Eye Therapy Effects on Visual Stress based on Electroencephalogram Signals

2015 ◽  
Vol 74 (6) ◽  
Author(s):  
Norlaili Mat Safri ◽  
Siti Nurainn Fayyadhah Adnan
Keyword(s):  
Frequency Band ◽  
Eye Drops ◽  
Search Performance ◽  
Visual Test ◽  
Test Task ◽  
Computer Screen ◽  
Gamma Frequency ◽  
Visual Stress ◽  
Eeg Data ◽  
High Gamma

Eye therapy such as eye massages, has been designed to reduce eye problems and improve blood circulation of the eyes. When reading, the signs and symptoms of visual exhaustion are related to visual stress and people may make use of eye therapy to reduce this visual stress. It is well-known that a relaxed mind can be analysed via the study of an electroencephalogram signal. In this paper, we investigated the effect of eye therapy on visual stress by analysing brain signals (EEG) in frequency domain. Ten subjects participated. In the control task, subjects were asked to relax while EEG data were captured for two minutes. The next part was a visual test task, where the subjects were asked to search for a specific word in a text displayed on a computer screen while their EEG data were recorded. One visual test was performed without prior eye therapy, while the other three visual test tasks were performed following different eye therapy routines. The visual test task was completed fastest when subjects received eye drops and eye massages prior to the visual test. The difference between the visual test with and without prior eye therapy can be observed in the high-gamma frequency band, where with eye therapy, the high-gamma frequency band significantly increases in the frontal, temporal and occipital areas, and the word search performance was improved, with a shorter time needed to complete the task. In conclusion, the high-gamma frequency band may be an indicator to study visual stress, while specific eye-therapy routines may contribute to better eye and brain performance in word searching in a text displayed on a computer screen.

scholarly journals Real-time functional mapping: potential tool for improving language outcome in pediatric epilepsy surgery

2014 ◽  
Vol 14 (3) ◽  
pp. 287-295 ◽  
Author(s):  
Milena Korostenskaja ◽  
Po-Ching Chen ◽  
Christine M. Salinas ◽  
Michael Westerveld ◽  
Peter Brunner ◽  
...  
Keyword(s):  
Real Time ◽  
Frequency Band ◽  
Expressive Language ◽  
Treatment Options ◽  
Functional Mapping ◽  
Pediatric Epilepsy ◽  
Temporal Region ◽  
Language Deficits ◽  
Gamma Frequency ◽  
High Gamma

Accurate language localization expands surgical treatment options for epilepsy patients and reduces the risk of postsurgery language deficits. Electrical cortical stimulation mapping (ESM) is considered to be the clinical gold standard for language localization. While ESM affords clinically valuable results, it can be poorly tolerated by children, requires active participation and compliance, carries a risk of inducing seizures, is highly time consuming, and is labor intensive. Given these limitations, alternative and/or complementary functional localization methods such as analysis of electrocorticographic (ECoG) activity in high gamma frequency band in real time are needed to precisely identify eloquent cortex in children. In this case report, the authors examined 1) the use of real-time functional mapping (RTFM) for language localization in a high gamma frequency band derived from ECoG to guide surgery in an epileptic pediatric patient and 2) the relationship of RTFM mapping results to postsurgical language outcomes. The authors found that RTFM demonstrated relatively high sensitivity (75%) and high specificity (90%) when compared with ESM in a “next-neighbor” analysis. While overlapping with ESM in the superior temporal region, RTFM showed a few other areas of activation related to expressive language function, areas that were eventually resected during the surgery. The authors speculate that this resection may be associated with observed postsurgical expressive language deficits. With additional validation in more subjects, this finding would suggest that surgical planning and associated assessment of the risk/benefit ratio would benefit from information provided by RTFM mapping.

scholarly journals Acoustic contamination of electrophysiological brain signals during speech production and sound perception

2019 ◽  
Author(s):  
Philémon Roussel ◽  
Gaël Le Godais ◽  
Florent Bocquelet ◽  
Marie Palma ◽  
Jiang Hongjie ◽  
...  
Keyword(s):  
Speech Production ◽  
Frequency Band ◽  
Spectral Power ◽  
Sound Waves ◽  
Sound Perception ◽  
Gamma Frequency ◽  
Brain Signals ◽  
High Gamma ◽  
Speech Features

AbstractA current challenge of neurotechnologies is the development of speech brain-computer interfaces to restore communication in people unable to speak. To achieve a proof of concept of such system, neural activity of patients implanted for clinical reasons can be recorded while they speak. Using such simultaneously recorded audio and neural data, decoders can be built to predict speech features using features extracted from brain signals. A typical neural feature is the spectral power of field potentials in the high-gamma frequency band (between 70 and 200 Hz), a range that happens to overlap the fundamental frequency of speech. Here, we analyzed human electrocorticographic (ECoG) and intracortical recordings during speech production and perception as well as rat microelectrocorticographic (µ-ECoG) recordings during sound perception. We observed that electrophysiological signals, recorded with different recording setups, often contain spectrotemporal features highly correlated with those of the sound, especially within the high-gamma band. The characteristics of these correlated spectrotemporal features support a contamination of electrophysiological recordings by sound. In a recording showing high contamination, using neural features within the high-gamma frequency band dramatically increased the performance of linear decoding of acoustic speech features, while such improvement was very limited for another recording showing weak contamination. Further analysis and in vitro replication suggest that the contamination is caused by a mechanical action of the sound waves onto the cables and connectors along the recording chain, transforming sound vibrations into an undesired electrical noise that contaminates the biopotential measurements. This study does not question the existence of relevant physiological neural information underlying speech production or sound perception in the high-gamma frequency band, but alerts on the fact that care should be taken to evaluate and eliminate any possible acoustic contamination of neural signals in order to investigate the cortical dynamics of these processes.

The Influences of Goal and Laterality of a Prepared Hand Response on a Co-Occurring Visual Search

2015 ◽  
Vol 74 (1) ◽  
pp. 55-60 ◽  
Author(s):  
Alexandre Coutté ◽  
Gérard Olivier ◽  
Sylvane Faure
Keyword(s):  
Visual Search ◽  
Visual Target ◽  
Motor Planning ◽  
Search Performance ◽  
Response Preparation ◽  
Manual Response ◽  
Response Hand ◽  
Computer Screen ◽  
Left Hand ◽  
Manual Interaction

Computer use generally requires manual interaction with human-computer interfaces. In this experiment, we studied the influence of manual response preparation on co-occurring shifts of attention to information on a computer screen. The participants were to carry out a visual search task on a computer screen while simultaneously preparing to reach for either a proximal or distal switch on a horizontal device, with either their right or left hand. The response properties were not predictive of the target’s spatial position. The results mainly showed that the preparation of a manual response influenced visual search: (1) The visual target whose location was congruent with the goal of the prepared response was found faster; (2) the visual target whose location was congruent with the laterality of the response hand was found faster; (3) these effects have a cumulative influence on visual search performance; (4) the magnitude of the influence of the response goal on visual search is marginally negatively correlated with the rapidity of response execution. These results are discussed in the general framework of structural coupling between perception and motor planning.

scholarly journals Untangling cortico-striatal connectivity and cross-frequency coupling in L-DOPA-induced dyskinesia

2015 ◽  
Author(s):  
Jovana Belic ◽  
Per Halje ◽  
Ulrike Richter ◽  
Per Petersson ◽  
Jeanette Hellgren Kotaleski
Keyword(s):  
Primary Motor Cortex ◽  
Effective Connectivity ◽  
Spectral Characteristics ◽  
Low Frequency ◽  
Frequency Range ◽  
Gamma Frequency ◽  
High Gamma ◽  
Freely Behaving ◽  
Beta Frequency ◽  
Cross Frequency Coupling

We simultaneously recorded local field potentials in the primary motor cortex and sensorimotor striatum in awake, freely behaving, 6-OHDA lesioned hemi-parkinsonian rats in order to study the features directly related to pathological states such as parkinsonian state and levodopa-induced dyskinesia. We analysed the spectral characteristics of the obtained signals and observed that during dyskinesia the most prominent feature was a relative power increase in the high gamma frequency range at around 80 Hz, while for the parkinsonian state it was in the beta frequency range. Here we show that during both pathological states effective connectivity in terms of Granger causality is bidirectional with an accent on the striatal influence on the cortex. In the case of dyskinesia, we also found a high increase in effective connectivity at 80 Hz. In order to further understand the 80- Hz phenomenon, we performed cross-frequency analysis and observed characteristic patterns in the case of dyskinesia but not in the case of the parkinsonian state or the control state. We noted a large decrease in the modulation of the amplitude at 80 Hz by the phase of low frequency oscillations (up to ~10 Hz) across both structures in the case of dyskinesia. This may suggest a lack of coupling between the low frequency activity of the recorded network and the group of neurons active at ~80 Hz.

Phasic basal ganglia activity associated with high-gamma oscillation during sleep in a songbird

2012 ◽  
Vol 107 (1) ◽  
pp. 424-432 ◽  
Author(s):  
Shin Yanagihara ◽  
Neal A. Hessler
Keyword(s):  
Basal Ganglia ◽  
Phase Locking ◽  
Critical Role ◽  
Field Potential ◽  
Vocal Plasticity ◽  
Song System ◽  
Gamma Frequency ◽  
High Gamma ◽  
Area X

The basal ganglia is thought to be critical for motor control and learning in mammals. In specific basal ganglia regions, gamma frequency oscillations occur during various behavioral states, including sleeping periods. Given the critical role of sleep in regulating vocal plasticity of songbirds, we examined the presence of such oscillations in the basal ganglia. In the song system nucleus Area X, epochs of high-gamma frequency (80–160 Hz) oscillation of local field potential during sleep were associated with phasic increases of neural activity. While birds were awake, activity of the same neurons increased specifically when birds were singing. Furthermore, during sleep there was a clear tendency for phase locking of spikes to these oscillations. Such patterned activity in the sleeping songbird basal ganglia could play a role in off-line processing of song system motor networks.

LFP Power Spectra in V1 Cortex: The Graded Effect of Stimulus Contrast

2005 ◽  
Vol 94 (1) ◽  
pp. 479-490 ◽  
Author(s):  
J. Andrew Henrie ◽  
Robert Shapley
Keyword(s):  
Frequency Band ◽  
Power Spectra ◽  
Low Frequency ◽  
Wide Band ◽  
Gamma Band ◽  
Single Units ◽  
Total Power ◽  
Stimulus Contrast ◽  
Stimulus Response ◽  
Gamma Frequency

We recorded local field potentials (LFPs) and single-unit activity simultaneously in the macaque primary visual cortex (V1) and studied their responses to drifting sinusoidal gratings that were chosen to be “optimal” for the single units. Over all stimulus conditions, the LFP spectra have much greater power in the low-frequency band (≤10 Hz) than higher frequencies and can be described as “1/f.” Analysis of the total power limited to the low, gamma (25–90 Hz), or broad (8–240 Hz) frequency bands of the LFP as a function of stimulus contrast indicates that the LFP power gradually increases with stimulus strength across a wide band in a manner roughly comparable to the increase in the simultaneously recorded spike activity. However, the low-frequency band power remains approximately constant across all stimulus contrasts. More specifically the gamma-band LFP power increases differentially more with respect to baseline than either higher or lower bands as stimulus contrast increases. At the highest stimulus contrasts, we report as others have previously, that the power spectrum of the LFP typically contains an obvious peak in the gamma-frequency band. The gamma-band peak emerges from the overall broadband enhancement in LFP power at stimulus contrasts where most single units' responses have begun to saturate. The temporal/spectral structures of the LFP located in the gamma band—which become most evident at the highest contrasts—provide additional constraints on potential mechanisms underlying the stimulus response properties of spiking neurons in V1.

scholarly journals Divergent paths to seizure-like events

2019 ◽  
Author(s):  
Neela K. Codadu ◽  
Robert Graham ◽  
Richard J. Burman ◽  
R. Thomas Jackson-Taylor ◽  
Joseph V. Raimondo ◽  
...  
Keyword(s):  
Activity Patterns ◽  
Brain Slices ◽  
Field Potential ◽  
Gamma Frequency ◽  
Adult Mice ◽  
Epileptiform Discharges ◽  
Seizure Models ◽  
High Gamma ◽  
Interictal Discharges

AbstractAimMuch debate exists about how the brain transitions into an epileptic seizure. One source of confusion is that there are likely to be critical differences between experimental seizure models. To address this, we compared the evolving activity patterns in two, widely used, in vitro models of epileptic discharges.MethodsWe compared brain slices, prepared in the same way from young adult mice, that were bathed either in 0 Mg2+, or 100µM 4AP, artificial cerebrospinal fluid.ResultsWe find that while local field potential recordings of epileptiform discharges in the two models appear broadly similar, patch-clamp analysis reveals an important difference in the relative degree of glutamatergic involvement. 4AP affects parvalbumin-expressing interneurons more than other cortical populations, destabilizing their resting state and inducing spontaneous bursting behavior. Consequently, the most prominent pattern of transient discharge (“interictal event”) in this model is almost purely GABAergic, although the transition to seizure-like events (SLEs) involves pyramidal recruitment. In contrast, interictal discharges in 0 Mg2+ are only maintained by a very large glutamatergic component that also involves transient discharges of the interneurons. Seizure-like events in 0 Mg2+ have significantly higher power in the high gamma frequency band (60-120Hz) than these events do in 4AP, and are greatly delayed in onset by diazepam, unlike 4AP events.ConclusionsThe 0 Mg2+ and 4AP models display fundamentally different levels of glutamatergic drive, demonstrating how ostensibly similar pathological discharges can arise from different sources. We contend that similar interpretative issues will also be relevant to clinical practice.

scholarly journals Neural underpinnnings of auditory salience natural soundscapes

2018 ◽  
Author(s):  
Nicholas Huang ◽  
Mounya Elhilali
Keyword(s):  
Frequency Band ◽  
Auditory Stimuli ◽  
Physiological Effects ◽  
Natural Scene ◽  
Neural Responses ◽  
Top Down ◽  
Gamma Frequency ◽  
Behavioral Methods

Salience is the mechanism whereby attention is automatically directed towards critical stimuli. Measuring the salience of a stimulus using behavioral methods risks confounds with top-down attention, particularly in the case of natural soundscapes. A distraction paradigm is employed here to measure physiological effects of salient auditory stimuli using electroencephalography. Several such effects are presented. In particular, a stimulus entrainment response is reduced by the presentation of distractor salient sounds. A reduction in oscillatory neural responses in the gamma frequency band is also observed following salient stimuli. These measures are used to identify salient portions of the natural scene. Finally, envelope decoding methods also indicate that salient stimuli attract attention away from other, task-related sounds.

Sign in / Sign up

Export Citation Format

Share Document