Search

Humans are social creatures, and many tasks in our daily lives are solved together. The two main forms of social interaction in problem solving could be defined as competition and cooperation. In our study, we compared the ERS/ERD when performing a creative task (Alternative Uses Test, AUT) and a control task ("naming the objects from the presented category") under competitive conditions in dyads (22 dyads, m-m, f-f, 18–23 years old) compared to the performance of tasks individually. The number of answers given by subjects under competitive conditions was significantly lower than during the execution of the tasks individually. The solving of the creative task in competition versus individual performance was accompanied by EEG synchronization (9–30 hz) clusters: 140–1220 ms and 900–1780 ms after stimulus presentation; 13.5–30 hz (1800–1980 ms), reflecting the creative thinking mode, and expected cognitive, emotional answers' assessment. The control task under competitive conditions was accompanied by pronounced synchronization of low frequencies in the frontal areas (2–7 hz, 0–1980 ms), due to a greater working memory load; synchronization clusters in broadband (10–30 hz, 100–320 ms, 400–860 ms) and in the beta EEG band (17–30 hz, 1140–1980 ms). The competitive conditions significantly modulated the brain activity underlying creative and non-creative cognitive task performance, and resulted in greater induced EEG synchronization. [ABSTRACT FROM AUTHOR]

In a recent study on visual episodic memory (Desaunay, Clochon, et al., 2020), we have shown event‐related potentials (ERPs) differences associated with priming (150–300 msec), familiarity (350–470 msec), and recollection (600–700 msec), in young people with autism spectrum disorders (ASD) compared with typical development (TD). To go further into the study of the processes of storage and retrieval of the memory trace, we re‐analyzed Desaunay, Clochon, et al's data using time‐frequency analysis, that is, event‐related synchronization and desynchronization (ERS/ERD). This allows a decomposition of the spectral power within frequency bands associated with these ERPs. We focused both on the same time windows and the same regions of interest as previously published. We mainly identified, in ASD compared with TD, reduced ERS in low‐frequencies (delta, theta) in early time‐windows, and non‐significant differences in ERD in higher frequencies (alpha, beta1) in all time‐windows. Reduced ERS during recognition confirmed previously reported diminution of priming effects and difficulties in manipulation and retrieval of both semantic and episodic information. Conversely, preserved ERD corroborates a preservation of memory storage processes. These observations are consistent with a cognitive model of memory in ASD, that suggests difficulties in cognitive operations or executive demand at retrieval, subsequent to successful long‐term storage of information. Lay Summary: We assessed the EEG synchronization and desynchronization, during visual episodic recognition. We observed, in youth with Autism, reduced synchronization in low‐frequencies (delta, theta), suggesting reduced access to and manipulation of long‐term stored information. By contrast, non‐significant differences in desynchronization at higher frequencies (alpha, beta frequency bands), that support long‐term stored semantic and episodic information, suggested preserved memory traces. [ABSTRACT FROM AUTHOR]

Results of several neuroimaging studies support the functional equivalence model, which states that motor imagery (MI) and motor execution (ME) involve the same processes, except for the final execution component. In contrast, the motor-cognitive model implies that MI additionally involves frontal executive control processes. However, according to some authors MI may actually be more comparable to motor preparation (MP). In the current electroencephalographic study, a version of the discrete sequence production paradigm was employed in which human participants initially had to prepare a sequence of five finger movements that subsequently had to be executed, imagined, or withheld. MI, ME, and MP were compared by computing event-related (de)-synchronization in the theta, alpha/mu, and beta bands. Results revealed a major increase in frontal theta power during MI as compared to ME and MP. At the end of the examined intervals, a posterior reduction in alpha power was present during ME and MP, but not during MI. Finally, above sensorimotor areas a decrease in beta power was observed that was most pronounced in the case of ME. The increase of frontal theta activity during MI may reflect increased effort, while the absence of a reduction in posterior alpha power suggests no major involvement of visuospatial attention and/or visual imagery. The present findings favor the motor-cognitive model, as it predicts extra involvement of frontal executive processes during MI. • Participants had to learn to execute response sequences of five button presses. • Motor imagery (MI) was compared with motor execution/preparation (ME/MP). • EEG was measured to determine event related synchronization or desynchronization. • MI showed increased frontal theta power (~increased effort). • ME and MP showed decreased posterior alpha power (~increased visual attention). [ABSTRACT FROM AUTHOR]

Working memory (WM) performance is very often measured using the n‐back task, in which the participant is presented with a sequence of stimuli, and required to indicate whether the current stimulus matches the one presented n steps earlier. In this study, we used high‐density electroencephalography (hdEEG) coupled to source localization to obtain information on spatial distribution and temporal dynamics of neural oscillations associated with WM update, maintenance and readout. Specifically, we a priori selected regions from a large fronto‐parietal network, including also the insula and the cerebellum, and we analyzed modulation of neural oscillations by event‐related desynchronization and synchronization (ERD/ERS). During update and readout, we found larger θ ERS and smaller β ERS respect to maintenance in all the selected areas. γLOW and γHIGH bands oscillations decreased in the frontal and insular cortices of the left hemisphere. In the maintenance phase we observed decreased θ oscillations and increased β oscillations (ERS) in most of the selected posterior areas and focally increased oscillations in γLOW and γHIGH bands in the frontal and insular cortices of the left hemisphere. Finally, during WM readout, we also found a focal modulation of the γLOW band in the left fusiform cortex and cerebellum, depending on the response trial type (true positive vs. true negative). Overall, our study demonstrated specific spectral signatures associated with updating of memory information, WM maintenance, and readout, with relatively high spatial resolution. [ABSTRACT FROM AUTHOR]

• Rotational uncertainty was characterized by larger ERPs and stronger ERD. • The slow wave difference can reflect the extent of rotational uncertainty effect. • Source of effect locates in precentral and postcentral gyri, precuneus, and inferior parietal lobule. Rotational uncertainty refers to the fact that the reaction time (RT) for identifying an upright stimulus is longer when the target stimulus is presented in a sequence of stimuli with different orientations (SU condition) than upright stimuli only (AU condition). Up until now, the rotational uncertainty effect has been only revealed by behavior measures, and its underlying neural mechanism remains unclear. In this study, using the hand mental rotation paradigm and electroencephalogram (EEG) recordings, we aimed to find the electrophysiological evidences of the rotational uncertainty from event-related potential (ERP) and event-related (de)synchronization (ERS/ERD) measurements. Compared with the upright hand stimuli in AU condition, the same stimuli in SU condition took longer RT, elicited stronger α-ERD and β-ERD, and evoked larger P100, P300 and the slow wave (SW) from −500 ms to −200 ms before response. In particular, the amplitude of SW difference (i.e., SW SU − SW AU) was negatively correlated with the extent of rotational uncertainty effect (i.e., RT SU − RT AU), with its source mainly in the right precentral and postcentral gyri, precuneus, and the left inferior parietal lobule. Our results suggested that identifying the upright hand stimuli in SU condition induced more activation of motor networks, and the rotational uncertainty influenced multiple cognitive processes from the early visual processing to the late mental rotation and judging phases. The results implied that in SU condition, subjects might maintain readiness for the next possible mental rotation immediately after the previous response, with more attention to the coming visual stimuli. Even for the upright stimuli, they might still prepare for the mental rotation, and even mentally rotate the stimuli in a minor angle. [ABSTRACT FROM AUTHOR]

Most people acquire motor skills through feedback-based training. How the human brain processes sensory feedbacks during training, especially in a gait training, remain largely unclear. The purpose of this paper is to explore how humans adopt a new gait pattern to reduce impacts during walking-with the aid of visual and audio feedbacks. This paper demonstrates the features of underlying brain activity in incorporating the visual or auditory cues to acquire a new gait pattern. Electroencephalography (EEG) and peak positive acceleration (PPA) of the heel were collected from 23 participants during walking on a treadmill with no feedback, with visual feedback, or with audio feedback. The feedbacks were presented after each foot strike, where a sub-threshold PPA triggered a positive feedback (green/low-pitched), and a suprathreshold PPA triggered a negative feedback (red/high-pitched). The participants were instructed to voluntarily control their gait, so that low PPA could be achieved. This control was perturbed in some sessions by an additional cognitive task, and the influence of such distraction was also explored. The PPA was significantly lower in the sessions with visual or audio feedback than in sessions without feedback, showing an immediate improvement in gait pattern, when the feedback was provided. Different feedbacks modulated neural activities at different locations and/or levels during training. Alpha event-related synchronization (ERS) was particularly increased during the encoding of auditory feedback or the introduction of a distracting task. In the meantime, prominent frontal and posterior theta ERS were coupled with negative feedback, and strong beta event-related desynchronization (ERD) was observed only in sessions with feedbacks. Our results indicate that feedback effectively enhances motor planning when acquiring a new gait. [ABSTRACT FROM AUTHOR]

Copyright of Computer Measurement & Control is the property of Magazine Agency of Computer Measurement & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Surface Laplacian methodology has been used to reduce the impact of volume conduction and arbitrary choice of EEG recording reference for the analysis of surface potentials. However, the empirical implications of employing these different transformations to the same EEG data remain obscure. This study directly compared the statistical effects of four commonly-used (nose, linked mastoids, average) or recommended (reference electrode standardization technique [REST]) references and their spherical spline current source density (CSD) transformation for a large data set stemming from a well-understood experimental manipulation. ERPs (72 sites) recorded from 130 individuals during a visual half-field paradigm with highly-controlled emotional stimuli were characterized by mid-parietooccipital N1 (125 ms peak latency) and event-related synchronization (ERS) of theta/delta (160 ms), which were most robust over the contralateral hemisphere. All five data transformations were rescaled to the same covariance and submitted to a single temporal or time-frequency PCA (Varimax) to yield simplified estimates of N1 or theta/delta ERS. Unbiased nonparametric permutation tests revealed that these hemifield-dependent asymmetries were by far most focal and prominent for CSD data, despite all transformations showing maximum effects at mid-parietooccipital sites. Employing smaller subsamples (signal-to-noise) or window-based ERP/ERS amplitudes did not affect these comparisons. Furthermore, correlations between N1 and theta/delta ERS at these sites were strongest for CSD and weakest for nose-referenced data. Contrary to the common notion that the spatial high pass filter properties of a surface Laplacian reduce important contributions of neuronal generators to the EEG signal, the present findings demonstrate that instead volume conduction inherent in surface potentials weakens the representation of neuronal activation patterns at scalp that directly reflect regional brain activity. [ABSTRACT FROM AUTHOR]

In a recent study on visual episodic memory (Desaunay, Clochon, et al., 2020), we have shown event-related potentials (ERPs) differences associated with priming (150-300 msec), familiarity (350-470 msec), and recollection (600-700 msec), in young people with autism spectrum disorders (ASD) compared with typical development (TD). To go further into the study of the processes of storage and retrieval of the memory trace, we re-analyzed Desaunay, Clochon, et al's data using time-frequency analysis, that is, event-related synchronization and desynchronization (ERS/ERD). This allows a decomposition of the spectral power within frequency bands associated with these ERPs. We focused both on the same time windows and the same regions of interest as previously published. We mainly identified, in ASD compared with TD, reduced ERS in low-frequencies (delta, theta) in early time-windows, and non-significant differences in ERD in higher frequencies (alpha, beta1) in all time-windows. Reduced ERS during recognition confirmed previously reported diminution of priming effects and difficulties in manipulation and retrieval of both semantic and episodic information. Conversely, preserved ERD corroborates a preservation of memory storage processes. These observations are consistent with a cognitive model of memory in ASD, that suggests difficulties in cognitive operations or executive demand at retrieval, subsequent to successful long-term storage of information. LAY SUMMARY: We assessed the EEG synchronization and desynchronization, during visual episodic recognition. We observed, in youth with Autism, reduced synchronization in low-frequencies (delta, theta), suggesting reduced access to and manipulation of long-term stored information. By contrast, non-significant differences in desynchronization at higher frequencies (alpha, beta frequency bands), that support long-term stored semantic and episodic information, suggested preserved memory traces., (© 2022 International Society for Autism Research and Wiley Periodicals LLC.)

Abstract: This study explores oscillatory brain activity by means of event-related synchronization and desynchronization (%ERS/ERD) of EEG activity during the use of phonological and orthographic-morphological spelling strategies in L2 (English) and L1 (German) in native German speaking children. EEG was recorded while 33 children worked on a task requiring either phonological or orthographic-morphological spelling strategies. L2 processing elicited more theta %ERS than L1 processing (particularly at bilateral frontal and right posterior parietal sites) which might suggest a stronger involvement of semantic encoding and retrieval of the less familiar L2. The highest level of theta %ERS was revealed for the orthographic-morphological strategy in L2 which might indicate a more intense way of lexical retrieval compared to the phonological strategy in L2 and the orthographic-morphological strategy in L1. Analyses moreover revealed that phonological processing (both in L1 and L2) was associated with comparatively strong left-hemispheric %ERD in the upper alpha frequency band. [Copyright &y& Elsevier]

Abstract: Objective: Recent reports show that theta-band (4–7Hz) power is enhanced by target detection in the standard oddball paradigm, which, together with increased P300, is considered as providing complementary neural mechanisms supporting memory and attention processes. We hypothesize that the increased theta event-related synchronization (ERS) may stem largely from not accounting for the trial-to-trial variability of the P300 evoked component and may not reflect a separate mechanism for target detection and related cognitive processing. Methods: EEG was recorded from healthy volunteers performing visual and auditory odd-ball tasks. Ongoing-activity was obtained using two methods: (a) subtracting the ASEO-estimated (analysis of single-trial event-related potentials and ongoing-activity) single-trial ERP from corresponding single-trial EEG time series and (b) subtracting the average event-related potential (AERP) from single-trial EEG time series. Event-related oscillatory activities obtained from the two methods were compared. Results: The amount of power increase in the theta-band was greatly attenuated for the single-trial based method relative to the traditional AERP method. Conclusions: Our results suggest that the theta-ERS arises largely from not modeling the trial-to-trial variability of the P300. Significance: ERP components such as the P300 vary from trial-to-trial in both amplitude and latency. The traditional AERP method leaves traces of evoked responses in the residual data which can negatively impact the inference of ongoing oscillatory dynamics. Thus, caution should be exercised in interpreting such phenomena in basic and clinical contexts. [Copyright &y& Elsevier]

Muscle or electromyogenic (EMG) artifact poses a serious risk to inferential validity for any electroencephalography (EEG) investigation in the frequency-domain owing to its high amplitude, broad spectrum, and sensitivity to psychological processes of interest. Even weak EMG is detectable across the scalp in frequencies as low as the alpha band. Given these hazards, there is substantial interest in developing EMG correction tools. Unfortunately, most published techniques are subjected to only modest validation attempts, rendering their utility questionable. We review recent work by our laboratory quantitatively investigating the validity of two popular EMG correction techniques, one using the general linear model (GLM), the other using temporal independent component analysis (ICA). We show that intra-individual GLM-based methods represent a sensitive and specific tool for correcting on-going or induced, but not evoked (phase-locked) or source-localized, spectral changes. Preliminary work with ICA shows that it may not represent a panacea for EMG contamination, although further scrutiny is strongly warranted. We conclude by describing emerging methodological trends in this area that are likely to have substantial benefits for basic and applied EEG research. [ABSTRACT FROM AUTHOR]

Abstract: Recent investigations on oscillatory EEG dynamics by means of event-related synchronisation and desynchronisation (ERS/ERD) suggest that first language semantic information processing is primarily reflected in the theta (4–7Hz) and alpha (7–13Hz) frequency bands. In this pilot study we explore whether similar ERS/ERD patterns emerge during language translation and which frequency bands sensitively respond to the difficulty of translation and the translation success. Thirteen female students of translation and interpreting were visually presented high and low frequency English words that had to be translated into German. Time–frequency representations of ERS/ERD between 2 and 50Hz displayed a theta ERS response about 200–600ms after word presentation, a beta ERD from about 400ms, and alpha ERS and ERD patterns about 200–400ms after word presentation. Statistical analyses of the ERS/ERD data in the theta (4–7Hz), two alpha frequency bands (7–10Hz and 10–13Hz), and a beta band (20–30Hz) predominantly revealed: (a) higher parietal theta ERS and frontal upper alpha ERD during the translation of low as compared to high frequency words, and (b) generally stronger ERD in the lower alpha band and larger left-hemispheric upper alpha ERD for successfully translated in contrast to not translated low frequency words. These findings provide first evidence of the sensitivity of the theta and alpha ERS/ERD measure to lexical–semantic processes involved in language translation. [Copyright &y& Elsevier]

Recent studies demonstrated that beta oscillations are elicited during cognitive processes. To investigate their potential as electrophysiological markers of amnestic mild cognitive impairment (aMCI), we recorded beta EEG activity during resting and during an omitted tone task in patients and healthy elderly. Thirty participants were enrolled (15 patients, 15 healthy controls). In particular, we investigated event-related spectral perturbation and intertrial coherence indices. Analyses showed that ( a) healthy elderly presented greater beta power at rest than patients with aMCI patients; ( b) during the task, healthy elderly were more accurate than aMCI patients and presented greater beta power than aMCI patients; ( c) both groups showed qualitatively similar spectral perturbation responses during the task, but different spatiotemporal response patterns; and ( d) aMCI patients presented greater beta phase locking than healthy elderly during the task. Results indicate that beta activity in healthy elderly differs from that of patients with aMCI. Furthermore, the analysis of task-related EEG activity extends evidences obtained during resting and suggests that during the prodromal phase of Alzheimer's disease there is a reduced efficiency in information exchange by large-scale neural networks. The study for the first time shows the potential of task-related beta responses as early markers of aMCI impairments.

Purpose: We sought to characterize back-ground cortical activity related to sequential sensory stimuli during reaction tasks. It should be considered that the back-ground cortical activity modulate the brain potentials and reaction times. The purpose of the study is to determine whether or not the event related potentials and synchronization I desynchronization (ERS/ERD) show the changes in orienting sensory modality. Method: we recorded electroencephalogram (EEG) from eleven healthy subjects who received visual and auditory stimuli and performed reaction tasks. The conditions of stimuli presentation consist of single, compound and multi modality condition. Visual and Auditory evoked potentials (YEP and AEP) were obtained and Multi band filter analysis (MBFA) was used to calculate EEG spectral power to analyze ERS/ERD; Results and Discussion: We found that, relative to single modality stimuli, the reaction times were increased under the compound stimuli condition, and decreased under the multi modality condition. The ERP obtained by multi modality stimuli showed integrated component and the ERS/ERD showed the different changes in single and multi modality stimuli. By correlating ERS/ERD and reaction times, we identify the back-ground cortical activity that related to orienting to sensory stimuli accompanying reaction tasks. [ABSTRACT FROM AUTHOR]