Neuroscan System Research Articles

Electroencephalography Study of Frontal Lobe Evoked by Dynamic Random-Dot Stereogram.

PurposeThe purpose of this study was to investigate the cortical electrical activity and electroencephalography (EEG) features of the frontal lobe evoked by dynamic random dot stereogram (DRDS) and to probe the functional connectivity (FC) between the frontal lobe and occipital lobe when processing 3D perception based on the binocular disparity.MethodsThe EEG experiment involved 14 healthy adults with normal stereopsis (<60″) and normal corrected visual acuity (20/20). The Neuroscan system and 32-channel EEG cap were used to record EEG signals based on the DRDS stimuli. The maximum energies of 3 frequency bands (theta-/alpha- /beta-wave) from 13 interesting channels (FP1, FP2, F7, F3, FZ, F4, F8, FC3, FCZ, FC4, O1, OZ, and O2) located in the frontal and occipital lobes were calculated and analyzed. The FC between any two electrodes from the frontal and occipital lobes was calculated based on the Phase lag index (PLI).ResultsThe maximum powers of theta- and alpha-waves in most channels of the frontal and occipital lobes were significantly increased (P < 0.05) when the depth perception was evoked by DRDS above the threshold, compared with that without stereo vision. The changes in the maximum powers of both theta- and alpha-waves were significantly different among the 13 electrodes (P = 0.0004 and 0.0015, respectively). Tukey's multiple comparisons showed that the changes in the maximum powers of theta-wave were significantly different in F8 vs. O1, F8 vs. OZ, and F4 vs. O1 (P = 0.0186, 0.0444, and 0.0412, respectively). Moreover, the changes in the maximum powers of alpha-waves were significantly different in FP1 vs. O1 (P = 0.0182). The FCs of theta-waves between the frontal channels and the occipital channels were significantly enhanced when processing the depth perception, compared with those without stereopsis. There was no significant change in the FCs of the alpha-waves when having 3D perception except for FC between F8 and O1 and FC between F8 and OZ.ConclusionsThe cortical electrical activity in the frontal lobe and the functional connectivity between the frontal lobe and the occipital lobe increase when participating in the processing binocular disparity and obtaining 3D perception. Theta-waves in the frontal lobe may be crucial in the stereo vision.

The Effects of Reward on Associative Memory Depend on Unitization Depths.

Previous studies have found that reward effect is stronger for more difficult to retrieve items, but whether this effect holds true for the associative memory remains unclear too. We investigated the effects and neural mechanisms of the different unitization depths and reward sets on encoding associative memory using event-related potentials (ERPs), which were recorded through a Neuroscan system with a 64-channel electrode cap according to the international 10–20 system, and five electrodes (Fz, FCz, Cz, CPz, and Pz) were selected for analysis. Thirty healthy college students took part in this study. During encoding, participants were carried out two encoding tasks, a congruity-judgment task with high unitization and a color-judgment task with low unitization, with half of the items rewarded. The test phase was conducted immediately after the encoding phase. The results for false alarm rates and Prs (i.e., hit rates for old pairs minus false alarm rates for new pairs) in relational retrieval revealed that the reward differences in the color-judgment task were greater than those in the congruity-judgment task. The ERP results further showed significant reward effects (i.e., the reward significantly improved the average amplitudes compared to no reward) at P300 (300–500 ms) and LPP (500–800 ms) in the color-judgment task both for intact and rearranged items, and the reward effects at LPP (electrodes Fz, FCz, Cz, CPz, and Pz) were distributed more widely than the reward effects at P300 (electrodes Fz and FCz) in the color-judgment task. These results suggest that reward provided a greater boost when retrieving associative memory of low unitized items.

INTELLIGENCE LEVEL MIGHT BE PREDICTED BY THE CHARACTERISTICS OF EEG SIGNALS AT SPECIFIC FREQUENCIES AND BRAIN REGIONS

The total energy the brain consumed and the intensities of information flows across different brain regions in an intellectual activity may help to explain an individual’s intelligence level. To verify this assumption, 43 students aged 18–25 were recruited as the research subjects. Their intelligence quotients (IQ) were scored by using Wechsler Adult Intelligence Scale (WAIS), while their electroencephalogram (EEG) signals were recorded simultaneously by using Neuroscan system. The total energy and distribution patterns of EEG signals were acquired in Curry 8.0. The intensities of information flow across different brain regions were measured by Phase Slope Index (PSI). 20 channels and 190 channel combinations were selected for data analysis. The results show that the IQ score negatively correlates to the EEG energy and positively correlates to the intensities of information flows at specific frequency bands in specific channel pairs, especially in some long distance (18–24[Formula: see text]cm) channel pairs.

F109. An event-related brain potential study of the arithmetic skills in college students

Introduction The arithmetic is fundamental in everyday life and represent an elemental part of learning of the individuals being a tool that allows an optimal performance in the resolution of problematic situations. One of the main research objectives of human behavior is understanding of cognitive processes such as arithmetic processing through neurophysiological techniques as the Event Related Potentials (ERPs). ERPs are a series of positive or negative oscillations, result of averaging segments where visual or auditory stimuli were presented to the participant during the electroencephalogram. Arithmetic processes have been associated to the Late Positive Component (LPC) located in central-parietal regions. Methods The sample consisted of 26 participants, 17 women and 9 men, with an average age of 21.3 years (SD ± 4.4 years). The EEG was performed with the software Curry XS Neuroscan System®, using 62 Au electrodes. The original file was converted, from data format to cnt format. The obtained signal was segmented in times with an analysis window of −400 to 1600 ms, rejection of muscular and ocular artifact was made, with Independent Component Analysis. Both the verification and the production paradigms were presented on a monitor with a resolution of 1280 × 960 pixels during the EEG. The verification paradigm had a total of 80 arithmetic operations of integers with a possible response, the participant had to answer if the response showed was either correct or incorrect, to record the responses a board with two buttons was used, one button for the correct answer and one for the incorrect answer. The production paradigm had a total of 80 arithmetic operations of whole numbers, the participant had to answer verbally during a neutral stimulus. With sampling frequency of 1000 Hz. Each arithmetic operation lasted 4000 ms followed by a neutral stimulus (a point in the center of the screen) with a duration of 500 ms where the participant gave the answer. The analyses with the EEGLAB tool of the MATLAB software. The PREs of each participant were analyzed and then the average of each stimulus was made Results The right answers in the complex operations were significantly lower than the those in the simple operations x2 (1, N = 80) = 42.89, p Conclusion There were no differences in the right answers of the participants between experimental paradigms. The type of operation and its difficulty did not affect the early ERPs however amplitude of the LPC appears to be sensitive to arithmetic production tasks.

The event-related potentials study on empathy for pain in the subjects with autistic traits

Objective To study the features and neural mechanism of pain empathy in autistic individuals. Methods Totally 21 subjects with high level autistic traits and 22 subjects with low level autism traits completed the pain empathy task, recording RT and accuracy automatically. The event-related potentials(ERPs) were recorded by Neuroscan system simultaneously. Results (1)From the behavioral results, the IRI scores of the two groups had significant differences in the factors of perspective taking ((23.71±4.16) vs (26.95±3.24)), empathy concerning ((24.10±4.04) vs (26.36±2.82)) and personal distress ((24.19±3.59) vs (19.82±3.96)) (t=-2.86, P 0.05). (2) According to the behavioral result of pain empathy test, the main effect of task type in reaction time and accuracy of the two groups had significant difference (F(1, 41)=24.21, P 0.05, F(1, 41)=0.29, P>0.05; F(1, 41)=3.20, P>0.05, F(1, 41)=0.14, P>0.05). (3)From the results of ERP, the main effect of emotion type, task type and group didn't reach the significant level in the N2 amplitude of the two groups(F(1, 41)=0.04, P>0.05; F(1, 41)=0.08, P>0.05; F(1, 41)=3.86, P>0.05). The main effect of emotion type had significant difference in the P3 amplitude of the two groups(F(1, 41)=8.27, P 0.05, F(1, 41)=0.25, P>0.05). It had significant difference in LPP amplitude in the main effect of emotion type, task type and group(F(1, 41)=32.07, P<0.01; F(1, 41)=8.63, P<0.01; F(1, 41)=4.73, P<0.05). Conclusions There are differences in the abilities of empathy between the high and low level autistic traits groups, especially in the late processing of pain empathy. Key words: Autism traits; Pain empathy; Event-related potentials

66. Preliminary analysis of Mismatch Negativity (MMN) in healthy preschool children

Objective To describe the spectral-temporal characteristics of the Mismatch Negativity (MMN) in preschool age children. Material and methods 10 children (5 boys, 5 girls), mean age of 5 years 4 months (SD = ± 2.6 months) participated in this study. EEG was recorded with Neuroscan system and the Curry 7.0.10XS software, using 60 AgCl active electrodes. The MMN was obtained by using an auditory oddball passive task, which included 320 frequent (/Ajos/) and 80 infrequent stimuli (/Ojos/). Latencies, amplitudes and band power were analyzed in the FCZ and Oz derivations using the MATLAB toolbox EEGLAB 13.5.4b. Results The MMN in boys had a latency of 263.7 ms and of −2.58 μ V of amplitude. In addition, the late component LDN at 441.4 ms and −2.81 μ V. In girls, the MMN was found at 285.2 ms with a peak amplitude of −2.58 μ V, and the LDN was found at 451.2 ms and −2.36 μ V. An increase in the gamma band was found in FCz at 250 ms related to the word/Ajos/ while in the word/Ojos/ produced an increase in gamma band between 300 and 400 ms. On the other hand, a decrease in gamma was obtained in Oz starting from stimulus onset. Conclusions Spectral-temporal analyses of the MMN revealed higher synchrony in the gamma band in frontocentral areas, while a desynchronization in occipital areas. Significance These findings, will contribute to the normative database of the MMN in preschool age population.

69. An approximation to time–frequency analysis of the Mismatch Negativity (MMN) in children with language impairment

Objective To describe in time and frequency the MMN of children with language impairments. Material and methods 12 children (6 boys, 6 girls) were selected with an average age of 5 years 5 months ( ± SD 4 months), classified in two groups: one with language impairments (LI) and other with typical developmental (TD). EEG was recorded and the MMN was obtained with an oddball paradigm using the words/ajos/ (standard) and/ojos/ (deviant), and 60 electrodes on the Curry 7.0 XS software from Neuroscan System; frontocentral regions were analyzed (FCz, FC3, FC4) by describing the latencies and amplitudes of the MMN and the frequency band power related to standard and deviant stimuli using EEGLAB 13.5.4b. Results The MMN was observed at 324 ms for both groups, and its late component called LDN, at 426 ms for TD and 438 ms for LI; there was a smaller amplitude of both components in children with LI. Gamma activity synchronization related to deviant stimuli was observed. Conclusions The smaller amplitude of MMN and LDN in children with language impairment could be related with a low neuronal synchronization in word discrimination. Significance The analysis of MMN in language impairments, shows the presence of a deficit in auditory perceptual discrimination that impedes a proper discrimination and expression of speech sounds. MMN characterization contributes to determine if the language difficulties of children are given by a dysfunctional neural substrate. The data obtained allow establishing an appropriate intervention for each case.

The event-related potentials study on attentional deployment in alexithymia

Objective To study the attentional deployment strategy of emotion regulation and its processing mechanisms in alexithymia. Methods 21 alexithymia subjects and 22 normal subjects completed attentional deployment task.The reaction time(RT) and accuracy were recorded automatically and the event-related potentials(ERPs) were recorded by neuroscan system. Results ①From the behavioral results, the differences of RT and accuracy to neutral pictures((1840.17±204.44)ms vs (1845.17±252.97)ms; (0.859±0.073) vs (0.884±0.068)) and negative pictures ((1888.94±200.09)ms vs(1890.38±263.72)ms); (0.845±0.088) vs (0.845±0.091))in calculation task between two groups were not statistically significant(all P>0.05). The differences of RT and accuracy in emotion task were not statistically significant(P>0.05). ②In RT and accuracy, the task main effects were statistically significant(F(1, 42)=637.40, P 0.05). P3 amplitude induced by negative pictures were significantly greater than those induced by neutral pictures in emotion task((–0.138±0.463)μV vs (0.789±0.541)μV). Conclusion The attentional deployment can effectively regulate the negative pictures processing and occur in the late stage of the picture processing. No attentional deployment defects in alexithymia. Key words: Alexithymia; Emotion regulation; Attentional deployment; Event-related potentials

Measuring the face-sensitive N170 with a gaming EEG system: A validation study

BackgroundThe N170 is a “face-sensitive” event-related potential (ERP) that occurs at around 170ms over occipito-temporal brain regions. The N170's potential to provide insight into the neural processing of faces in certain populations (e.g., children and adults with cognitive impairments) is limited by its measurement in scientific laboratories that can appear threatening to some people. New methodThe advent of cheap, easy-to-use portable gaming EEG systems provides an opportunity to record EEG in new contexts and populations. This study tested the validity of the face-sensitive N170 ERP measured with an adapted commercial EEG system (the Emotiv EPOC) that is used at home by gamers. ResultsThe N170 recorded through both the gaming EEG system and the research EEG system exhibited face-sensitivity, with larger mean amplitudes in response to the face stimuli than the non-face stimuli, and a delayed N170 peak in response to face inversion. Comparison with existing methodThe EPOC system produced very similar N170 ERPs to a research-grade Neuroscan system, and was capable of recording face-sensitivity in the N170, validating its use as research tool in this arena. ConclusionsThis opens new possibilities for measuring the face-sensitive N170 ERP in people who cannot travel to a traditional ERP laboratory (e.g., elderly people in care), who cannot tolerate laboratory conditions (e.g., people with autism), or who need to be tested in situ for practical or experimental reasons (e.g., children in schools)

Validation of the Emotiv EPOC EEG system for research quality auditory event-related potentials in children.

Background. Previous work has demonstrated that a commercial gaming electroencephalography (EEG) system, Emotiv EPOC, can be adjusted to provide valid auditory event-related potentials (ERPs) in adults that are comparable to ERPs recorded by a research-grade EEG system, Neuroscan. The aim of the current study was to determine if the same was true for children.Method. An adapted Emotiv EPOC system and Neuroscan system were used to make simultaneous EEG recordings in nineteen 6- to 12-year-old children under “passive” and “active” listening conditions. In the passive condition, children were instructed to watch a silent DVD and ignore 566 standard (1,000 Hz) and 100 deviant (1,200 Hz) tones. In the active condition, they listened to the same stimuli, and were asked to count the number of ‘high’ (i.e., deviant) tones.Results. Intraclass correlations (ICCs) indicated that the ERP morphology recorded with the two systems was very similar for the P1, N1, P2, N2, and P3 ERP peaks (r = .82 to .95) in both passive and active conditions, and less so, though still strong, for mismatch negativity ERP component (MMN; r = .67 to .74). There were few differences between peak amplitude and latency estimates for the two systems.Conclusions. An adapted EPOC EEG system can be used to index children’s late auditory ERP peaks (i.e., P1, N1, P2, N2, P3) and their MMN ERP component.

The event-related potentials study on positive emotional Stroop effect in male subjects

Objective To study the mechanism underlying attentional biases toward event-related potentials (ERPs) in healthy male subjects. Methods 18 male healthy subjects performed emotional stroop task by pressing the buttons to the picture border color of two categories including the neutral and positive. The RT and Accuracy were recorded automatically. The ERPs were recorded by Neuroscan system. Results The behavioral results showed that neither the reaction time(628.11±55.46)ms vs(628.81±53.92)ms nor accuracy (96.87±4.42)% vs (95.76±7.41)% found difference under two conditions. ERPs results showed that the positive pictures evoked more greater P2 ((8.16±4.99)μV vs (4.30±3.83)μV) and P3 ((6.31±4.53)μV vs (4.27±4.16)μV) than neutral pictures. Conclusion Attentional biases toward positive emotion can be found in healthy male subjects, which can be related to emotional control process. Key words: Event-related potentials; Positive emotional; Stroop; Attention bias

Assessment of SOMNOwatch plus EEG for sleep monitoring in healthy individuals

Polysomnography (PSG) is still the standard in sleep monitoring, with several alternative solutions developed, including simplified electroencephalographic recorders such as SOMNOwatch plus EEG. In this study, we aimed to evaluate the validity of the recordings and of the analysis of the proprietary software of this solution, compared to PSG and semiautomatic scoring, respectively. From thirteen healthy adults, we recorded 27 nights simultaneously with a classical EEG amplifier (NeuroScan system) and the ambulatory SOMNOwatch plus EEG. Thereafter, we performed (semi-) automatic sleep analysis in Somnolyzer 24x7 and DOMINO Light (SOMNOwatch software). AASM scoring sensitivity of SOMNOwatch plus EEG, as revealed by Somnolyzer 24x7, was 97.79%, and specificity 87.19%. Paired T tests revealed no significant differences between the recordings of the two EEG systems, with intraclass correlation coefficients ranging from moderate to very good. When data were analyzed in DOMINO Light, sensitivity was 92.99% and specificity was 80.90%. Our data suggest that SOMNOwatch plus EEG might serve as a reliable instrument for recording sleep in healthy individuals, but its proprietary software, DOMINO Light, still seems to have weaknesses in terms of automatic sleep staging.

Identification of a novel dynamic red blindness in human by event-related brain potentials

Dynamic color is an important carrier that takes information in some special occupations. However, up to the present, there are no available and objective tests to evaluate dynamic color processing. To investigate the characteristics of dynamic color processing, we adopted two patterns of visual stimulus called "onset-offset" which reflected static color stimuli and "sustained moving" without abrupt mode which reflected dynamic color stimuli to evoke event-related brain potentials (ERPs) in primary color amblyopia patients (abnormal group) and subjects with normal color recognition ability (normal group). ERPs were recorded by Neuroscan system. The results showed that in the normal group, ERPs in response to the dynamic red stimulus showed frontal positive amplitudes with a latency of about 180 ms, a negative peak at about 240 ms and a peak latency of the late positive potential (LPP) in a time window between 290 and 580 ms. In the abnormal group, ERPs in response to the dynamic red stimulus were fully lost and characterized by vanished amplitudes between 0 and 800 ms. No significant difference was noted in ERPs in response to the dynamic green and blue stimulus between the two groups (P>0.05). ERPs of the two groups in response to the static red, green and blue stimulus were not much different, showing a transient negative peak at about 170 ms and a peak latency of LPP in a time window between 350 and 650 ms. Our results first revealed that some subjects who were not identified as color blindness under static color recognition could not completely apperceive a sort of dynamic red stimulus by ERPs, which was called "dynamic red blindness". Furthermore, these results also indicated that low-frequency ERPs induced by "sustained moving" may be a good and new method to test dynamic color perception competence.

Abnormal co-contraction in yips-affected but not unaffected golfers: Evidence for focal dystonia

Up to 30% of golfers develop the yips, an inability to complete a golf stroke, most often affecting short putts, which worsens with anxiety.1,2 Yips may be organic (task-specific dystonia) or psychological (anxiety or “choking”).2–4 We previously found abnormal trains of 4 to 8 Hz, rhythmic, co-contracting bursts of EMG activity in arm muscles of three golfers suggesting a movement disorder. This led to the current investigation. We studied 20 age- and handicap-matched male right-handed golfers, 10 with the yips and 10 without. Handicap is the golfer's average score over par over the past ∼10 rounds of golf. Surface EMG electrodes were placed bilaterally on the pectoralis major, deltoid, biceps, triceps, wrist flexors, pronator teres, flexor pollicis longis, wrist extensors, abductor pollicis brevis, and abductor digiti minimi. EEG electrodes were in a standard montage. Recordings were made at a sampling rate of 1,000 Hz, bandpass 1 to 200 Hz using the Neuroscan system (Neuroscan Compumedics, El Paso, TX). Investigators were not …