Enhancement of electroencephalogram activity in the theta-band range during unmatched olfactory-taste stimulation

AbstractTranscranial static magnetic stimulation (tSMS) is a novel non-invasive brain stimulation technique that reduces cortical excitability at the stimulation site. We investigated the effects of tSMS over the left primary motor cortex (M1) for 20 min on the local electroencephalogram (EEG) power spectrum and interregional EEG coupling. Twelve right-handed healthy subjects participated in this crossover, double-blind, sham-controlled study. Resting-state EEG data were recorded for 3 min before the intervention and 17 min after the beginning of the intervention. The power spectrum at the left central electrode (C3) and the weighted phase lag index (wPLI) between C3 and the other electrodes was calculated for theta (4–8 Hz), alpha (8–12 Hz), and beta (12–30 Hz) frequencies. The tSMS significantly increased theta power at C3 and the functional coupling in the theta band between C3 and the parietal midline electrodes. The tSMS over the left M1 for 20 min exhibited modulatory effects on local cortical activity and interregional functional coupling in the theta band. The neural oscillations in the theta band may have an important role in the neurophysiological effects induced by tSMS over the frontal cortex.

Download Full-text

Theta-band phase tracking in the two-talker problem

Brain and Language ◽

10.1016/j.bandl.2014.05.003 ◽

2014 ◽

Vol 135 ◽

pp. 52-56 ◽

Cited By ~ 16

Author(s):

Dillon A. Hambrook ◽

Matthew S. Tata

Keyword(s):

Theta Band ◽

Phase Tracking

Download Full-text

Adaptation of Rehabilitation System Based on User’s Mental Engagement

Volume 3: 17th International Conference on Advanced Vehicle Technologies; 12th International Conference on Design Education; 8th Frontiers in Biomedical Devices ◽

10.1115/detc2015-47720 ◽

2015 ◽

Cited By ~ 1

Author(s):

Ehsan T. Esfahani ◽

Shrey Pareek ◽

Pramod Chembrammel ◽

Mostafa Ghobadi ◽

Thenkurussi Kesavadas

Keyword(s):

Brain Activity ◽

Difficulty Level ◽

The Novel ◽

Theta Band ◽

Robotic Rehabilitation ◽

Designed Experiments ◽

Power Spectral ◽

Rehabilitation System ◽

Alpha Beta ◽

The Brain

Recognition of user’s mental engagement is imperative to the success of robotic rehabilitation. The paper explores the novel paradigm in robotic rehabilitation of using Passive BCI as opposed to the conventional Active ones. We have designed experiments to determine a user’s level of mental engagement. In our experimental study, we record the brain activity of 3 healthy subjects during multiple sessions where subjects need to navigate through a maze using a haptic system with variable resistance/assistance. Using the data obtained through the experiments we highlight the drawbacks of using conventional workload metrics as indicators of human engagement, thus asserting that Motor and Cognitive Workloads be differentiated. Additionally we propose a new set of features: differential PSD of Cz-Poz at alpha, Beta and Sigma band, (Mental engagement) and relative C3-C4 at beta (Motor Workload) to distinguish Normal Cases from those instances when haptic where applied with an accuracy of 92.93%. Mental engagement is calculated using the power spectral density of the Theta band (4–7 Hz) in the parietal-midline (Pz) with respect to the central midline (Cz). The above information can be used to adjust robotic rehabilitation parameters I accordance with the user’s needs. The adjustment may be in the force levels, difficulty level of the task or increasing the speed of the task.

Download Full-text

Detect AD Patients by Using EEG Coherence Analysis

Journal of Medical Engineering ◽

10.1155/2014/236734 ◽

2014 ◽

Vol 2014 ◽

pp. 1-5 ◽

Cited By ~ 7

Author(s):

Ming-Chung Ho ◽

Tsung-Ching Chen ◽

Chin-Fei Huang ◽

Cheng-Hsieh Yu ◽

Jhih-Ming Chen ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Healthy Subjects ◽

Normal Aging ◽

Oddball Paradigm ◽

Coherence Analysis ◽

Eeg Coherence ◽

Theta Band ◽

Corticocortical Connections ◽

Auditory Oddball ◽

Auditory Oddball Paradigm

The purpose of this study is to discriminate mild Alzheimer’s disease (AD) patients from the normal aging. The EEG coherence was applied to analyze the data from auditory oddball paradigm to discriminate the differences of corticocortical connections between mild AD patients and healthy subjects. The results showed that the lower values of coherence were performed in mild AD patients than in the normal aging subjects, especially in theta band. The implications and suggestions are shown in this study.

Download Full-text

Beta-band desynchronization reflects uncertainty in effector selection during motor planning

10.1101/2021.04.23.441147 ◽

2021 ◽

Author(s):

Milou J.L. van Helvert ◽

Leonie Oostwoud Wijdenes ◽

Linda Geerligs ◽

W. Pieter Medendorp

Keyword(s):

Time Window ◽

Brain Activity ◽

Motor Planning ◽

Reaction Times ◽

Motor Preparation ◽

Motion Artifact ◽

Theta Band ◽

Beta Band ◽

Target Uncertainty ◽

Band Power

AbstractWhile beta-band activity during motor planning is known to be modulated by uncertainty about where to act, less is known about its modulations to uncertainty about how to act. To investigate this issue, we recorded oscillatory brain activity with EEG while human participants (n = 17) performed a hand choice reaching task. The reaching hand was either predetermined or of participants’ choice, and the target was close to one of the two hands or at about equal distance from both. To measure neural activity in a motion-artifact-free time window, the location of the upcoming target was cued 1000-1500 ms before the presentation of the target, whereby the cue was valid in 50% of trials. As evidence for motor planning during the cueing phase, behavioral observations showed that the cue affected later hand choice. Furthermore, reaction times were longer in the choice than in the predetermined trials, supporting the notion of a competitive process for hand selection. Modulations of beta-band power over central cortical regions, but not alpha-band or theta-band power, were in line with these observations. During the cueing period, reaches in predetermined trials were preceded by larger decreases in beta-band power than reaches in choice trials. Cue direction did not affect reaction times or beta-band power, which may be due to the cue being invalid in 50% of trials, retaining effector uncertainty during motor planning. Our findings suggest that effector uncertainty, similar to target uncertainty, selectively modulates beta-band power during motor planning.New & NoteworthyWhile reach-related beta-band power in central cortical areas is known to modulate with the number of potential targets, here we show, using a cueing paradigm, that the power in this frequency band, but not in the alpha or theta-band, is also modulated by the uncertainty of which hand to use. This finding supports the notion that multiple possible effector-specific actions can be specified in parallel up to the level of motor preparation.

Download Full-text