Journal: Brain Topography

Abbreviation

Brain Topogr

Publisher

Springer

Journal Volumes

ISSN

0896-0267
1573-6792

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2012 - 2019162020 - 20222
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Publications 1 - 10 of 18
  • EEG Microstates During Resting Represent Personality Differences
    Item type: Journal Article
    Schlegel, Felix; Lehmann, Dietrich; Faber, Pascal L.; et al. (2012)
    Brain Topography
  • Resisting Sleep Pressure: Impact on Resting State Functional Network Connectivity
    Item type: Journal Article
    Tüshaus, Laura; Balsters, Joshua H.; Schläpfer, Anthony; et al. (2017)
    Brain Topography
  • On the modulation of brain activation during simulated weight bearing in supine gait-like stepping
    Item type: Journal Article
    Jäger, Lukas; Marchal-Crespo, Laura; Wolf, Peter; et al. (2016)
    Brain Topography
  • Towards Using Microstate-Neurofeedback for the Treatment of Psychotic Symptoms in Schizophrenia. A Feasibility Study in Healthy Participants
    Item type: Journal Article
    Diaz Hernandez, Laura; Rieger, Kathryn; Baenninger, Anja; et al. (2016)
    Brain Topography
  • Stimulus-Specific Adaptation in Field Potentials and Neuronal Responses to Frequency-Modulated Tones in the Primary Auditory Cortex
    Item type: Journal Article
    Klein, Carsten; von der Behrens, Wolfger; Gaese, Bernhard H. (2014)
    Brain Topography
  • Frontal Midline Theta Reflects Individual Task Performance in a Working Memory Task
    Item type: Journal Article
    Maurer, Urs; Brem, Silvia; Liechti, Martina; et al. (2015)
    Brain Topography
    Frontal midline (fm-)theta activity has been related to working memory (WM) processes, as it typically increases with WM load. The robustness of this effect, however, varies across studies and subjects, putting limits to its interpretation. We hypothesized that variation in the fm-theta effect may reflect individual differences in task difficulty with increasing WM load as indicated by behavioural responses. We further tested whether effects in the alpha range are robust markers of WM load. We recorded 64-channel EEG from 24 healthy adults while they memorized either 2 or 4 unfamiliar symbols (low vs. high WM load) in a modified Sternberg task. The last 2 s of the retention phase were analyzed for WM load-related changes in the theta (5–7 Hz) and alpha range (lower: 8–10 Hz, upper: 10.5–12.5 Hz). Higher WM load led to less accurate and slower responses. The increase of fm-theta with WM load was most pronounced at fm electrodes, localized to anterior cingulate regions, and correlated with the participants’ decrease in accuracy due to higher WM load. Alpha peak frequency increased in the high compared to the low WM load condition, corresponding to a decrease in lower alpha range across all channels. The results demonstrate that previously reported variation in fm-theta workload effects can partly be explained by variation in task difficulty indexed by individual task accuracy. Moreover, the results also demonstrate that alpha WM load effects are prominent when separating upper and lower alpha.
  • Real-time Neurofeedback Using Functional MRI Could Improve Down-Regulation of Amygdala Activity During Emotional Stimulation: A Proof-of-Concept Study
    Item type: Journal Article
    Brühl, Annette B.; Scherpiet, Sigrid; Sulzer, James; et al. (2014)
    Brain Topography
    The amygdala is a central target of emotion regulation. It is overactive and dysregulated in affective and anxiety disorders and amygdala activity normalizes with successful therapy of the symptoms. However, a considerable percentage of patients do not reach remission within acceptable duration of treatment. The amygdala could therefore represent a promising target for real-time functional magnetic resonance imaging (rtfMRI) neurofeedback. rtfMRI neurofeedback directly improves the voluntary regulation of localized brain activity. At present, most rtfMRI neurofeedback studies have trained participants to increase activity of a target, i.e. up-regulation. However, in the case of the amygdala, down-regulation is supposedly more clinically relevant. Therefore, we developed a task that trained participants to down-regulate activity of the right amygdala while being confronted with amygdala stimulation, i.e. negative emotional faces. The activity in the functionally-defined region was used as online visual feedback in six healthy subjects instructed to minimize this signal using reality checking as emotion regulation strategy. Over a period of four training sessions, participants significantly increased down-regulation of the right amygdala compared to a passive viewing condition to control for habilitation effects. This result supports the concept of using rtfMRI neurofeedback training to control brain activity during relevant stimulation, specifically in the case of emotion, and has implications towards clinical treatment of emotional disorders.
  • EEG Source Imaging Indices of Cognitive Control Show Associations with Dopamine System Genes
    Item type: Journal Article
    McLoughlin, Grainne; Palmer, Jason; Makeig, Scott; et al. (2018)
    Brain Topography
    Cognitive or executive control is a critical mental ability, an important marker of mental illness, and among the most heritable of neurocognitive traits. Two candidate genes, catechol-O-methyltransferase (COMT) and DRD4, which both have a roles in the regulation of cortical dopamine, have been consistently associated with cognitive control. Here, we predicted that individuals with the COMT Met/Met allele would show improved response execution and inhibition as indexed by event-related potentials in a Go/NoGo task, while individuals with the DRD4 7-repeat allele would show impaired brain activity. We used independent component analysis (ICA) to separate brain source processes contributing to high-density EEG scalp signals recorded during the task. As expected, individuals with the DRD4 7-repeat polymorphism had reduced parietal P3 source and scalp responses to response (Go) compared to those without the 7-repeat. Contrary to our expectation, the COMT homozygous Met allele was associated with a smaller frontal P3 source and scalp response to response-inhibition (NoGo) stimuli, suggesting that while more dopamine in frontal cortical areas has advantages in some tasks, it may also compromise response inhibition function. An interaction effect emerged for P3 source responses to Go stimuli. These were reduced in those with both the 7-repeat DRD4 allele and either the COMT Val/Val or the Met/Met homozygous polymorphisms but not in those with the heterozygous Val/Met polymorphism. This epistatic interaction between DRD4 and COMT replicates findings that too little or too much dopamine impairs cognitive control. The anatomic and functional separated maximally independent cortical EEG sources proved more informative than scalp channel measures for genetic studies of brain function and thus better elucidate the complex mechanisms in psychiatric illness.
  • Integration of Spoken and Written Words in Beginning Readers
    Item type: Journal Article
    Jost, Lea B.; Eberhard-Moscicka, Aleksandra K.; Frisch, Christine; et al. (2014)
    Brain Topography
    Integrating visual and auditory language information is critical for reading. Suppression and congruency effects in audiovisual paradigms with letters and speech sounds have provided information about low-level mechanisms of grapheme-phoneme integration during reading. However, the central question about how such processes relate to reading entire words remains unexplored. Using ERPs, we investigated whether audiovisual integration occurs for words already in beginning readers, and if so, whether this integration is reflected by differences in map strength or topography (aim 1); and moreover, whether such integration is associated with reading fluency (aim 2). A 128-channel EEG was recorded while 69 monolingual (Swiss)-German speaking first-graders performed a detection task with rare targets. Stimuli were presented in blocks either auditorily (A), visually (V) or audiovisually (matching: AVM; nonmatching: AVN). Corresponding ERPs were computed, and unimodal ERPs summated (A + V = sumAV). We applied TANOVAs to identify time windows with significant integration effects: suppression (sumAV–AVM) and congruency (AVN–AVM). They were further characterized using GFP and 3D-centroid analyses, and significant effects were correlated with reading fluency. The results suggest that audiovisual suppression effects occur for familiar German and unfamiliar English words, whereas audiovisual congruency effects can be found only for familiar German words, probably due to lexical-semantic processes involved. Moreover, congruency effects were characterized by topographic differences, indicating that different sources are active during processing of congruent compared to incongruent audiovisual words. Furthermore, no clear associations between audiovisual integration and reading fluency were found. The degree to which such associations develop in beginning readers remains open to further investigation.
  • Heart–Brain Interactions in the MR Environment: Characterization of the Ballistocardiogram in EEG Signals Collected During Simultaneous fMRI
    Item type: Journal Article
    Marino, Marco; Liu, Quanying; Del Castello, Mariangela; et al. (2018)
    Brain Topography
    The ballistocardiographic (BCG) artifact is linked to cardiac activity and occurs in electroencephalographic (EEG) recordings acquired inside the magnetic resonance (MR) environment. Its variability in terms of amplitude, waveform shape and spatial distribution over subject’s scalp makes its attenuation a challenging task. In this study, we aimed to provide a detailed characterization of the BCG properties, including its temporal dependency on cardiac events and its spatio-temporal dynamics. To this end, we used high-density EEG data acquired during simultaneous functional MR imaging in six healthy volunteers. First, we investigated the relationship between cardiac activity and BCG occurrences in the EEG recordings. We observed large variability in the delay between ECG and subsequent BCG events (ECG–BCG delay) across subjects and non-negligible epoch-by-epoch variations at the single subject level. The inspection of spatial–temporal variations revealed a prominent non-stationarity of the BCG signal. We identified five main BCG waves, which were common across subjects. Principal component analysis revealed two spatially distinct patterns to explain most of the variance (85% in total). These components are possibly related to head rotation and pulse-driven scalp expansion, respectively. Our results may inspire the development of novel, more effective methods for the removal of the BCG, capable of isolating and attenuating artifact occurrences while preserving true neuronal activity.
Publications 1 - 10 of 18