Use Of Event-related Potentials Research Articles

Research on the Preference of Public Art Design in Urban Landscapes: Evidence from an Event-Related Potential Study

As urbanization quickens, the role of public art in urban landscape design gains prominence. Nevertheless, how stylistic characteristics of landscape public art affect aesthetic preferences remains insufficiently discussed, particularly with objective assessment methods. The use of event-related potential (ERP) can offer neurophysiological evidence to support research and practice in landscape art design. We employed a 2 (artistic features) × 2 (professional proficiency) repeated-measures design, involving abstract and figurative experimental stimuli; both experts and non-experts participated, with their aesthetic reactions and relevant electroencephalographic data recorded. Behavioral findings show a preference for figurative public artworks regardless of professional background. From neurophysiological outcomes, stimuli elicit an elevated N100 during early perceptual processing, signifying increased attentional resources. During aesthetic processing, figurative stimuli more effectively evoke positive emotions, particularly among professionals, yielding a heightened P200 response. Conversely, abstract stimuli may evoke a higher N200 amplitude, reflecting augmented negative biases. Nevertheless, non-experts exhibit no marked differences in their stimulus responses during aesthetic processing. Research indicates that low-level physical attributes of public artworks are initially noted, while the visual processing of artistic traits lies at a higher perceptual level, necessitating specialized expertise involvement. Furthermore, the complexity of visual perceptual processing plays a significant role in the assessment of landscape art preferences. This study not only offers crucial reference indices for designing urban landscapes that satisfy diverse public aesthetic needs but also lays the foundation for neural techniques to assess landscape design preferences and expands the field of landscape design research.

Use of Event-Related Potentials to Assess Visual–Auditory Multisensory Information in the Decision-Making Processes Related to Fast-Consuming Behavior

People are accustomed to using mobile phones to purchase products online. Previous studies identified brain activities associated with online buying decisions but did not assess mismatch negativity (MMN), P300 (P3a and P3b), and slow waves. We applied visual animation and sound effects to test visual–auditory multisensory concepts in product promotion strategies. Event-related potential (ERP) responses from 53 participants were analyzed to help design sound effects based on MMN, P300, and slow waves. We designed five short visual–auditory animation videos: visual animation sound effect (VASE), VA sound beep (VASB), visual standard sound beep (VSSB), visual animation–no sound (VANS), and visual standard–no sound (VSNS). These five apps were used to test how matched and unmatched multisensory user experience (UX) influences online shopping decisions. We also used Arrow’s impossibility theorem to design the purchasing experiment. VASE evoked MMN (cluster p = 0.0184) compared with VSSB. VASE evoked the strongest P300 (P3a and P3b) responses (cluster p = 1 × 10−5), and VASB evoked more negative slow wave amplitudes (cluster p = 1.7 × 10−4) compared with VASE. Participants buy products unconsciously via most VASE and VANS mobile apps compared with via VASB and VSNS. Our findings suggest that sensory memory from multisensory UX can promote product consumption in mobile phone shopping interfaces. This study’s testing of memory and attention from MMN, P300, and slow waves makes a novel contribution to the marketing discipline. The implications can motivate researchers to apply ERP to analyze the multisensory concept in future interdisciplinary research.

Effects of Healthy Aging and Gender on the Electrophysiological Correlates of Semantic Sentence Comprehension: The Development of Dutch Normative Data.

The clinical use of event-related potentials in patients with language disorders is increasingly acknowledged. For this purpose, normative data should be available. Within this context, healthy aging and gender effects on the electrophysiological correlates of semantic sentence comprehension were investigated. One hundred and ten healthy subjects (55 men and 55 women), divided among three age groups (young, middle aged, and elderly), performed a semantic sentence congruity task in the visual modality during electroencephalographic recording. The early visual complex was affected by increasing age as shown by smaller P2 amplitudes in the elderly compared to the young. Moreover, the N400 effect in the elderly was smaller than in the young and was delayed compared to latency measures in both middle-aged and young subjects. The topography of age-related amplitude changes of the N400 effect appeared to be gender specific. The late positive complex effect was increased at frontal electrode sites from middle age on, but this was not statistically significant. No gender effects were detected regarding the early P1, N1, and P2, or the late positive complex effect. Especially aging effects were found during semantic sentence comprehension, and this from the level of perceptual processing on. Normative data are now available for clinical use.

Validation of a suite of ERP and QEEG biomarkers in a pre-competitive, industry-led study in subjects with schizophrenia and healthy volunteers.

Complexity and lack of standardization have mostly limited the use of event-related potentials (ERPs) and quantitative EEG (QEEG) biomarkers in drug development to small early phase trials. We present results from a clinical study on healthy volunteers (HV) and patients with schizophrenia (SZ) that assessed test-retest, group differences, variance, and correlation with functional assessments for ERP and QEEG measures collected at clinical and commercial trial sites with standardized instrumentation and methods, and analyzed through an automated data analysis pipeline. 81 HV and 80 SZ were tested at one of four study sites. Subjects were administered two ERP/EEG testing sessions on separate visits. Sessions included a mismatch negativity paradigm, a 40Hz auditory steady-state response paradigm, an eyes-closed resting state EEG, and an active auditory oddball paradigm. SZ subjects were also tested on the Brief Assessment of Cognition (BAC), Positive and Negative Syndrome Scale (PANSS), and Virtual Reality Functional Capacity Assessment Tool (VRFCAT). Standardized ERP/EEG instrumentation and methods ensured few test failures. The automated data analysis pipeline allowed for near real-time analysis with no human intervention. Test-retest reliability was fair-to-excellent for most of the outcome measures. SZ subjects showed significant deficits in ERP and QEEG measures consistent with published academic literature. A subset of ERP and QEEG measures correlated with functional assessments administered to the SZ subjects. With standardized instrumentation and methods, complex ERP/EEG testing sessions can be reliably performed at clinical and commercial trial sites to produce high-quality data in near real-time.

Long-Term Potentiation-Like Visual Synaptic Plasticity Is Negatively Associated With Self-Reported Symptoms of Depression and Stress in Healthy Adults.

Long-term potentiation (LTP) is one of the most extensively studied forms of neuroplasticity and is considered the strongest candidate mechanism for memory and learning. The use of event-related potentials and sensory stimulation paradigms has allowed for the translation from animal studies to non-invasive studies of LTP-like synaptic plasticity in humans. Accumulating evidence suggests that synaptic plasticity as measured by stimulus-specific response modulation is reduced in neuropsychiatric disorders such as major depressive disorder (MDD), bipolar disorders and schizophrenia, suggesting that impaired synaptic plasticity plays a part in the underlying pathophysiology of these disorders. This is in line with the neuroplasticity hypothesis of depression, which postulate that deficits in neuroplasticity might be a common pathway underlying depressive disorders. The current study aims to replicate and confirm earlier reports that visual stimulus-specific response modulation is a viable probe into LTP-like synaptic plasticity in a large sample of healthy adults (n = 111). Further, this study explores whether impairments in LTP-like synaptic plasticity is associated with self-reported subclinical depressive symptoms and stress in a healthy population. Consistent with prior research, the current study replicated and confirmed reports demonstrating significant modulation of visual evoked potentials (VEP) following visual high-frequency stimulation. Current results further indicate that reduced LTP-like synaptic plasticity is associated with higher levels of self-reported symptoms of depression and perceived stress. This indicate that LTP-like plasticity is sensitive to sub-clinical levels of psychological distress, and might represent a vulnerability marker for the development of depressive symptoms.

The roles of object and action, and concreteness and imageability, in the distinction between nouns and verbs: An ERP study on monosyllabic words in Chinese

The dissociation between nouns and verbs has been reported in behavioral, electrophysiological, and neuroimaging studies. It is still unclear whether the spatial and temporal differences between nouns and verbs arise from semantic differences or morpho-syntactic differences associated with the two word classes. Regarding the semantic accounts, it is also unknown whether the word class effect should be attributed to differences in object and action, or in concreteness and imageability, associated with nouns and verbs. As the question with respect to semantic accounts for the word class effect is unsettled, the two types of semantic attributes have not been well distinguished in previous studies that support morpho-syntactic accounts, and this may lead to a confounding effect between morpho-syntactic factors and semantic factors. Therefore, to better understand the origins of the noun-verb distinction, it is essential to figure out whether the word class effect is driven by the contrast between object and action or by concreteness and imageability. With tight matching of stimuli and the use of event-related potentials (ERPs), we investigated the neural processing of monosyllabic nouns and verbs in Chinese that were presented without context. The results showed that when concreteness and imageability were balanced, nouns elicited more negative N400 than verbs over a broad scalp region, suggesting distinct semantic processing between the two word classes. Furthermore, nouns elicited more late negativity than verbs at frontal sites, which may reflect differences in the semantic representation of nouns and verbs in the working memory or differences in the working memory load associated with the word classes. These ERP results showed that the distinction between nouns and verbs persists even after concreteness and imageability are matched, revealing that the semantic account for the word class effect might arise from the contrast of object and action rather than the concreteness and imageability effect. The findings of the current study draw attention to the importance of object and action distinction in studies on nouns and verbs.

The Use of Event-Related Potentials and Machine Learning to Improve Diagnostic Testing and Prediction of Disease Progression in Parkinson's Disease.

Current tests of disease status in Parkinson's disease suffer from high variability, limiting their ability to determine disease severity and prognosis. Event-related potentials, in conjunction with machine learning, may provide a more objective assessment. In this study, we will use event-related potentials to develop machine learning models, aiming to provide an objective way to assess disease status and predict disease progression in Parkinson's disease.

The data-processing multiverse of event-related potentials (ERPs): A roadmap for the optimization and standardization of ERP processing and reduction pipelines

In studies of event-related brain potentials (ERPs), numerous decisions about data processing are required to extract ERP scores from continuous data. Unfortunately, the systematic impact of these choices on the data quality and psychometric reliability of ERP scores or even ERP scores themselves is virtually unknown, which is a barrier to the standardization of ERPs. The aim of the present study was to optimize processing pipelines for the error-related negativity (ERN) and error positivity (Pe) by considering a multiverse of data processing choices. A multiverse analysis of a data processing pipeline examines the impact of a large set of different reasonable choices to determine the robustness of effects, such as the impact of different decisions on between-trial standard deviations (i.e., data quality) and between-condition differences (i.e., experimental effects). ERN and Pe data from 298 healthy young adults were used to determine the impact of different methodological choices on data quality and experimental effects (correct vs. error trials) at several key stages: highpass filtering, lowpass filtering, ocular artifact correction, reference, baseline adjustment, scoring sensors, and measurement procedure. This multiverse analysis yielded 3,456 ERN scores and 576 Pe scores per person. An optimized pipeline for ERN included a 15 Hz lowpass filter, ICA-based ocular artifact correction, and a region of interest (ROI) approach to scoring. For Pe, the optimized pipeline included a 0.10 Hz highpass filter, 30 Hz lowpass filter, regression-based ocular artifact correction, a -200 to 0 ms baseline adjustment window, and an ROI approach to scoring. The multiverse approach can be used to optimize pipelines for eventual standardization, which would support efforts toward establishing normative ERP databases. The proposed process of analyzing the data-processing multiverse of ERP scores paves the way for better refinement, identification, and selection of data processing parameters, ultimately improving the precision and utility of ERPs.

The Combination of N60 with Mismatch Negativity Improves the Prediction of Awakening from Coma.

Our objective was to evaluate the use of event-related potentials and the middle-latency somatosensory evoked potential (MLSEP) for the prediction of awakening in coma, determine the evaluation day that evoked potentials (EPs) best predict an awakening outcome, and determine whether the mismatch negativity (MMN) combined with the MLSEP, when recorded at 7days after coma, improved the prediction of awakening from coma. Design prospective blinded cohort study. Setting neurointensive care unit of a university hospital. Patients 113 consecutive patients who were severely comatose, whose etiologies of coma included stroke (65 patients), hypoxic-ischemic encephalopathy (28 patients), intracranial infection (6 patients), and other (14 patients). Interventions none. Measurements we gathered Glasgow Coma Scale scores and recorded EPs for all patients who were comatose at 7, 14, and 30days after coma onset, unless the patients returned to consciousness. The EPs examined included the MLSEP, the middle-latency auditory evoked potential, the N100, and the MMN. With telephone follow-up after 3months, the patients were classified as awakening or nonawakening according to Glasgow Outcome Scale. When predicting an awakening outcome, at least the unilateral presence of the N60 had the highest sensitivity (82.7%), whereas the presence of the MMN showed the highest specificity (82.0%). The area under the receiver operating characteristic curve for the EPs were high at 7days after coma onset. At 7days after coma onset, the combination of the N60 and MMN offered good predictive performance for awakening (area under the receiver operating characteristic curve = 0.852, 95% confidence interval 0.765-0.940), with increased sensitivity (70.0%) and improved specificity (91.7%). The N60 and MMN were the strongest prognostic factors for an awakening outcome. Furthermore, at 7days after coma onset, the combination of the N60 and MMN improved the prediction of an awakening outcome in patients who were comatose.

The role and use of event-related potentials in aphasia: A scoping review

Event-related potentials (ERPs) can provide important insights into underlying language processes in both unimpaired and neurologically impaired populations and may be particularly useful in aphasia. This scoping review was conducted to provide a comprehensive summary of how ERPs have been used with people with aphasia (PWA), with the goal of exploring the potential clinical application of ERPs in aphasia assessment and treatment. We identified 117 studies that met inclusionary criteria, reflecting six thematic domains of inquiry that relate to understanding both unimpaired and aphasic language processing and the use of ERPs with PWA. In these studies, a wide variety of ERP components were reported. Inconsistencies in reporting of participant characteristics and study protocols limit our ability to generalize beyond the individual studies and understand implications for clinical applicability. We discuss the potential roles of ERPs in aphasia management and make recommendations for further developing ERPs for clinical utility in PWA.

Deficits in Visual Processing During Hypoxia as Evidenced by Visual Mismatch Negativity.

INTRODUCTION: Hypoxia is an ever-present threat in tactical aviation and gained recent attention due to its putative role in physiological episodes. Previous work has demonstrated that hypoxia negatively impacts a variety of sensory, cognitive, and motor systems. In particular, the visual system is one of the earliest systems affected by hypoxia. While the majority of previous studies have relied on self-report and behavioral testing, the use of event-related potentials as a novel tool to monitor responses to low oxygen in humans has recently been investigated. Specifically, ERP components that are evoked passively in response to unattended changes in background sensory stimulation have been explored.METHOD: Subjects (N 28) completed a continuous visuomotor tracking task while EEG was recorded. During the tracking task, a series of standard color checkerboard patterns were presented in the periphery while occasionally a deviant color checkerboard was presented. The visual mismatch negativity (MMN) component was assessed in response to the deviant compared to the standard stimuli. Subjects completed two sessions in counterbalanced order that only differed by the oxygen concentration breathed (10.6% vs. 20.4%).RESULTS: Results demonstrated a significant reduction in the amplitude of the visual MMN under hypoxic compared to normoxic conditions, showing a 50% reduction in amplitude during hypoxia. Our results suggest that during low-oxygen exposure the ability to detect environmental changes and process sensory information is impaired.DISCUSSION: The visual MMN may represent an early and reliable predictor of sensory and cognitive deficits during hypoxia exposure, which may be of great use to the aviation community.Blacker KJ, Seech TR, Funke ME, Kinney MJ. Deficits in visual processing during hypoxia as evidenced by visual mismatch negativity. Aerosp Med Hum Perform. 2021; 92(5):326332.

Oxytocin weakens self-other distinction in males during empathic responses to sadness: an event-related potentials study.

By making use of event-related potential (ERP) technology, a randomized, double-blind, between-subject design study was performed in order to investigate whether OXT can weaken men’s self-other distinction during empathic responses to sad expressions. In the two experimental tasks, 39 male subjects were asked to either evaluate the emotional state shown in a facial stimulus (other-task) or to evaluate their own emotional responses (self-task). The results revealed that OXT reduced the differences in P2 (150–200 ms) amplitudes between sad and neutral expressions in the self-task but enhanced P2 to sad expressions in the other-task, indicating OXT’s role in integrating the self with others instead of separating them. In addition, OXT also reduced the LPC (400–600 ms) amplitudes between sad-neutral expressions in the self-task, implying that OXT’s weakening effects on the self-other distinction could occur at both the early and late cognitive control stages of the empathic response.

Neurophysiological correlates of abnormal auditory processing in episodic migraine during the interictal period.

The characteristics of the hypersensitivity to auditory stimuli during the interictal period in episodic migraine are discussed. The combined use of event-related potentials, time-frequency power and phase-synchronization can provide relevant information about the time-course of sensory-attentional processing in migraine and its underlying mechanisms. The aim of this nested case-control study was to examine these processes in young, female, episodic migraine patients interictally and compare them to controls using an active auditory oddball task. We recorded, using 20 channels, the electrophysiological brain activity of 21 women with episodic migraine without aura and 21 healthy matched controls without family history of migraine, during a novelty oddball paradigm. We collected sociodemographic and clinical data as well as scores related to disability, quality of life, anxiety and depression. We calculated behavioural measures including reaction times, hit rates and false alarms. Spectral power and phase-synchronization of oscillatory activity as well as event-related potentials were obtained for standard stimuli. For target and novel stimuli, event-related potentials were acquired. There were no significant differences at the behavioural level. In migraine patients, we found an increased phase-synchronization at the theta frequency range and a higher N1 response to standard trials. No differences were observed in spectral power. No evidence for a lack of habituation in any of the measures was seen between migraine patients and controls. The Reorienting Negativity was reduced in migraine patients as compared to controls on novel but not on target trials. Our findings suggest that migraine patients process stimuli as more salient, seem to allocate more of their attentional resources to their surrounding environment, and have less available resources to reorient attention back to the main task.

Auditory event-related potentials in individuals with subjective and mild cognitive impairment

ObjectiveThe analysis of event-related potentials (ERPs) is a useful tool to differentiate between healthy older adults, and individuals with mild cognitive impairment (MCI). Less is known about the ERPs’ sensitivity of differentiating between individuals with subjective cognitive impairment (SCI) and MCI, as early evidence indicates similar brain alterations between these two groups. In order, to establish tests that are sensitive to subclinical impairment, this study compared auditory evoked ERPs between individuals with SCI and MCI. MethodsBesides assessing cognitive performance in four neuropsychological tests (Trail Making Test A + B, verbal fluency letter and category task), latency and amplitude of ERP components evoked by an auditory oddball paradigm were compared between two groups of either individuals with SCI (n = 13) or MCI (n = 13). ResultsWhile individuals with MCI performed significantly worse in all neuropsychological tests (TMT A: p = 0.001, Cohen’s d = 1.5; TMT B: p = 0.030, Cohen’s d = 0.94; verbal fluency letter: p = 0.0011, Cohen’s d = 1.08; verbal fluency category: p = 0.038; Cohen’s d = 0.86), no significant differences (p > 0.05) were found in ERP components with small to moderate effect sizes (Cohen’s d ranged between 0.11 – 0.59). ConclusionERPs evoked by an auditory oddball paradigm lack sensitivity to differentiate between individuals with SCI and MCI, although significant differences in cognitive performance were detected by neuropsychological tests. Similar pathophysiological brain alterations may limit utility of ERPs as indicated by previous research and results of this study. Cognitively more challenging tasks than the auditory oddball paradigm may be considered by future investigations.

The neurocognitive basis of metamemory: Using the N400 to study the contribution of fluency to judgments of learning.

Metamemory is crucial for monitoring, evaluating, and optimizing memory performance. The basis of metamemory, however, is a matter of considerable debate. In the present study, we examined the contribution of processing fluency-the ease of processing information during learning-to metamemory judgments. We recorded event-related potentials (ERPs) while participants studied related and unrelated word pairs across two study-test cycles in a judgment of learning (JOL) task. In the first study-test cycle, related pairs were associated with better cued recall, higher JOLs, and a reduced N400 amplitude than unrelated pairs. Crucially, between- and within subject correlational analyses indicated that reduced N400 amplitudes, indexing more fluent processing, were associated with higher JOLs. Furthermore, single-trial N400 mediated a small but significant portion of the relatedness effect on JOLs. In the second study-test cycle, relatedness still increased recall and JOLs. However, related and unrelated pairs did not differ in N400 amplitude. Rather, unrelated pairs elicited a parietal positivity in a later time window that partially mediated the relatedness effect on JOLs. Together, these results suggest that processing fluency, indexed by the N400, contributes to the relatedness effect on JOLs when novel word pairs are learned, but not when previously studied pairs are relearned. Our results also imply that aspects of fluency not captured by the N400 and/or explicit beliefs about memory contribute to JOLs. This study demonstrates the utility of ERPs in gaining new insights into the neurocognitive mechanisms of metamemory.

Chapter 20 - Clinical neurophysiology: Research methods and event-related potential components as assessment tools

The paramount importance of research design and research methodologies within the shared space of neurology, clinical neurophysiology, and cognitive neuroscience serves as the theme around which a range of topics is presented. After a tour of historical figures of human electrophysiology and electroencephalography (EEG), the discussion turns to event-related potential (ERP). Emphasizing the lengthy history of these manifestations of cognition, the chapter outlines the extensive research literature that has demonstrated the sensitivity of ERPs to a range cognitive functions, including attention, language processing, and memory. There follows a series of examples of ERP applications in the clinical domain, including disorders of consciousness, stroke, autism, coma, and concussion. These examples not merely demonstrate the general utility of these electrophysiological responses but stress that their independence from behavioral responses provides a much needed clinical method to assess individuals who are literally or virtually impossible to assess using traditional behaviorally based clinical tools. The chapter concludes with the suggestion that is time that the incontrovertible utility of ERPs be employed more fully within clinical contexts to assist the clinical community in providing objective assessments of a range of neurologic conditions.

An Exploratory Study on the Use of Event-Related Potentials as an Objective Measure of Auditory Processing and Therapy Effect in Patients With Tinnitus: A Transcranial Direct Current Stimulation Study.

Treatment effect in tinnitus research is commonly evaluated by use of self-report questionnaires. As this is a solely subjective assessment method, the need for an objective measurement is paramount to genuinely evaluate the effects of therapeutic interventions. The current study explores the value of event-related potentials (ERPs) in the evaluation of high-definition transcranial direct current stimulation (HD-tDCS) for tinnitus treatment. Prospective exploratory study. Tertiary referral center. Twenty-two chronic tinnitus patients. HD-tDCS. ERPs. The results show a significant shortening of the N1, P2, N2, and P3 latencies after HD-tDCS treatment. Moreover, the increased amplitude of the P2 and N2 peaks result in more salient and clear peaks, with the amplitude of N2 being significant larger after HD-tDCS. However, the ERP changes are not significantly correlated with the change in tinnitus functional index (TFI) total score. The current study was the first to explore ERPs as objective measure in a study with HD-tDCS in tinnitus patients. Adding ERPs to the outcome measures in tinnitus research may lead to a better understanding of the therapeutic effect in the future. The results showed a shortening of ERP latencies and an increased N2 amplitude, possibly reflecting more effective sound processing with higher recruitment of synchronized neurons in the auditory cortex. Future studies should elaborate on these results, by collecting control data and adding a sham group, to provide a better insight in the underlying mechanism of the ERP changes after tinnitus treatment.

The Utility of Event-Related Potentials in Clinical Psychology.

Event-related potentials (ERPs) are direct measures of brain activity that can be leveraged for clinically meaningful research. They can relate robustly both to continuous measures of individual difference and to categorical diagnoses in ways that clarify similarities and distinctions between apparently related disorders and traits. ERPs can be linked to genetic risk, can act as moderators of developmental trajectories and responses to stress, and can be leveraged to identify those at greater risk for psychopathology, especially when used in combination with other neural and self-report measures. ERPs can inform models of the development of, and risk for, psychopathology. Finally, ERPs can be used as targets for existing and novel interventions and prevention efforts. We provide concrete examples for each of these possibilities by focusing on programmatic research on the error-related negativity and anxiety, and thus show that ERPs are poised to make greater contributions toward the identification, prediction, treatment, and prevention of mental disorders.

Deficits of visuospatial working memory and executive function in single- versus multiple-domain amnestic mild cognitive impairment: A combined ERP and sLORETA study

ObjectiveAccording to recent criteria of classification, amnestic mild cognitive impairment (aMCI) could be divided into two categories: single-domain aMCI (sd-aMCI) and multiple-domain aMCI (md-aMCI). The difference between sd-aMCI and md-aMCI needs further exploration. The present study aimed to compare deficits in visuospatial working memory (VSWM) and executive function between sd-aMCI versus md-aMCI patients by use of event-related potentials (ERP) and standardized low-resolution brain electromagnetic tomography analysis (sLORETA). MethodsThe ERP data were measured and analyzed in 26 sd-aMCI, 13 md-aMCI patients and 46 healthy elderly controls (HEC) during VSWM and Go/Nogo processes. ResultsDuring VSWM task, md-aMCI patients showed decreased P300 amplitude compared to HEC and sd-aMCI patients (All p < 0.05). As compared to sd-aMCI, md-aMCI showed a hypoactivation in the right middle frontal gyrus in 1-back task during the P300 time range. During the Go/Nogo task, sd-aMCI and md-aMCI patients showed reduced N200 amplitude, compared to HEC (All p < 0.05). However, md-aMCI patients had decreased N200 amplitude, with respect to sd-aMCI patients. Further, as compared to sd-aMCI patients, md-aMCI patients showed a hypoactivation in the right superior frontal gyrus during the N200 time range. ConclusionsThese findings with a combined ERP and sLORETA study showed more severe deficits in updating operations of WM, detections of the target stimulus and conflict processes in md-aMCI, compared to sd-aMCI patients. SignificanceThe present study showed that a combined ERP and sLORETA study during the VSWM and Go/Nogo tasks could distinguish md-aMCI from sd-aMCI.

Habituation of Somatosensory Event-Related Potentials in Subthreshold Rhythmic (1 Hz) Electrocutaneous Stimulation of the Arm during the Slow-Wave Stage of Daytime Sleep

Previous studies have shown that low-frequency subthreshold electrocutaneous stimulation of the arm during deep slow-wave sleep in humans improves sleep quality. The main cognitive processes are known to operate during sleep, and use of event-related potentials is the main method for analysis of these processes. The aims of the present work were to study the characteristics of somatosensory event-related potentials (sERP) on rhythmic (1 Hz) subthreshold electrocutaneous volley stimulation of the arm during the slow-wave stage of daytime sleep and to evaluate the potential for habituation of sERP to rhythmic stimulation during sleep. Subthreshold stimulation during sleep produced somatosensory event-related potentials (ERP) (group mean, n = 16) in which three long-latency components could be identifi ed, which were more marked in the frontal lead of the contralateral hemisphere. Comparison of sERP averaged from the beginning and end of the volley of stimuli (30 stimuli) demonstrated signifi cant decreases in the amplitudes of all sERP components by the end of the volley. It is suggested that the decrease in sERP amplitude in slow-wave sleep is due to the simplest form of stimulus-dependent nonassociative learning - habituation.