P3a Latency Research Articles

Impact of chronic smoking on P3 components in a three-stimulus oddball paradigm

Background: The P3 is related to cognitive functions, psychopathology and effects of cognition-improving and -impairing drugs. Studies assessing the chronic effects of smoking on P3 mostly reported a reduction of P3 amplitude for chronic and former smokers. To date, only a few studies have analyzed this impact by using a three-stimulus oddball paradigm. This study tries to replicate previous smoking associations applying an eyes-closed active three-stimulus oddball paradigm in a well-diagnosed population based sample of healthy elderly subjects who were allowed to smoke ad libitum. The study also tries to estimate whether smoking is a relevant confounder in P3 assessment within the analyzed sample. Methods: From the Leipzig Health Care Study (LIFE) current, former and non-smokers without mental or neurological disorders were matched by age, sex and qualification. Risky alcohol consumption was further exclusion criterion given the strong association between alcoholism and P3 amplitude reduction. Results: Smoking status was not associated with any P3 parameter, with exception of prolonged P3a latency at Fz in former smokers compared to never smokers. Also, there were no significant effects of smoking status on any of the behavioral measures or a correlation with smoking-related data. Discussion: This study indicates that smoking does not seem to relevantly impact the P3 components in non-abstaining healthy elderly subjects when confounders are controlled for. This publication is supported by LIFE – Leipzig Research Center for Civilization Diseases, Universitat Leipzig. LIFE is funded by means of the European Union, by the European Regional Development Fund (ERDF) and by means of the Free State of Saxony within the framework of the excellence initiative.

Auditory Middle Latency Response and Phonological Awareness in Students with Learning Disabilities.

Introduction Behavioral tests of auditory processing have been applied in schools and highlight the association between phonological awareness abilities and auditory processing, confirming that low performance on phonological awareness tests may be due to low performance on auditory processing tests. Objective To characterize the auditory middle latency response and the phonological awareness tests and to investigate correlations between responses in a group of children with learning disorders. Methods The study included 25 students with learning disabilities. Phonological awareness and auditory middle latency response were tested with electrodes placed on the left and right hemispheres. The correlation between the measurements was performed using the Spearman rank correlation coefficient. Results There is some correlation between the tests, especially between the Pa component and syllabic awareness, where moderate negative correlation is observed. Conclusion In this study, when phonological awareness subtests were performed, specifically phonemic awareness, the students showed a low score for the age group, although for the objective examination, prolonged Pa latency in the contralateral via was observed. Negative weak to moderate correlation for Pa wave latency was observed, as was positive weak correlation for Na-Pa amplitude.

Amelioration of Auditory Response by DA9801 in Diabetic Mouse.

Diabetes mellitus (DM) is a metabolic disease that involves disorders such as diabetic retinopathy, diabetic neuropathy, and diabetic hearing loss. Recently, neurotrophin has become a treatment target that has shown to be an attractive alternative in recovering auditory function altered by DM. The aim of this study was to evaluate the effect of DA9801, a mixture of Dioscorea nipponica and Dioscorea japonica extracts, in the auditory function damage produced in a STZ-induced diabetic model and to provide evidence of the mechanisms involved in enhancing these protective effects. We found a potential application of DA9801 on hearing impairment in the STZ-induced diabetic model, demonstrated by reducing the deterioration produced by DM in ABR threshold in response to clicks and normalizing wave I–IV latencies and Pa latencies in AMLR. We also show evidence that these effects might be elicited by inducing NGF related through Nr3c1 and Akt. Therefore, this result suggests that the neuroprotective effects of DA9801 on the auditory damage produced by DM may be affected by NGF increase resulting from Nr3c1 via Akt transformation.

Maturation of mismatch negativity and P3a response across adolescence

Adolescents experience significant changes in various physiological and psychological domains due to changes in their brain’s structure and function. A lot is known about structural changes in the brain across adolescence. However, less research has investigated changes in brain function during this period. In this study, we tracked the maturation of the auditory mismatch negativity (MMN) and P3a brain responses – both posited as neural indices of auditory discrimination – in 90 adolescents aged 10–18 years. We found that P3a mean amplitude and latency decreased significantly across adolescence, but there was no reliable change in the MMN. These results suggest that neural processes associated with passive auditory processing continue to develop well into adolescence.

Neurophysiological handover from MMN to P3a in first-episode and recurrent major depression

BackgroundMismatch negativity (MMN) and P3a components are sequential and co-occur. MMN represents the pre-attentive index of deviance detection and P3a represents the attention orienting response. Major depressive disorder (MDD) is characterized by impaired pre-attentive information processing. To assess whether impaired pre-attentive information processing can lead to an impairment of subsequent orienting process as the neurophysiological transmission spreads from MMN to P3a in MDD. MethodsMMN/P3a was obtained during a two-tone auditory paradigm with 8% duration deviants in 45 first-episode major depression subjects (F-MD), 40 recurrent major depression subjects (R-MD), and 46 healthy controls (HC). ResultsCompared with HC, F-MD and R-MD had lower MMN amplitudes and no differences were found between F-MD and R-MD. Notably, R-MD had lower P3a amplitudes and longer P3a latencies compared to HC, while F-MD had no differences. Interestingly, no correlations were found between the severity of depression and the deficits of MMN amplitude. The deficits of P3a amplitude, however, were negatively correlated with the severity of depression in F-MD and R-MD. Furthermore, the P3a amplitude deficits were positively correlated with the number of episodes in R-MD. LimitationsPatients were on antidepressant medication. ConclusionsThe recurrence of depressive episodes can lead to impaired pre-attentive information processing, causing an impairment of subsequent orienting process as the neurophysiological transmission from MMN to P3a. It further suggests that the impaired processing indexed by MMN amplitude may be a stable trait biomarker for the appearance of depression, while P3a amplitude can be used a potential biomarker for recurrence.

Alterations in attention capture to auditory emotional stimuli in job burnout: An event-related potential study

Job burnout is a significant cause of work absenteeism. Evidence from behavioral studies and patient reports suggests that job burnout is associated with impairments of attention and decreased working capacity, and it has overlapping elements with depression, anxiety and sleep disturbances. Here, we examined the electrophysiological correlates of automatic sound change detection and involuntary attention allocation in job burnout using scalp recordings of event-related potentials (ERP). Volunteers with job burnout symptoms but without severe depression and anxiety disorders and their non-burnout controls were presented with natural speech sound stimuli (standard and nine deviants), as well as three rarely occurring speech sounds with strong emotional prosody. All stimuli elicited mismatch negativity (MMN) responses that were comparable in both groups. The groups differed with respect to the P3a, an ERP component reflecting involuntary shift of attention: job burnout group showed a shorter P3a latency in response to the emotionally negative stimulus, and a longer latency in response to the positive stimulus. Results indicate that in job burnout, automatic speech sound discrimination is intact, but there is an attention capture tendency that is faster for negative, and slower to positive information compared to that of controls.

P.1.g.031 The neuroprotective and anti-amnestic effects of carbamylated erythropoietin derivates in ischemic brain injury

Purpose: To compare the neuroprotection of carbamylated erythropoietin (CEPO) and EPO fusion protein containing TR domain from glycoprotein MUC1 (CEPO-TR), and EPO fusion protein with modified Fc fragments of IgG1 (CEPO-Fc) against ischemic brain injury, including behavioral disturbances in a bilateral focal ischemic infarction of the rat prefrontal cortex. Methods: The carbamylated erythropoietin and erythropoietin derivates were produced by treatment of purified proteins with potassium cyanate in borate buffer. The resulting carbamylated erythropoietin and derivates exhibit no erythropoietic activity in UT-7/EPOR cell viability assay. Bilateral focal ischemic infarction of the prefrontal cortex (areas Frl and Fr2) was induced by the method of photochemical thrombosis in rats. After passive avoidance training and testing rats were treated, respectively, with following regimens: saline, 50mg/kg CEPO, 50mg/kg CEPO-TR, 50mg/kg CEPO-Fc. The substance was injected intraperitoneally in 1 h after operation. Neurological deficit scores and infarct volume were assessed at 4 and 7 days after operation. Functional state of CNS was determined by conditioned passive avoidance response (PA), i.e. by the latency of transition from light compartment to dark compartment (in sec). Morphometric measurements of the areas and volumes of the ischemic focus on serial slices were carried out on animal brain fixed by plunging into formalinethanol-acetic acid mixture (2:7:1). The data were statistically processed using Statistica 6.0 software. Summary of results: Additional oligosaccharides, linked to the erythropoietin, prolong its half-life and increase bioactivity in vivo. For this purpose we, for the first time, used TR domain from glycoprotein MUC1, bearing 5 additional sites for O-glycosylation. Our result indicated that ligation of TR-domain to the coding sequence of EPO did not affect secretion of the chimeric protein into the medium, receptor binding affinity in vitro bioactivity, compared with EPO wild type. However, both the in vitro potency and half-life in circulation of EPO bearing TR or Fc fragments were significantly enhanced. After photothrombosis and injection of saline, the latency of entry into the dark compartment decreased from 300 s to 76 s. Treatment of rats with CEPO, CEPOTR, and CEPO-Fc after photothrombosis restored latency of PA to 243, 258, 227 s, respectively, on day 4. Only injection of CEPOTR retains passive avoidance latency 207 s on the day 7. Ischemic damage volume in animals treated with CEPO-TR on 7th day after operation was 15.8±5.4 against 24.22±4.7 with control injection of saline (P< 0.05). This phenomenon on 7th day was observed only with CEPO-TR. Protection efficiency coefficient, calculated from these experiments represented 34%. Another erythropoietin derivate did not give statistically significant results. Conclusion: Treatment of rats with CEPO and CEPO fusion proteins after photothrombosis of cortex resulted in restoration of passive avoidance response and diminishing of volume of ischemic damage. Those, our study indicates that CEPO-Fc and CEPO-TR display neuroprotectionand anti-amnestic activity, while CEPO-TR demonstrates prolongation ability.

Auditory Middle Latency Responses in Chronic Smokers Compared to Nonsmokers: Differential Effects of Stimulus and Age

Effects of clicks and tonebursts on early and late auditory middle latency response (AMLR) components were evaluated in young and older cigarette smokers and nonsmokers. Participants ( n = 49) were categorized by smoking and age into 4 groups: (a) older smokers, (b) older nonsmokers, (c) young smokers, and (d) young nonsmokers. Monaural, 2-channel AMLRs were acquired from Fz and Cz electrodes with 3 stimuli (clicks, 500 Hz, and 3000 Hz). Group differences included significantly higher V-Na amplitude in young adults and shorter Pb latency in older nonsmokers. Young smokers had a significantly higher Nb-Pb amplitude and shorter Nb latency than other groups. Toneburst stimuli yielded significantly longer V, Na, and Pa latencies compared to clicks. Pb latency was shorter at Fz than at Cz. Relative amplitudes were significantly higher at Fz than at Cz overall; Pa-Nb and Nb-Pb were significantly lower for 3000 Hz than for 500 Hz and clicks. Responses from young smokers revealed a higher amplitude and shorter latency for later AMLR waves, reflecting an arousal effect of smoking in cortical and subcortical generators. AMLR differences in older adults may be due to age-related neurochemical changes in the central nervous system. Stimulus and electrode differences plus smoking and aging effects can guide neurodiagnostic AMLR protocols, especially in young adult smokers.

Event‐Related Potential Responses to the Acute and Chronic Effects of Alcohol in Adolescent and Adult Wistar Rats

This study explored the hypothesis that adolescent ethanol (EtOH) exposure may cause long-lasting changes in EtOH sensitivity by exploring the age-related effects of acute alcohol on intoxication and on event-related potential (ERP) responses to acoustic stimuli in EtOH-naïve adolescent and adult male Wistar rats and in adult rats that were exposed to chronic EtOH/control conditions during adolescence. EtOH-naïve adolescent (postnatal day 32 [PD32]) and adult male rats (PD99) were included in the first study. In a second study, rats were exposed to 5weeks of EtOH vapor (blood EtOH concentrations at 175mg%) or air from PD24 to 59 and allowed to mature until PD90. In both studies, rats were implanted with cortical recording electrodes, and the effects of acute EtOH (0.0, 1.5, and 3.0g/kg) on behavioral and ERP responses were assessed. Adolescents were found to have higher amplitude and longer latency P3a and P3b components at baseline as compared to adult rats, and EtOH was found to produce a robust dose-dependent increase in the latency of the P3a and P3b components of the auditory ERP recorded in cortical sites in both adolescents and adults. However, EtOH produced significantly larger delays in P3a and P3b latencies in adults as compared to adolescents. Acute EtOH administration was also found to produce a robust dose-dependent increase in the latency of the P3a and P3b components in adult animals exposed to EtOH vapor as adolescents and air exposed controls; however, larger acute EtOH-induced increases in P3a and P3b latencies were seen in controls as compared to adolescent vapor exposed rats. Adolescent rats have a less intense P3 latency response to acute EtOH administration when compared to adult rats. Exposure to chronic EtOH during adolescence can cause "retention" of the adolescent phenotype of reduced P3 latency sensitivity to EtOH.

Transcranial Direct Current Stimulation of the Dorsolateral Prefrontal Cortex Modulates Repetition Suppression to Unfamiliar Faces: An ERP Study

Repeated visual processing of an unfamiliar face suppresses neural activity in face-specific areas of the occipito-temporal cortex. This "repetition suppression" (RS) is a primitive mechanism involved in learning of unfamiliar faces, which can be detected through amplitude reduction of the N170 event-related potential (ERP). The dorsolateral prefrontal cortex (DLPFC) exerts top-down influence on early visual processing. However, its contribution to N170 RS and learning of unfamiliar faces remains unclear. Transcranial direct current stimulation (tDCS) transiently increases or decreases cortical excitability, as a function of polarity. We hypothesized that DLPFC excitability modulation by tDCS would cause polarity-dependent modulations of N170 RS during encoding of unfamiliar faces. tDCS-induced N170 RS enhancement would improve long-term recognition reaction time (RT) and/or accuracy rates, whereas N170 RS impairment would compromise recognition ability. Participants underwent three tDCS conditions in random order at ∼72 hour intervals: right anodal/left cathodal, right cathodal/left anodal and sham. Immediately following tDCS conditions, an EEG was recorded during encoding of unfamiliar faces for assessment of P100 and N170 visual ERPs. The P3a component was analyzed to detect prefrontal function modulation. Recognition tasks were administered ∼72 hours following encoding. Results indicate the right anodal/left cathodal condition facilitated N170 RS and induced larger P3a amplitudes, leading to faster recognition RT. Conversely, the right cathodal/left anodal condition caused N170 amplitude and RTs to increase, and a delay in P3a latency. These data demonstrate that DLPFC excitability modulation can influence early visual encoding of unfamiliar faces, highlighting the importance of DLPFC in basic learning mechanisms.

Cortical Activity During Perception of Musical Pitch

This study investigates the effects of music training on brain activity to violations of melodic expectancies. We recorded behavioral and event-related brain potential (ERP) responses of musicians and nonmusicians to discrepancies of pitch between pairs of unfamiliar melodies based on Western classical rules. Musicians detected pitch deviations significantly better than nonmusicians. In musicians compared to nonmusicians, auditory cortical potentials to notes but not unrelated warning tones exhibited enhanced P200 amplitude generally, and in response to pitch deviations enhanced amplitude for N150 and P300 (P3a) but not N100 was observed. P3a latency was shorter in musicians compared to nonmusicians. Both the behavioral and cortical activity differences observed between musicians and nonmusicians in response to deviant notes were significant with stimulation of the right but not the left ear, suggesting that left-sided brain activity differentiated musicians from nonmusicians. The enhanced amplitude of N150 among musicians with right ear stimulation was positively correlated with earlier age onset of music training. Our data support the notion that long-term music training in musicians leads to functional reorganization of auditory brain systems, and that these effects are potentiated by early age onset of training.

Early and late auditory event-related potentials in cognitively high functioning male adolescents with autism spectrum disorder

Event-related potentials (ERP) studies have offered diverging results in characterizing the basic nature of abnormal sensory processing and discrimination in autism spectrum disorders (ASDs). In the present study we report duration mismatch negativity (MMN) and later ERP components (P3a and P3b) derived from auditory odd-ball paradigms in a homogenous sample of cognitively high functioning male adolescents with ASD. We find significantly reduced frontal and temporal MMN amplitudes and no differences in P3a or P3b amplitudes or latencies compared to controls. These findings are in contrast to recent studies reporting enhanced ERP amplitudes to auditory stimuli, and are more in support of a weakened automatic auditory sensory processing as being central to the abnormal auditory behavioral responses commonly encountered in ASD.

Reduced P3a amplitudes in antipsychotic naïve first-episode psychosis patients and individuals at clinical high-risk for psychosis

Event related potentials (ERP) associated with early sensory information processing have been proposed as possible vulnerability markers for psychosis. Compared to other ERPs reported in schizophrenia research, like Mismatch Negativity (MMN), little is known about P3a, an ERP related to novelty detection. The aim of this study was to analyze the MMN-P3a complex in 20 antipsychotic naïve first-episode psychosis patients (FEP), 23 antipsychotic naïve individuals at clinical high-risk for psychosis (CHR) and 24 healthy controls. The MMN-P3a amplitudes and latencies were obtained during a passive auditory mismatch frequency deviant ERP paradigm and analyzed in frontal and central scalp regions. There were no significant differences in MMN amplitude between groups. There was a significant group difference in P3a due to reduced amplitude (F[2,64] = 3.7, p = 0.03) in both CHR and FEP groups (Mean difference (MD) = 0.39, p = 0.04 and MD = 0.49, p = 0.02, respectively) compared to the control group and this effect was most prominent on the right side (Group × laterality effect: MD = 0.57, p < 0.01 and MD = 0.58, p < 0.01, respectively). No significant differences were observed for MMN or P3a latencies between groups. Although a P3a decrement in chronic schizophrenia and FEP has been previously reported, our results suggest that this novelty detection impairment is present even in pre-psychosis stages in antipsychotic naïve subjects. This study supports the evidence that P3a could represent a neurophysiological vulnerability marker for the development of psychosis.

Multi‐components of evoked‐brain potentials in deficit and nondeficit schizophrenia

The present study aims to detect the specific and common impairment index relative to evoked brain potentials (EBPS ) in deficit schizophrenia (DS) and nondeficit schizophrenia (NDS), and investigates the relationship between EBPs and clinical variables. The study used EBPs in 21 patients with DS, 38 patients with NDS, and 50 healthy controls (HCs) to investigate P300 waves, mismatch negative (MMN), sensory gating (SG) P50 and contingent negative variation (CNV). A comparison of three groups and the relationship between EBPs and clinical variables were performed using general linear model analyses and partial correlation, respectively. Compared with HCs, both groups of patients showed delayed N1 , N2 , and P3a latency, and reduced N1 and N2 amplitude. The MMN showed delayed latency. The P50 ratios and the inhibited ratios were impaired, whereas SG loss ratios increased. CNV amplitude was reduced. Compared with HCs, NDS showed delayed latency of S2'-C in CNV, whereas DS showed shortened latency. Only NDS, when compared with HCs, showed delayed latency of P3b , Also, only DS, when compared with HCs, showed delayed latency of point A in CNV. Latency of point A in CNV of DS, correlated with a poorer Global Assessment of Functioning Scale (6 weeks) and was independent of clinical characteristics. Schizophrenia represents a clinical syndrome with shared impairments in brain function, whereas DS is a relatively homogeneous subgroup of schizophrenia with unique pathophysiological changes.

Demand and modality of directed attention modulate “pre-attentive” sensory processes in schizophrenia patients and nonpsychiatric controls

BackgroundMismatch negativity (MNN) and P3a are event related potential (ERP) measures of early sensory information processing. These components are usually conceptualized as being “pre-attentive” and therefore immune to changes with variations in attentional functioning. This study aimed to determine whether manipulations of attention influence the amplitudes and latencies of MMN and P3a and, if so, the extent to which these early sensory processes govern concurrent behavioral vigilance performance in schizophrenia patients and normal subjects. MethodsSchizophrenia patients (SZ; n=20) and Nonpsychiatric Control Subjects (NCS; n=20) underwent auditory ERP testing to assess MMN and P3a across 4 EEG recording sessions in which attentional demand (low vs. high) and sensory modality of directed attention (visual vs. auditory) were experimentally varied. ResultsAcross conditions, SZ patients exhibited deficits in MMN and P3a amplitudes. Significant amplitude and latency modulation were observed in both SZ and NCS but there were no group-by-condition interactions. The amount of MMN amplitude attenuation from low- to high-demand tasks was significantly associated with increased vigilance performance in both SZ and NCS groups (r=−0.67 and r=−0.60). Several other robust associations were also observed among neurophysiologic, clinical and cognitive variables. ConclusionsAttentional demand and modality of directed attention significantly influence the amplitude and latencies of “pre-attentive” ERP components in both SZ and NCS. Deficits in MMN and P3a were not “normalized” when attention was directed to the auditory stimuli in schizophrenia patients. The adaptive modulation of early sensory information processing appears to govern concurrent attentional task performance. The temporal window reflecting automatic sensory discrimination as indexed as MMN and P3a may serve as a gateway to some higher order cognitive operations necessary for psychosocial functioning.

Reduced duration mismatch negativity in adolescents with psychotic symptoms: further evidence for mismatch negativity as a possible biomarker for vulnerability to psychosis

BackgroundDeficits in the mismatch negativity (MMN) and P3a components are the most reliable and robust findings in schizophrenia. These abnormalities have also been recently documented in individuals clinically at risk for psychosis, indicating that the MMN may be a potential biomarker for psychosis. However, the at risk samples included in MMN studies are characterised by pre-existing clinical symptomatology and significant functional decline which are related to MMN amplitude. These factors may be potential confounds in determining whether deficient MMN is present prior to clinical manifestation of the disorder. Therefore, investigating the MMN in the extended psychosis phenotype comprising adolescents with psychotic symptoms from the general population may provide important information on whether abnormal MMN is apparent in the earliest stages of risk.MethodsThirty six adolescents completed a duration deviant MMN task. Fourteen adolescents with psychotic symptoms comprised the at risk group and 22 with no psychotic symptoms comprised the Controls. The task consisted of 85% standard tones (25 ms) and 15% deviant tones (50 ms). The groups were compared on MMN and P3a amplitude and latency across frontocentral and temporal electrodes.ResultsAdolescents with psychotic symptoms were characterised by a reduction in MMN amplitude at frontal and temporal regions compared to the controls.ConclusionsThis is the first study to demonstrate impaired auditory discrimination for duration deviant tones in nonclinical adolescents with psychotic symptoms. These findings suggest that MMN amplitude may be a possible biomarker for vulnerability to psychosis.

Attention in essential tremor: evidence from event-related potentials

Clinically subtle executive dysfunctions have recently been described in essential tremor (ET), though the presence of attentional deficits is still unclear. We investigated the psychophysiological aspects of attention in ET, using event-related potentials (ERPs). Twenty-one non-demented patients with ET and 21 age- and sex-matched healthy controls underwent a psychophysiological evaluation. P300 components and the Contingent Negative Variation (CNV) were recorded. The latencies and amplitudes of the P3a and P3b subcomponents and CNV areas were evaluated. Possible correlations between clinical parameters and ERP data were investigated. P3a latency was significantly longer in the ET group (p<0.05), while no differences emerged between patients and controls in P3b latency. No differences were observed between the two groups in the CNV parameters. ET patients display a difficulty in the response to novelty and in the recruitment of prefrontal attentive circuits, while the memory context-updating process appears to be spared. This selective cognitive dysfunction does not appear to interfere with the attentional set linked to the expectancy evaluated during a complex choice-reaction time task, which is preserved in ET. This multitask psychophysiological approach reveals the presence of a peculiar attentional deficit in patients with ET, thus expanding the clinical features of this disease.

Absence of P300 reduction in South African treatment-naïve adolescents with alcohol dependence.

Event-related potential studies show reduced P300 amplitudes in alcohol use disorders (AUDs). Alcohol exposure, genetic vulnerability to alcoholism, and comorbid psychopathology may contribute to this reduction. Most previous research has studied treated adult AUD samples, which have more severe alcoholism, a greater family history of AUDs, and more comorbidity than untreated samples. Untreated AUD samples tend to have little or no P300 amplitude reduction. We compared P300 between treatment-naïve alcohol-dependent (TNAD) adolescents with no diagnosable substance abuse or psychiatric comorbidity and nonsubstance-abusing control (NSAC) adolescents. Individuals between the ages of 13 and 18 years were recruited into either TNAD (n = 45) or NSAC (n = 64) groups. Alcohol use variables, family history density of alcohol problems, and psychiatric symptom counts were assessed in a clinician-administered evaluation. EEGs were recorded during performance of a 3-condition visual target detection task. P300 amplitudes were of comparable size in TNAD adolescents and NSAC adolescents. Boys demonstrated larger P3a and P3b amplitudes than girls. Within TNAD, P3b amplitude was reduced in those who drank more frequently, and P3a latency was more prolonged in subjects with higher internalizing symptom counts. The P300 deficit was not present in TNAD adolescents without comorbidities. In comparison to results of reduced P300 in treated adolescent AUD samples, this finding likely reflects moderate alcohol exposure, lower genetic vulnerability to alcoholism, and lack of comorbidity in our sample. Further work is needed to determine the relative contributions of these factors to changes in the P300.

Processing of facial expressions of emotions in healthy volunteers: An exploration with event-related potentials and personality traits

Previous studies have shown that event-related potentials (ERPs) are modulated by anxiety or psychopathic personality traits. Therefore, we hypothesized that the automatic processing of facial expressions of emotions (FEE) is also correlated with related disordered personality traits. Thirty-seven healthy volunteers underwent both an "oddball" ERP recording to facial expressions of Anger, Happiness, Sadness, and Neutral, and a test of the Dimensional Assessment of Personality Pathology (DAPP). Mean reaction time was longer in response to anger than to other facial expressions. Facial expressions of Anger, Happiness and Sadness did not affect N1 (N170). By contrast, Happiness elicited a delayed P2, Anger elicited both a smaller N2 and a delayed P3b, and both Happiness and Anger elicited a P3b of higher amplitude. In addition, P3a latencies to Happiness were negatively correlated with DAPP Identity problems, and P3b latencies to Happiness were negatively correlated with DAPP Stimulus seeking, Callousness, Passive aggressivity, and Narcissism. Our study demonstrates that Anger implicitly captures attentional resources, and Happiness triggers more facilitated processing in individuals with dissocial traits.

Cognitive deficits following exposure to pneumococcal meningitis: an event-related potential study.

BackgroundPneumococcal meningitis (PM) is a severe and life-threatening disease that is associated with cognitive impairment including learning difficulties, cognitive slowness, short-term memory deficits and poor academic performance. There are limited data on cognitive outcomes following exposure to PM from Africa mainly due to lack of culturally appropriate tools. We report cognitive processes of exposed children as measured by auditory and visual event-related potentials.MethodsSixty-five children (32 male, mean 8.4 years, SD 3.0 years) aged between 4-15 years with a history of PM and an age-matched control group of 93 children (46 male; mean 8.4 years, SD 2.7 years) were recruited from a well-demarcated study area in Kilifi. In the present study, both baseline to peak and peak-to-peak amplitude differences are reported.ResultsChildren with a history of pneumococcal meningitis had significantly longer auditory P1 and P3a latencies and smaller P1 amplitudes compared to unexposed children. In the visual paradigm, children with PM seemingly lacked a novelty P3a component around 350 ms where control children had a maximum, and showed a lack of stimulus differentiation at Nc. Further, children with exposure to PM had smaller peak to peak amplitude (N2-P1) compared to unexposed children.ConclusionThe results suggest that children with a history of PM process novelty differently than do unexposed children, with slower latencies and reduced or absent components. This pattern suggests poorer auditory attention and/or cognitive slowness and poorer visual attention orienting, possibly due to disruption in the functions of the lateral prefrontal and superior temporal cortices. ERPs may be useful for assessment of the development of perceptual-cognitive functions in post brain-injury in African children by providing an alternate way of assessing cognitive development in patient groups for whom more typical standardized neuropsychological assessments are unavailable.