Increase In Alpha Band Research Articles

An exploration of BCI performance variations in people with amyotrophic lateral sclerosis using longitudinal EEG data

Objective. Brain–computer interface (BCI) technology enables people to use direct measures of brain activity for communication and control. The National Center for Adaptive Neurotechnologies and Helen Hayes Hospital are studying long-term independent home use of P300-based BCIs by people with amyotrophic lateral sclerosis (ALS). This BCI use takes place without technical oversight, and users can encounter substantial variation in their day-to-day BCI performance. The purpose of this study is to identify and evaluate features in the electroencephalogram (EEG) that correlate with successful BCI performance during home use with the goal of improving BCI for people with neuromuscular disorders. Approach. Nine people with ALS used a P300-based BCI at home over several months for communication and computer control. Sessions from a routine calibration task were categorized as successful (70%) or unsuccessful (<70%) BCI performance. The correlation of temporal and spectral EEG features with BCI performance was then evaluated. Main results. BCI performance was positively correlated with an increase in alpha-band (8–14 Hz) activity at locations PO8, P3, Pz, and P4; and beta-band (15–30 Hz) activity at occipital locations. In addition, performance was significantly positively correlated with a positive deflection in EEG amplitude around 220 ms at frontal mid-line locations (i.e. Fz and Cz). BCI performance was negatively correlated with delta-band (1–3 Hz) activity recorded from occipital locations. Significance. These results highlight the variability found in the EEG and describe EEG features that correlate with successful BCI performance during day-to-day use of a P300-based BCI by people with ALS. These results should inform studies focused on improved BCI reliability for people with neuromuscular disorders.

33. Effects of global proprioceptive resonance on resting state EEG in healthy subjects

In the last few years Multifocal Vibration (MFV) has been evaluated as a tool to modify posture and to speed recovery after physical exercise. The aim of this study is to assess whether MFV can also modify resting state EEG. Eleven healthy subjects were included in this study. All subjects underwent a resting state EEG recording of six minutes (three with eyes closed and three minutes with eyes open) for evaluation of resting cortical rhythms, before and after one session of MFV with KEOPE-GPR. Data obtained were collapsed in four region of interest (ROIs): frontal, central, temporal and occipital. Frequency bands of interest were δ (0.5–3.5 Hz), θ (4–7.5 Hz), α 1 (8–10.5 Hz), α 2 (11–12.5 Hz), β 1 (13–19.5 Hz), and β 2 (20–30 Hz). The ratio between slow (delta + theta) and faster (alpha1 + alpha2) rhythms was evaluated using paired t -test. Subsequent statistical analysis was carried on using repeated measures ANOVA (RM-ANOVA) using time (2-levels), side (2-levels) and rhythm (6-levels) as within-subjects factors for each ROI. No statistically significant variations were observed on qEEG with eyes closed. The analysis of ratios between slow and faster frequencies after MFV identified significant variations following MFV ( p MFV can modulate oscillatory activity as observed by qEEG. The increase in alpha band observed in central regions could be related to an enhancement in mu rhythm.

Reorganization of the brain and heart rhythm during autogenic meditation.

The underlying changes in heart coherence that are associated with reported EEG changes in response to meditation have been explored. We measured EEG and heart rate variability (HRV) before and during autogenic meditation. Fourteen subjects participated in the study. Heart coherence scores were significantly increased during meditation compared to the baseline. We found near significant decrease in high beta absolute power, increase in alpha relative power and significant increases in lower (alpha) and higher (above beta) band coherence during 3~min epochs of heart coherent meditation compared to 3~min epochs of heart non-coherence at baseline. The coherence and relative power increase in alpha band and absolute power decrease in high beta band could reflect relaxation state during the heart coherent meditation. The coherence increase in the higher (above beta) band could reflect cortico-cortical local integration and thereby affect cognitive reorganization, simultaneously with relaxation. Further research is still needed for a confirmation of heart coherence as a simple window for the meditative state.

Alpha and beta EEG power reflects L-dopa acute administration in parkinsonian patients.

Aim: To evaluate the effect of an acute L-dopa administration on eye-closed resting state electroencephalographic (EEG) activity of cognitively preserved Parkinsonian patients.Methods: We examined 24 right-handed patients diagnosed as uncomplicated probable Parkinson’s disease (PD). Each patient underwent Unified Parkinson’s Disease Rating Scale (UPDRS)-part-III evaluation before and 60 min after an oral load of L-dopa-methyl-ester/carbidopa 250/25 mg. Resting condition eyes-closed EEG data were recorded both pre- and post L-dopa load. Absolute EEG power values were calculated at each scalp derivation for Delta, Theta, Alpha and Beta frequency bands. UPDRS scores (both global and subscale scores) and EEG data (power values of different frequency bands for each scalp derivation) were submitted to a statistical analysis to compare Pre and Post L-Dopa conditions. Finally, a correlation analysis was carried out between EEG spectral content and UPDRS scores.Results: Considering EEG power spectral analysis, no statistically significant differences arose on Delta and Theta bands after L-dopa intake. Conversely, Alpha and Beta rhythms significantly increased on centro-parietal scalp derivations, as a function of L-dopa administration. Correlation analysis indicated a significant negative correlation between Beta power increase on centro-parietal areas and UPDRS subscores (Rigidity of arms and Bradykinesia). A minor significant negative correlation was also found between Alpha band increase and resting tremor.Conclusions: Assuming that a significant change in EEG power spectrum after L-dopa intake may be related to dopaminergic mechanisms, our findings are consistent with the hypothesis that dopaminergic defective networks are implicated in cortical oscillatory abnormalities at rest in non-demented PD patients.

Evaluating the Changes in Alpha-1 Band Due to Exposure to Magnetic Field

Introduction Increase in alpha band is observed when blood perfusion in frontal area of head decreases. The present study evaluated some changes in the alpha band particularly, alpha-1 of frontal and central areas of the head, when several areas were exposed simultaneously to magnetic field. Materials and Methods Five points of head (F3, F4, Cz, T3, and T4) of twenty healthy male participants were exposed to magnetic fields simultaneously by five separate coils at different frequencies of 45, 17, 10, 5, and 3 Hz, in five separate sessions. The magnetic field intensity was 100 µT at 1.5 cm distance from the coil. At the end, relative powers over these areas in common frequency and alpha-1 bands were evaluated by paired t-test. Results Significant reduction (p<0.05) in alpha-1 band was observed by exposure of local ELF magnetic field at frequencies of higher than 5 Hz in closed-eye. These reductive effects were enormous at 5 and 45 Hz frequency. Conclusion Observed reduction in alpha-1 band may be due to the influence of magnetic field exposure on production centers of alpha band, particularly the thalamus. Hence, increased blood perfusion in some areas is probably the cause of this reduction which requires more research.

Somatosensory working memory performance in humans depends on both engagement and disengagement of regions in a distributed network

Successful working memory (WM) requires the engagement of relevant brain areas but possibly also the disengagement of irrelevant areas. We used magnetoencephalography (MEG) to elucidate the temporal dynamics of areas involved in a somatosensory WM task. We found an increase in gamma band activity in the primary and secondary somatosensory areas during encoding and retention, respectively. This was accompanied by an increase of alpha band activity over task-irrelevant regions including posterior and ipsilateral somatosensory cortex. Importantly, the alpha band increase was strongest during successful WM performance. Furthermore, we found frontal gamma band activity that correlated both with behavioral performance and the alpha band increase. We suggest that somatosensory gamma band activity reflects maintenance and attention-related components of WM operations, whereas alpha band activity reflects frontally controlled disengagement of task-irrelevant regions. Our results demonstrate that resource allocation involving the engagement of task-relevant and disengagement of task-irrelevant regions is needed for optimal task execution.

Effects of Age and Task Complexity on EEG and Performance in Relation to Psychological States

The purpose of the present study is to analyse the effects of task complexity on the EEG spectral parameters and the extent to which age modulates this relationship. Subjects were divided into a junior and a senior group and engaged in a simple and a complex version of “Go/No go” tasks. Cognitive, subjective and electrophysiological data were combined. Our results indicated that there was an increase in alpha power over time only in the junior group in the simple task and the senior group in the complex one, suggesting that, depending on age, the increase in alpha band vary in a different way according with the degree of task complexity and could reflect some different phenomena. Cognitive performance were independent of age but for the main dimensions of motivation, seniors had higher scores, and they were less sleepy than juniors. Finally, this study showed correlations between cognitive performance, subjective evaluations and electrophysiological measures, and their value for understanding the subject’s engagement in a task.

Oscillatory brain activity during human somatosensory working memory maintenance

Event Abstract Back to Event Oscillatory brain activity during human somatosensory working memory maintenance Saskia Haegens1*, D. Osipova1, R. Oostenveld1 and O. Jensen1 1 F.C. Donders Centre for Cognitive Neuroimaging, Netherlands We used magnetoencephalography (MEG) to investigate somatosensory working memory maintenance. The somatosensory system is an excellent model system to study the involvement of primary and secondary sensory areas in working memory. MEG allows us to explore the temporal dynamics of the somatosensory system in terms of oscillatory activity. Subjects performed a delayed-match-to-sample task, with stimuli consisting of pulse trains delivered using median nerve stimulation. Time-frequency representations of power were calculated for the retention period. The maintenance of somatosensory working memory representations was reflected by sustained gamma band activity over bilateral somatosensory regions. Moreover, we observed transient involvement of contralateral primary somatosensory cortex in working memory retention. Additionally, we observed an increase in alpha band activity over posterior areas and ipsilateral somatosensory cortex. This alpha band increase was stronger for trials with correct memory performance than for incorrect trials. Previous studies in the visual and auditory domains found a similar engagement of sustained gamma activity during working memory maintenance, in the respective sensory areas. Our findings extend the notion that sustained gamma band activity reflects the mechanism of working memory maintenance to the somatosensory system. We interpret the alpha activity to reflect a functional inhibitory mechanism, since it was identified in brain regions not required for the task. We propose that the ipsilateral alpha activity plays a similar role for the somatosensory system as posterior alpha plays for the visual system. This study suggests that findings from other modalities, such as the visual system, can be extended to the somatosensory system. Conference: 10th International Conference on Cognitive Neuroscience, Bodrum, Turkey, 1 Sep - 5 Sep, 2008. Presentation Type: Poster Presentation Topic: Brain Electrical Oscillations in Cognition Citation: Haegens S, Osipova D, Oostenveld R and Jensen O (2008). Oscillatory brain activity during human somatosensory working memory maintenance. Conference Abstract: 10th International Conference on Cognitive Neuroscience. doi: 10.3389/conf.neuro.09.2009.01.123 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 05 Dec 2008; Published Online: 05 Dec 2008. * Correspondence: Saskia Haegens, F.C. Donders Centre for Cognitive Neuroimaging, Nijmegen, Netherlands, saskia.haegens@fcdonders.ru.nl Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Saskia Haegens D. Osipova R. Oostenveld O. Jensen Google Saskia Haegens D. Osipova R. Oostenveld O. Jensen Google Scholar Saskia Haegens D. Osipova R. Oostenveld O. Jensen PubMed Saskia Haegens D. Osipova R. Oostenveld O. Jensen Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Attentional modulation of oscillatory activity in human visual cortex

The effects of attentional modulation on activity within the human visual cortex were investigated using magnetoencephalography. Chromatic sinusoidal stimuli were used to evoke activity from the occipital cortex, with attention directed either toward or away from the stimulus using a bar-orientation judgment task. For five observers, global magnetic field power was plotted as a function of time from stimulus onset. The major peak of each function occurred at about 120 ms latency and was well modeled by a current dipole near the calcarine sulcus. Independent component analysis (ICA) on the non-averaged data for each observer also revealed one component of calcarine origin, the location of which matched that of the dipolar source determined from the averaged data. For two observers, ICA revealed a second component near the parieto-occipital sulcus. Although no effects of attention were evident using standard averaging procedures, time-varying spectral analyses of single trials revealed that the main effect of attention was to alter the level of oscillatory activity. Most notably, a sustained increase in alpha-band (7–12 Hz) activity of both calcarine and parieto-occipital origin was evident. In addition, calcarine activity in the range of 13–21 Hz was enhanced, while calcarine activity in the range of 5–6 Hz was reduced. Our results are consistent with the hypothesis that attentional modulation affects neural processing within the calcarine and parieto-occipital cortex by altering the amplitude of alpha-band activity and other natural brain rhythms.