Identification of neural circuits underlying P300 abnormalities in schizophrenia.

Event-related potentials (ERPs) provide a noninvasive method to evaluate neural activation and cognitive processes in schizophrenia. The pathophysiological significance of these findings would be greatly enhanced if scalp-recorded ERP abnormalities could be related to specific neural circuits and/or regions of the brain. Using quantitative approaches in which scalp-recorded ERP components are correlated with underlying neuroanatomy in schizophrenia, we focused on biophysical and statistical procedures (partial least squares) to relate the auditory P300 component to anatomic measures obtained from quantitative magnetic resonance imaging. These findings are consistent with other evidence that temporal lobe structures contribute to the generation of the scalp-recorded P300 component and that P300 amplitude asymmetry over temporal recording sites on the scalp may reflect anatomic asymmetries in the volume of the superior temporal gyrus in schizophrenia.     

Schizophrenia: the broken P300 and beyond.

Many of the social, economic, and political problems facing people with schizophrenia are due to a misconception in the community that schizophrenia is not a biologically based disease but a myth. Because the diagnosis is based on self-reported symptoms, it is difficult for many people to acknowledge that schizophrenia is real. One goal of psychophysiological research has been to anchor both diagnosis and symptoms in biological reality. Reduction of the amplitude of the P300 component of the event-related potential (ERP) is the most replicable biological marker of the disease. Data are presented suggesting that P300 is both a state and a trait marker of the disease and may be sensitive to the progressive/degenerative course of the disease. Although the P300 tracks changes in clinical symptoms, it remains reduced even in patients in relative remission. P300 amplitude reduction is related to enduring negative symptoms, waning of attention, and gray matter volume deficits. ERP components other than P300 can also manifest the biological reality of various symptoms of the disease.     

慢性精神分裂症患者血清S100B水平与事件相关电位P300的相关性

目的:探讨慢性精神分裂症患者血清S100B水平与事件相关电位P300(Event-related potential P300,P300)的关系。方法:随机将年龄在18~60岁之间符合ICD-10及CCMD-3诊断标准的慢性精神分裂症患者40例作为研究组,选择40例健康者作为对照组。同时检测血清S100B水平及以P300评定认知功能,并将结果加以分析、比较。结果:与对照组相比,研究组CZ、PZ点的N1、P2、N2、P3潜伏期均明显延长(t=2.24~3.85,P0.05或0.01),研究组CZ、PZ点的N2、P3波幅明显降低(t=3.04~5.26,P0.01);研究组的血清S100B水平高于对照组(t=4.15,P0.01);CZ、PZ点P300潜伏期与血清S100B水平呈正相关(r=0.35~0.48,P0.05或0.01),CZ、PZ点P300波幅与血清S100B水平则呈负相关(r=-0.48~-0.58,P0.01)。结论:慢性精神分裂症患者血清S100B水平高于健康者并且认知功能存在损害,其认知功能损害可能与血清S100B水平有关。     

血管性痴呆患者事件相关电位P300及相关因素研究

目的：研究血管性痴呆患者的事件相关电位P300及相关因素诊断的应用。方法：对42例VD和36例无痴呆脑梗死患者进行听觉P300检测，并进行病因、病变部位等危险因素对比分析。结果：VD组常有高血压、糖尿病、震颤麻痹、皮质下病灶、双侧半球病灶及脑萎缩，并有2次以上座中发生。VD组N1、P2、N2、和P3潜伏期均明显延长，P2、P3波幅分别降低，与对照组比较差异有显著意义（P＜0．01）。结论：高血压、糖尿病、震颤麻痹，反复卒中、皮质病灶、多发性病灶、脑萎缩均是VD的危险因素，与VD的发生、发展有关。事件相关电位P300是一种客观的神经生理学指标，对VD的早期诊断有实用价值。     

P300 topography and modality effects from a single-stimulus paradigm

The P300 event-related brain potential (ERP) was elicited with auditory and visual stimuli in two different tasks. The oddball paradigm presented both target and standard stimuli; the single-stimulus paradigm presented a target but no standard stimulus, with the intertarget interval the same as that for the oddball condition. Target probability was .20 for the oddball task, with target stimuli occurring at the same temporal frequency in the single-stimulus paradigm. Scalp topography was assessed with 15 electrode locations. P300 amplitude was larger and latency was longer for the oddball than for single-stimulus procedure. P300 from auditory stimuli was smaller and shorter in latency than that from the visual stimuli, and both modalities showed similar but not identical scalp topographies. The findings suggest that the single-stimulus paradigm may be useful in experimental and applied contexts that require very simple ERP task conditions.     

Subjective and objective probability effects on P300 amplitude revisited

Does objective probability affect P300 size independently and in addition to subjective probability? The latter was manipulated by the number of stimuli presented and classification task. Five groups saw target and frequent stimuli. Two saw these with p=.2 or .067, with two different button presses. Three groups saw two additional nontarget stimuli each with p=.067. One group pressed a different button for each stimulus. A second group pressed one button for the three oddballs, another for the frequent. A third critical group pressed one button for the target and another for other stimuli. In this group, P300 was larger for targets versus nontargets, and larger for nontargets versus frequents. Although nontargets were classified with frequents, their actual low probability distinguished them from frequents, and their subjective probability distinguished them from targets. Therefore, actual and subjective probability effects were independently found.     

Taking Attention to Task: P300, Task Response Probability, and Within-Category Deviation Detection

Previously, we reported enhanced P3 amplitudes to between-category deviations among high and low probability events. Here, we tested the effects of a within-category difference. Subjects performed a go/no-go button press task as they viewed repeated, randomly-ordered presentations of nine double-digit numbers. Eight numbers fell within a prescribed range (42-49, standards); prior to testing, subjects selected one standard number for later recall. A ninth, out-of-range (91, deviant) number was also included. Subjects were tested under two conditions, in which they responded either to one (low response probability) or to seven (high response probability) standard nonselected numbers, designated as targets. Relatively larger P3s were consistently apparent only when the deviant nontarget was associated with a low probability response to a nontarget. There was a selective effect of nontarget response probability on P3 amplitude to the deviant nontarget. Our results indicate that within-category deviation detection is facilitated by "controlled" attention to the structure of the stimulus field.     

P300 and Long-Term Memory: Latency Predicts Recognition Performance

The study-test paradigm was used to investigate memory acquisition processes and the effects of repetition on long-term recognition memory. In this procedure, subjects are presented with a list of words (“targets”) to be memorized (Study series). They are later tested for recognition on a word list comprised of the target words mixed randomly with an equal number of new, distractor words (Test series). Both reaction time and the P300 component of the event-related brain potential were used as measures of processing time. During the Study series, large P300s were elicited despite a word category probability of 1.0. When the words from the Study series were divided on the basis of recognition performance, words that were subsequently recognized elicited P300s with shorter latencies than unrecognized words. P300 amplitude to words in the Study series increased with repetition while maintaining a constant latency. During the Test series, P300 latency and reaction time decreased with repetition for both target and distractor words. P300 amplitude to all words increased substantially over Test repetitions with target words eliciting larger P300s than distractor words. Words that were recognized more consistently during the Test series elicited larger and earlier P300s than words that were recognized less consistently. The P300 amplitude and latency results from both the Study and Test series are interpreted as reflecting the increased discriminability of the target words as the memory trace increases in strength.     

精神分裂症P300的临床研究进展

目的探讨事件相关电位P300与精神分裂症的相关性,介绍P300与神经心理测验,CT、MRI、SPECT及LORETA在临床中的应用,为精神分裂症的研究、治疗提供科学依据。方法以最近20年国外有关精神分裂症P300研究的成果为基础,采用文献研究法分析总结了近40余篇有关的研究论文的研究成果。结果精神分裂症P300波幅降低,潜伏期延长,存在的认知障碍与大脑左侧颞叶区相关,CT、MRI、SPECT及LORETA均可显现患者左侧颞叶区与正常人的不同。     

P300, Probability, and Interstimulus Interval

The relationship between target stimulus probability and interstimulus interval on the P300 (P3) component of the event-related potential was assessed in three experiments. In each study an auditory discrimination paradigm was employed wherein subjects indicated with a finger tap response the occurrence of a randomly presented 2000 Hz target tone embedded in a series of 1,000 Hz tones. Target stimuli were presented with a probability of either .20 or .80 in different conditions which were combined factorially with different interstimulus intervals. Experiment 1 presented stimuli at 2.0, 2.5, or 3.0 second intervals; Experiment 2 presented stimuli at 2.0, 3.0, or 4.0 second intervals; Experiment 3 presented stimuli at 4.0, 6.0, or 10.0 second intervals. P3 amplitude was larger for the .20 relative to the .80 target probability conditions for the shorter interstimulus intervals but not for the longer intervals. P3 latency was consistently longer for the .20 relative to the .80 target probability conditions, with generally little effect observed for interstimulus interval changes. The results suggest that interstimulus interval affects component amplitude by determining the amount of processing resources available when the P3 is produced.     

The P300 component in patients with Alzheimer's disease and their biological children

OBJECTIVE: There are few studies examining P300 in the biological children of patients with Alzheimer's disease (AD). In addition to examining P300 in patients with AD, the current study examined the utility of P300 as a preclinical marker in the offspring of AD patients. METHODS: P300 was elicited from an AD group, their biological children, and two age- and gender-matched control groups using the auditory oddball paradigm. Each group consisted of 20 subjects each. ERPs recorded from sites Fz, Cz, and Pz were analysed using analysis of variance. RESULTS: Amplitudes were significantly smaller in the AD group when compared to controls. Both amplitude and latency values in the FH+ group were significantly impaired when compared to its control group. CONCLUSION: These findings replicate previous P300 amplitude abnormalities found in patients with AD. Further, participants with a family history of AD demonstrate possible preclinical evidence at the electrophysiological level. Comparisons with other findings and theoretical implications are discussed.     

躯体形式障碍患者认知功能情况与事件相关电位P300的研究

目的 探讨躯体形式障碍患者认知功能状况与事件相关电位P300特征.方法 随机将年龄在18～65岁之间符合《中国精神障碍分类与诊断标准第3版》(CCMD--3)躯体形式障碍诊断标准患者35例作为实验组,选择35例健康者作为对照组.各组分别给予听觉P300检测和蒙特利尔认知评估量表(MoCA)筛查实验,将两组结果加以分析、比较.结果 与对照组相比,实验组CZ、PZ点N1、P2、N2、P3波、FZ点P3波及OZ点P2、P3波潜伏期明显延长(P＜0.05或P＜0.01);实验组FZ、CZ、PZ、OZ点波幅明显延长(P＜0.05或0.01);实验组蒙特利尔认知评估量表中7个因子分及总分值均低于对照组,差异有统计学意义(P＜0.05或P＜0.01);PZ点潜伏期及波幅与MoCA中7个因子分具有相关性,PZ点潜伏期与各因子分值呈负相关(P＜0.01),波幅则呈正相关(P＜0.01).结论 躯体形式障碍患者存在认知功能障碍.P300电位可作为评价躯体形式障碍患者认知状况的客观指标之一应用于临床.     

P300 wave elicited by a stimulus-change paradigm in acutely prepared rats

Presentation of a long sequence of stimuli in one modality followed by infrequent substitution of stimuli in a different modality produced a very large P300 wave in the evoked potential to the infrequent stimulus. The P300 wave was never observed in a repetitive train of stimuli in one modality or to the background stimuli during the stimulus-change procedure. This phenomenon was observed in cortical recordings from anesthetized rats. This P300 wave corresponds in latency to that observed in human cognitive studies, and the use of this paradigm in animal studies could greatly facilitate work to determine the neural basis of the P300 wave.     

疑病症患者述情障碍与事件相关电位P300的相关

目的 探讨疑病症患者述情障碍与事件相关电位P300相关性.方法 随机将年龄在18 ～65岁之间符合ICD-10疑病症诊断标准患者35例作为研究组,选择35例健康者作为对照组.两组均给予多伦多述情障碍20个条目量表（TAS-20）测评和P300检测,并将结果加以分析、比较.结果 与对照组相比,研究组PZ点N1、P2、N2、P3潜伏期明显延长（P＜0.05或＜0.01）,研究组PZ点N2、P3波幅明显延长（P＜0.05或0.01）;研究组TAS-20总分及各因子分均高于对照组（P＜0.05或＜0.01）;PZ点N2、P3潜伏期与TAS-20总分及各因子分呈正相关（r=0.34～0.47,P＜0.05或＜0.01）,PZ点N2、P3波幅与TAS-20总分及各因子分值则呈负相关（r=-0.31 ～-0.49,P＜0.05或＜0.01）.结论 疑病症患者述情障碍可能与认知功能受损有关.     

认知事件相关诱发电位P300的研究进展

目的 探讨认知事件相关诱发电位（ERP）P300的研究进展。方法 在万方数据、Pubmed等数据库查阅与认知ERP P300研究相关的文献,进行汇总分析。结果 ERP P300反映了大脑认知的加工过程,可对痴呆、脑血管疾病、脑外伤、癫痫、精神疾病等多种疾病进行早期认知减退的检测、认知功能和损害程度的评估以及认知功能的定量分析,具有较广泛的临床应用价值。但P300的临床应用存在没有业内公认的评定标准值、实际检测中影响因素较多等问题,其具体机制及相关问题的解决还有待于进一步更深入地探讨。结论 P300可以检测大脑神经细胞的动态认知过程,具有可靠、有效、客观、无创伤等特点,是其他脑影像技术所不能取代的一种检测方法。未来还需在P300及其亚波的产生定位及临床诊断的统一化标准化等方面做进一步的深入探索和研究。     

癫(癎)儿童事件相关电位P300检测报告

目的:探讨事件相关电位(ERP)的P300成分检测对癫癎儿童认知功能的评价。方法:利用ERP、韦氏儿童智力量表中国修订版(WIS-CR)对32例癫癎儿童进行P300测定和心理评估,以28例性别、年龄相匹配的正常儿童作对照。结果:与正常对照组比较,癫癎组儿童总智商(FIQ)、语言智商(VIQ)和操作智商(PIQ)得分均明显降低(P<0．01),32例癫癎患儿中有28％有智能障碍;ERP的P300波潜伏期也明显延长,P<0．01。结论:癫癎儿童易发生智力障碍,P300波潜伏期检测能早期、客观、准确地评价癫癎儿童的认知功能状况。     

P3 event-related potential impairments in antisocial and psychopathic individuals: A meta-analysis

Prior findings on P3 event-related potential deficits in antisocial populations are mixed and it has been suggested that these abnormalities may not apply to psychopaths. A meta-analysis of 38 studies (total N = 2616) was conducted to investigate the relationship of P3 measures to antisocial behavior. Reduced P3 amplitudes (d = 0.252, p < .001) and longer P3 latencies (d = 0.130, p = .019) were significantly associated with antisocial behavior across all electrode sites, and when using both normal and non-normal control groups. A significant moderating effect of electrode site indicated longer latencies at Fz but not Pz. Compared to non-psychopathic offenders, psychopathic offenders showed P3 amplitudes impairments in standard oddball tasks, but not other tasks. Findings suggest that reduced P3 amplitudes and prolonged P3 latencies may reflect inefficient deployment of neural resources in processing cognitive task-relevant information in individuals characterized with generic antisocial behavior (i.e., aggression, antisocial personality disorder, conduct disorder/oppositional-defiant disorder, and psychopathy), whereas this association in psychopaths may be moderated by the type of tasks.     

Seasonal photoperiod,gender, and P300

The photoperiod model of seasonal affective disorder (SAD) suggests that SAD is caused by abnormal responses to seasonal changes in day length. Clarifying the utility of event-related brain potentials (ERPs) as diagnostic aids or measures of therapeutic efficacy in SAD requires understanding the range of naturally occurring seasonal patterns of variation in human responses. This investigation studied ERPs from non-patients (402 from men, 415 from women) during the pronounced photoperiod variation of the Alaskan subarctic where light availability ranges from 3.20 h in winter to 21.98 h in summer. ANOVA showed significant (P=0.03) main effect of photoperiod in the amplitude and latency of P300 responses, as well as a main effect of sensory modality (P=0.002). There was neither a main effect of gender, nor any significant gender-interactive effect in ERP responses. In clients with SAD, the ERP variability attributed to seasonal photoperiod remains to be clarified.     

The Wisconsin Card Sort Test and P300 responses to novel auditory stimuli in schizophrenic patients

The authors studied the relationship between performance on the Wisconsin Card Sort Test (WCST) and P300 activity in schizophrenics and normal controls. Fourteen male predominantly medicated schizophrenics and matched non-ill controls were administered the WCST and tests of temporal lobe (delayed verbal and spatial memory) and general intellectual functioning (Shipley). Patients were rated with negative and positive symptom scales extracted from the Brief Psychiatric Rating Scale. Subjects performed a tone discrimination task requiring identification of rare targets in both a standard oddball paradigm and a three-stimulus paradigm that included rare novel sounds. Reference independent data from 16 scalp electrodes yielded Global Field Power (GFP), from which P300 latency was determined. P300 amplitude measures included amplitude at this identified latency as well as amplitude integrated over a 100 ms time window centered over it. These amplitude measures were examined at six selected electrode locations. Schizophrenics produced smaller P300 responses that tended to be slower, but there were no group differences in the relationships between neuropsychological performance and P300 responses. Across diagnostic groups percent perseverative errors predicted lower integrated and peak P300 amplitude during the novel but not the standard oddball paradigm. The effect on integrated P300 amplitude was localized to anterior leads after novel stimuli. Negative symptoms predicted lower WCST performance, lower integrated P300 amplitude, and smaller GFP after novel stimuli. Positive symptoms predicted reduced overall GFP and specific but inconsistent reductions in parietal P300 amplitude. The results suggest relationships between dorsolateral prefrontal competence, P300 activity in response to stimulus novelty, and negative symptoms in schizophrenic patients, paralleling findings obtained from blood flow and other measures of brain activity.     

Functional Differences Between Members of the P300 Complex: P3e and P3b

The main findings of this study bear upon differences in the functional roles of P3b and a shorter latency, more centrally distributed endogenous positive component denoted as P3e. At the present writing, we have observed P3e only in conjunction with P3b. As in the case of P3b, P3e is fully endogenous in that it can be- elicited by omission of a stimulus if stimulus omission conveys relevant information to the subject. It was found that P3e and P3b relate differently to information delivery. Information delivery was manipulated by varying event probabilities and the discriminability of the events. The well known properties of P3b, namely that its amplitude is large when elicited by low probability (high information content) events and is reduced by perceptual difficulty (information loss-equivocation), were replicated in the current study. In contrast to P3b, variation of event probability had no effect upon P3e amplitude, but increased perceptual difficulty markedly reduced P3e amplitude. In addition, two CNV-type negativities were observed in the epochs prior to presentation of the informative signal event: 1) A negativity that was maximal over central scalp related to the subject's prediction that a rare or frequent event would be presented; 2) A negativity that was maximal over occipital scalp related to a stimulus that informed the subject whether the subsequent discrimination of the signal would be easy or difficult. Finally, there was a serendipitous Hading of an apparently new short duration component, tentatively labeled Px, which is elicited by presentation of the signal that informs the subject whether the subsequent discrimination will be easy or difficult.