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The aim of our work was to assess the cognitive function in patients recovered from COVID-19 infection using P300 analysis. Methods 50 subjects recovered from COVID-19 infection (at least 8 weeks following recovery). The patients were recruited in the period between April 2022 and December 2022.The cases were recruited from the Chest hospital, Beni-Suef governorate and from chest department, Beni-Suef University hospital. Results Our results revealed significantly impaired cognitive function, delayed P300 latency and small P300 amplitude among severe cases. Also, there was a significantly delayed P300 latency and small amplitude in hypoxic critically severe patients. In addition, our results revealed a significant positive correlation between cognitive function, P300 latency, and the duration of hospital stay. Also, our study detects the value of vaccination we revealed that patients who received vaccination before COVID-19 infection had less delay in P300 latency in comparison to those who did not receive vaccination before infection Conclusion COVID-19 can affect cognitive function demonstrated by increased P300 latency and small p300 amplitude. [ABSTRACT FROM AUTHOR]

Background: Time series analysis is critical for understanding brain signals and their relationship to behavior and cognition. Cluster-based permutation tests (CBPT) are commonly used to analyze a variety of electrophysiological signals including EEG, MEG, ECoG, and sEEG data without a priori assumptions about specific temporal effects. However, two major limitations of CBPT include the inability to directly analyze experiments with multiple fixed effects and the inability to account for random effects (e.g. variability across subjects). Here, we propose a flexible multi-step hypothesis testing strategy using CBPT with Linear Mixed Effects Models (LMEs) and Generalized Linear Mixed Effects Models (GLMEs) that can be applied to a wide range of experimental designs and data types. Methods: We first evaluate the statistical robustness of LMEs and GLMEs using simulated data distributions. Second, we apply a multi-step hypothesis testing strategy to analyze ERPs and broadband power signals extracted from human ECoG recordings collected during a simple image viewing experiment with image category and novelty as fixed effects. Third, we assess the statistical power differences between analyzing signals with CBPT using LMEs compared to CBPT using separate t-tests run on each fixed effect through simulations that emulate broadband power signals. Finally, we apply CBPT using GLMEs to high-gamma burst data to demonstrate the extension of the proposed method to the analysis of nonlinear data. Results: First, we found that LMEs and GLMEs are robust statistical models. In simple simulations LMEs produced highly congruent results with other appropriately applied linear statistical models, but LMEs outperformed many linear statistical models in the analysis of “suboptimal” data and maintained power better than analyzing individual fixed effects with separate t-tests. GLMEs also performed similarly to other nonlinear statistical models. Second, in real world human ECoG data, LMEs performed at least as well as separate t-tests when applied to predefined time windows or when used in conjunction with CBPT. Additionally, fixed effects time courses extracted with CBPT using LMEs from group-level models of pseudo-populations replicated latency effects found in individual category-selective channels. Third, analysis of simulated broadband power signals demonstrated that CBPT using LMEs was superior to CBPT using separate t-tests in identifying time windows with significant fixed effects especially for small effect sizes. Lastly, the analysis of high-gamma burst data using CBPT with GLMEs produced results consistent with CBPT using LMEs applied to broadband power data. Conclusions: We propose a general approach for statistical analysis of electrophysiological data using CBPT in conjunction with LMEs and GLMEs. We demonstrate that this method is robust for experiments with multiple fixed effects and applicable to the analysis of linear and nonlinear data. Our methodology maximizes the statistical power available in a dataset across multiple experimental variables while accounting for hierarchical random effects and controlling FWER across fixed effects. This approach substantially improves power leading to better reproducibility. Additionally, CBPT using LMEs and GLMEs can be used to analyze individual channels or pseudo-population data for the comparison of functional or anatomical groups of data.

Diglossia in Arabic describes the existence and the use of two varieties of the same language: spoken Arabic (SA) and literary Arabic (LA). SA, the dialect first spoken by Arabic native speakers, is used in non‐formal situations for everyday conversations, and varies from one region to another in the Arabic world. LA, acquired later in life when the children learn to read and write at school, is used for formal purposes such as media, speeches in public and religious sermons. Previous research showed that, in the auditory modality, SA words are processed faster than LA ones. In the visual modality, written LA words are processed faster than SA ones, the latter comparing with low‐frequency words. This study analysed event‐related potentials (ERPs) during the processing of high‐frequency (LAHF), LA low‐frequency (LALF) and SA high‐frequency words (SAHF) in a visual lexical decision task. Faster reaction times were observed for LAHF, followed by SAHF and then by LALF. ERPs showed a modulation of the early components starting from the P100 component and of the late P600 component, supposedly related to memory processes. These findings, indicating that processing written SAHF words was largely comparable with processing of LALF, are discussed in the context of Arabic diglossia. [ABSTRACT FROM AUTHOR]

Auditory stimulus intensity of innocuous tones is generally thought to have a direct effect on the amplitude of ERP components, but these effects have rarely been explored across a wide component range, or in multiple paradigms. Here we investigate component sensitivity to stimulus intensity differences in two studies. Study 1 (N = 36) employed a between-participants paradigm in which repeated trains of standard stimuli were presented as 50 or 80 dB SPL 1000 Hz tones. Study 2 (N = 18) used a within-participant presentation of alternating 60 and 80 dB SPL 1000 Hz tones. Electrode caps with 19 channels (referred to linked ears) generated ERPs covering the first 600 ms of each participant's EEG responses; these were submitted to separate temporal PCAs in each study. A similar series of components was obtained in each study: P1, N1a, N1b, N1c, P2, P3a, P3b, nP3, SW1, and SW2; an N2 was found in Study 2 only. Loud tones in Study 1 produced greater amplitudes in all components except SW1. In Study 2, Loud cf. Soft tones produced smaller P1 and nP3, larger N1 components, P2, and P3a, with no effect on N2, P3b, SW1 or SW2. These results indicate similar sequential processes underlying sensory processing in one- and two-stimulus paradigms, with the later stimulus intensity effects varying with paradigm. • We examined ERP components as a function of auditory intensity in 2 studies. • P1, N1a, N1b, N1c, P2, P3a, P3b, nP3, SW1, and SW2 occurred in each study. • All except SW1 increased with intensity in the between-subjects Study 1. • Intensity in Study 2 (within-subjects) increased only N1a, N1b, N1c, P2, P3a. • Results are related to sequential processing in 1- and 2-stimulus paradigms. [ABSTRACT FROM AUTHOR]

Prospective memory (PM) is essential in the everyday activities of children because it involves remembering intentions for the future, such as doing their homework or bringing written parental permissions to school. Developmental studies have shown increases in PM performance throughout childhood, but the specific processes underlying this development are still under debate. In the present study, event-related potentials were used to examine whether the focality of the PM task is related to the PM increments by testing two groups of children (first and last cycle of primary school) and assessing differences in N300 (cue detection), frontal positivity (switching), parietal positivity (retrieval of the intention) and frontal slow waves (monitoring of the retrieved intention). The results showed significant differences in focality in the group of older children but no differences in any of the components for their younger counterparts. In addition, the differences between prospective and ongoing trials were smaller for younger than older children. These findings suggest that the ability to adjust attentional strategies, monitor, switch and retrieve the intention develops across childhood and affects PM performance in attentionally demanding conditions. [ABSTRACT FROM AUTHOR]

• Combining CBPT with GLMEs allows statistical analysis to match experimental design. • CBPT with GLMEs accounts for subject variability and hierarchical random effects. • The proposed method maintains control of type I error, type II error, and FWER. • CBPT with GLMEs can be applied to individual channels and pseudo-population data. Time series analysis is critical for understanding brain signals and their relationship to behavior and cognition. Cluster-based permutation tests (CBPT) are commonly used to analyze a variety of electrophysiological signals including EEG, MEG, ECoG, and sEEG data without a priori assumptions about specific temporal effects. However, two major limitations of CBPT include the inability to directly analyze experiments with multiple fixed effects and the inability to account for random effects (e.g. variability across subjects). Here, we propose a flexible multi-step hypothesis testing strategy using CBPT with Linear Mixed Effects Models (LMEs) and Generalized Linear Mixed Effects Models (GLMEs) that can be applied to a wide range of experimental designs and data types. We first evaluate the statistical robustness of LMEs and GLMEs using simulated data distributions. Second, we apply a multi-step hypothesis testing strategy to analyze ERPs and broadband power signals extracted from human ECoG recordings collected during a simple image viewing experiment with image category and novelty as fixed effects. Third, we assess the statistical power differences between analyzing signals with CBPT using LMEs compared to CBPT using separate t-tests run on each fixed effect through simulations that emulate broadband power signals. Finally, we apply CBPT using GLMEs to high-gamma burst data to demonstrate the extension of the proposed method to the analysis of nonlinear data. First, we found that LMEs and GLMEs are robust statistical models. In simple simulations LMEs produced highly congruent results with other appropriately applied linear statistical models, but LMEs outperformed many linear statistical models in the analysis of "suboptimal" data and maintained power better than analyzing individual fixed effects with separate t-tests. GLMEs also performed similarly to other nonlinear statistical models. Second, in real world human ECoG data, LMEs performed at least as well as separate t-tests when applied to predefined time windows or when used in conjunction with CBPT. Additionally, fixed effects time courses extracted with CBPT using LMEs from group-level models of pseudo-populations replicated latency effects found in individual category-selective channels. Third, analysis of simulated broadband power signals demonstrated that CBPT using LMEs was superior to CBPT using separate t-tests in identifying time windows with significant fixed effects especially for small effect sizes. Lastly, the analysis of high-gamma burst data using CBPT with GLMEs produced results consistent with CBPT using LMEs applied to broadband power data. We propose a general approach for statistical analysis of electrophysiological data using CBPT in conjunction with LMEs and GLMEs. We demonstrate that this method is robust for experiments with multiple fixed effects and applicable to the analysis of linear and nonlinear data. Our methodology maximizes the statistical power available in a dataset across multiple experimental variables while accounting for hierarchical random effects and controlling FWER across fixed effects. This approach substantially improves power leading to better reproducibility. Additionally, CBPT using LMEs and GLMEs can be used to analyze individual channels or pseudo-population data for the comparison of functional or anatomical groups of data. [ABSTRACT FROM AUTHOR]

Prospective memory (PM) is essential in the everyday activities of children because it involves remembering intentions for the future, such as doing their homework or bringing written parental permissions to school. Developmental studies have shown increases in PM performance throughout childhood, but the specific processes underlying this development are still under debate. In the present study, event-related potentials were used to examine whether the focality of the PM task is related to the PM increments by testing two groups of children (first and last cycle of primary school) and assessing differences in N300 (cue detection), frontal positivity (switching), parietal positivity (retrieval of the intention) and frontal slow waves (monitoring of the retrieved intention). The results showed significant differences in focality in the group of older children but no differences in any of the components for their younger counterparts. In addition, the differences between prospective and ongoing trials were smaller for younger than older children. These findings suggest that the ability to adjust attentional strategies, monitor, switch and retrieve the intention develops across childhood and affects PM performance in attentionally demanding conditions.

Vigilance, also known as sustained attention, is defined as the ability to maintain concentrated attention over prolonged time periods. Many methods for vigilance detection, based on biological and behavioural characteristics, have been proposed in the literature. In general, the existing approaches do not provide any solution to measure vigilance level quantitatively and adopt costly equipment. This paper utilizes a portable electroencephalography (EEG) device and presents a new method for estimation of vigilance level of an individual by utilizing event-related potentials (P300 and N100) of EEG signals and eye blink rate. Here, we propose a fuzzy rule-based system using amplitude and time variations of the N100 and P300 components and blink variability to establish the correlation among N100, P300, eye blink and the vigilance activity. We have shown, with the help of our proposed fuzzy model, we can efficiently calculate and quantify the vigilance level, and thereby obtain a numerical value of vigilance instead of its mere presence or absence. To validate the results obtained from our fuzzy model, we performed subjective analysis (for assessing the mood and stress level of participants), reaction time analysis and compared the vigilance values with target detection accuracy. The obtained results prove the efficacy of our proposal. [ABSTRACT FROM AUTHOR]

Highlights • Video-clips can be used to study the electro-cortical correlates of multi-sensory integration. • Stimuli of fear, but not disgust, produce significant speedup of responses in the bimodal compared to the visual condition. • Stimuli of fear, more so than disgust, increase the visual P100 amplitude in the bimodal compared to the visual condition. • Stimuli of fear, but not disgust, increase the visual N170 amplitude in the bimodal compared to the visual condition. Abstract Multisensory integration (MSI) is crucial for human communication and social interaction and has been investigated in healthy populations and neurodevelopmental disorders. However, the use of stimuli with high ecological validity is sparse, especially in event-related potential (ERP) studies. The present study examined the ERP correlates of MSI in healthy adults using short (500 ms) ecologically valid professional actor-produced emotions of fear or disgust as vocal exclamation or facial expression (unimodal conditions) or both (bimodal condition). Behaviourally, our results show a general visual dominance effect (similarly fast responses following bimodal and visual stimuli) and an MSI-related speedup of responses only for fear. Electrophysiologically, both P100 and N170 showed MSI-related amplitude increases only following fear, but not disgust stimuli. Our results show for the first time that the known differential neural processing of fear and disgust also holds for the integration of dynamic auditory and visual information. [ABSTRACT FROM AUTHOR]

The brain’s ability to recognize acoustic changes occurring in rapid temporal succession is important for speech and successful language development. Children with specific language impairment (SLI) are characterized by deficient dynamics of temporal information processing (TIP) in the millisecond time range accompanied by disordered language development. Furthermore, previous studies have found that intervention based on amelioration of TIP resulted in improvement of both language and other cognitive functions. This study aimed to explain the changes associated with TIP training from the perspective of event-related potentials (ERPs). Thirty-six children aged 5–8 years (26 boys, 10 girls) diagnosed with SLI underwent two types of intense audio-visual computer intervention: experimental TIP training targeted at the millisecond time range (n = 18) or control non-TIP training (n = 18). Paired 50 ms tones of 1000 Hz and 1200 Hz were presented with inter-stimulus intervals (ISIs) of either 50 ms (Short ISI Condition) or 200 ms (Long ISI Condition). Auditory ERPs were measured in a passive oddball paradigm before and after each type of training. The mismatch negativity (MMN) paradigm was applied as an electrophysiological indicator of the brain’s ability to automatically detect violations of regularity in paired tones presented in rapid succession. Moreover, the P3a component was also analyzed. After 24 sessions of temporal training (in the experimental group) MMN amplitude enhancement was observed in both ISI conditions, reflecting increased efficiency in perceiving changes in rapid auditory sequences. In both experimental and control groups, P3a amplitude was enhanced in both ISIs. This may be due to the improvement of involuntary attention shifting to the auditory events involved in each training type. To conclude, temporal training, compared to non-temporal control training, improved the ability to detect changes in a rapid auditory stream in children with SLI.

The brain’s ability to recognize acoustic changes occurring in rapid temporal succession is important for speech and successful language development. Children with specific language impairment (SLI) are characterized by deficient dynamics of temporal information processing (TIP) in the millisecond time range accompanied by disordered language development. Furthermore, previous studies have found that intervention based on amelioration of TIP resulted in improvement of both language and other cognitive functions. This study aimed to explain the changes associated with TIP training from the perspective of event-related potentials (ERPs). Thirty-six children aged 5–8 years (26 boys, 10 girls) diagnosed with SLI underwent two types of intense audio-visual computer intervention: experimental TIP training targeted at the millisecond time range (n = 18) or control non-TIP training (n = 18). Paired 50 ms tones of 1000 Hz and 1200 Hz were presented with inter-stimulus intervals (ISIs) of either 50 ms (Short ISI Condition) or 200 ms (Long ISI Condition). Auditory ERPs were measured in a passive oddball paradigm before and after each type of training. The mismatch negativity (MMN) paradigm was applied as an electrophysiological indicator of the brain’s ability to automatically detect violations of regularity in paired tones presented in rapid succession. Moreover, the P3a component was also analyzed. After 24 sessions of temporal training (in the experimental group) MMN amplitude enhancement was observed in both ISI conditions, reflecting increased efficiency in perceiving changes in rapid auditory sequences. In both experimental and control groups, P3a amplitude was enhanced in both ISIs. This may be due to the improvement of involuntary attention shifting to the auditory events involved in each training type. To conclude, temporal training, compared to non-temporal control training, improved the ability to detect changes in a rapid auditory stream in children with SLI. [ABSTRACT FROM AUTHOR]

It is generally recognised that event related potentials (ERPs) of electroencephalogram (EEG) primarily reflect summed post-synaptic activity of the local pyramidal neural population(s). However, it is still not understood how the positive and negative deflections (e.g. P1, N1 etc) observed in ERP recordings are related to the underlying excitatory and inhibitory post-synaptic activity. We investigated the neurogenesis of P1 and N1 in ERPs by pharmacologically manipulating inhibitory post-synaptic activity in the somatosensory cortex of rodent, and concurrently recording EEG and local field potentials (LFPs). We found that the P1 wave in the ERP and LFP of the supragranular layers is determined solely by the excitatory post-synaptic activity of the local pyramidal neural population, as is the initial segment of the N1 wave across cortical depth. The later part of the N1 wave was modulated by inhibitory post-synaptic activity, with its peak and the pulse width increasing as inhibition was reduced. These findings suggest that the temporal delay of inhibition with respect to excitation observed in intracellular recordings is also reflected in extracellular field potentials (FPs), resulting in a temporal window during which only excitatory post-synaptic activity and leak channel activity are recorded in the ERP and evoked LFP time series. Based on these findings, we provide clarification on the interpretation of P1 and N1 in terms of the excitatory and inhibitory post-synaptic activities of the local pyramidal neural population(s). [ABSTRACT FROM AUTHOR]

This article has two main objectives. First, we offer an introduction to the subfield of generative third language (L3) acquisition. Concerned primarily with modeling initial stages transfer of morphosyntax, one goal of this program is to show how initial stages L3 data make significant contributions towards a better understanding of how the mind represents language and how (cognitive) economy constrains acquisition processes more generally. Our second objective is to argue for and demonstrate how this subfield will benefit from a neuro/psycholinguistic methodological approach, such as event related potential (ERP) experiments, to complement the claims currently made on the basis of exclusively behavioral experiments.

Background: previous studies investigated neural substrates of emotional face processing in adolescents and its comparison with adults. As emotional faces elicit more of emotional expression recognition rather than direct emotional responding, it remains undetermined how adolescents are different from adults in brain susceptibility to emotionally stressful stimuli. Methods: Event-Related Potentials were recorded for highly negative (HN), moderately negative (MN) and Neutral pictures in 20 adolescents and 20 adults while subjects performed a standard/deviant distinction task by pressing different keys, irrespective of the emotionality of deviant stimuli. Results: Adolescents exhibited more negative amplitudes for HN versus neutral pictures in N1 (100-150ms), P2 (130-190ms), N2 (210-290ms) and P3 (360-440ms) components. In addition, adolescents showed more negative amplitudes for MN compared to neutral pictures in N1, P2 and N2 components. By contrast, adults exhibited significant emotion effects for HN stimuli in N2 and P3 amplitudes but not in N1 and P2 amplitudes, and they did not exhibit a significant emotion effect for MN stimuli at all these components. In the 210-290ms time interval, the emotion effect for HN stimuli was significant across frontal and central regions in adolescents, while this emotion effect was noticeable only in the central region for adults. Conclusions: Adolescents are more emotionally sensitive to negative stimuli compared to adults, regardless of the emotional intensity of the stimuli, possibly due to the immature prefrontal control system over the limbic emotional inputs during adolescence. Keywords: Event-Related Potentials (ERPs); Adolescence; Emotion intensity; Negative pictures; Emotional Susceptibility

Deficits in visual short-term memory (VSTM) binding have been proposed as an early and specific marker for Alzheimer's disease (AD). However, no studies have explored the neural correlates of this domain in clinical categories involving prodromal stages with different risk levels of conversion to AD. We assessed underlying electrophysiological modulations in patients with mild cognitive impairment (MCI), patients in the MCI stages of familial AD carrying the mutation E280A of the presenilin-1 gene (MCI-FAD), and healthy controls. Moreover, we compared the behavioral performance and neural correlates of both patient groups. Participants completed a change-detection VSTM task assessing recognition of changes between shapes or shape-color bindings, presented in two consecutive arrays (i.e., study and test) while event related potentials (ERPs) were recorded. Changes always occurred in the test array and consisted of new features replacing studied features (shape-only) or features swapping across items (shape-color binding). Both MCI and MCI-FAD patients performed worse than controls in the shape-color binding condition. Early electrophysiological activity (100-250 ms) was significantly reduced in both clinical groups, particularly over fronto-central and parieto-occipital regions. However, shape-color binding performance and their reduced neural correlates were similar between MCI and MCI-FAD. Our results support the validity of the VSTM binding test and their neural correlates in the early detection of AD and highlight the importance of studies comparing samples at different risk for AD conversion. The combined analysis of behavioral and ERP data gleaned with the VSTM binding task can offer a valuable memory biomarker for AD. [ABSTRACT FROM AUTHOR]

Studies on perceptual decision-making showed that manipulating the proportion of target and non-target stimuli affects the behavioral performance. Tasks with high frequency of targets are associated to faster response times (RTs) conjunctively to higher number of errors (reflecting a response bias characterized by speed/accuracy trade-off) when compared to conditions with low frequency of targets. Electroencephalographic studies well described modulations of post-stimulus event-related potentials as effect of the stimulus probability; in contrast, in the present study we focused on the pre-stimulus preparatory activities subtending the response bias. Two versions of a Go/No-go task characterized by different proportion of Go stimuli (88% vs. 12%) were adopted. In the task with frequent go trials, we observed a strong enhancement in the motor preparation as indexed by the Bereitschaftspotential (BP, previously associated with activity within the supplementary motor area), faster RTs, and larger commission error rate than in the task with rare go trials. Contemporarily with the BP, a right lateralized prefrontal negativity (lateral pN, previously associated with activity within the dorsolateral prefrontal cortex) was larger in the task with rare go trial. In the post-stimulus processing stage, we confirmed that the N2 and the P3 components were larger for rare trials, irrespective of the Go/No-go stimulus category. The increase of activities recorded in the preparatory phase related to frequency of targets is consistent with the view proposed in accumulation models of perceptual decision for which target frequency affects the subjective baseline, reducing the distance between the starting-point and the response boundary, which determines the response speed. [ABSTRACT FROM AUTHOR]

In the present paper, a novel approach is introduced for comparing and classifying recorded ERP signals from subjects applying valid (Aristotle's) and paradox (Zeno's) syllogisms. In fact, the authors conceived and realized a corresponding experiment, as well as a new method for processing, fitting and classifying the corresponding captured ERP signals into groups according to their similarity. Subsequently, for each such group, an ideal curve that represents all signals of the group has been evaluated for valid and paradox reasoning separately. These “ideal representatives” manifest essential statistical differences per subject for a considerable number of electrodes (5 electrodes with 99% level of confidence, 14 electrodes with 95% level of confidence, 17 electrodes with 90% level of confidence). These results support the assumption that the obtained ideal representatives may indeed reflect essential differences in the underlying brain functions which generated the obtained ERPs. Equivalently, one may claim that the performed experiment and the associated results manifest statistically essential differences between the mental functions during valid and paradox reasoning. [ABSTRACT FROM AUTHOR]

Emotional perception has been extensively studied in literature, but only few studies have investigated the brain activity preceding exposure to emotional stimuli, especially when they are triggered by the subject himself. Here, we sought to investigate the emotional expectancy by means of movement related cortical potentials (MRCPs) in a self-paced task, in which the subjects begin the affective experience by pressing a key. In this experiment, participants had to alternatively press two keys in order to concomitantly display positive, negative, neutral and scramble images extracted from the International Affective Pictures System (IAPS). Each key press corresponded to a specific emotional category and the experimenter communicated the coupling before each trial, so that the subjects always knew the valence of the forthcoming picture. The main results of the present study consist in a bilateral positive activity in prefrontal areas during expectancy of more arousing pictures (positive and negative), and an early and sustained positivity over occipital areas, especially during negative expectancy. In addition, we observed more pronounced and anteriorly distributed Late Positive Potentials (LPPs) components in the emotional conditions. In conclusion, these results show that the emotional expectancy can influence brain activity in both motor preparation and stimuli perception, suggesting enhanced pre-processing in the to be stimulated areas. We propose that before a predictable emotional stimuli both appetitive and defensive motivational systems act facilitating the forthcoming processing of survival-relevant contents, by means of an enhancement of attention towards more arousing pictures.

Although much is known about the underlying neural systems that support recollection, exactly how recollection operates remains unclear. One possibility is that recollection reflects the operation of a continuous retrieval process, whereby test cues always elicit some information from memory. Alternatively, recollection may reflect the operation of a thresholded process that allows for retrieval failure, whereby test cues sometimes elicit no information from memory at all. Here we demonstrate that recollection is thresholded by measuring a commonly reported electrophysiological correlate of episodic retrieval – known as the Left Parietal old/new effect. We use a novel source task designed to directly measure the accuracy of retrieval success, finding that the neural correlate of retrieval was sensitive to the precision of responses when recollection succeeded, but was absent when recollection failed. The results clarify the nature of the neural mechanism underlying episodic memory, providing novel evidence in support of some-or-none threshold models of recollection. [ABSTRACT FROM AUTHOR]

Background: Educational psychology research has linked fluid intelligence with learning and memory abilities and neuroimaging studies have specifically associated fluid intelligence with event related potentials (ERPs). The objective of this study is to find the relationship of ERPs with learning and memory recall and predict the memory recall score using P300 (P3) component.Method: A sample of thirty-four healthy subjects between twenty and thirty years of age was selected to perform three tasks: (1) Raven's Advanced Progressive Matrices (RAPM) test to assess fluid intelligence; (2) learning and memory task to assess learning ability and memory recall; and (3) the visual oddball task to assess brain-evoked potentials. These subjects were divided into High Ability (HA) and Low Ability (LA) groups based on their RAPM scores. A multiple regression analysis was used to predict the learning & memory recall and fluid intelligence using P3 amplitude and latency.Results: Behavioral results demonstrated that the HA group learned and recalled 10.89 % more information than did the LA group. ERP results clearly showed that the P3 amplitude of the HA group was relatively larger than that observed in the LA group for both the central and parietal regions of the cerebrum; particularly during the 300-400 ms time window. In addition, a shorter latency for the P3 component was observed at Pz site for the HA group compared to the LA group. These findings agree with previous educational psychology and neuroimaging studies which reported an association between ERPs and fluid intelligence as well as learning performance.Conclusion: These results also suggest that the P3 component is associated with individual differences in learning and memory recall and further indicate that P3 amplitude might be used as a supporting factor in standard psychometric tests to assess an individual's learning & memory recall ability; particularly in educational institutions to aid in the predictability of academic skills. [ABSTRACT FROM AUTHOR]

Electroencephalography (EEG) has identified human brain potentials elicited by Artificial Grammar (AG) learning paradigms, which present participants with rule-based sequences of stimuli. Nonhuman animals are sensitive to certain AGs; therefore, evaluating which EEG Event Related Potentials (ERPs) are associated with AG learning in nonhuman animals could identify evolutionarily conserved processes. We recorded EEG potentials during an auditory AG learning experiment in two Rhesus macaques. The animals were first exposed to sequences of nonsense words generated by the AG. Then surface-based ERPs were recorded in response to sequences that were ‘consistent’ with the AG and ‘violation’ sequences containing illegal transitions. The AG violations strongly modulated an early component, potentially homologous to the Mismatch Negativity (mMMN), a P200 and a late frontal positivity (P500). The macaque P500 is similar in polarity and time of occurrence to a late EEG positivity reported in human AG learning studies but might differ in functional role. [ABSTRACT FROM AUTHOR]

The event-related potential (ERP) literature described two error-related brain activities: the error-related negativity (Ne/ERN) and the error positivity (Pe), peaking immediately after the erroneous response. ERP studies on error processing adopted a response-locked approach, thus, the question about the activities preceding the error is still open. In the present study, we tested the hypothesis that the activities preceding the false alarms (FA) are different from those occurring in the correct (responded or inhibited) trials. To this aim, we studied a sample of 36 Go/No-go performers, adopting a stimulus-locked segmentation also including the pre-motor brain activities. Present results showed that neither pre-stimulus nor perceptual activities explain why we commit FA. In contrast, we observed condition-related differences in two pre-response components: the fronto-central N2 and the prefrontal positivity (pP), respectively peaking at 250 ms and 310 ms after the stimulus onset. The N2 amplitude of FA was identical to that recorded in No-go trials, and larger than Hits. Because the new findings challenge the previous interpretations on the N2, a new perspective is discussed. On the other hand, the pP in the FA trials was larger than No-go and smaller than Go, suggesting an erroneous processing at the stimulus-response mapping level: because this stage triggers the response execution, we concluded that the neural processes underlying the pP were mainly responsible for the subsequent error commission. Finally, sLORETA source analyses of the post-error potentials extended previous findings indicating, for the first time in the ERP literature, the right anterior insula as Pe generator. [ABSTRACT FROM AUTHOR]

The present study was aimed at identifying potential behavioral and neural correlates of Emotional Intelligence (EI) by using scalp-recorded Event-Related Potentials (ERPs). EI levels were defined according to both self-report questionnaire and a performance-based ability test. We identified ERP correlates of emotional processing by using a visual-emotional oddball paradigm, in which subjects were confronted with one frequent standard stimulus (a neutral face) and two deviant stimuli (a happy and an angry face). The effects of these faces were then compared across groups with low and high EI levels. The ERP results indicate that participants with high EI exhibited significantly greater mean amplitudes of the P1, P2, N2, and P3 ERP components in response to emotional and neutral faces, at frontal, posterior-parietal and occipital scalp locations. P1, P2 and N2 are considered indexes of attention-related processes and have been associated with early attention to emotional stimuli. The later P3 component has been thought to reflect more elaborative, top–down, emotional information processing including emotional evaluation and memory encoding and formation. These results may suggest greater recruitment of resources to process all emotional and non-emotional faces at early and late processing stages among individuals with higher EI. The present study underscores the usefulness of ERP methodology as a sensitive measure for the study of emotional stimuli processing in the research field of EI. [ABSTRACT FROM AUTHOR]

Psychophysiological investigations of traumatic brain injury (TBI) are being conducted for several reasons, including the objective of learning more about the underlying physiological mechanisms of the pathological processes that can be initiated by a head injury. Additional goals include the development of objective physiologically based measures that can be used to monitor the response to treatment and to identify minimally symptomatic individuals who are at risk of delayed onset neuropsychiatric disorders following injury. Research programs studying TBI search for relationships between psychophysiological measures, particularly ERP component properties (e.g. timing, amplitude, scalp distribution), and a participant’s clinical condition. Moreover, the complex relationships between brain injury and psychiatric disorders are receiving increased research attention, and ERP technologies are making contributions to this effort. This review has two objectives supporting such research efforts. The first is to review evidence indicating that traumatic brain injury is a significant risk factor for post-injury neuropsychiatric disorders. The second objective is to introduce ERP researchers who are not familiar with neuropsychiatric assessment to the instruments that are available for characterizing traumatic brain injury, post-concussion syndrome, and psychiatric disorders. Specific recommendations within this very large literature are made. We have proceeded on the assumption that, as is typically the case in an ERP laboratory, the investigators are not clinically qualified and that they will not have access to participant medical records.

The study investigates the neurocognitive stages involved in the speed-accuracy trade-off (SAT). Contrary to previous approach, we did not manipulate speed and accuracy instructions: participants were required to be fast and accurate in a go/no-go task, and we selected post-hoc the groups based on the subjects' spontaneous behavioral tendency. Based on the reaction times, we selected the fast and slow groups (Speed-groups), and based on the percentage of false alarms, we selected the accurate and inaccurate groups (Accuracy-groups). The two Speed-groups were accuracy-matched, and the two Accuracy-groups were speed-matched. High density electroencephalographic (EEG) and stimulus-locked analyses allowed us to observe group differences both before and after the stimulus onset. Long before the stimulus appearance, the two Speed-groups showed different amplitude of the Bereitschaftspotential (BP), reflecting the activity of the supplementary motor area (SMA); by contrast, the two Accuracy-groups showed different amplitude of the prefrontal negativity (pN), reflecting the activity of the right prefrontal cortex (rPFC). In addition, the post-stimulus event-related potential (ERP) components showed differences between groups: the P1 component was larger in accurate than inaccurate group; the N1 and N2 components were larger in the fast than slow group; the P3 component started earlier and was larger in the fast than slow group. The go minus no-go subtractive wave enhancing go-related processing revealed a differential prefrontal positivity (dpP) that peaked at about 330 ms; the latency and the amplitude of this peak were associated with the speed of the decision process and the efficiency of the stimulus-response mapping, respectively. Overall, data are consistent with the view that speed and accuracy are processed by two interacting but separate neurocognitive systems, with different features in both the anticipation and the response execution phases. [ABSTRACT FROM AUTHOR]

Abstract: Event-related potential studies of grammatical gender agreement often report a left anterior negativity (LAN) when agreement violations occur. Some studies have shown that during sentence comprehension gender violations can also interact with semantic processing to modulate a negativity associated with processing meaning — the N400. Given that the LAN and N400 overlap in time, they are identified by their scalp distributions and purported functional roles. Critically, grammatical gender violations also elicit a right posterior positivity that can overlap temporally and potentially affect the scalp distribution of the LAN/N400. We measured the effect of grammatical gender violations in the LAN/N400 window and late positive component (LPC) during comprehension of Spanish sentences. A post-nominal adjective could either make sense or not, and either agree or disagree in gender with the preceding noun. We observed a negativity to gender agreement violations in the LAN/N400 window (300–500ms post stimulus onset) that was smaller than the semantic-congruity N400, but overlapped with it in time and distribution. The early portion of the LPC to gender violations was modulated by sentence constraint, occurring as early as 450ms in highly constraining sentences. A subadditive interaction occurred at the later portion of the LPC with equivalent effects for single and double violations (gender and semantics), reflecting a general stage of reprocessing. Overall, our data support models of language comprehension whereby both semantic and morphosyntactic information can affect processing at similar time points. [Copyright &y& Elsevier]

Emotional perception has been extensively studied, but only a few studies have investigated the brain activity preceding exposure to emotional stimuli, especially when they are triggered by the subject himself. Here, we sought to investigate the emotional expectancy by means of movement related cortical potentials (MRCPs) in a self-paced task, in which the subjects begin the affective experience by pressing a key. In this experiment, participants had to alternatively press two keys to concomitantly display positive, negative, neutral, and scrambled images extracted from the International Affective Pictures System (IAPS). Each key press corresponded to a specific emotional category, and the experimenter communicated the coupling before each trial so that the subjects always knew the valence of the forthcoming picture. The main results of the present study included a bilateral positive activity in prefrontal areas during expectancy of more arousing pictures (positive and negative) and an early and sustained positivity over occipital areas, especially during negative expectancy. In addition, we observed more pronounced and anteriorly distributed Late Positive Potential (LPPs) components in the emotional conditions. In conclusion, these results show that emotional expectancy can influence brain activity in both motor preparation and stimulus perception, suggesting enhanced pre-processing in the to-be-stimulated areas. We propose that before a predictable emotional stimulus, both appetitive and defensive motivational systems act to facilitate the forthcoming processing of survival-relevant contents by means of an enhancement of attention toward more arousing pictures. [ABSTRACT FROM AUTHOR]

Highlights: [•] Cue processing is influenced by knowledge of when a stimulus was first encoded. [•] Consistent recent/remote test blocks produce different ERPs than a mixed block. [•] Mixed block ERPs are more positive and recollection is impaired. [•] Retrieval orientation indices negatively correlates with remember discrimination. [ABSTRACT FROM AUTHOR]

Abstract: The present study investigates the human brains′ sensitivity to the valence strength of emotionally positive and negative chinese words. Event-Related Potentials were recorded, in two different experimental sessions, for Highly Positive (HP), Mildly Positive (MP) and neutral (NP) words and for Highly Negative (HN), Mildly Negative (MN) and neutral (NN) words, while subjects were required to count the number of words, irrespective of word meanings. The results showed a significant emotion effect in brain potentials for both HP and MP words, and the emotion effect occurred faster for HP words than MP words: HP words elicited more negative deflections than NP words in N2 (250–350ms) and P3 (350–500ms) amplitudes, while MP words elicited a significant emotion effect in P3, but not in N2, amplitudes. By contrast, HN words elicited larger amplitudes than NN words in N2 but not in P3 amplitudes, whereas MN words produced no significant emotion effect across N2 and P3 components. Moreover, the size of emotion-neutral differences in P3 amplitudes was significantly larger for MP compared to MN words. Thus, the human brain is reactive to both highly and mildly positive words, and this reactivity increased with the positive valence strength of the words. Conversely, the brain is less reactive to the valence of negative relative to positive words. These results suggest that human brains are equipped with increased sensitivity to the valence strength of positive compared to negative words, a type of emotional stimuli that are well known for reduced arousal. [Copyright &y& Elsevier]

Abstract: Research using event related potentials (ERPs) to explore recognition memory has linked late parietal old/new effects to the recollection of episodic information. In the vast majority of these studies, the retrieval phase immediately follows encoding and consequently, very little is known about the ERP correlates of long term recollection. This is despite the fact that in other areas of the memory literature there is considerable interest in consolidation theories and the way episodic memory changes over time. The present study explored the idea that consolidation and forgetting processes operating over a moderate retention interval can alter the ERP markers of recollection memory. A remember/know test probed memory for stimuli studied either 15 minutes (recent memory) or 1 week (remote memory) prior to the test phase. Results revealed an attenuated late parietal effect for remote compared to recent remember responses, a finding that remained significant even when these recognition judgments were matched for reaction time. Experiments 2a and 2b identified characteristic differences between recent and remote recognition at the behavioural level. The 1 week delay produced an overall decline in recognition confidence and a dramatic loss of episodic detail. These behavioural changes are thought to underlie the ERP effects reported in the first experiment. The results highlight that although the neural basis of memory may exhibit significant changes as the length of the retention interval increases, it is important to consider the extent to which this is a direct effect of time or an indirect effect due to changes in memory quality, such as the amount of detail that can be recollected. [Copyright &y& Elsevier]

Abstract: A previous dual-task study (Capizzi, Sanabria, & Correa, 2012) showed that temporal orienting of attention was disrupted by performing a concurrent working memory task, while sequential effects were preserved. Here, we recorded event related potentials (ERPs) during single- and dual-task performance to investigate how this behavioural dissociation would be expressed in neural activity measures. The single-task condition required participants to respond to a visual target stimulus that could be anticipated on the basis of a highly predictive temporal cue. The dual-task condition introduced a concurrent working memory task, in which colour information had to be updated on every trial. The behavioural results replicated our previous findings of impaired temporal orienting, but preserved sequential effects, under dual-task relative to single-task conditions. The ERPs results showed that temporal orienting and sequential effects both modulated the cue-locked preparatory contingent negative variation (CNV) and the target-locked N2 amplitude and P3 latency under single-task, but not under dual-task conditions. In contrast to temporal orienting, sequential effects were also observed at the early target-locked P1 and N1 potentials. Crucially, only the P1 modulation survived dual-task interference. These findings provide novel electrophysiological evidence that performance of a concurrent working memory task may interfere in a selective way with neural activity specifically linked to temporal orienting of attention. [Copyright &y& Elsevier]

Abstract: Objective: This study aimed to investigate sex differences in the temporal dynamics of experiencing empathy by using electrophysiological measurements. Methods: Twenty-five females and 27 males viewed 414 pictures of the International affective picture system varying in emotional valence (positive, negative and neutral) and presence of humans (human and scenes). EEG event related potentials (ERPs) were obtained and correlations were computed with self-reported empathy. Results: Compared to males, females showed increased anterior N2 and parietal LPP amplitudes to humans contrasted with scenes (independent of emotional valence) and to negative contrasted with neutral emotions (independent of human presence). Independent of sex the N1 and anterior N2 were specifically increased for positive human emotions and the parietal LPP for negative human emotions. Across sexes, the N2 and LPP human emotion effects and LPP human effects were associated with self-reported affective empathy, but not with cognitive empathy. Conclusions: This study provides electrophysiological evidence that women prioritize the processing of socially relevant and negative emotional information, but that women did not show enhanced brain potentials to pictures with positive or negative emotions in humans. [Copyright &y& Elsevier]

Abstract: Classifying brain activities is a challenging task since Electroencephalography (EEG) recordings exhibit distinct and individualized spatial and temporal characteristics correlated with noise and various physical and mental activities. To increase classification accuracy, it is thus crucial to identify discriminant spatio-temporal features. This paper presents a method for analyzing the spatio-temporal characteristics associated with Event related Potentials (ERPs). First, a resampling procedure based on Global Field Power (GFP) extracts temporal features. Second, a spatially weighted SVM (sw-SVM) is used to learn a spatial filter optimizing the classification performance for each temporal feature. Third, the so-obtained ensemble of sw-SVM classifiers are combined using a weighted combination of all sw-SVM outputs. Results indicate that the inclusion of temporal features provides useful insight regarding classification performance and physiological understanding. [Copyright &y& Elsevier]

Abstract: Objective: To develop a high performance machine learning (ML) approach for predicting the age and consequently the state of brain development of infants, based on their event related potentials (ERPs) in response to an auditory stimulus. Methods: The ERP responses of twenty-nine 6-month-olds, nineteen 12-month-olds and 10 adults to an auditory stimulus were derived from electroencephalogram (EEG) recordings. The most relevant wavelet coefficients corresponding to the first- and second-order moment sequences of the ERP signals were then identified using a feature selection scheme that made no a priori assumptions about the features of interest. These features are then fed into a classifier for determination of age group. Results: We verified that ERP data could yield features that discriminate the age group of individual subjects with high reliability. A low dimensional representation of the selected feature vectors show significant clustering behavior corresponding to the subject age group. The performance of the proposed age group prediction scheme was evaluated using the leave-one-out cross validation method and found to exceed 90% accuracy. Conclusions: This study indicates that ERP responses to an acoustic stimulus can be used to predict the age and consequently the state of brain development of infants. Significance: This study is of fundamental scientific significance in demonstrating that a machine classification algorithm with no a priori assumptions can classify ERP responses according to age and with further work, potentially provide useful clues in the understanding of the development of the human brain. A potential clinical use for the proposed methodology is the identification of developmental delay: an abnormal condition may be suspected if the age estimated by the proposed technique is significantly less than the chronological age of the subject. [Copyright &y& Elsevier]

Abstract: Objective: This paper examined neurophysiological correlates of speech in children with language impairment (LI) and typical language development (TLD) across four experiments using different speech stimuli and tasks. Methods: The T-complex event-related potential (ERP) components and other ERP components (e.g., mismatch negativity [MMN]; N400) were examined. A subset of the children participated in more than one of the experiments. Results: 73% of the children with LI had poor T-complex measures compared to only 13% of children with TLD. The T-complex measures were more comparable, in terms of indicating typical versus deviant processing, to neurophysiological measures of language processing, such as lexical discrimination, than to other measures of auditory and speech processing, such as the MMN. Only one LI child showed no poor measures and 64% showed three or more poor neurophyisological measures. However, 50% of children with TLD showed no poor neurophysiological measures, and 82% of the TLD children showed no more than two poor measures. Conclusions: These results suggest that poor auditory processing, as measured by the T-complex, is a marker for LI and that multiple deficits serve to mark LI. Significance: The T-complex measures, indexing secondary auditory cortex, reflect an important aspect of processing in speech and language development. [Copyright &y& Elsevier]

Abstract: Event related potentials (ERPs) were employed to investigate whether and when brain activity related to face recognition varies according to the processing level undertaken at encoding. Recognition was assessed when preceded by a “shallow” (orientation judgement) or by a “deep” study task (occupation judgement). Moreover, we included a further manipulation by presenting at encoding faces either in the upright or inverted orientation. As expected, deeply encoded faces were recognized more accurately and more quickly with respect to shallowly encoded faces. The ERP showed three main findings: i) as witnessed by more positive-going potentials for deeply encoded faces, at early and later processing stage, face recognition was influenced by the processing strategy adopted during encoding; ii) structural encoding, indexed by the N170, turned out to be “cognitively penetrable” showing repetition priming effects for deeply encoded faces; iii) face inversion, by disrupting configural processing during encoding, influenced memory related processes for deeply encoded faces and impaired the recognition of faces shallowly processed. The present study adds weight to the concept that the depth of processing during memory encoding affects retrieval. We found that successful retrieval following deep encoding involved both familiarity- and recollection-related processes showing from 500ms a fronto-parietal distribution, whereas shallow encoding affected only earlier processing stages reflecting perceptual priming. [Copyright &y& Elsevier]

Abstract: Using single-trial parameters as a regressor in the General Linear Model (GLM) is becoming an increasingly popular method for informing fMRI analysis. However, the parameter used to characterise or to differentiate brain regions involved in the response to a particular task varies across studies (e.g. ERP amplitude, ERP latency, reaction time). Furthermore, the way in which the single-trial information is used in the fMRI analysis is also important. For example, the single-trial parameters can be used as regressors in the GLM or to modify the duration of the events modelled in the GLM. The aim of this study was to investigate the BOLD response to a target detection task when including P3 amplitude, P3 latency and reaction time parameters in the GLM. Simultaneous EEG-fMRI was recorded from fifteen subjects in response to a visual choice reaction time task. Including P3 amplitude as a regressor in the GLM yielded activation in left central opercular cortex, left postcentral gyrus, left insula, left middle frontal gyrus, left insula and left parietal operculum. Using P3 latency and reaction time as an additional regressor yielded no additional activation in comparison with the conventional fMRI analysis. However, when P3 latency or reaction time was used to determine the duration of events at a single-trial level, additional activation was observed in the left postcentral gyrus, left precentral gyrus, anterior cingulate cortex and supramarginal gyrus. Our findings suggest that ERP amplitudes and latencies can yield different activation patterns when used to modify relevant aspects of the GLM. [Copyright &y& Elsevier]

Abstract: In a recent fMRI study with identical word stimuli we demonstrated task-dependent lateralization of brain activity during visual processing, with left-hemispheric activations for letter decisions and right-hemispheric activations for visuospatial decisions (Stephan, K.E., Marshall, J.C., Friston, K.J., Rowe, J.B., Ritzl, A., Zilles, K., Fink, G.R., 2003. Lateralized Cognitive Processes and Lateralized Task Control in the Human Brain. Science 301, 384–386). In order to explore the temporal dynamics of these lateralized processes we here recorded multichannel event-related potentials (ERPs) using the same stimuli. ERP data were analysed with current source density reconstruction (CDR). Contrasting the ERP results elicited by the two tasks, source deconvolution showed enhanced activity during letter decisions in Broca''s area from 200–250 ms during letter decisions and during visuospatial decisions in the right posterior parietal cortex (PPC) from 175–200 ms and 250–275 ms. Prior to these activations ERP data revealed an initiation of activity within the anterior cingulate cortex (ACC) from 125–150 ms followed by a late activation of this region from 400–425 ms. Consistent with our previous fMRI study the current electrophysiological data support the notion that lateralized cognitive processes may depend on task requirements rather than stimulus properties. The current results extend our previous findings as they allow insights into the temporal dynamics of these lateralized processes and their relations to task control processes. The temporal deconvolution of ERPs suggests an early differential involvement of Broca''s area in letter-processing and of PPC during visuospatial processing. In addition, activation of ACC prior and after this differential activation is consistent with previous findings suggesting that this area may be involved in cognitive control. [Copyright &y& Elsevier]

Abstract: Aims: Abnormal emotion processing in schizophrenia affects social and functional outcome. Spatiotemporal brain mechanisms underlying this deficit are unclear. Materials and methods: Event-related potential (ERP) responses to emotional and neutral face processing during an implicit (gender detection) and an explicit (expression detection) task were compared between a group of healthy volunteers (n = 10) and a group of patients with schizophrenia (n =10). Results: Whereas patients had normal primary visual cortex responses, the early modulation of occipital, temporal, and frontal responses by emotional expression observed in controls was absent in patients. The occipito-temporal N170 amplitude was reduced in patients relative to controls during expression detection, but not during gender detection. Frontal activity within 180–250ms was reduced in patients compared to controls. As opposed to controls, no significant difference was seen in patients at the right temporal electrode (T6) between amplitudes of long-latency ERPs elicited by distinct emotions during the expression detection task. Conclusion: In patients with schizophrenia, abnormal early extraction of expression-related information in the occipito-temporal cortex (before 170ms) impairs structural encoding of facial expressions (N170) and may disrupt motivation- and task-dependent context processing (180–250ms time window) of expression-related facial features. Moreover, top–down neuromodulation from frontal and limbic structures to visual occipito-temporal cortex may not be sufficient to optimize the extraction of expression-specific face features. [Copyright &y& Elsevier]

Abstract: Cognitive impairment in multiple sclerosis (MS) has received considerable interest over the last decades. Heterogeneous patterns of cognitive dysfunction have been reported in literature in relation to the subtype of the disease and the severity of specific cognitive domains affected. Event related potentials (ERPs), especially P300, have been employed to evaluate the cognitive decline in MS and neurophysiological findings agree with data obtained by neuropsychological testing. The objectivity, the reliability and the easy administration are the main features of ERP technique but more specific attention and memory tasks are needed to enhance the clinical value of the methodology. Moreover, ERP recording has the advantage of being feasible even in severe disabled patients. Finally, longitudinal ERP studies are required to investigate the natural course of cognitive dysfunction in MS, to estimate the prognostic value of subclinical defects in different clinical form of the disease and to evaluate clinical benefits of therapeutic and rehabilitative interventions. [Copyright &y& Elsevier]

The objective of this research was to measure the effects of energising drinks containing caffeine and glucose, upon mental activity during sustained selective attention. Non-invasive electrophysiological brain recordings were made during a behavioural study of selective attention in which participants received either energising or placebo drinks. We tested specifically whether energising drinks have significant effects upon behavioural measures of performance during a task requiring sustained visual selective attention, as well as on accompanying components of the event-related potential (ERPs) related to information processing in the brain. Forty healthy volunteers were blindly assigned to receive either the energising drink or a similar-tasting placebo drink. The behavioural task involved identifying predefined target stimulus among rapidly presented streams of peripheral visual stimuli, and making speeded motor responses to this stimulus. During task performance, accuracy, reaction times and ongoing brain activity were stored for analysis. The energising drink enhanced behavioural performance both in terms of accuracy and speed of reactions. The energising drink also had significant effects upon the event-related potentials. Effects started from the enhancement of the earliest components (C1/P1), reflecting early visual cortical processing in the energising-drink group relative to the placebo group over the contralateral scalp. The later N1, N2 and P3 components related to decision-making and responses were also modulated by the energising drink. Energising drinks containing caffeine and glucose can enhance behavioural performance during demanding tasks requiring selective attention. The behavioural benefits are coupled to direct effects upon neural information processing. [ABSTRACT FROM AUTHOR]

Background. The aim of this study was to show, whether a certain prophylacting applicable radiation affects the cognition, particularly, the specific cognitive components P50, N100, P300 and N400 of auditory event related potentials (ERPs) during a short memory test. Methods and materials. Eleven patients with small cell lung cancer (SCLC), who had presented complete response of disease after chemotherapy and radical radiotherapy in the lung, were prescribed to receive a prophylacting cranial irradiation (PCI) with a 6 MeV linear accelerator. The dose schedule was consisting of a total dose up to 30 Gy in 10 fractions, within 12 days (5 days a week). The psychophysiological approach before and after PCI was assessed by measurements of the auditory ERPs during a short memory performance using the digit-span Wechsler test. Components of ERP were recorded from 15 scalp electrodes. Additionally, symptomatology of depression and anxiety were assessed using Zung Self-Rating Depression Scale and Spielberger Anxiety Inventory, respectively, for pre- and post-PCI. Results. No significant difference was noticed pre- and post-radiotherapy of all particular level of psychophysiological analysis concerning both the latencies and the amplitudes of ERPs auditory components P50, N100, P300 and N400 ( P > 0.05, Wilcoxon signed test). Additionally, no changes were found with regard to behavioral performance (memory recall), depression symptomatology and state anxiety, according to pre- and post-radiation measurements. However, the self-reported depression symptomatology showed that the patients presented moderate depression. Conclusion. No short-term psychophysiological neurotoxicity was detected with this PCI schedule using these instruments, lending additional support to evidence suggesting the benefit of this certain PCI schedule for patients with SCLC. [ABSTRACT FROM AUTHOR]

Subjects were shown the terms of simple sentences in sequence (e.g., "A sparrow / is not / a vehicle") and manually indicated whether the sentence was true or false. When the sentence form was affirmative (i.e., "X is a Y"), false sentences produced scalp potentials that were significantly more negative than those for true sentences, in the region of about 250 to 450 msec following presentation of the sentence object. In contrast, when the sentence form was negative (i.e., "X is not a Y"), it was the true statements that were associated with the ERP negativity. Since both the false-affirmative and the true-negative sentences consist of "mismatched" subject and object terms (e.g., sparrow / vehicle), it was concluded that the negativity in the potentials reflected a semantic mismatch between terms at a preliminary stage of sentence comprehension, rather than the falseness of the sentence taken as a whole. Similarities between the present effects of semantic mismatches and the N400 associated with incongruous sentences (Kutas & Hillyard, 1980) are discussed. The pattern of response latencies and of ERPs taken together supported a model of sentence comprehension in which negatives are dealt with only after the proposition to be negated is understood. [ABSTRACT FROM AUTHOR]