Event Related Potentials

Unilateral Cerebral Palsy (CP) is a neurodevelopmental disorder that is a very common cause of disability in childhood. It is characterized by unilateral motor impairments that are frequently dominated in the upper limb. In addition to a reduced movement capacity of the affected upper limb, several children with unilateral CP show a reduced awareness of the remaining movement capacity of that limb. This phenomenon of disregarding the preserved capacity of the affected upper limb is regularly referred to as Developmental Disregard (DD). Different theories have been postulated to explain DD, each suggesting slightly different guidelines for therapy. Still, cognitive processes that might additionally contribute to DD in children with unilateral CP have never been directly studied. The current protocol was developed to study cognitive aspects involved in upper limb control in children with unilateral CP with and without DD. This was done by recording event-related potentials (ERPs) extracted from the ongoing EEG during target-response tasks asking for a hand-movement response. ERPs consist of several components, each of them associated with a well-defined cognitive process (e.g., the N1 with early attention processes, the N2 with cognitive control and the P3 with cognitive load and mental effort). Due to its excellent temporal resolution, the ERP technique enables to study several covert cognitive processes preceding overt motor responses and thus allows insight into the cognitive processes that might contribute to the phenomenon of DD. Using this protocol adds a new level of explanation to existing behavioral studies and opens new avenues to the broader implementation of research on cognitive aspects of developmental movement restrictions in children.

Whether contextual regularities facilitate perceptual stages of scene processing is widely debated, and empirical evidence is still inconclusive. Specifically, it was recently suggested that contextual violations affect early processing of a scene only when the incongruent object and the scene are presented a-synchronously, creating expectations. We compared event-related potentials (ERPs) evoked by scenes that depicted a person performing an action using either a congruent or an incongruent object (e.g., a man shaving with a razor or with a fork) when scene and object were presented simultaneously. We also explored the role of attention in contextual processing by using a pre-cue to direct subjects' attention towards or away from the congruent/incongruent object. Subjects' task was to determine how many hands the person in the picture used in order to perform the action. We replicated our previous findings of frontocentral negativity for incongruent scenes that started $ 210 ms post stimulus presentation, even earlier than previously found. Surprisingly, this incongruency ERP effect was negatively correlated with the reaction times cost on incongruent scenes. The results did not allow us to draw conclusions about the role of attention in detecting the regularity, due to a weak attention manipulation. By replicating the 200-300 ms incongruity effect with a new group of subjects at even earlier latencies than previously reported, the results strengthen the evidence for contextual processing during this time window even when simultaneous presentation of the scene and object prevent the formation of prior expectations. We discuss possible methodological limitations that may account for previous failures to find this an effect, and conclude that contextual information affects object model selection processes prior to full object identification, with semantic knowledge activation stages unfolding only later on.

Contextual regularities help us analyze visual scenes and form judgments on their constituents. The present study investigates the effect of context violation on scene processing using event-related potentials (ERPs). We compared ERPs evoked by congruent vs. incongruent visual scenes (e.g., a man playing a violin vs. a man "playing" a broomstick), when the scene and object are presented simultaneously, so subjects cannot form previous expectations about the object's identity. As expected, an ongoing anterior negativity emerged around 270 ms post-stimulus presentation, lasting for about 330 ms. This negativity, resembling the N300/N400 effect previously associated with semantic integration, was followed by a later and broadly distributed negativity between 650 and 850 ms, possibly related to late processes of semantic evaluation and response preparation. The results confirm that contextual congruity affects scene processing starting from ∼300 ms or earlier, and that this early electrophysiological congruity effect indeed reflects context violation processing, rather than indexing a mismatch between expected vs. actual events, or between prepared vs. correct responses. They also suggest that contextual information may affect object model selection processes, and influence later stages of semantic knowledge activation and/or decision-making.

This study builds on a specific characteristic of letters of the Roman alphabet-namely, that each letter name is associated with two visual formats, corresponding to their uppercase and lowercase versions. Participants had to read aloud the names of single letters, and event-related potentials (ERPs) for six pairs of visually dissimilar upper-and lowercase letters were recorded. Assuming that the end product of processing is the same for upper-and lowercase letters sharing the same vocal response, ERPs were compared backward, starting from the onset of articulatory responses, and the first significant divergence was observed 120 ms before response onset. Given that naming responses were produced at around 414 ms, on average, these results suggest that letter processing is influenced by visual information until 294 ms after stimulus onset. This therefore provides new empirical evidence regarding the time course and interactive nature of visual letter perception processes.

Event‐related brain potentials (ERPs) are important research tools because they provide insights into mental processing at high temporal resolution. Their usefulness, however, is limited by the need to average over a large number of trials, sacrificing information about the trial‐by‐trial variability of latencies or amplitudes of specific ERP components. Here we propose a novel method based on an iteration strategy of the residues of averaged ERPs (RIDE) to separate latency‐variable component clusters. The separated component clusters can then serve as templates to estimate latencies in single trials with high precision. By applying RIDE to data from a face‐priming experiment, we separate priming effects and show that they are robust against latency shifts and within‐condition variability. RIDE is useful for a variety of data sets that show different degrees of variability and temporal overlap between ERP components.

We report the results of a study comparing the temporal dynamics of thematic and taxonomic knowledge activation in a picture-word priming paradigm using event-related potentials. Although we found no behavioral differences between thematic and taxonomic processing, ERP data revealed distinct patterns of N400 and P600 amplitude modulation for thematic and taxonomic priming. Thematically related target stimuli elicited less negativity than taxonomic targets between 280-460 ms after stimulus onset, suggesting easier semantic processing of thematic than taxonomic relationships. Moreover, P600 mean amplitude was significantly increased for taxonomic targets between 520-600 ms, consistent with a greater need for stimulus reevaluation in that condition. These results offer novel evidence in favor of a dissociation between thematic and taxonomic thinking in the early phases of conceptual evaluation.

There is something about the sound of a pseudoword like takete that goes better with a spiky, than a curvy shape (Köhler, 1929(Köhler, :1947). Yet despite decades of research into sound symbolism, the role of this effect on real words in the lexicons of natural languages remains controversial. We report one behavioural and one ERP study investigating whether sound symbolism is active during normal language processing for real words in a speaker's native language, in the same way as for novel word forms. The results indicate that sound-symbolic congruence has a number of influences on natural language processing: Written forms presented in a congruent visual context generate more errors during lexical access, as well as a chain of differences in the ERP. These effects have a very early onset (40-80 ms, 100-160 ms, 280-320 ms) and are later overshadowed by familiar types of semantic processing, indicating that sound symbolism represents an early sensory-co-activation effect.

During language acquisition in the first year of life, children become sensitive to phonotactic probabilities such as the likelihood of speech sound occurrences in the ambient language. Because this sensitivity is acquired at an early age, the extent to which the neural system that underlies speech processing in adults is tuned to these phonological regularities can reflect difficulties in processing languagespecific phonological regularities that can persist into adulthood. Here, we examined the neural processing of phonotactic probabilities in 18 adults with dyslexia and 18 non-dyslexic controls using mismatch negativity, a pre-attentive neurophysiological response. Stimuli that differed in phonotactic probability elicited similar mismatch negativity responses among the adults with dyslexia, whereas the controls responded more strongly to stimuli with a high phonotactic probability than to stimuli with a low phonotactic probability, suggesting that controls -but not adults with dyslexia -are sensitive to the phonological regularities of the ambient language. These findings suggest that the underlying neural system in adults with dyslexia is not properly tuned to language-specific phonological regularities, which may partially account for the phonological deficits that are often reported in dyslexic individuals.

Auditory hallucinations (AH), the perception of sounds and voices in the absence of external stimuli, remain a serious problem for a large subgroup of patients with schizophrenia. Functional imaging of brain activity associated with AH is dif®cult, since the target event is involuntary and its timing cannot be predicted. Prior efforts to image the patterns of cortical activity during AH have yielded con¯icting results. In this study, MEG was used to directly image the brain electrophysiological events associated with AH in schizophre-nia. We observed an increase in theta rhythm, as sporadic bursts, in the left superior temporal area during the AH states, whereas there was steady theta band activity in the resting state. The present ®nding suggests strong association of the left superior temporal cortex with the experience of AH in this patient. This is consistent with the hypothesis that AH arises from areas of auditory cortex subserving receptive language processing.

Children raised in a bilingual environment are faced with the daunting task of learning to extract meaning from language input that can differ between caregivers but, depending on the social context, also within caregivers. Here, we investigated monolingual and bilingual toddlers' brain responses to an unexpected language change. We presented 2-3 year old children with picture-word pairs and occasionally changed the language of the spoken word while recording event-related potentials (ERPs). In line with previous results obtained in adults, bilingual children differentiated between the languages of input faster than their monolingual peers, i.e., within 200 ms of spoken word onset, a time range previously associated with lexical access. However, while adult bilinguals displayed a late stimulus re-evaluation ERP response to a language change, no such modulation was found in bilingual toddlers. These results suggest that although bilingual individuals are sensitive to phonemic language cues already from an early age, language awareness and language monitoring mechanisms probably develop later in life.

How do the two languages of bilingual individuals interact in everyday communication? Numerous behavioral-and event-related brain potential studies have suggested that information from the non-target language is spontaneously accessed when bilinguals read, listen, or speak in a given language. While this finding is consistent with predictions of current models of bilingual processing, most paradigms used so far have mixed the two languages by using language ambiguous stimuli (e.g., cognates or interlingual homographs) or explicitly engaging the two languages because of experimental task requirements (e.g., word translation or language selection). These paradigms will have yielded different language processing contexts, the effect of which has seldom been taken into consideration. We propose that future studies should test the effect of language context on cross-language interactions in a systematic way, by controlling and manipulating the extent to which the experiment implicitly or explicitly prompts activation of the two languages.

A number of studies have shown that from an early age, bilinguals outperform their monolingual peers on executive control tasks. We previously found that bilingual children and adults also display greater attention to unexpected language switches within speech. Here, we investigated the effect of a bilingual upbringing on speech perception in one language. We recorded monolingual and bilingual toddlers' event-related potentials (ERPs) to spoken words preceded by pictures. Words matching the picture prime elicited an early frontal positivity in bilingual participants only, whereas later ERP amplitudes associated with semantic processing did not differ between groups. These results add to the growing body of evidence that bilingualism increases overall attention during speech perception whilst semantic integration is unaffected.

To elucidate serotonin modulation of selective attention, 13 volunteers (21 -30 years) were studied in two sessions, 5 h after either acute tryptophan depletion (ATD) that decreases brain serotonin synthesis, or control-mixture ingestion (randomized, double-blind, cross-over design). Simultaneous electroencephalogram and magnetoencephalogram were measured during dichotic listening of two concurrent trains of standard and deviant tones. Subjects counted the deviants presented to one ear and ignored those presented to the other ear. ATD lowered plasma total tryptophan by 75% and free tryptophan by 39%. ATD suppressed the amplitude enhancement of P50 and N1 to selectively attended tones, but did not affect the later aspects of processing negativity. The P50 latencies were increased after ATD, irrespective of attention. In conclusion, serotonin may regulate attentional modulation of early cortical stimulus processing.

Age-related decline in cognitive capacities has been attributed to a generalized slowing of processing speed and a reduction in working memory (WM) capacity. Nevertheless, it is unclear how age affects visuospatial WM recognition and its underlying brain electrical activity. Whether age modulates the effects of memory load or information maintenance duration, which determine the limits of WM, remains also elusive. In this exploratory study, performance in a delayed match to sample task declined with age, particularly in conditions with high memory load. Event related potentials analysis revealed longer N2 and P300 latencies in old than in young adults during WM recognition, which may reflect slowing of stimulus evaluation and classification processes, respectively. Although there were no differences between groups in N2 or P300 amplitudes, the latter was more homogeneously distributed in old than in young adults, which may indicate an age-related increased reliance in frontal vs par...

Working memory (WM) involves three cognitive events: information encoding, maintenance, and retrieval; these are supported by brain activity in a network of frontal, parietal and temporal regions. Manipulation of WM load and duration of the maintenance period can modulate this activity. Although such modulations have been widely studied using the event-related potentials (ERP) technique, a precise description of the time course of brain activity during encoding and retrieval is still required. Here, we used this technique and principal component analysis to assess the time course of brain activity during encoding and retrieval in a delayed match to sample task. We also investigated the effects of memory load and duration of the maintenance period on ERP activity. Brain activity was similar during information encoding and retrieval and comprised six temporal factors, which closely matched the latency and scalp distribution of some ERP components: P1, N1, P2, N2, P300, and a slow wave. Changes in memory load modulated task performance and yielded variations in frontal lobe activation. Moreover, the P300 amplitude was smaller in the high than in the low load condition during encoding and retrieval. Conversely, the slow wave amplitude was higher in the high than in the low load condition during encoding, and the same was true for the N2 amplitude during retrieval. Thus, during encoding, memory load appears to modulate the processing resources for context updating and post-categorization processes, and during retrieval it modulates resources for stimulus classification and context updating. Besides, despite the lack of differences in task performance related to duration of the maintenance period, larger N2 amplitude and stronger activation of the left temporal lobe after long than after short maintenance periods were found during information retrieval. Thus, results regarding the duration of maintenance period were complex, and future work is required to test the time-based decay theory predictions.

The inferential system anticipates the external environment by building up internal representations of its regularities. To that purpose, two sources of information are especially important and attract attentional resources: expected and unexpected events, which are useful for checking the accuracy of internal representations. In the present study, we investigated the behavioural properties and the neural mechanisms underlying the strategic allocation of attention triggered by those events. To that end, event-related potentials (ERPs) were recorded during the performance of two tasks requiring detection of predictable and unpredictable response events embedded in a visuospatial or numeric sequence. The behavioural results in the two tasks mirror each other, suggesting the recruitment of similar attentional allocation processes between the two domains. The ERPs showed partially similar effects. In both tasks, a P3a-like component signalled the capture of attention by events clashing ...

Twelve subjects performed a tracking task and a memory search task simultaneously on a computer screen. The dual task continued for approximately 10 min and was repeated three times, interrupted by a short break for subjective ratings: the NASA Task Load Index (NASA-TLX) and the Check List of Mental Condition. Event related potentials (ERP) evoked by the presentation of memory task stimuli were also recorded. All the subjects participated in three experimental sessions, which varied in difficulty of tracking task. Results demonstrated that the NASA-TLX and ERP were sensitive only to the change in task difficulty and were not affected by time-on-task or interaction between task difficulty and time-on-task.

Dyslexics are diagnosed for their poor reading skills, yet they characteristically also suffer from poor verbal memory and often from poor auditory skills. To date, this combined profile has been accounted for in broad cognitive terms. Here we hypothesize that the perceptual deficits associated with dyslexia can be understood computationally as a deficit in integrating prior information with noisy observations. To test this hypothesis we analyzed the performance of human participants in an auditory discrimination task using a two-parameter computational model. One parameter captures the internal noise in representing the current event, and the other captures the impact of recently acquired prior information. Our findings show that dyslexics' perceptual deficit can be accounted for by inadequate adjustment of these components; namely, low weighting of their implicit memory of past trials relative to their internal noise. Underweighting the stimulus statistics decreased dyslexics&...

Ryan, thank you for being an excellent mentor and a great friend. The software architecture of this work was only possible because of your guidance, thanks. Eyup, it was your initial work and help during the Bio-Robotics Class that inspired this work, thanks. Dan, our discussions about the human-behavior were very helpful while designing the user interface of the proposed Brain Computer Interface, thanks. For the rest not mentioned I thank you all.

Ryan, thank you for being an excellent mentor and a great friend. The software architecture of this work was only possible because of your guidance, thanks. Eyup, it was your initial work and help during the Bio-Robotics Class that inspired this work, thanks. Dan, our discussions about the human-behavior were very helpful while designing the user interface of the proposed Brain Computer Interface, thanks. For the rest not mentioned I thank you all.

While cannabis is associated with positive syndrome schizophrenia (SZ), it is unclear whether cannabinoids are also related to negative symptoms such as affective blunting. We examined whether cannabis use is associated with schizotypy and utilized eventrelated potentials (ERPs) to assess affect processing. Cannabis users demonstrated increased P300 amplitudes for unpleasant trait words, and demonstrated higher positive syndrome schizotypy which correlated with levels of cannabis use. The cannabis group also exhibited lower negative syndrome schizotypy. The lack of blunted responses during the affect ERP and decreased negative subscale schizotypy scores provide evidence that the endocannabinoid theory of schizophrenia may be primarily relevant in relation to positive syndrome SZ.

We reanalyzed, modeled and simulated Event-Related Potential (ERP) data from 13 healthy children (Mean age = 5.12, Standard Deviation = 0.75) during a computerized visual sustained target detection task. Extending an ERP-based ACT–R (Adaptive Control of Thought–Rational) neurocognitive modeling approach, we tested whether visual sustained selective-set attention in preschool children involves the enhancement of neural response to targets, and it shows key adult-like features (neurofunctional homology). Blinded automatic peaks analysis was conducted on vincentized binned grand ERP averages. Time-course and distribution of scalp activity were detailed through topographic mapping and paths analysis. Reaction times and accuracy were also measured. Adult Magnetic Resonance Imaging-based mapping using ACT–R dipole source modeling and electric-field spiking simulation provided very good fit with the actual ERP data (R2 > 0.70). In most electrodes, between 50 and 400 ms, ERPs concurrent ...

It has been suggested that poor habituation to stimuli might explain atypical sensory behaviours in autism, i.e. over-responsiveness to some stimuli and undersensitivity to other. We investigated habituation to repeated sounds using an oddball paradigm in 9 month-old infants with an older sibling with autism and hence at high risk for developing autism. Auditory evoked responses to repeated sounds in control infants (at low risk of developing autism) decreased over time, demonstrating habituation, and their responses to deviant sounds were larger than responses to standard sounds, indicating discrimination. In contrast, neural responses in infants at high risk showed no habituation, and reduced sensitivity to changes in frequency. Reduced sensory habituation may be present at a younger age than the emergence of autistic behaviour in some individuals, and we propose that this could play a role in the sensory atypicalities observed in autism.

This study examined the maturation of cortical auditory eventrelated potentials (ERPs) from birth until 12 months of age. In the 15 infants studied, all ERP peaks observable at 12 months of age, the P150, N250, P350, and N450 were identi¢able already at birth. As in previous studies, the amplitudes of the ERP peaks increased and latencies shortened with increasing age. In addition, the time courses of the amplitude growth of these peaks di¡ered from each other. It was concluded, that the generators of all the infantile ERP peaks are functional already at birth, and that the maturational changes in the waveform morphology can mostly be accounted for by the changing relative strengths of the di¡erent generators. NeuroReport13:47^51

The onset of pitch within an ongoing noise signal evokes a particular brain activity, the pitch onset response (POR). Using wholehead MEG, PORs to iterated rippled noise (IRN) and Huggins pitch (HP), representing prototypical pitch-in-noise signals, were measured in twenty subjects during a pitch identi¢cation task (333 Hz, 400 Hz, randomized). HP and IRN yielded similar responses, lateralized to the left hemisphere and peaking about 180 ms after pitch onset. The initial phase (140 ms) showed stronger activations to 400 than to 333 Hz whereas later stages (200^300 ms) showed target vs nontarget e¡ects.These results suggest, ¢rst, that di¡erent pitches converge into a common cortical representation and, second, that the POR encompasses various successive processing stages. NeuroReport 16:193^196

Artificial neural networks (ANNs) are showing increasing promise as decision support tools in medicine and particularly in neuroscience and neuroimaging. Recently, there has been increasing work on using neural networks to classify individuals with concussion using electroencephalography (EEG) data. However, to date the need for research grade equipment has limited the applications to clinical environments. We recently developed a deep learning long short-term memory (LSTM) based recurrent neural network to classify concussion using raw, resting state data using 64 EEG channels and achieved high accuracy in classifying concussion. Here, we report on our efforts to develop a clinically practical system using a minimal subset of EEG sensors. EEG data from 23 athletes who had suffered a sport-related concussion and 35 non-concussed, control athletes were used for this study. We tested and ranked each of the original 64 channels based on its contribution toward the concussion classification performed by the original LSTM network. The top scoring channels were used to train and test a network with the same architecture as the previously trained network. We found that with only six of the top scoring channels the classifier identified concussions with an accuracy of 94%. These results show that it is possible to classify concussion using raw, resting state data from a small number of EEG sensors, constituting a first step toward developing portable, easy to use EEG systems that can be used in a clinical setting.

ObjectiveThis international multicenter, prospective, observational study aimed at identifying predictors of short-term clinical outcome in patients with prolonged disorders of consciousness (DoC) due to acquired severe brain injury.MethodsPatients in vegetative state/unresponsive wakefulness syndrome (VS/UWS) or in minimally conscious state (MCS) were enrolled within 3 months from their brain injury in 12 specialized medical institutions. Demographic, anamnestic, clinical, and neurophysiologic data were collected at study entry. Patients were then followed up for assessing the primary outcome, that is, clinical diagnosis according to standardized criteria at 6 months postinjury.ResultsWe enrolled 147 patients (44 women; mean age 49.4 [95% confidence interval 46.1–52.6] years; VS/UWS 71, MCS 76; traumatic 55, vascular 56, anoxic 36; mean time postinjury 59.6 [55.4–63.6] days). The 6-month follow-up was complete for 143 patients (VS/UWS 70; MCS 73). With respect to study entry, the c...

The capacity to deceive others is a complex mental skill that requires the ability to suppress truthful information. The polygraph is widely used in countries such as the USA to detect deception. However, little is known about the effects of emotional processes (such as the fear of being found guilty despite being innocent) on the physiological responses that are used to detect lies. The aim of this study was to investigate the time course and neural correlates of untruthful behavior by analyzing electrocortical indexes in response to visually presented neutral and affective questions. Affective questions included sexual, shameful or disgusting topics. A total of 296 questions that were inherently true or false were presented to 25 subjects while ERPs were recorded from 128 scalp sites. Subjects were asked to lie on half of the questions and to answer truthfully on the remaining half. Behavioral and ERP responses indicated an increased need for executive control functions, namely working memory, inhibition and task switching processes, during deceptive responses. Deceptive responses also elicited a more negative N400 over the prefrontal areas and a smaller late positivity (LP 550-750 ms) over the prefrontal and frontal areas. However, a reduction in LP amplitude was also elicited by truthful affective responses. The failure to observe a difference in LP responses across conditions likely results from emotional interference. A swLORETA inverse solution was computed on the N400 amplitude (300-400 ms) for the dishonest -honest contrast. These results showed the activation of the superior, medial, middle and inferior frontal gyri (BA9, 11, 47) and the anterior cingulate cortex during deceptive responses. Our results conclude that the N400 amplitude is a reliable neural marker of deception.

Accumulating evidence suggests that thalamic nuclei relay corollary discharge information of saccadic eye movements, enabling the visual system to update the representation of visual space. The present study aimed to explore the effect of thalamic lesions in humans on updating-related cortical processing. Event-related potentials were recorded while four patients with impairments in using corollary discharge information and 12 healthy control subjects performed a saccadic double-step task. In the experimental condition, which required the use of corollary discharge information, control subjects showed a pronounced positivity over the parietal cortex starting about 150 ms after first saccade onset, reflecting the updating process. In the patients, parietal processing related to updating was altered. Three patients showed evidence of reduced updating event-related potential effects, consistent with a unilateral deficit in using corollary discharge information. In two patients, the event-related potential topography differed significantly from the topography pattern observed in controls. Thalamic damage affects updating-related processing, presumably due to insufficient transfer of saccade-related information to parietal areas. This study thus provides further evidence for thalamic involvement in relaying corollary discharge information related to saccadic eye movements. Our data suggest that integration of corollary discharge and motor information occurs directly before the second saccade in a double-step task.

Many investigators found that iron deficiency anemia (IDA) had a great influence on cognitive functions in infants and children. However, studies of such topic in adults are few and controversial. We prospectively assessed the possible influence of IDA and iron supplementation (for 3 months) on cognitive function and intelligence of 28 young adults with IDA. We used group of hematological, cognitive, neurophysiological tests for assessment including: minimental state examination (MMSE), Wechsler memory scale-revised (WMS-R), Wechsler adult intelligence scale-revised (WAIS-R), event-related potentials (ERPs), and electroencephalography (EEG). Compared to controls, patients demonstrated lower scores of different cognitive tests (MMSE, WMS-R, and WAIS-R), which showed significant improvement after treatment. Prolongation of ERPs latencies (N200 and P300) and reduction in their amplitudes (P200 and P300) were identified with significant increase in amplitude occurred after treatment. EEG abnormalities were observed in 55% of patients which showed improvement in 35% after treatment. Positive correlation was identified before and after treatment between hemoglobin levels and MMSE (P = 0.01, 0.05), total verbal (P = 0.04) and performance (P = 0.05, 0.04) IQ scores. Negative correlation was identified between before and after treatment between P300 latency and total IQ of WAIS-R (P = 0.03, 0.008) and hemoglobin level (P = 0.4, 0.01). Positive correlation was found before and after treatment between P300 amplitude and total IQ (P = 0.028, 0.01) and serum iron (P = 0.01, 0.001). In conclusion, IDA is a significant factor in cognitive performance in adult population, which can be partially reversed by treatment.

The urge people get to squeeze or bite cute things, albeit without desire to cause harm, is known as "cute aggression." Using electrophysiology (ERP), we measured components related to emotional salience and reward processing. Participants aged 18-40 years (n = 54) saw four sets of images: cute babies, less cute babies, cute (baby) animals, and less cute (adult) animals. On measures of cute aggression, feeling overwhelmed by positive emotions, approachability, appraisal of cuteness, and feelings of caretaking, participants rated more cute animals significantly higher than less cute animals. There were significant correlations between participants' self-report of behaviors related to cute aggression and ratings of cute aggression in the current study. N200: A significant effect of "cuteness" was observed for animals such that a larger N200 was elicited after more versus less cute animals. A significant correlation between N200 amplitude and the tendency to express positive emotions in a dimorphous manner (e.g., crying when happy) was observed. RewP: For animals and babies separately, we subtracted the less cute condition from the more cute condition. A significant correlation was observed between RewP amplitude to cute animals and ratings of cute aggression toward cute animals. RewP amplitude was used in mediation models. Mediation Models: Using PROCESS (Hayes, 2018), mediation models were run. For both animals and babies, the relationship between appraisal and cute aggression was significantly mediated by feeling overwhelmed. For cute animals, the relationship between N200 amplitude and cute aggression was significantly mediated by feeling overwhelmed. For cute animals, there was significant serial mediation for RewP amplitude through caretaking, to feeling overwhelmed, to cute aggression, and RewP amplitude through appraisal, to feeling overwhelmed, to cute aggression. Our results indicate that feelings of cute aggression relate to feeling overwhelmed and feelings of caretaking. In terms of neural mechanisms, cute aggression is related to both reward processing and emotional salience.

The P3(OO)event-related potential (ERP) was elicited in 80 normal, right-handed male subjects using a simple visual discrimination task, with electroencephalographic (EEG) activity recorded at 19 electrodes. P3 amplitude was larger over the right than over the left hemisphere electrode sites primarily at anteromediallocations (F3/4, C3/4) for target, novel, and standard stimuli. The NI, P2, and N2 components also demonstrated hemispheric asymmetries. The strongest P3 hemispheric asymmetries for all stimuli were observed at anterior locations, suggesting a frontal right hemisphere localization for initial stimulus processing, although target stimuli produced larger P3 amplitudes at parietal locations than did novel stimuli. The relationships of hemispheric asymmetries to anatomical variables, background EEG activity, and neurocognitive factors are discussed.

The brain activity associated with processing numerical end values has received limited research attention. The present study explored the neural correlates associated with processing semantic end values under conditions of automatic number processing. Event-related potentials (ERPs) were recorded while participants performed the numerical Stroop task, in which they were asked to compare the physical size of pairs of numbers, while ignoring their numerical values. The smallest end value in the set, which is a task irrelevant factor, was manipulated between participant groups. We focused on the processing of the lower end values of 0 and 1 because these numbers were found to be automatically tagged as the "smallest." Behavioral results showed that the size congruity effect was modulated by the presence of the smallest end value in the pair. ERP data revealed a spatially extended centro-parieto-occipital P3 that was enhanced for congruent versus incongruent trials. Important...

THE neural mechanism supporting performance during single and feature conjunction detection was investigated using event-related brain potentials. In different blocks of trials, participants responded to visual targets de®ned by one of two colors, one of two orientations, or both color and orientation. Participants were faster and more accurate in detecting targets de®ned by a single feature than for targets de®ned by a conjunction of features. Compared with the single feature conditions, conjunction targets were associated with enhanced negativity between 230 and 270 ms poststimulus and showed a delayed P3 latency. The relative timing of feature speci®c attention effects isolated in difference potential shows that feature conjunction occurs concurrently with the analysis of single features.

Since its modern inception, psychiatry has relied on diagnostic tools that are restricted to the evaluation of behavioral and clinical phenotypes. Diagnoses are based on description of symptoms, mental status examinations, and on clinical behavioral observations in line with diagnostic categories listed in the Diagnostic and Statistical Manual of Mental Disorders 4th Edition (DSM-IV) (1) or the International Statistical Classification of Diseases and Related Health Problems 10th Revision (ICD-10) (2). While these tools have enabled important and necessary decisions in relation to diagnosis, the inherently heterogeneous symptom presentation of most, if not all, psychiatric disorders has led to somewhat arbitrary cut-offs for disorder and subtype classifications. Recent major advances in understanding of the genetic, neurobiological, and developmental underpinnings of psychopathology have indicated further heterogeneity in the etiology and pathophysiology of disorders that are clinically described as homogeneous constructs. Against this background of complexity, there is an intensive search for specific and sensitive biological markers, or biomarkers, which might be used in place of the highly variable and subjective clinical parameters currently used in clinical diagnosis, and as phenotypes for etiological and pathophysiological investigations.

Deficits in amplitudes of auditory event-related potentials (ERP) indexing preattentive, automatic (mismatch negativity, MMN) and controlled, attention-dependent (N2, P3) auditory information processing have been well described in chronic schizophrenia. Normal MMN, but deficient N2 and P3 have been reported in first-episode patients. No study has investigated these ERPs concurrently in first-episode patients; thus, reported differences in MMN, N2 and P3 generation may reflect differences in patient samples rather than genuine differences in abnormal generation of these ERPs. We recorded MMN, N2 and P3 in 26 first-episode patients, 25 recent-onset patients within 1.5 to 5 years after first admission, 25 chronic patients and 39 healthy controls. Recent-onset and chronic, but not first-episode patients showed reduced MMN. However, among first-episode patients those with low premorbid educational achievement demonstrated significantly reduced MMN. All patient groups showed pronounced N2 deficits and, to a variable extent, abnormalities in P3 generation. Abnormalities in N2 and P3 generation appear to reflect premorbid neuropathology, whereas MMN deficits may index both ongoing disease processes associated with illness progression as well as premorbid neurocognitive impairment. ERPs may provide tools to assess static and progressive neuropathology in schizophrenia. These findings need confirmation in longitudinal studies.

Background: Mismatch negativity (MMN) is an auditory event-related potential that provides an index of auditory sensory memory. Deficits in MMN generation have been repeatedly demonstrated in chronic schizophrenia. Their specificity to schizophrenia has not been established. Methods: Mismatch negativity to both duration and frequency deviants was investigated in gender-and agematched patients with schizophrenia or schizoaffective disorder (n ϭ 26), bipolar disorder (n ϭ 16), or major depression (n ϭ 22) and healthy control subjects (n ϭ 25). Results: Only patients with schizophrenia demonstrated significantly smaller mean MMN than did healthy control subjects. Detailed analyses showed significantly smaller MMN to both duration and frequency deviants in patients with schizophrenia than in healthy control subjects; however, the reduction of frequency MMN in patients with schizophrenia was not significant in the comparison across all groups. Mismatch negativity topography did not differ among groups. No consistent correlations with clinical, psychopathologic, or treatment variables were observed. Conclusions: Mismatch negativity deficits, and by extension deficits in early cortical auditory information processing, appear to be specific to schizophrenia. Animal and human studies implicate dysfunctional N-methyl-Daspartate receptor functioning in MMN deficits. Thus MMN deficits may become a useful endophenotype to investigate the genetic underpinnings of schizophrenia, particularly with regard to the N-methyl-D-aspartate receptor.

Background: Schizophrenia is associated with cognitive deficits that are an intrinsic component of the disorder. Clozapine is an atypical antipsychotic that is superior to typical agents in the treatment of positive symptoms. The degree to which clozapine ameliorates cognitive deficits, however, is still controversial. Mismatch negativity (MMN), N200 (N2), and P300 (P3) are cognitive eventrelated potentials (ERPs) that index preattentive (MMN) and attention-dependent information processing (N2, P3) and provide a measure of cognitive deficits associated with schizophrenia. In schizophrenic patients deficient generation of MMN, N2, and P3 has been observed, suggesting impairments of discrete stages of information processing. Methods: This study investigates the effects of clozapine treatment on MMN, N2, and P3 generation. Patients were recruited from a haloperidol-controlled, double-blind treatment study of clozapine in chronic schizophrenia. ERPs were obtained at the beginning of the study and after 9 weeks (4 patients) and 16 weeks (13 patients) of treatment. Results: Clozapine treatment was associated with a significant increase of P3 amplitude, which was not observed in the haloperidol group; however, clozapine treatment did not affect deficits in MMN and N2. Conclusions: These findings suggest that clozapine-in contrast to conventional antipsychotics-improves electrophysiological measures of attention-dependent information processing, but does not ameliorate preattentive deficits.

Accurate classification of electroencephalography (EEG) data is much needed for early identification of diseases to treat various disorders. In this paper, we propose EEG classification technique based on statistical denoising and modified k-nearest neighbor (k-NN) algorithm with bipolar sigmoid rectified linear units (ReLU) function. The EEG data is subjected to statistical methods to remove the artifacts and then applied to modified k-NN algorithm to categorize the appropriate features giving preference to neighbors closer to one another considering the weighted votes of the k-nearest neighbors before selecting the class label based on the highest weighted vote. A customized activation function that combines these two functions called as hybrid function that uses various portions of each function in particular ranges is used in our work i.e., use of bipolar sigmoid for negative values and the ReLU function for positive values which helps to limit the signal in a particular range. The proposed algorithm's detection accuracy is tested for the confusion matrix of true positive (TP), false positive (FP), false negative (FN)and true negative (TN) and compared to the detection accuracy of other existing algorithms, demonstrating the algorithm's efficiency with a classification accuracy of almost 85 percent and sensitivity of 91% for standard Kaggle dataset.

Background: One of the main challenges for clinicians is to ensure that alcohol withdrawal treatment is the most effective possible after discharge. To address this issue, we designed a pilot study to investigate the efficacy of the rehabilitation treatment on the main stages of information processing, using an electroencephalographic method. This topic is of main importance as relapse rates after alcohol withdrawal treatment remain very high, indicating that established treatment methods are not fully effective in all patients in the long run.Method: We examined in alcohol-dependent patients (ADP) the effects of the benzodiazepine-based standard detoxification program on event-related potential components at incoming (D0) and completion (D15) of the treatment, using tasks of increasing difficulty (with and without workload) during an auditory oddball target paradigm. Untreated non-alcohol-dependent-volunteers were used as matching controls.Results: At D0, ADP displayed significantl...

Objective: This dissertation explored the neurophysiological correlates of lifetime externalizing (EXT) spectrum disorders in two studies using a community-based sample of 29-year-old adult men assessed longitudinally. The first study used high-density EEG brain data to test the hypothesis that reductions in time-domain and time-frequency component measures previously identified in 17-year-old youth with EXT continue to be present in adults at age 29 when participants have largely passed through the age of heaviest substance misuse, and when brain development is further complete. The second study tested the notion that reductions on these brain measures could serve as endophenotypes (or inherited biomarkers) for EXT risk by investigating the developmental stability of these associations across a 12-year span. We further uniquely tested whether significant reduction in time-domain P3 amplitude could be used to predict the eventual diagnosis of an externalizing disorder over a decade later. Method: In both studies, EEG data were obtained using a visual oddball task. Participants were assessed from age-17 through age-29 for the lifetime presence of EXT disorders. The first study used data from 378 male twin participants from the original 17-year-old cohort of the Minnesota Twin Family Study (MTFS) who had high-density EEG data that allowed for regional scalp analyses, including data from the frontal region that was not available before. The second study included the same 29-year-old males who had EEG data collected from a midline parietal site (site-Pz) at both their age-17 and age-29 assessments (n = 325). All comparisons were made against controls free of any EXT diagnosis by age 29. Results: The hypothesis tested in the first study was supported with

The McGurk effect demonstrates the existence of a fusion process in audiovisual speech perception (McGurk & MacDonald, 1976). Recent experiments question the automaticity of this process (Alsius et al., 2005; Tiippana et al., 2004). We consider here the assumption that fusion is controlled by a conditional binding process, which can block fusion in the case of strong audiovisual inconsistencies. To test this hypothesis, we designed two experiments in which a consistent or inconsistent audiovisual context is placed before McGurk stimuli, and we show that inconsistent contexts can remove the McGurk effect..

Visual event-related potentials (ERPs) were examined in 16 children (aged 5-14 y) with phenylketonuria (PKU) and 16 age-and sex-matched controls. Lifetime median measures of phenylalanine (Phe) were 230-460 mmol/l. The most recent Phe levels were 56-624 mmol/l. ERPs were recorded whilst the children performed a discrimination task. All stimuli were square wave gratings degree, which appeared for 33 ms. A response to an infrequent grating that differed in orientation or spatial frequency was required. The older children with PKU had a delay in the first peak (P1) of the ERP, and age-related changes in the amplitude of P1. There was attenuation of the second peak across age groups in PKU. There was no evidence of reduced response accuracy or longer reaction times in children with PKU. Latencies of the cognitive P3 were not delayed in PKU. The delayed early peaks are consistent with previous studies that have shown delayed visual evoked potentials in PKU. The lack of differences in reaction time and P3 may be due to relatively good Phe control in children with PKU, or to the simplicity of the task. Suggestions are made for future ERP studies of PKU. & Event-related potentials, phenylalanine, phenylketonuria, reaction time, P3, visual evoked potentials

of consciousness EEG evoked potentials event-related potentials vegetative state minimally conscious state coma h i g h l i g h t s We provide an overview of EEG-based techniques in the prognostic and diagnostic assessment of DoC. We highlight bridging principles between conventional and investigational approaches. We share expert opinions and considerations on the technical and conceptual caveats.

Human listeners are extraordinarily sensitive to a transient break in interaural correlation (called binaural gap). In this study, a binaural gap embedded in interaurally correlated noise markers elicited marked scalp event-related potentials (ERPs). ERPs to the binaural gap in narrowband noise with the center frequency of 1600 Hz were signi¢cantly weaker than those for narrowband noise with the center frequency of 400 or 800 Hz. Introducing the interaural time di¡erence (ITD) of 4 ms weakened the ERPs for either 400 -Hz or 800 -Hz noise. Introducing the ITD of 2 ms, however, only weakened the ERPs for 800 -Hz but not 400 -Hz noise. Thus central representations of a transient break in interaural correlation for narrowband noises are a¡ected by both frequency and ITD.