Event-related Potential Recordings Research Articles

Insights from simultaneous EEG-fMRI and patient data illuminate the role of the anterior medial temporal lobe in N400 generation

The N400, a negative event-related potential (ERP) peaking approximately 400 ms after stimulus onset, is known to reflect the processing of semantic information. While scalp recordings have contributed to understanding the psychological processes underlying the N400, they have been limited in identifying its neural basis. However, recent intracranial ERP recordings and fMRI studies have shed light on the crucial role of the anterior medial temporal lobe (AMTL) in semantic information processing. These findings suggest that the N400 partially represents activity in the AMTL structures. To investigate the neural underpinnings of the N400 effect, we simultaneously recorded ERPs and event-related fMRI during a semantic priming paradigm in a sample of 12 young, healthy subjects. Additionally, we collected ERPs and structural brain data from older healthy adults and patients with amnestic mild cognitive impairment (aMCI), a population characterized by neurodegenerative changes in the AMTL. In our fMRI results, we identified bilateral loci in the AMTL as the global maxima. Employing an EEG-informed fMRI analysis, we explored trial-to-trial fluctuations in semantic processing by linking single-trial N400 amplitudes to the Blood Oxygen Level Dependent (BOLD) signal. This approach provided the first direct evidence linking the N400 recorded at the scalp level to the corresponding BOLD signal in the AMTL. Consistent with these findings, patients with aMCI exhibited a diminished N400 effect compared to healthy older adults. Furthermore, voxel-based morphometry analysis revealed a correlation between the magnitude of the N400 effect and the integrity of the AMTL. By integrating data from simultaneous EEG-fMRI, and patient studies, our research advances our understanding of the neural substrate of the N400 and highlights the critical involvement of the AMTL in semantic processing.

Tonal and syllabic encoding in overt Cantonese Chinese speech production: An ERP study.

This study was conducted to investigate how syllables and lexical tones are processed in Cantonese speech production using the picture-word interference task with concurrent recording of event-related brain potentials (ERPs). Cantonese-speaking participants were asked to name aloud individually presented pictures and ignore an accompanying auditory word distractor. The target and distractor either shared the same word-initial syllable with the same tone (Tonal-Syllable related), the same word-initial syllable without the same tone (Atonal-Syllable related), the same tone only (Tone alone related), or were phonologically unrelated. Participants' naming responses were faster, relative to an unrelated control, when the target and distractor shared the same tonal- or atonal-syllable but null effect was found in the Tone alone related condition. The mean ERP amplitudes (per each 100-ms time window) were subjected to stimulus-locked (i.e., time-locked to stimulus onset) and response-locked (i.e., time-locked to response onset) analyses. Significant differences between related and unrelated ERP waves were similarly observed in both Tonal-Syllable related and Atonal-Syllable related conditions in the time window of 400-500 ms post-stimulus. However, distinct ERP effects were observed in these two phonological conditions within the 500-ms pre-response period. In addition, null effects were found in the Tone alone related condition in both stimulus-locked and response-locked analyses. These results suggest that in Cantonese spoken word production, the atonal syllable of the target is retrieved first and then associated with the target lexical tone, consistent with the view that tone has an important role to play at a late stage of phonological encoding in tonal language production.

The dissociation of semantically congruent and incongruent cross-modal effects on the visual attentional blink.

Recent studies have found that the sound-induced alleviation of visual attentional blink, a well-known phenomenon exemplifying the beneficial influence of multisensory integration on time-based attention, was larger when that sound was semantically congruent relative to incongruent with the second visual target (T2). Although such an audiovisual congruency effect has been attributed mainly to the semantic conflict carried by the incongruent sound restraining that sound from facilitating T2 processing, it is still unclear whether the integrated semantic information carried by the congruent sound benefits T2 processing. To dissociate the congruence-induced benefit and incongruence-induced reduction in the alleviation of visual attentional blink at the behavioral and neural levels, the present study combined behavioral measures and event-related potential (ERP) recordings in a visual attentional blink task wherein the T2-accompanying sound, when delivered, could be semantically neutral in addition to congruent or incongruent with respect to T2. The behavioral data clearly showed that compared to the neutral sound, the congruent sound improved T2 discrimination during the blink to a higher degree while the incongruent sound improved it to a lesser degree. The T2-locked ERP data revealed that the early occipital cross-modal N195 component (192-228 ms after T2 onset) was uniquely larger in the congruent-sound condition than in the neutral-sound and incongruent-sound conditions, whereas the late parietal cross-modal N440 component (400-500 ms) was prominent only in the incongruent-sound condition. These findings provide strong evidence that the modulating effect of audiovisual semantic congruency on the sound-induced alleviation of visual attentional blink contains not only a late incongruence-induced cost but also an early congruence-induced benefit, thereby demonstrating for the first time an unequivocal congruent-sound-induced benefit in alleviating the limitation of time-based visual attention.

Statistical Learning of Chord-Transition Regularities in a Novel Equitempered Scale: An MMN Study

In music and language domains, it has been suggested that patterned transitions of sounds can be acquired implicitly through statistical learning. Previous studies have investigated the statistical learning of auditory regularities by recording early neural responses to a sequence of tones presented at high or low transition probabilities. However, it remains unclear whether the statistical learning of musical chord transitions is reflected in endogenous, regularity-dependent components of the event-related potential (ERP). The present study aimed to record the mismatch negativity (MMN) elicited by chord transitions that deviated from newly learned transitional regularities. Chords were generated in a novel 18 equal temperament pitch class scale to avoid interference from the existing tonal representations of the 12 equal temperament pitch class system. Thirty-six adults without professional musical training listened to a sequence of randomly inverted chords in which certain chords were presented with high (standard) or low (deviant) transition probabilities. An irrelevant timbre change detection task was assigned to make them attend to the sequence during the ERP recording. After that, a familiarity test was administered in which the participants were asked to choose the more familiar chord sequence out of two successive sequences. The results showed that deviant transitions elicited the MMN, although the participants could not recognize the standard transition beyond the level of chance. These findings suggest that humans can statistically learn new transitional regularities of chords in a novel musical scale, even though they did not recognize them explicitly. This study provides further evidence that music-syntactic regularities can be acquired implicitly through statistical learning.

PRedicting the EVolution of SubjectIvE Cognitive Decline to Alzheimer’s Disease With machine learning: the PREVIEW study protocol

BackgroundAs disease-modifying therapies (DMTs) for Alzheimer's disease (AD) are becoming a reality, there is an urgent need to select cost-effective tools that can accurately identify patients in the earliest stages of the disease. Subjective Cognitive Decline (SCD) is a condition in which individuals complain of cognitive decline with normal performances on neuropsychological evaluation. Many studies demonstrated a higher prevalence of Alzheimer’s pathology in patients diagnosed with SCD as compared to the general population. Consequently, SCD was suggested as an early symptomatic phase of AD. We will describe the study protocol of a prospective cohort study (PREVIEW) that aim to identify features derived from easily accessible, cost-effective and non-invasive assessment to accurately detect SCD patients who will progress to AD dementia.MethodsWe will include patients who self-referred to our memory clinic and are diagnosed with SCD. Participants will undergo: clinical, neurologic and neuropsychological examination, estimation of cognitive reserve and depression, evaluation of personality traits, APOE and BDNF genotyping, electroencephalography and event-related potential recording, lumbar puncture for measurement of Aβ42, t-tau, and p-tau concentration and Aβ42/Aβ40 ratio. Recruited patients will have follow-up neuropsychological examinations every two years. Collected data will be used to train a machine learning algorithm to define the risk of being carriers of AD and progress to dementia in patients with SCD.DiscussionThis is the first study to investigate the application of machine learning to predict AD in patients with SCD. Since all the features we will consider can be derived from non-invasive and easily accessible assessments, our expected results may provide evidence for defining cost-effective and globally scalable tools to estimate the risk of AD and address the needs of patients with memory complaints. In the era of DMTs, this will have crucial implications for the early identification of patients suitable for treatment in the initial stages of AD.Trial registration number (TRN)NCT05569083.

Examining the relationship between aerobic fitness and cognitive control processes: An SFT and ERP study

Previous studies have demonstrated a positive relationship between aerobic fitness and cognitive control, the ability to inhibit distractions (conflict control) or impulsive actions (response inhibition). However, it is unknown whether these sub-processes and their underlying information processing capacity are differentially related to aerobic fitness. To address this question, we employed a go/no-go version of the redundant-target task, which was administered concurrently with the recording of event-related potentials (ERPs) and the use of a reaction-time based diagnostic tool known as system factorial technology (SFT). Our sample consisted of 46 young male adults with varying levels of aerobic fitness: the high-fit group (n = 23; aged 21.33 ± 2.44 years; VO2max 58.83 ± 6.93 ml/kg/min) and the low-fit group (n = 23; aged 22.30 ± 1.40 years; VO2max 41.90 ± 4.01 ml/kg/min). The results showed that the high-fit group exhibited a lower false-alarm rate compared to the low-fit group. However, there was no difference in processing speed between the two groups. The SFT analysis revealed that the high-fit group had more efficient information processing for earlier responses, but not later responses, compared to the low-fit group. Analysis of the ERPs indicated that the high-fit group had larger N2d amplitudes and shorter P3d latencies during conflict control compared to the low-fit group, while there were no such effects for the process of response inhibition. These findings suggest that aerobic fitness may be differentially related to the temporal dynamics and sub-processes of cognitive control.

Category Mistakes Electrified

AbstractOccurrences of sentences that are traditionally considered category mistakes, such as ‘The red number is divisible by three’, tend to elicit a sense of oddness in assessors. In attempting to explain this oddness, existing accounts in the philosophical literature commonly claim that occurrences of such sentences are associated with a defect or phenomenology unique to the class of category mistakes. It might be thought that recent work in experimental psycholinguistics—in particular, the recording of event-related brain potentials (patterns of voltage variation in the brain)—holds the potential to shed new light on this debate. I review the relevant experimental results, before arguing that they present advocates of accounts of category mistakes with a dilemma: either the uniqueness claims should be rejected, or the experimental technique in question cannot be used to test existing accounts of category mistakes in the manner that philosophers might hope.

The predictability and plausibility effects on N400 reflect the language deficit in patients with mild cognitive impairment

AbstractBackgroundReliable markers of language decline in patients with amnesic mild cognitive impairment (aMCI) are critical for the early detection of Alzheimer’s disease. However, language impairments may be subtle and difficult to be detected from behavioral performance measures. N400 is an Event‐Related Potentials (ERP) component to index the semantic processing and has been used to reflect the deficit of language comprehension in aphasic patients (Chang et al., 2016). This study manipulated the predictability and plausibility of the Chinese classifier‐noun agreement to examine whether these two effects on N400 may serve as potential markers for the early detection of aMCI.MethodThis study recruited 16 MCI patients and 17 age‐matched healthy elders from the memory clinic of Cardinal Tian Hospital in Taiwan. All participants received [18F] florbetaben PET and a set of standardized cognitive tests, including Mini‐Mental State Examination (MMSE), verbal fluency, and Wechsler Memory Scale‐III (WMS‐III), for MCI diagnosis. The positivity rate of the aMCI group was 43.75%, and 31.25% for the healthy elder group. During the ERP recording, participants would read a series of classifier‐noun phrases, and each classifier was paired with a highly predictable, a low predictable, or an implausible noun.ResultWe performed the Linear mixed models to examine whether the predictability effect (high vs. low predictable nouns) and plausibility effect (high vs. implausible nouns) on N400 (300‐500ms) would be explained by the particpants’ cognitive performance. The data revealed that participants with higher scores of MMSE (b = ‐0.019, SE = 0.010, t = ‐1.969), verbal fluency (b = ‐0.023, SE = 0.008, t = ‐2.781), and WMS‐III (b = ‐0.002, SE = 0.001, t = ‐2.370) showed more pronounced predictability effects, which reflecting better semantic integration processing. Meanwhile, participants with poor memory engendered a reduced plausibility effect (b = ‐0.004, SE = 0.001, t = ‐3.972).ConclusionOur findings suggest that MCI patients would exhibit a deficit in semantic process. The predictability and plausibility effects on N400 may serve as ERPs markers to detect the language deficits in aMCI.

Brain Lateralization for Language, Vocabulary Development and Handedness at 18 Months

Is hemisphere lateralization for speech processing linked to handedness? To answer this question, we compared hemisphere lateralization for speech processing and handedness in 18-month-old infants, the age at which infants start to produce words and reach a stable pattern of handedness. To assess hemisphere lateralization for speech perception, we coupled event-related potential (ERP) recordings with a syllable-discrimination paradigm and measured response differences to a change in phoneme or voice (different speaker) in the left and right clusters of electrodes. To assess handedness, we gave a 15-item grasping test to infants. We also evaluated infants’ range of vocabulary to assess whether it was associated with direction and degree of handedness and language brain asymmetries. Brain signals in response to a change in phoneme and voice were left- and right-lateralized, respectively, indicating functional brain lateralization for speech processing in infants. Handedness and brain asymmetry for speech processing were not related. In addition, there were no interactions between the range of vocabulary and asymmetry in brain responses, even for a phoneme change. Together, a high degree of right-handedness and greater vocabulary range were associated with an increase in ERP amplitudes in voice condition, irrespective of hemisphere side, suggesting that they influence discrimination during voice processing.

A Comparative Event-Related Potentials Study between Alcohol Use Disorder, Gambling Disorder and Healthy Control Subjects through a Contextual Go/NoGo Task.

(1) Background: Inhibitory and rewarding processes that mediate attentional biases to addiction-related cues may slightly differ between patients suffering from alcohol use (AUD) or gambling (GD) disorder. (2) Methods: 23 AUD inpatients, 19 GD patients, and 22 healthy controls performed four separate Go/NoGo tasks, in, respectively, an alcohol, gambling, food, and neutral long-lasting cueing context during the recording of event-related potentials (ERPs). (3) Results: AUD patients showed a poorer inhibitory performance than controls (slower response latencies, lower N2d, and delayed P3d components). In addition, AUD patients showed a preserved inhibitory performance in the alcohol-related context (but a more disrupted one in the food-related context), while GD patients showed a specific inhibitory deficit in the game-related context, both indexed by N2d amplitude modulations. (4) Conclusions: Despite sharing common addiction-related mechanisms, AUD and GD patients showed different patterns of response to (non-)rewarding cues that should be taken into account in the therapeutic context.

Different impacts of long-term abacus training on symbolic and non-symbolic numerical magnitude processing in children

Abacus-based mental calculation (AMC) has been shown to be effective in promoting math ability in children. Given that AMC relies on a visuospatial strategy to perform rapid and precise arithmetic, previous studies mostly focused on the promotion of AMC training on arithmetic ability and mathematical visual-spatial ability, as well as its transfer of advanced cognitive ability. However, little attention has been given to its impact on basic numerical comparison ability. Here, we aim to examine whether and how long-term AMC training impacts symbolic and non-symbolic numerical comparisons. The distance effect (DE) was utilized as a marker, indicating that the comparison between two numbers becomes faster as their numerical distance enlarges. In the current study, forty-one children matched for age and sex were recruited at primary school entry and randomly assigned to the AMC group and the control group. After three years of training, the event-related potential (ERP) recording technique was used to explore the temporal dynamics of number comparison, of which tasks were given in symbolic (Arabic number) or non-symbolic (dot array) format. In the symbolic task, the children in the AMC group showed a smaller DE than those in the control group. Two ERP components, N1 and P2p, located in parietal areas (PO7, PO8) were selected as neural markers of numerical processing. Both groups showed DE in the P2p component in both tasks, but only the children in the AMC group showed DE in the N1 component in the non-symbolic task. In addition, the DE size calculated from reaction times and ERP amplitudes was correlated with higher cognitive capacities, such as coding ability. Taken together, the present results provide evidence that long-term AMC training may be beneficial for numerical processing in children, which may be associated with neurocognitive indices of parietal brain regions.

Emojis vs. facial expressions: An electrical neuroimaging study on perceptual recognition

ABSTRACT The aim of this study was to investigate the neural underpinnings and the time course of emoji recognition through the recording of event-related potentials in 51 participants engaged in a categorization task involving an emotional word paradigm. Forty-eight happy, sad, surprised, disgusted, fearful, angry emojis, and as many facial expressions, were used as stimuli. Behavioral data showed that emojis were recognized faster and more accurately (92.7%) than facial expressions displaying the same emotions (87.35%). Participants were better at recognizing happy, disgusted, and sad emojis, and happy and angry faces. Fear was difficult to recognize in both faces and emojis. The N400 response was larger to incongruently primed emojis and faces, while the opposite was observed for the P300 component. However, both N400 and P300 were considerably later in response to faces than emojis. The emoji-related N170 component (150–190 ms) discriminated stimulus affective content, similar to face-related N170, but its neural generators did not include the face fusiform area but the occipital face area (OFA) for processing face details, and object-related areas. Both faces and emojis activated the limbic system and the orbitofrontal cortex supporting anthropomorphization. The schematic nature of emojis might determine an easier classification of their emotional content.

Neurobiological effects of exercise intervention for premenstrual syndrome.

Up to 75%-90% of women have varying degrees of premenstrual syndrome (PMS). Exercises are recognized to be beneficial to regulate the negative emotions associated with PMS; however, the effects of exercise on sadness inhibition have not yet been investigated from the neurobiological perspective. This study examined the effects of a single exercise intervention on the neural mechanisms mediating sadness response inhibition at the cortical level using multichannel event-related potential (ERP) recording in women with PMS. Participants performed Go/No-go trials while viewing of sad or neutral images before and after exercise intervention, and changes in the No-go-evoked N200 (N2) ERP component were measured by electroencephalography (EEG) at multiple cortical sites. The associations of PMS Inventory scores with N2 amplitude and latency changes were then examined using Pearson's correlation analysis. There were no significant differences in N2 latency and response error rate following exercise compared to baseline. However, women with higher PMS Inventory scores (greater symptom severity) demonstrated significantly lengthen N2 latency at the Fz electrode sites during correct sad face No-go trials after exercise (p < 0.05), which was not the case in the pre-exercise baseline. We detected no significant relationship between the PMS score and N2 amplitude, either pre- or post-exercise. Women with higher PMS severity exhibited longer sad N2 latencies as well as slow down the speed of reaction to negative stimuli by exercise, suggesting that the prefrontal emotion regulation network is involved in PMS symptoms and is sensitive to the beneficial effects of exercise.

Cognitive mechanisms of the face context effect: An event related potential study of the effects of emotional contexts on neutral face perception

Face context effect refers to the influence of the emotional context on facial expression perception. Numerous empirical studies have explored the mechanisms of the face context effect, but no consistent conclusions have been drawn. Hence, we investigated the cognitive mechanisms of the face context effect using recordings of event-related potentials. In Experiment 1, we adopted the context-target paradigm to explore the mechanisms of the effect of context with different emotional valences on the neutral face perception (emotional valence-based face context effect). In Experiment 2, we explored the mechanisms of the effect of context with different emotional types on the neutral face perception (specific emotion-based face context effect). The results of Experiment 1 indicated that the participants were biased toward contextual valence when recognizing the emotional valence of neutral faces, and that the neutral target faces under emotional contexts with different valences induced significant differences in the P1, N170, and LPP amplitudes. In Experiment 2, the results of Experiment 2 indicated that the participants were biased toward specific contextual emotions when recognizing the emotion type of neutral faces, and that the neutral target faces under contexts of different emotional types induced significant differences in the LPP amplitude, but not in the P1 or N170 amplitude. We concluded that the emotional valence-based face context effect occurred in the early processing stage, whereas the specific emotion-based face context effect occurred in the late processing stage.

Ongoing Sign Processing Facilitates Written Word Recognition in Deaf Native Signing Children.

Signed and written languages are intimately related in proficient signing readers. Here, we tested whether deaf native signing beginning readers are able to make rapid use of ongoing sign language to facilitate recognition of written words. Deaf native signing children (mean 10 years, 7 months) received prime target pairs with sign word onsets as primes and written words as targets. In a control group of hearing children (matched in their reading abilities to the deaf children, mean 8 years, 8 months), spoken word onsets were instead used as primes. Targets (written German words) either were completions of the German signs or of the spoken word onsets. Task of the participants was to decide whether the target word was a possible German word. Sign onsets facilitated processing of written targets in deaf children similarly to spoken word onsets facilitating processing of written targets in hearing children. In both groups, priming elicited similar effects in the simultaneously recorded event related potentials (ERPs), starting as early as 200 ms after the onset of the written target. These results suggest that beginning readers can use ongoing lexical processing in their native language – be it signed or spoken – to facilitate written word recognition. We conclude that intimate interactions between sign and written language might in turn facilitate reading acquisition in deaf beginning readers.

Media Neuroscience on a Shoestring

Abstract: Event-related potentials (ERPs) capture neural responses to media stimuli with a split-second resolution, opening the door to examining how attention modulates the reception process. However, the relatively high cost and difficulty of incorporating ERP methods have prevented broader adoption. This study tested the potential of a new mobile, relatively easy-to-mount, and highly affordable device for electroencephalography (EEG) measurement – the Muse EEG system – combined with a free, open-source platform for ERP recording and analysis. Specifically, we compared ERPs with affective visual stimuli – representative of the kind of engaging content that pervades modern social media. Our results confirm that the Muse system provides robust visual ERPs, highly reliable across two samples. Although there was no difference between ERPs to moderately positive and neutral stimuli in the expected time windows (200–300 ms, 400–600 ms), an exploratory analysis provided some evidence for differential processing of positive versus neutral images at the right temporal sensor site (TP10). Additionally, a compliance-gaining manipulation in participant instructions significantly improved data quality. These results support the use of the Muse EEG system in large-scale studies examining brain responses to screen media. They also suggest an easy social influence tactic that can enhance data quality as communication neuroscience is scaled up. The availability of a mobile EEG system for 250 USD makes it possible to incorporate neuroimaging into various communication paradigms beyond visual communication.

The Influence of Lactobacillus paracasei HII01 Supplementation on Performance in Attention (Go/No-Go) Tasks and Quinolinic Acid and 5-Hydroxyindoleacetic Acid Levels in Thai Children—A Preliminary Study

Cognitive development is defined as the capacity of a child to think, reason, and use language, which are all vital to their overall growth. Attention deficit/hyperactivity disorder (ADHD) is the most common neurodevelopmental disorder. Though several factors are associated with the incidence of ADHD, gut microbiota and gut homeostasis play critical roles in it. Gut dysbiosis and altered gut homeostasis are linked to several physical and psychological complications that affect gut–brain communication (the gut–brain axis). Probiotics, live microorganisms that confer a health benefit to the host when administered in adequate amounts, are considered therapeutic supplements that can be used to manage mental and cognitive disorders. Intervention with probiotics can improve the gut microbial ecosystem and the gut–brain axis, thereby improving cognitive function. We hypothesized that the supplementation of Lactobacillus paracasei HII01 might reduce the risk of the development of neuropsychiatric disorders; thus, we evaluated the efficacy of L. paracasei HII01 on the attention state of healthy children and the changes in representative neuroinflammatory markers. Ten healthy Thai children were supplemented with 109 CFU of L. paracasei HII01 for 12 weeks. Go/no-go tasks were undertaken to assess changes in attention state. Alterations in brain waves were measured by electroencephalographic (EEG)/event-related potential (ERP) recordings. The levels of quinolinic acid (QA, a metabolite of tryptophan) and 5-hydroxyindoleacetic acid (5-HIAA, a metabolite of serotonin) were determined in the urine at baseline and after 12 weeks of probiotic intervention. The levels of QA and 5-HIAA significantly decreased and increased, respectively. The QA/5-HIAA ratio also decreased significantly. Go/No-go tasks revealed that the percentages of go accuracy and go error increased and decreased significantly, respectively. EEG/ERP recordings showed that theta, alpha, and beta waves were substantially altered at the 12th week of study compared to baseline values. The results suggested that L. paracasei HII01 might improve the gut microbiota and oscillate the brain function, which sustained the attention state of the subjects. These preliminary findings require further detailed study to confirm the role of L. paracasei HII01 in the improvement in the attention of healthy children.

Frequency Effects on Spelling Error Recognition: An ERP Study.

Spelling errors are ubiquitous in all writing systems. Most studies exploring spelling errors focused on the phonological plausibility of errors. However, unlike typical pseudohomophones, spelling errors occur in naturally produced written language. We investigated the time course of recognition of the most frequent orthographic errors in Russian (error in an unstressed vowel in the root) and the effect of word frequency on this process. During event-related potentials (ERP) recording, 26 native Russian speakers silently read high-frequency correctly spelled words, low-frequency correctly spelled words, high-frequency words with errors, and low-frequency words with errors. The amplitude of P200 was more positive for correctly spelled words than for misspelled words and did not depend on the frequency of the words. In addition, in the 350–500-ms time window, we found a more negative response for misspelled words than for correctly spelled words in parietal–temporal-occipital regions regardless of word frequency. Considering our results in the context of a dual-route model, we concluded that recognizing misspelled high-frequency and low-frequency words involves common orthographic and phonological processes associated with P200 and N400 components such as whole word orthography processing and activation of phonological representations correspondingly. However, at the 500–700 ms stage (associated with lexical-semantic access in our study), error recognition depends on the word frequency. One possible explanation for these differences could be that at the 500–700 ms stage recognition of high-frequency misspelled and correctly spelled words shifts from phonological to orthographic processes, while low-frequency misspelled words are accompanied by more prolonged phonological activation. We believe these processes may be associated with different ERP components P300 and N400, reflecting a temporal overlap between categorization processes based on orthographic properties for high-frequency words and phonological processes for low-frequency words. Therefore, our results complement existing reading models and demonstrate that the neuronal underpinnings of spelling error recognition during reading may depend on word frequency.

Does transcranial direct current stimulation enhance cognitive performance in Parkinson's disease mild cognitive impairment? An event-related potentials and neuropsychological assessment study.

Parkinson's disease-mild cognitive impairment (PD-MCI) is garnering attention as a key interventional period for cognitive impairment. Currently, there are no approved treatments for PD-MCI and encouraging results of transcranial direct current stimulation (tDCS) combined with other interventions have been proposed, though the efficacy and neural mechanisms of tDCS alone have not been studied in PD-MCI yet. The present double-blind, randomized, sham-controlled study assessed the effects of tDCS over the dorsolateral prefrontal cortex on cognitive functions via neuropsychological and electrophysiological evaluations in individuals with PD-MCI for the first time. Twenty-six individuals with PD-MCI were administered 10 sessions of active (n = 13) or sham (n = 13) prefrontal tDCS twice a day, for 5days. Changes were tested through a comprehensive neuropsychological battery and event-related potential recordings, which were performed before, immediately, and 1month after the administrations. Neuropsychological assessment showed an improvement in delayed recall and executive functions in the active group. N1 amplitudes in response to targets in the oddball test-likely indexing attention and discriminability and NoGo N2 amplitudes in the continuous performance test-likely indexing cognitive control and conflict monitoring increased in the active group. Active stimulation elicited higher benefits 1month after the administrations. The present findings substantiate the efficacy of tDCS on cognitive control and episodic memory, along with the neural underpinnings of cognitive control, highlighting its potential for therapeutic utility in PD-MCI. NCT 04,171,804. Date of registration: 21/11/2019.

Semantic Transparency in Chinese Compound Word Processing: Evidence from Mismatch Negativity

This study examined how semantic transparency modulated the processing of spoken Chinese compound words with event-related potential (ERP) recording. A reverse-block passive oddball paradigm was adopted to elicit mismatch negativity (MMN), which responds to holistic and combinatorial processing in opposite directions. Specifically, linguistic inputs that are processed as holistic lexical representations will elicit stronger MMNs (lexical enhancement) than those that do not have such representations. In contrast, when they are processed by combining the constituents, smaller MMNs will be elicited (combinatorial reduction) as compared to non-combinable inputs. We compared the strengths of MMNs among transparent words, opaque words, and pseudocompounds (that did not have lexical representations and were non-combinable). It was shown that transparent words triggered smaller MMNs than pseudocompounds, which supported combinatorial processing. Opaque words did not differ from pseudocompounds, which was interpreted as parallel employment of the holistic and combinatorial processing routes. Overall, the results are consistent with the idea that native Chinese speakers routinely attempt to process Chinese compound words by retrieving and combining morphemes. However, because the meanings of opaque words are irrelevant to their constituent morphemes, Chinese speakers must construct and retrieve their holistic representations to ensure accurate processing.