相关性研究

目的：探讨精神分裂症患者事件相关电位P300的特点及事件相关电位与阴性、阳性症状的相关性。方法：对28例精神分裂症患者及21名健康志愿者进行事件相关电位P300的检测。结果：两组靶刺激时P300的N2、P3潜伏期和P2、P3波幅有显著差异。结论：提示事件相关电位P300在协助精神分裂症的诊断、分型及推测预后方面有一定意义。     

精神病风险综合征事件相关电位P300研究

目的探讨精神病风险综合征(clinical high risk of psychosis,CHR)者听觉事件相关电位P300波幅、潜伏期以及认知功能的特征。方法采用Oddball范式,对36例CHR者(研究组)和35名正常对照(对照组)进行事件相关电位P300测定,利用MATRICS成套认知测试评估两组被试认知功能,中文版精神病风险综合征定式访谈中精神疾病高危症状量表(scale of psychosis-risk symptoms,SOPS)评估CHR者临床症状。结果研究组信息处理速度、注意/警觉性、工作记忆、词语学习、视觉学习、推理和问题解决以及社会认知等7个领域认知功能得分均差于对照组(P0.01)。研究组Fz、Cz、Pz导联P300波幅比对照组降低(P0.05),Pz导联P300潜伏期延长(P0.05)。研究组Cz点P300潜伏期与SOPS阳性症状得分呈正相关(r=0.544,P=0.001),P300波幅与信息处理速度(言语流畅性)得分呈正相关(r=0.339,P=0.043)。结论 CHR者认知功能、事件相关电位P300存在异常。P300与CHR精神病症状、认知缺陷存在一定的相关性,提示其在精神病风险监控中的作用值得重视。     

阿尔茨海默病的事件相关电位P300研究

目的　探讨阿尔茨海默病 (AD)P3 0 0 的特点以及P3 0 0 与简易智力状况检查 (MMSE)评分的相关性。方法　对 32例AD患者和 30名健康老年人应用NicoletBravo脑诱发电位仪进行事件相关电位P3 0 0 检测 ;同时用MMSE进行认知功能评估。结果　 (1)AD组MMSE评分 [(16 5 2± 2 17)分 ]低于正常对照组 [(2 6 5 7± 1 4 3)分 ,P <0 0 1]。 (2 )AD组与正常对照组相比 ,靶刺激中的P2 、N2 、P3 潜伏期长 ,P2 、P3 波幅低 ;非靶刺激P2 波幅低 (P <0 0 5～ 0 0 1) ;AD组Cz、Pz、Fz各点间的P3 0 0 指标相比 ,差异均无显著性 (P >0 0 5 )。 (3)AD组P3 0 0 靶刺激中的P2 、P3 波潜伏期与MMSE分值呈负相关 (P <0 0 5～ 0 0 1)。结论　AD患者的P3 0 0 有多指标变异 ,且与其认知功能缺损的程度有关。     

癫痫患者智能状况与事件相关电位P300的研究

目的探讨癫痫患者智能状况、事件相关电位P300(ERP P300)的特点及ERP P300对癫痫患者智能状况的评定价值.方法对40例癫痫患者进行智商及ERP P300测定.结果40例癫痫患者中总智商FIQ≤89者14例,占35%;P300异常者16例,占40%.癫痫智能障碍组的VIQ、PIQ、FIQ、P300 PL分别与智能正常组及正常对照组比较,均具有显著性差异(P<0.01).且癫痫患者P300PL与VIQ、PIQ、FIQ呈负相关.结论癫痫患者易发生智能损害,且智能损害无选择性.智力量表和ERPP300二种检测方法对评判癫痫患者智能障碍具有良好的一致性,而ERP P300能更早期、更客观、快捷、准确地评价癫痫患者智能状况.     

血管源性痴呆的事件相关电位P300研究

目的 评价事件相关电位P300在血管源性痴呆（Vascular dementia,VD)认知功能障碍诊断中的价值。方法 对30例VD和30例正常人,利用磁共振成像（MRI）技术测定额叶,颞叶,顶叶,枕叶和海马结构的体积,采用简明精神状态量表（MMSE）,简易痴呆筛查量表（BSSD）和瑞文标准智力测验量表（RSPM）评定认知功能,记录分析听觉刺激诱发的事件相关电位P300。结果 （1）与正常对照比较,VD患者额叶和颞叶体积显著缩小,而顶叶,枕叶和海马结构的体积无显著差异。（2）VD患者MMSE,BSSD和RSPM3种量表的评分均显著低于正常对照。（3）VD患者MMSE、BSSD评分的降低与额叶,颞叶萎缩程度和局限病灶位于额叶,颞叶相关,（4）VD患者P300峰潜伏时（peak latency,PL)较正常对照明显延长,（5）VD患者P300PL的延长与额叶,颞叶的萎缩程度和局限病灶位于额叶,颞叶相关。（6）VD患者P300PL的延长与认知功能损害的严重程度相关,结论 （1）P300可以作为认知功能评价的额观指标。（2）VD患者额叶和颞叶的萎缩与其认知功能障碍有关。（3）P300PL的延长可反映VD患者脑局部病理改变。（4）P300PL的延长可客观反映VD患者认知功能损害的严重程度。（5）P300在临床上可以作为诊断VD的重要客观指标。     

P300 event-related potential in euthymic patients with bipolar disorder

Auditory P300 event-related potential (ERP) and performance on Sustained Attention were evaluated in 24 euthymic bipolar patients and 38 healthy volunteers. There were no significant differences between groups, and performance in sustained attention had no significant influence in the P300 responses. P300 response might be driven by the presence of mood symptoms.     

Dipolar source modeling of the P300 event-related potential after somatosensory stimulation.

The cerebral generators of the P300 potential evoked by somatosensory stimuli were investigated. Event-related potentials elicited by an oddball paradigm were recorded in 15 healthy subjects by 19 scalp electrodes. Nontarget and target electric stimuli were delivered on the anterior surface of the left elbow and of the wrist, respectively. Target traces showed an N140 potential followed by a widely distributed P300 response. Dipolar source modeling of target traces resulted in a six-dipole model. In the earlier latency range (up to 200 ms), one dipole in the contralateral perirolandic region and two dipoles in the parasylvian cortex of both hemispheres were activated. Two dipolar sources located bilaterally in the medial temporal region (MTR) showed their maximal activity at the P300 latency. Finally, a dipole in the contralateral frontal lobe was activated both at the latency of the N140 response and after 200 ms. It was found that two symmetrical MTR sources and a frontal dipole contributed to P300 generation.     

Intracranial potentials correlated with an event-related potential, P300, in the cat

Intracranial recordings of long-latency, event-related potentials were obtained from paralyzed, artificially respirated cats. A modified oddball paradigm was employed in which cats were presented with a randomized series of two tones, a 'frequent' 4 kHz stimulus and a 'rare' 1 kHz stimulus. A tail shock was administered 700 ms after onset of the rare tone. Under these circumstances the stimulus elicited a positive component at the vertex similar to the human P300. Intracranial potentials associated with the rare tone usually manifested components of greater amplitude than did potentials associated with the frequent tone. A positive component occurring in latency between 200 and 350 ms only accompanied the presentation of the rare stimulus. The P300 component, which was positive at the dura, appeared as a negative component within a few millimeters of the surface over a wide area of the marginal and suprasylvian gyri. Changing the probability of the rare stimulus resulted in a reduction in the amplitudes of both the intracranial negative component and the P300 recorded at the skull. Components of large amplitude associated with the rare stimulus were obtained from the region of the hippocampus. These components reversed polarity, sometimes more than once, as the electrode was advanced. Substantial latency differences were often observed between the P300 recorded at the skull and P300-like intracranial components associated with the rare stimulus. These results suggest that the cortices of the marginal and suprasylvian gyri and the hippocampal region contribute to the generation of the cat P300.     

事件相关电位P300对慢性精神分裂症认知功能的评估

目的：探讨事件相关电位P300在评估慢性精神分裂症认知功能中的价值。方法：应用事件相关电位P300、韦氏记忆量表（WMS）、韦氏成人智力量表（WAIS-RC）及威斯康星卡片分类测验（WCST）分别对60例慢性精神分裂症患者（患者组）与60名健康志愿者（对照组）进行测查,分析P300潜伏期、波幅与神经心理学测验成绩的相关性。结果：患者组P300潜伏期延长及波幅降低,言语智商、操作智商、韦氏记忆商、WCST各项指标均低于对照组（P〈0.05）。P300潜伏期与操作智商、持续性错误百分数、随机错误百分数呈负相关;波幅与短时记忆、随机错误百分数呈正相关。结论：慢性精神分裂症患者存在全面的认知功能损害,P300潜伏期和波幅可作为其客观评估指标。