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.     

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.     

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.     

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.     

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。     

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。     

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.     

The effect of the skull on event-related P300.

OBJECTIVES: Event-related potentials (EP) indicate neuronal processes with a high temporal resolution, while functional magnetic resonance imaging (fMRI) has a high spatial distribution. Information from both techniques may complement each other. However, this combination is fraught with difficulty because of a possible interference of the skull or the scalp with scalp-recorded EP. The aim of the present study was to investigate this influence of skull and scalp thicknesses on event-related P300 potentials. METHODS: Thirty healthy controls were examined using an auditory evoked P300 elicited by a standard oddball paradigm. Skull and scalp thicknesses were determined using coronal T2-weighted magnetic resonance imaging (MRI). RESULTS: P3b-amplitudes were significantly correlated with temporo-parietal skull thickness (r=-0.42; P=0.021; regression slope of -1.14 microV/mm skull thickness), whereas scalp had no influence on P300. The amplitude of the more frontal subcomponent P3a was not related to frontal skull thickness. CONCLUSIONS: Therefore, the utility of P300 as a research tool can be enhanced when adjustment for skull thickness is made.     

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.     

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.     

Alcoholism risk, tobacco smoking, and P300 event-related potential.

OBJECTIVE: The P300 event-related potential (ERP) is sometimes larger for individuals at low- compared to high-risk for alcoholism. These effects are inconsistent, and how P300 is affected by tobacco smoking in the context of alcoholism risk is unknown. The present study used P300 to examine the inter-relationship between alcoholism heritability and smoking status. METHODS: P300 was elicited with a visual discrimination task from young adults at low- and high-risk for alcoholism. Half of the subjects in each risk category reported that they did not smoke cigarettes, and the other half reported that they smoked regularly, with equal numbers of male and female subjects assessed. ERPs were recorded, and subjects were instructed to respond only to an infrequently presented target stimulus that occurred in a series of standard and distracter stimuli. RESULTS: P300 amplitude from the target stimuli was larger for the low-risk compared to high-risk subjects overall. However, smoking status demonstrated even stronger effects, with non-smokers producing consistently larger component amplitudes than smokers and accounting for more variance than alcoholism risk. These group factors also significantly affected P300 scalp topography. No reliable alcoholism risk or smoking group effects were obtained for the ERPs from the other stimuli. CONCLUSIONS: The findings suggest that P300 measures of alcoholism risk in young adults are moderated by smoking status. Theoretical implications are discussed.     

Study of the P300 event-related potential through brain mapping in phonological dyslexics.

The auditory P300 was studied through brain mapping in 10 phonological dyslexics (7 M and 3 F), who were found to differ significantly from normals in presenting a longer P300 latency and smaller amplitude on the N2-P3 wave. Interesting too was the asymmetry of the P300 distribution between the two hemispheres, with less amplitude on the right. These findings confirm the hypothesis of reduced right hemisphere functioning during the process of information analysis in phonological dyslexics.     

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.     

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。     

The P300 component of the auditory event-related potential in monozygotic and dizygotic twins

The P300 component of the auditory event-related potential was recorded from 10 pairs of monozygotic (MZ) twins and 11 pairs of dizygotic (DZ) twins during an auditory discrimination task. The within-pair similarity of P300 latency was significantly greater in MZ than in DZ twins. The within-pair similarity of P300 amplitude was not significantly greater in MZ than in DZ twins. These results support previous findings suggesting that P300 latency is largely genetically determined.     

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。     

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.     

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.