Event-related Spectral Perturbation Research Articles

Delayed Functional Networks Development and Altered Fast Oscillation Dynamics in a Rat Model of Cortical Malformation.

Malformations of cortical development (MCD) is associated with a wide range of developmental delay and drug resistant epilepsy in children. By using resting-state functional magnetic resonance imaging (RS-fMRI) and event-related spectral perturbation (ERSP) of cortical electroencephalography (EEG) data, we tried to investigate the neural changes of spatiotemporal functional connectivity (FC) and fast oscillation (FO) dynamics in a rat model of methylazoxymethanol (MAM)-induced MCD. A total of 28 infant rats with prenatal exposure to MAM and those of age matched 28 controls with prenatal saline exposure were used. RS-fMRI were acquired at postnatal day 15 (P15) and 29 (P29), and correlation coefficient analysis of eleven region of interests (ROI) was done to find the differences of functional networks between four groups. Two hour-cortical EEGs were also recorded at P15 and P29 and the ERSP of gamma (30–80 Hz) and ripples (80–200 Hz) were analyzed. The rats with MCD showed significantly delayed development of superior colliculus-brainstem network compared to control rats at P15. In contrast to marked maturation of default mode network (DMN) in controls from P15 to P29, there was no clear development in MCD rats. The MCD rats showed significantly higher cortical gamma and ripples-ERSP at P15 and lower cortical ripples-ERSP at P29 than those of control rats. This study demonstrated delayed development of FC and altered cortical FO dynamics in rats with malformed brain. The results should be further investigated in terms of the epileptogenesis and cognitive dysfunction in patients with MCD.

Changes in the EEG spectral power during dual-task walking with aging and Parkinson's disease: initial findings using Event-Related Spectral Perturbation analysis.

The ability to maintain adequate motor-cognitive performance under increasing task demands depends on the regulation and coordination of neural resources. Studies have shown that such resources diminish with aging and disease. EEG spectral analysis is a method that has the potential to provide insight into neural alterations affecting motor-cognitive performance. The aim of this study was to assess changes in spectral analysis during dual-task walking in aging and disease METHODS: 10 young adults, ten older adults, and ten patients with Parkinson's disease (PD) completed an auditory oddball task while standing and while walking on a treadmill. Spectral power within four frequency bandwidths, delta (< 4Hz), theta (4-8Hz), alpha (8-12Hz), and beta (12-30Hz), was calculated using Event-Related Spectral Perturbation (ERSP) analyses and compared between single task and dual task and between groups. Differences in ERSP were found in all groups between the single and dual-task conditions. In response to dual-task walking, beta increased in all groups (p < 0.026), delta decreased in young adults (p = 0.03) and patients with PD (0.015) while theta increased in young adults (p = 0.028) but decreased in older adults (p = 0.02) and patients with PD (p = 0.015). Differences were seen between the young, the older adults, and the patients with PD. These findings are the first to show changes in the power of different frequency bands during dual-task walking with aging and disease. These specific brain modulations may reflect deficits in readiness and allocation of attention that may be responsible for the deficits in dual-task performance.

Effects of (+)-bicuculline, a GABAa receptor antagonist, on auditory steady state response in free-moving rats.

Auditory steady-state responses (ASSRs) are states in which the electrical activity of the brain reacts steadily to repeated auditory stimuli. They are known to be useful for testing the functional integrity of neural circuits in the cortex, as well as for their capacity to generate synchronous activity in both human and animal models. Furthermore, abnormal gamma oscillations on ASSR are typically observed in patients with schizophrenia (SZ). Changes in neural synchrony may reflect aberrations in cortical gamma-aminobutyric acid (GABA) neurotransmission. However, GABA’s impact and effects related to ASSR are still unclear. Here, we examined the effect of a GABAa receptor antagonist, (+)-bicuculline, on ASSR in free-moving rats. (+)-Bicuculline (1, 2 and 4 mg/kg, sc) markedly and dose-dependently reduced ASSR signals, consistent with current hypotheses. In particular, (+)-bicuculline significantly reduced event-related spectral perturbations (ERSPs) at 2 and 4 mg/kg between 10 and 30 minutes post-dose. Further, bicuculline (2 and 4 mg/kg) significantly and dose-dependently increased baseline gamma power. Furthermore, the occurrence of convulsions was consistent with the drug’s pharmacokinetics. For example, high doses of (+)-bicuculline such as those greater than 880 ng/g in the brain induced convulsion. Additionally, time-dependent changes in ERSP with (+)-bicuculline were observed in accordance with drug concentration. This study partially unraveled the contribution of GABAa receptor signals to the generation of ASSR.

Effects of Transcranial Direct Current Stimulation Over the Dorsolateral Prefrontal Cortex (PFC) on Cognitive-Motor Dual Control Skills.

This randomized crossover study investigated whether anodal transcranial direct current stimulation (tDCS) over the dorsolateral prefontal cortex (dlPFC) modulates memory-guided finger isometric maintenance during single motor and dual cognitive-motor tasks, based on electroencephalogram (EEG) signals. Twenty-three healthy participants (14 female; M age = 29.130 years, SD = 10.918) underwent both sham and 2-mA stimulation sessions over the dlPFC for 20 minutes, with a minimum washout period of seven days. We analyzed finger-force isometric maintenance and event-related spectral perturbation (ERSP) of the EEG during early and later phases of both tasks. We observed a significant motor accuracy improvement (p = .014) and significant variation of force output (p = .027) with significant decrease in ERSP on the dorsomedial prefrontal cortex (dmPFC) (early phase, p = .027; later phase, p = .023) only after 2 mA stimulation. Thus, anodal tDCS over the dlPFC may improve memory-guided force control during cognitive-motor dual tasks.

Exercise practice associates with different brain rhythmic patterns during vigilance

Cardiovascular fitness has repeatedly been associated to enhanced cognitive and brain functioning, generally in the form of differences in reaction time and response accuracy, as well as in event-related potentials (ERPs) and blood-oxygen-level-dependent imaging while participants performed executive demanding tasks. However, the evidence regarding potential differences in oscillatory neural activity, an inherent characteristic of brain functioning, is scarce. To fill this gap, here, we extracted and analysed (using a data-driven exploratory approach) brain oscillatory activity, both tonic (overall electroencephalographic – EEG – oscillatory activity) and transient (event related spectral perturbation [ERSP] and inter-trial coherence [ITC]), from a previous published dataset (Luque-Casado et al. 2016), where we showed different behavioural and ERP patterns during a vigilance/sustained attention task as a function of cardiovascular fitness in young adults. The ERSP results of the current study revealed increased theta (4-8 Hz) and upper beta (20-40 Hz) power and reduced lower beta (14-20 Hz) suppression after the target stimulus presentation in the higher-fit group compared to their lower-fit peers, but these differences disappeared in the second part of the task. ITC results mimicked the ERSP pattern within theta (4-8 Hz), while no differences were observed for the remaining frequency bands. Interestingly, the overall time-dependent effect in transient oscillatory activity followed the reaction time pattern of results. The analysis of the overall EEG oscillatory (tonic) dynamics did not show significant differences between groups. In sum, cardiorespiratory fitness was related to a brain oscillatory differential response pattern over a wide range of the frequency spectrum and spatio-temporal distribution, which seems to underlie the positive relationship between aerobic fitness and behavioural performance in a sustained attention task. Future studies are warranted to study the causal nature (beyond mere association) of these findings.

Sex differences in high-level appreciation of automobile design-evoked gamma broadband synchronization

The present study was conducted to provide neuroimaging correlates for neurodesign of automobile for marketing aesthetics, using event-related spectral perturbations (ERSPs) and participant reports. Thirty men and women aged 22–27 years were presented with various 3-dimensional automobile modelling shapes (rectangular, streamlined, and round), which were cross-matched with various interior colour tones (pure hue/vivid, light, and dark tones) in the experimental conditions, i.e., rectangular exterior with a vivid tone interior. The stimuli pairs were to be rated by participants to facilitate our understanding of the emotional dimensions of automotive design qualities. Significant differences were observed in the high gamma band of 80–100 Hz in the left temporal area between the two sexes. Men elicited a stronger high gamma band signals for dark colour tone interiors and rectangular or round automobile modelling designs because of the meaningful and comprehensible signals associated with the mechanisms of working memory. In contrast, women had fewer reactions than men, and elicited higher beta-band dynamics in the anterior cingulate cortex for rectangular automobile modelling design, and higher gamma-band dynamics for light colour tone interiors, which might relate to their higher self-awareness of positive emotional reward.

Classification of EEG signals produced by musical notes as stimuli

In this paper, we present the classification of electroencephalograph (EEG) signals produced by the first-octave musical notes of the piano as stimuli. The EEG classification of musical notes is attempted for the first time, to the best of our knowledge. This type of classification could be applied towards the development of Brain-Computer Interfaces (BCIs) for the composition of music via thought as well as the definition of mappings between different stimuli for Sensory Substitution Devices (SSDs) that are based on their actual impact on brain signals and thus serve better the purpose of SSDs, which is to translate between senses at the perceptual level. Event-Related Spectral Perturbations (ERSP) are extracted as features and are fed into a Support Vector Machine (SVM) classifier. Our aim was to classify musical notes as C, C#, D, D#, E, F, F#, G, G#, A, A#, B and we have achieved it with an average accuracy of 70%.

Spatiotemporal dynamics of working memory under the influence of emotions based on EEG

Objective. Previous studies have reported that working memory (WM) may be affected by emotions and that the effect may exist in different stages of WM. However, at present it remains controversial whether emotions inhibit or facilitate WM, and how the mechanism of dynamic information transmission in the brain during WM is affected by emotions. Approach. In this study, we used a video database to induce three emotions (negative, neutral, and positive) and adopted a change detection paradigm based on electroencephalography. Event-related potential (ERP) analysis, event-related spectral perturbation analysis, source location analysis based on the dipole localization method and the distributed source localization method, and effective connectivity analysis were performed. Main results. Both behavioral and ERP results suggest that positive emotions have no significant effect on WM capacity, while negative emotions could facilitate WM capacity. Furthermore, the effective connectivity results based on two source location methods suggest that the long-range connectivity between the frontal and posterior areas can reflect the influence of positive and negative emotions on the WM network, in which the connectivity under the positive emotion condition occurs in the earlier period of WM maintenance, while the connectivity under the negative emotion condition occurs in the later period of WM maintenance. Significance. The consistency of the behavioral, ERP, and effective connectivity results suggests that under the negative emotion condition, the top-down attention modulation between the frontoparietal area and posterior area could promote the most relevant information storage during WM maintenance.

Improving the Performance of Brain-Computer Interface using Deep Learning Algorithms and Event-Related Spectral Perturbation

Brain Computer Interface allows disabled people to communicate with the external world by using their brain signals. The main goal of a BCI is to provide patients who suffer form any neuromuscular disorders whith a communication channel based on their brain signals. In this paper, the aim is to explore the effects of applying deep learning algorithms and Event Related Spectral Perturbation analyses on the performance of different EEG-based BCI paradigms. Two paradigms were investigated: one is based on the Matrix paradigm (known as oddball); and the other one utilizes the Rapid serial visual Presentation (RSVP) for presenting the stimuli. Deep learning algorithms of convolutional Neural Network (CNN) and Recurrent Neural Network (RNN) were utilized to evaluate the two paradigms. Our findings showed that Matrix paradigm is more effective in detecting P300 signal. In terms of classification methods, deep learning of CNN algorithm has shown superiority performance in comparison with the other machine learning algorithms.

Oscillatory dynamics of perception of emotional sentences in healthy subjects with different severity of depressive symptoms

The aim of the study was to investigate the characteristics of the oscillatory dynamics of brain activity during the perception of negative, positive, and neutral sentences in healthy individuals with differing severity of depressive symptoms at the preclinical stage. The study involved 34 healthy people (22 women). The severity of the symptoms of depression was assessed using Beck's Depression Inventory (BDI II). Using independent component analysis and the function of dipfit in the EEGlab software, the EEG was divided into components and their localizations were calculated. To assess the induced responses, event-related spectral perturbations were calculated. The perception of emotional sentences was accompanied by a more pronounced increase in theta rhythm in the group with lower severity of depressive symptoms. The perception of all types of sentences was accompanied by a decrease in beta rhythm in the group with lower severity of depressive symptoms. The effects were localized to the precuneus. The decrease of oscillatory responses in the theta and beta ranges in individuals with a high severity of depressive symptoms suggests a reduction of attention to the emotional content and meaning of the sentences.

A new paradigm to study the influence of attentional load on cortical activity for motor preparation of step initiation.

Motor programme for gait initiation can vary as a function of attentional resources. The objective of the present study was to determine whether alertness, orientation and executive control can modulate cortical activation during step initiation. The attention network test (ANT) was used to control the influence of different attentional components on kinetic characteristics of step initiation and the associated cortical activity. Thirty healthy adults performed ANT combined with step initiation. The step execution time (SET) and anticipatory postural adjustments (APAs) were recorded. Movement-related cortical potentials (MRCPs) and event-related spectral perturbations (ERSPs) after response emission were analysed according to the presence or absence of cueing or conflict resolution. Step reaction time and thus SET were significantly shorter with cueing, whereas APA duration and SET were longer during conflict resolution. Moreover, alertness was related to a higher rate of anticipated responses, and conflicting situations were associated with a greater amount of multiple APAs. Attentional load did not affect MRCPs but ERSPs: trials with a cue showed earlier posterior alpha and beta desynchronisations before APA onset. Furthermore, we found earlier, more pronounced and longer alpha- and beta-band desynchronisations over the sensorimotor cortex for trials with incongruent flankers. Our results showed that attention has an impact on step initiation. A specific pattern of response-locked ERSPs seems to mirror behavioural effects of attentional load on step initiation. This new paradigm combining ANT and step initiation is, therefore, promising to investigate the interaction between attention and gait initiation in pathological populations.

Lateralization of brain responses to auditory motion: A study using single-trial analysis

The present study investigates hemispheric asymmetry of the ERPs and low-frequency oscillatory responses evoked in both hemispheres of the brain by the sound stimuli with delayed onset of motion. EEG was recorded for three patterns of sound motion produced by changes in interaural time differences. Event-related spectral perturbation (ERSP) and inter-trial phase coherence (ITC) were computed from the time-frequency decomposition of EEG signals. The participants either read books of their choice (passive listening) or indicated the sound trajectories perceived using a graphic tablet (active listening). Our goal was to find out whether the lateralization of the motion-onset response (MOR) and oscillatory responses to sound motion were more consistent with the right-hemispheric dominance, contralateral or neglect model of interhemispheric asymmetry.Apparent dominance of the right hemisphere was found only in the ERSP responses. Stronger contralaterality of the left hemisphere corresponding to the “neglect model” of asymmetry was shown by the MOR components and by the phase coherence of the delta-alpha oscillations. Velocity and attention did not change consistently the interhemispheric asymmetry of both the MOR and the oscillatory responses. Our findings demonstrate how the lateralization pattern shown by the MOR potential was interrelated with that of the motion-related single-trial measures.

Influence of Judo Experience on Neuroelectric Activity During a Selective Attention Task.

ObjectiveWe compared the cognitive performance and neuroelectric responses during a selective attentional task in judo athletes with different levels of expertise.MethodsJudo black and white belt athletes performed both general and specific fitness tests while simultaneously completing a Stroop color-word test recorded by 64 electroencephalogram channels.ResultsCognitive behavioral performance and event-related spectral perturbation (ERSP) present no differences between groups. However, the topographic analysis found different neural source patterns in each group. Judo black belts compared to judo white belts presented a greater peak amplitude of P300 in the middle frontal gyrus and of N200 in the cuneus, but slower latency of P300 in the precuneus.ConclusionDespite no difference in cognitive behavioral performance, judo expertise causes a difference in the allocation of attentional and conflict detection neural resources.

A concept of sub-bands event related potentials to increase classes of brain computer interface system

Event related potential (ERP) based brain computer interfacing (BCI) achieves significant stability. Changes in electroencephalogram (EEG) signals related to various tasks have been significantly observed. However, each ERP related to particular task can be only exploited as one-to-one relation with specific command or operation. This limits the variability of BCI system and increases the amount of work to identify task related accurate pattern changes in EEG. In this paper, sub-band analysis of detected ERP is proposed in order to factorise one-to-one relation into one-to-many for increasing the variability of BCI system. First, the hypothesis based on analysis of event related spectral perturbation (ERSP) is stated, and then the hypothetical concept is generalised with sub-bands decomposition of ERP, followed by culminative power estimation. Results show that the proposed technique can be easily implemented as a method of combined factorised feature extraction (CFFE) to execute multiple commands from single ERP.

Brain Activity During Unilateral Physical and Imagined Isometric Contractions.

By convention, it is believed that the ipsilateral side of the body is controlled by the contralateral side of the brain. Past studies measuring brain activity primarily recorded changes before and after an intervention is performed on one side of the body within one hemisphere (usually the contralateral) of the brain. The purpose of this investigation was to observe the brain activity within the left and right hemispheres of the prefrontal and sensorimotor cortices during physical and imagined, dominant and non-dominant unilateral isometric elbow flexion. Fifteen right hand dominant individuals (six males and nine females) between the ages of 18 and 21 performed four different isometric contractions of their biceps brachii at a preacher curl bench: dominant physical contraction (DomCon), non-dominant physical contraction (NonCon), dominant imagined contraction (DomImagine), and non-dominant imagined contraction (NonImagine). Each contraction was sustained for 5 s followed by 30 s of rest. Motor activity-related cortical potential (MRCP) and event-related spectral perturbation (ERSP) within the right and left hemispheres of the sensorimotor and prefrontal cortices were determined for each condition at 500–1,000 ms and 2,000–2,500 ms after initiation of contraction. MRCP and ERSP were both changed at the 500–1,000 ms time window for all conditions. Changes in the 2,000–2,500 ms window were most consistently observed during physical contractions. While the changes during DomCon occurred in the left (contralateral) side of the brain, the greatest changes observed in MRCP and ERSP occurred in both sides of the brain during the NonCon condition. Further understanding of bilateral changes in brain activity during unilateral tasks is valuable for improving rehabilitation practices through mental and physical exercise.

Influence of Time Pressure on Inhibitory Brain Control During Emergency Driving

It is believed that failures of people’s reaction to emergencies occurred during driving are closely related to the inhibitory mechanism of brain’s operations. To investigate the role of this function in emergency driving, two virtual realistic driving conditions based on stop signal task were designed and time limitation was manipulated to increase the stress in one condition. Sixteen subjects with behavioral encephalography recordings were collected and analyzed. By comparing successful and unsuccessful stop trials with event-related spectral perturbation analysis, ${\delta }$ and ${\theta }$ band power increases in frontal and central areas are correlated with driving inhibitory control of the brain. Moreover, ${\beta }$ and ${\gamma }$ band power in frontal and central areas showed more increases upon stress condition. Time pressure in driving could adjust the operation of brain’s inhibition control, to benefit the people’s reactive ability upon emergency.

Impact of Polymorphisms in the Serotonin Transporter Gene on Oscillatory Dynamics during Inhibition of Planned Movement in Children.

The serotonin transporter plays an important role in serotonergic neuromodulation. It is known that polymorphisms in the serotonin transporter gene are linked to the dysregulation of emotions. In the current study, we aimed to investigate the impact of variation in the gene encoding serotonin transporter polymorphism on oscillatory dynamics during inhibition of planned movement in the stop signal paradigm. During performance the stop signal paradigm, electroencephalograms (EEGs) were recorded in 90 healthy Caucasian children (39 girls) from 7 to 12 years. Buccal epithelium probes were taken from all participants. The La, Lg, and S alleles of serotonin transporter-linked polymorphic region (5-HTTLPR) polymorphism were detected in the DNA samples using PCR. LaLa genotype carriers did not differ from LaS\\LgS and LgS\\LgLg\\SS carriers in a number of successful inhibitions of a prepotent response. Carriers of LaLa exhibit higher alpha and beta event-related spectral perturbations (ERSP) in parietal and occipital cortices after the presentation of signal of inhibition of movement than LaS\\LgS and LgS\\LgLg\\SS carriers. Results are consistent with current literature and confirm that S allele carriers are more predisposed to disturbances in cognitive control.

Characteristics of Kinematic Parameters in Decoding Intended Reaching Movements Using Electroencephalography (EEG).

The utility of premovement electroencephalography (EEG) for decoding movement intention during a reaching task has been demonstrated. However, the kind of information the brain represents regarding the intended target during movement preparation remains unknown. In the present study, we investigated which movement parameters (i.e., direction, distance, and positions for reaching) can be decoded in premovement EEG decoding. Eight participants performed 30 types of reaching movements that consisted of 1 of 24 movement directions, 7 movement distances, 5 horizontal target positions, and 5 vertical target positions. Event-related spectral perturbations were extracted using independent components, some of which were selected via an analysis of variance for further binary classification analysis using a support vector machine. When each parameter was used for class labeling, all possible binary classifications were performed. Classification accuracies for direction and distance were significantly higher than chance level, although no significant differences were observed for position. For the classification in which each movement was considered as a different class, the parameters comprising two vectors representing each movement were analyzed. In this case, classification accuracies were high when differences in distance were high, the sum of distances was high, angular differences were large, and differences in the target positions were high. The findings further revealed that direction and distance may provide the largest contributions to movement. In addition, regardless of the parameter, useful features for classification are easily found over the parietal and occipital areas.

Empathy for pain in fibromyalgia patients: An EEG study

BackgroundRecent research in cognitive neurosciences highlights how the neural circuitries are activated during pain responses in empathic context. AimsThe present study was designed to test if healthy subjects and Fibromyalgia (FM) patients, both evaluated by Laser Evoked Potentials (LEPs) and Event-Related Spectral Perturbation (ERSP), might reveal the empathic response to the partner's nociceptive stimulation. MethodsThe emphatic nociceptive paradigm was recorded through 64 channels EEG and laser stimulation of the right hand in a shared visual open setting (Open Condition) or in a blind setting (Blind condition) where the subjects didn't receive visual information about partner nociceptive condition. Twenty one healthy subjects and 19 FM patients were evaluated in pairs. All subjects were tested by the Empathy for Pain Scale (EPS). ResultsThe averaged LEPs were similar between patients and controls in the different conditions. In attendance of the partner's stimulation, FM patients desynchronized the same fronto-central regions as before own stimulation, while healthy subjects shared the other's pain by activating scalp areas compatible with visual attention. These EEG features were more represented in subjects with higher EPS scores. ConclusionsWhile empathic features of healthy subjects seemed influenced by the specific visual attentional task, patients expressed an EEG pattern compatible with somatosensory circuits activation in the expectation of own and other's pain. The visual empathic involvement in other's noxious stimulation could evoke a different EEG response depending upon the experience of chronic pain.

Mid-Frontal Theta Modulates Response Inhibition and Decision Making Processes in Emotional Contexts.

Inhibitory control is an integral part of executive functions. In this study, we report event-related spectral perturbation (ERSP) results from 15 healthy adults performing an emotional stop-signal task with the use of happy, disgusted, and neutral emotional faces. Our ERSP results at the group level suggest that changes in low frequency oscillatory power for emotional and neutral conditions start at as early as 200 ms after stimulus onset and 300 ms before button press for successful go trials. To quantify the dynamics of trial-by-trial theta power, we applied the hierarchical drift diffusion model to single-trial ERSP at the mid-frontal electrode site for the go condition. Hierarchical drift diffusion modeling (HDDM) assigned higher frontal low-frequency oscillatory power for evidence accumulation in emotional contexts as compared to a neutral setting. Our results provide new evidence for dynamic modulation of sensory processing of go stimuli in inhibition and extend our knowledge for processing of response inhibition in emotional contexts.