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.

scholarly journals Altered effective connectivity in migraine patients during emotional stimuli: a multi-frequency magnetoencephalography study

2022 ◽  
Vol 23 (1) ◽  
Author(s):  
Jing Ren ◽  
Qun Yao ◽  
Minjie Tian ◽  
Feng Li ◽  
Yueqiu Chen ◽  
...  
Keyword(s):  
Brain Activity ◽  
Effective Connectivity ◽  
Temporal Cortex ◽  
Primary Headache ◽  
Clustering Coefficient ◽  
Frequency Range ◽  
Emotional Stimuli ◽  
Emotional Modulation ◽  
Gamma Frequency ◽  
Wide Range

Abstract Background Migraine is a common and disabling primary headache, which is associated with a wide range of psychiatric comorbidities. However, the mechanisms of emotion processing in migraine are not fully understood yet. The present study aimed to investigate the neural network during neutral, positive, and negative emotional stimuli in the migraine patients. Methods A total of 24 migraine patients and 24 age- and sex-matching healthy controls were enrolled in this study. Neuromagnetic brain activity was recorded using a whole-head magnetoencephalography (MEG) system upon exposure to human facial expression stimuli. MEG data were analyzed in multi-frequency ranges from 1 to 100 Hz. Results The migraine patients exhibited a significant enhancement in the effective connectivity from the prefrontal lobe to the temporal cortex during the negative emotional stimuli in the gamma frequency (30–90 Hz). Graph theory analysis revealed that the migraine patients had an increased degree and clustering coefficient of connectivity in the delta frequency range (1–4 Hz) upon exposure to positive emotional stimuli and an increased degree of connectivity in the delta frequency range (1–4 Hz) upon exposure to negative emotional stimuli. Clinical correlation analysis showed that the history, attack frequency, duration, and neuropsychological scales of the migraine patients had a negative correlation with the network parameters in certain frequency ranges. Conclusions The results suggested that the individuals with migraine showed deviant effective connectivity in viewing the human facial expressions in multi-frequencies. The prefrontal-temporal pathway might be related to the altered negative emotional modulation in migraine. These findings suggested that migraine might be characterized by more universal altered cerebral processing of negative stimuli. Since the significant result in this study was frequency-specific, more independent replicative studies are needed to confirm these results, and to elucidate the neurocircuitry underlying the association between migraine and emotional conditions.

scholarly journals Intracranial-EEG evidence for medial temporal pole driving amygdala activity induced by multi-modal emotional stimuli

2020 ◽  
Author(s):  
Saurabh Sonkusare ◽  
Vinh Thai Nguyen ◽  
Rosalyn Moran ◽  
Johan van der Meer ◽  
Yudan Ren ◽  
...  
Keyword(s):  
Low Frequency ◽  
Gamma Activity ◽  
Cortical Region ◽  
Frequency Range ◽  
Intracranial Eeg ◽  
Social And Emotional ◽  
Temporal Pole ◽  
High Gamma ◽  
Amygdala Activity ◽  
Computational Analyses

AbstractThe temporal pole (TP) is an associative cortical region required for complex cognitive functions such as social and emotional cognition. However, functional mapping of the TP with functional magnetic resonance imaging is technically challenging and thus understanding of its interaction with other key emotional circuitry, such as the amygdala, remain elusive. We exploited the unique advantages of stereo-electroencephalography (SEEG) to assess the responses of the TP and the amygdala during the perception of emotionally salient stimuli of pictures, music and movies. These stimuli consistently elicited high gamma responses (70-140 Hz) in both the TP and the amygdala, accompanied by functional connectivity in the low frequency range (2-12 Hz). Computational analyses suggested the TP driving this effect in the theta-alpha frequency range and which was modulated by the emotional salience of the stimuli. Of note, cross-frequency analysis indicated the phase of theta-alpha oscillations in the TP modulated the amplitude of high gamma activity in the amygdala. These results were reproducible with three types of stimuli including naturalistic stimuli suggesting a hierarchical influence of the TP over the amygdala in non-threatening stimuli.

Transcranial alternating stimulation in a high gamma frequency range applied over V1 improves contrast perception but does not modulate spatial attention

2012 ◽  
Vol 5 (4) ◽  
pp. 484-491 ◽  
Author(s):  
Bence Laczó ◽  
Andrea Antal ◽  
Robert Niebergall ◽  
Stefan Treue ◽  
Walter Paulus
Keyword(s):  
Spatial Attention ◽  
Frequency Range ◽  
Gamma Frequency ◽  
High Gamma ◽  
Contrast Perception

scholarly journals The Impact of Neurodegeneration on Network Connectivity: A Study of Change Detection in Frontotemporal Dementia

2013 ◽  
Vol 25 (5) ◽  
pp. 802-813 ◽  
Author(s):  
Laura E. Hughes ◽  
James B. Rowe
Keyword(s):  
Change Detection ◽  
Frontotemporal Dementia ◽  
Network Connectivity ◽  
Frequency Range ◽  
Behavioral Variant Frontotemporal Dementia ◽  
Gamma Frequency ◽  
Interhemispheric Coherence ◽  
Cortical Responses ◽  
Beta Frequency ◽  
The Impact

The neural response to unpredictable auditory events is suggested to depend on frontotemporal interactions. We used magnetoencephalography in patients with behavioral variant frontotemporal dementia to study change detection and to examine the impact of disease on macroscopic network connectivity underlying this core cognitive function. In patients, the amplitudes of auditory cortical responses to predictable standard tones were normal but were reduced for unpredictable deviant tones. Network connectivity, in terms of coherence among frontal, temporal, and parietal sources, was also abnormal in patients. In the beta frequency range, left frontotemporal coherence was reduced. In the gamma frequency range, frontal interhemispheric coherence was reduced whereas parietal interhemispheric coherence was enhanced. These results suggest impaired change detection resulting from dysfunctional frontotemporal interactions. They also provide evidence of a rostro-caudal reorganization of brain networks in disease. The sensitivity of magnetoencephalography to cortical network changes in behavioral variant frontotemporal dementia enriches the understanding of neurocognitive systems as well as showing potential for studies of experimental therapies for neurodegenerative disease.

scholarly journals Intracortical dynamics underlying repetitive stimulation predicts changes in network connectivity

2019 ◽  
Author(s):  
Yuhao Huang ◽  
Boglárka Hajnal ◽  
László Entz ◽  
Dániel Fabó ◽  
Jose L. Herrero ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Effective Connectivity ◽  
Low Frequency ◽  
Network Connectivity ◽  
Repetitive Stimulation ◽  
Direct Electrical Stimulation ◽  
Treatment Optimization ◽  
High Gamma ◽  
Highly Correlated ◽  
Cortical Regions

AbstractTargeted stimulation can be used to modulate the activity of brain networks. Previously we demonstrated that direct electrical stimulation produces predictable post-stimulation changes in brain excitability. However, understanding the neural dynamics during stimulation and its relationship to post-stimulation effects is limited but critical for treatment optimization. Here, we applied 10Hz direct electrical stimulation across several cortical regions in 14 patients implanted with intracranial electrodes for seizure monitoring. The stimulation train was characterized by a consistent increase in high gamma (70-170Hz) power. Immediately post-train, low-frequency (1-8Hz) power increased, resulting in an evoked response that was highly correlated with the neural response during stimulation. Using two measures of network connectivity, cortico-cortical evoked potentials (indexing effective connectivity) and theta coherence (indexing functional connectivity), we found a stronger response to stimulation in regions that were highly connected to the stimulation site. In these regions, repeated cycles of stimulation trains and rest progressively altered the stimulation response. Finally, after just 2 minutes (10%) of repetitive stimulation, we were able to predict post-stimulation connectivity changes with high discriminability. Taken together, this work reveals a relationship between stimulation dynamics and post-stimulation connectivity changes in humans. Thus, measuring neural activity during stimulation can inform future plasticity-inducing protocols.

Preliminary Model Analysis of Acoustic Noise Levels for Space Station

2014 ◽  
Vol 1016 ◽  
pp. 287-291
Author(s):  
Yao Qi Feng ◽  
Jiang Yang ◽  
Guo Song Feng ◽  
Yao Wu
Keyword(s):  
Acoustic Analysis ◽  
Acoustic Noise ◽  
Spectral Characteristics ◽  
Space Station ◽  
Low Frequency ◽  
Frequency Range ◽  
Analysis Model ◽  
Noise Levels ◽  
Noise Sources ◽  
Modeling And Analysis

This paper presents the modeling and analysis method of acoustic noise levels of whole audible frequency range for Chinese Space Station (CSS) module. UsingBoundaryElementModeling(BEM), the acoustic analysis model of low frequency range for CSS module was established. The analysis model of high frequency range was created by usingStatistical EnergyAnalysis(SEA) method. Based on the established models, the acoustic noise levels in all areas of CSS module were analyzed and the results for some typical areas are provided. Finally, the acoustic contribution of noise sources according to their spectral characteristics is analyzed and the implementation of noise control methods to reduce acoustic levels in CSS module is discussed.

scholarly journals A Time-Series Model of Phase Amplitude Cross Frequency Coupling and Comparison of Spectral Characteristics with Neural Data

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Kyle Q. Lepage ◽  
Sujith Vijayan
Keyword(s):  
Time Series ◽  
High Frequency ◽  
Spectral Characteristics ◽  
Low Frequency ◽  
Time Series Model ◽  
High Frequency Component ◽  
Frequency Oscillation ◽  
Low Frequency Oscillation ◽  
Frequency Coupling ◽  
Cross Frequency Coupling

Stochastic processes that exhibit cross-frequency coupling (CFC) are introduced. The ability of these processes to model observed CFC in neural recordings is investigated by comparison with published spectra. One of the proposed models, based on multiplying a pulsatile function of a low-frequency oscillation (θ) with an unobserved and high-frequency component, yields a process with a spectrum that is consistent with observation. Other models, such as those employing a biphasic pulsatile function of a low-frequency oscillation, are demonstrated to be less suitable. We introduce the full stochastic process time series model as a summation of three component weak-sense stationary (WSS) processes, namely,θ,γ, andη, withηa1/fαnoise process. Theγprocess is constructed as a product of a latent and unobserved high-frequency processxwith a function of the lagged, low-frequency oscillatory component (θ). After demonstrating that the model process is WSS, an appropriate method of simulation is introduced based upon the WSS property. This work may be of interest to researchers seeking to connect inhibitory and excitatory dynamics directly to observation in a model that accounts for known temporal dependence or to researchers seeking to examine what can occur in a multiplicative time-domain CFC mechanism.

Evaluation of Special Hearing Aids for Deaf Children

1971 ◽  
Vol 36 (4) ◽  
pp. 527-537 ◽  
Author(s):  
Norman P. Erber
Keyword(s):  
Hearing Aids ◽  
High Frequency ◽  
Hearing Aid ◽  
Low Frequency ◽  
Acoustic Stimulation ◽  
Deaf Children ◽  
Frequency Range ◽  
Frequency Limit ◽  
Unpublished Studies ◽  
Published Research

Two types of special hearing aid have been developed recently to improve the reception of speech by profoundly deaf children. In a different way, each special system provides greater low-frequency acoustic stimulation to deaf ears than does a conventional hearing aid. One of the devices extends the low-frequency limit of amplification; the other shifts high-frequency energy to a lower frequency range. In general, previous evaluations of these special hearing aids have obtained inconsistent or inconclusive results. This paper reviews most of the published research on the use of special hearing aids by deaf children, summarizes several unpublished studies, and suggests a set of guidelines for future evaluations of special and conventional amplification systems.

Dynamic Damping and Stiffness Characteristics of the Rolling Tire

2001 ◽  
Vol 29 (4) ◽  
pp. 258-268 ◽  
Author(s):  
G. Jianmin ◽  
R. Gall ◽  
W. Zuomin
Keyword(s):  
Dynamic Behavior ◽  
Variable Parameter ◽  
Low Frequency ◽  
Vertical Load ◽  
Frequency Range ◽  
Inflation Pressure ◽  
Vehicle Simulation ◽  
Dynamic Damping ◽  
Speed Range ◽  
Stiffness Characteristics

Abstract A variable parameter model to study dynamic tire responses is presented. A modified device to measure terrain roughness is used to measure dynamic damping and stiffness characteristics of rolling tires. The device was used to examine the dynamic behavior of a tire in the speed range from 0 to 10 km/h. The inflation pressure during the tests was adjusted to 160, 240, and 320 kPa. The vertical load was 5.2 kN. The results indicate that the damping and stiffness decrease with velocity. Regression formulas for the non-linear experimental damping and stiffness are obtained. These results can be used as input parameters for vehicle simulation to evaluate the vehicle's driving and comfort performance in the medium-low frequency range (0–100 Hz). This way it can be important for tire design and the forecasting of the dynamic behavior of tires.

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