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Jonas Obleser – One of the best experts on this subject based on the ideXlab platform.

  • Orienting auditory attention in time: Lateralized Alpha Power reflects spatio-temporal filtering.
    NeuroImage, 2020
    Co-Authors: Malte Wöstmann, Burkhard Maess, Jonas Obleser
    Abstract:

    Abstract The deployment of neural Alpha (8–12 Hz) lateralization in service of spatial attention is well-established: Alpha Power increases in the cortical hemisphere ipsilateral to the attended hemifield, and decreases in the contralateral hemisphere, respectively. Much less is known about humans’ ability to deploy such Alpha lateralization in time, and to thus exploit Alpha Power as a spatio-temporal filter. Here we show that spatially lateralized Alpha Power does signify – beyond the direction of spatial attention – the distribution of attention in time and thereby qualifies as a spatio-temporal attentional filter. Participants (N = 20) selectively listened to spoken numbers presented on one side (left vs right), while competing numbers were presented on the other side. Key to our hypothesis, temporal foreknowledge was manipulated via a visual cue, which was either instructive and indicated the to-be-probed number position (70% valid) or neutral. Temporal foreknowledge did guide participants’ attention, as they recognized numbers from the to-be-attended side more accurately following valid cues. In the magnetoencephalogram (MEG), spatial attention to the left versus right side induced lateralization of Alpha Power in all temporal cueing conditions. Modulation of Alpha lateralization at the 0.8-Hz presentation rate of spoken numbers was stronger following instructive compared to neutral temporal cues. Critically, we found stronger modulation of lateralized Alpha Power specifically at the onsets of temporally cued numbers. These results suggest that the precisely timed hemispheric lateralization of Alpha Power qualifies as a spatio-temporal attentional filter mechanism susceptible to top-down behavioural goals.

  • Orienting spatial attention in time: Lateralized Alpha Power reflects spatio-temporal filtering
    , 2020
    Co-Authors: Malte Woestmann, Burkhard Maess, Jonas Obleser
    Abstract:

    The deployment of neural Alpha (8-12 Hz) lateralization in service of spatial attention is well-established: Alpha Power increases in the cortical hemisphere ipsilateral to the attended hemifield, and decreases in the contralateral hemisphere, respectively. Much less is known about humans ability to deploy such Alpha lateralization in time, and to thus exploit Alpha Power as a spatio-temporal filter. Here we show that spatially lateralized Alpha Power does signify – beyond the direction of spatial attention – the distribution of attention in time and thereby qualifies as a spatio-temporal attentional filter. Participants (N = 20) selectively listened to spoken numbers presented on one side (left vs right), while competing numbers were presented on the other side. Key to our hypothesis, temporal foreknowledge was manipulated via a visual cue, which was either instructive and indicated the to-be-probed number position (70% valid) or neutral. Temporal foreknowledge did guide participants attention, as they recognized numbers from the to-be-attended side more accurately following valid cues. In the magnetoencephalogram (MEG), spatial attention to the left versus right side induced lateralization of Alpha Power in all temporal cueing conditions. Modulation of Alpha lateralization at the 0.8-Hz presentation rate of spoken numbers was stronger following instructive compared to neutral temporal cues. Critically, we found stronger modulation of lateralized Alpha Power specifically at the onsets of temporally cued numbers. These results suggest that the precisely timed hemispheric lateralization of Alpha Power qualifies as a spatio-temporal attentional filter mechanism susceptible to top-down behavioral goals.

  • Prestimulus neural Alpha Power predicts confidence in discriminating identical auditory stimuli.
    The European journal of neuroscience, 2018
    Co-Authors: Malte Woestmann, Leonhard Waschke, Jonas Obleser
    Abstract:

    When deciding upon a sensory stimulus, the Power of prestimulus neural Alpha oscillations (~10 Hz) has been shown to hold information on a perceiver’s bias, or confidence, as opposed to perceptual sensitivity per se. Here, we test whether this link between prestimulus Alpha Power and decision confidence, previously established in vision and somatosensation, also holds in the auditory modality. Moreover, confidence usually depends on the physical evidence available in the stimulus as well as on decision accuracy. It is unclear in how far the link between prestimulus Alpha Power and confidence holds when physical stimulus evidence is entirely absent, and thus accuracy does not vary. We here analysed electroencephalography data from a paradigm where human listeners (N = 17) rated their confidence in the discrimination of the pitch of two tones that were, unbeknownst to the listeners, identical. Lower prestimulus Alpha Power as recorded at central channel sites was predictive of higher confidence ratings. Furthermore, this link was not mediated by auditory evoked activity. Our results support a direct link between prestimulus Alpha Power and decision confidence. This effect, first, shows up in the auditory modality similar to vision and somatosensation, and second, is present also in the complete absence of physical evidence in the stimulus and in the absence of varying accuracy. These findings speak to a model wherein low prestimulus Alpha Power increases neural baseline excitability, which is reflected in enhanced stimulus-evoked neural responses and higher confidence.

Richard J. Davidson – One of the best experts on this subject based on the ideXlab platform.

  • Thalamic metabolic rate predicts EEG Alpha Power in healthy control subjects but not in depressed patients.
    Biological psychiatry, 1999
    Co-Authors: Kristen A. Lindgren, Ruth M. Benca, Christine L. Larson, Scott B. Perlman, Heather C. Abercrombie, Robert T. Ward, Stacey M. Schaefer, James E. Holden, Terrence R. Oakes, Richard J. Davidson
    Abstract:

    Abstract Background: EEG Alpha Power has been demonstrated to be inversely related to mental activity and has subsequently been used as an indirect measure of brain activation. The hypothesis that the thalamus serves as a neuronal oscillator of Alpha rhythms has been supported by studies in animals, but only minimally by studies in humans. Methods: In the current study, PET-derived measures of regional glucose metabolism, EEG, and structural MRI were obtained from each participant to assess the relation between thalamic metabolic activity and Alpha Power in depressed patients and healthy controls. The thalamus was identified and drawn on each subject’s MRI. The MRI was then co-registered to the corresponding PET scan and metabolic activity from the thalamus extracted. Thalamic activity was then correlated with a 30-min aggregated average of Alpha EEG Power. Results: Robust inverse correlations were observed in the control data, indicating that greater thalamic metabolism is correlated with decreased Alpha Power. No relation was found in the depressed patient data. Conclusions: The results are discussed in the context of a possible abnormality in thalamocortical circuitry associated with depression.

  • EEG Alpha Power and Alpha Power asymmetry in sleep and wakefulness.
    Psychophysiology, 1999
    Co-Authors: Ruth M. Benca, William H. Obermeyer, Christine L. Larson, Blenda Yun, Isa Dolski, Kenneth D. Kleist, Steven M. Weber, Richard J. Davidson
    Abstract:

    Asymmetry of waking electroencephalography (EEG) Alpha Power in frontal regions has been correlated with waking emotional reactivity and the emotional content of dream reports. Little is known regarding Alpha asymmetry during sleep. The present study was performed to compare Alpha Power and Alpha Power asymmetry in various brain regions across states of sleep and wakefulness. Waking and sleep EEG were recorded in a group of patients undergoing polysomnographic evaluation for possible sleep disorders. Alpha EEG asymmetry in frontal and temporal regions was significantly correlated in waking versus sleep, particularly during rapid eye movement (REM) sleep. These results suggest that patterns of frontal Alpha asymmetry are stable across sleep and waking and may be related to emotional reactivity during dreaming. During sleep, Alpha Power was highest during slow-wave sleep and lowest during REM sleep. Implications of these data for understanding the functional significance of Alpha Power during waking and sleeping are considered.

  • Relations between PET-derived measures of thalamic glucose metabolism and EEG Alpha Power
    Psychophysiology, 1998
    Co-Authors: Christine L. Larson, Richard J. Davidson, Heather C. Abercrombie, Robert T. Ward, Stacey M. Schaefer, Daren C. Jackson, James E. Holden, Scott B. Perlman
    Abstract:

    Electroencephalogram (EEG) Alpha Power has been demonstrated to be inversely related to mental activity and has subsequently been used as an indirect measure of brain activation. The thalamus has been proposed as an important site for modulation of rhythmic Alpha activity. Studies in animals have suggested that cortical Alpha rhythms are correlated with Alpha rhythms in the thalamus. However, little empirical evidence exists for this relation in humans. In the current study, resting EEG and a fluorodeoxyglucose positron emission tomography scan were measured during the same experimental session. Over a 30-min period, average EEG Alpha Power across 28 electrodes from 27 participants was robustly inversely correlated with glucose metabolic activity in the thalamus. These data provide the first evidence for a relation between Alpha EEG Power and thalamic activity in humans.

Sadaf Manzoor – One of the best experts on this subject based on the ideXlab platform.

  • A Gull Alpha Power Weibull distribution with applications to real and simulated data.
    PloS one, 2020
    Co-Authors: Muhammad Ijaz, Syed Muhammad Asim, Alamgir, Muhammad Farooq, Sajjad Ahmad Khan, Sadaf Manzoor
    Abstract:

    In this paper, we produced a new family of distribution called Gull Alpha Power Family of distributions (GAPF). A Special case of GAPF is derived by considering the Weibull distribution as a baseline distribution called Gull Alpha Power Weibull distribution (GAPW). The suitability of the proposed distribution derives from its ability to model both the monotonic and non-monotonic hazard rate functions which are a common practice in survival analysis and reliability engineering. Various statistical properties were derived in addition to their special cases. The unknown parameters of the model are estimated using the maximum likelihood method. Moreover, the usefulness of the proposed distribution is supported by using two real lifetime data sets as well as simulated data.

  • AlphaPower Pareto distribution: Its properties and applications.
    PloS one, 2019
    Co-Authors: Shumaila Ihtisham, Sadaf Manzoor, Sajjad Ahmad Khan, Alamgir Khalil, Amjad Ali
    Abstract:

    In Statistical theory, inclusion of an additional parameter to standard distributions is a usual practice. In this study, a new distribution referred to as AlphaPower Pareto distribution is introduced by including an extra parameter. Several properties of the proposed distribution, including moment generating function, mode, quantiles, entropies, mean residual life function, stochastic orders and order statistics are obtained. Parameters of the proposed distribution have been estimated using maximum likelikelihood estimation technique. Two real datasets have been considered to examine the usefulness of the proposed distribution. It has been observed that the proposed distribution outperforms different variants of Pareto distribution on the basis of model selection criteria.

Andreas Fink – One of the best experts on this subject based on the ideXlab platform.

  • Creativity is associated with a characteristic U-shaped function of Alpha Power changes accompanied by an early increase in functional coupling.
    Cognitive affective & behavioral neuroscience, 2019
    Co-Authors: Christian Rominger, Mathias Benedek, Ilona Papousek, Elisabeth M. Weiss, Corinna M. Perchtold, Andreas Schwerdtfeger, Andreas Fink
    Abstract:

    Although there exists increasing knowledge about brain correlates underlying creative ideation in general, the specific neurocognitive mechanisms implicated in different stages of the creative thinking process are still under-researched. Some recent EEG studies suggested that Alpha Power during creative ideation varies as a function of time, with the highest levels of Alpha Power after stimulus onset and at the end of the creative thinking process. The main aim of the present study was to replicate and extend this finding by applying an individual differences approach, and by investigating functional coupling between long distance cortical sites during the process of creative ideation. Eighty-six participants performed the Alternate Uses (AU) task during EEG assessment. Results revealed that more original people showed increased Alpha Power after stimulus onset and before finalizing the process of idea generation. This U-shaped Alpha Power pattern was accompanied by an early increase in functional communication between frontal and parietal-occipital sites during the creative thinking process, putatively indicating activation of top-down executive control processes. Participants with lower originality showed no significant time-related variation in Alpha Power and a delayed increase in long distance functional communication. These findings are in line with dual process models of creative ideation and support the idea that increased Alpha Power at the beginning of the creative ideation process may indicate more associative modes of thinking and memory processes, while the Alpha increases at later stages may indicate executive control processes, associated with idea elaboration/evaluation.

  • Alpha Power increases in right parietal cortex reflects focused internal attention
    Neuropsychologia, 2014
    Co-Authors: Mathias Benedek, Andreas Fink, Rainer J. Schickel, Emanuel Jauk, Aljoscha C. Neubauer
    Abstract:

    This study investigated the functional significance of EEG Alpha Power increases, a finding that is consistently observed in various memory tasks and specifically during divergent thinking. It was previously shown that Alpha Power is increased when tasks are performed in mind—e.g., when bottom-up processing is prevented. This study aimed to examine the effect of task-immanent differences in bottom-up processing demands by comparing two divergent thinking tasks, one intrinsically relying on bottom-up processing (sensory-intake task) and one that is not (sensory-independence task). In both tasks, stimuli were masked in half of the trials to establish conditions of higher and lower internal processing demands. In line with the hypotheses, internal processing affected performance and led to increases in Alpha Power only in the sensory-intake task, whereas the sensory-independence task showed high levels of task-related Alpha Power in both conditions. Interestingly, conditions involving focused internal attention showed a clear lateralization with higher Alpha Power in parietal regions of the right hemisphere. Considering evidence from fMRI studies, right-parietal Alpha Power increases may correspond to a deactivation of the right temporoparietal junction, reflecting an inhibition of the ventral attention network. Inhibition of this region is thought to prevent reorienting to irrelevant stimulation during goal-driven, top-down behavior, which may serve the executive function of task shielding during demanding cognitive tasks such as idea generation and mental imagery.

  • The time-course of EEG Alpha Power changes in creative ideation.
    Frontiers in human neuroscience, 2014
    Co-Authors: Daniela Schwab, Mathias Benedek, Ilona Papousek, Elisabeth M. Weiss, Andreas Fink
    Abstract:

    Increases in EEG Alpha Power during creative ideation are among the most consistent findings in the neuroscientific study of creativity, but existing studies did not focus on time-related changes of EEG Alpha activity patterns during the process of creative ideation so far. Since several cognitive processes are involved in the generation of creative ideas, different EEG correlates may result as a function of time. In this study we addressed this crucial point. Forty-five participants worked on the “Alternative Uses Task” while the EEG was recorded and changes in task-related Power (relative to rest) in the upper-frequency band (10-12 Hz) for three isochronous time intervals of the idea generation period were determined. Alpha Power changes during idea generation followed a characteristic time course: we found a general increase of Alpha Power at the beginning of idea generation that was followed by a decrease and finally by a re-increase of Alpha prior to responding that was most pronounced at parietal and temporal sites of the right hemisphere. Additionally, the production of more original ideas was accompanied by increasing hemispheric asymmetry (more Alpha in the right than left hemisphere) with increasing duration of the idea generation period. The observed time course of brain activity may reflect the progression of different but well-known stages in the idea generation process: that is the initial retrieval of common and old ideas followed by the actual generation of novel and more creative ideas by overcoming typical responses through processes of mental simulation and imagination.

Muhammad Ijaz – One of the best experts on this subject based on the ideXlab platform.

  • AlphaPower Exponentiated Inverse Rayleigh distribution and its applications to real and simulated data.
    PloS one, 2021
    Co-Authors: Muhammad Ali, Muhammad Ijaz, Alamgir Khalil, Noor Saeed
    Abstract:

    The main goal of the current paper is to contribute to the existing literature of probability distributions. In this paper, a new probability distribution is generated by using the Alpha Power Family of distributions with the aim to model the data with non-monotonic failure rates and provides a better fit. The proposed distribution is called Alpha Power Exponentiated Inverse Rayleigh or in short APEIR distribution. Various statistical properties have been investigated including they are the order statistics, moments, residual life function, mean waiting time, quantiles, entropy, and stress-strength parameter. To estimate the parameters of the proposed distribution, the maximum likelihood method is employed. It has been proved theoretically that the proposed distribution provides a better fit to the data with monotonic as well as non-monotonic hazard rate shapes. Moreover, two real data sets are used to evaluate the significance and flexibility of the proposed distribution as compared to other probability distributions.

  • A Gull Alpha Power Weibull distribution with applications to real and simulated data.
    PloS one, 2020
    Co-Authors: Muhammad Ijaz, Syed Muhammad Asim, Alamgir, Muhammad Farooq, Sajjad Ahmad Khan, Sadaf Manzoor
    Abstract:

    In this paper, we produced a new family of distribution called Gull Alpha Power Family of distributions (GAPF). A Special case of GAPF is derived by considering the Weibull distribution as a baseline distribution called Gull Alpha Power Weibull distribution (GAPW). The suitability of the proposed distribution derives from its ability to model both the monotonic and non-monotonic hazard rate functions which are a common practice in survival analysis and reliability engineering. Various statistical properties were derived in addition to their special cases. The unknown parameters of the model are estimated using the maximum likelihood method. Moreover, the usefulness of the proposed distribution is supported by using two real lifetime data sets as well as simulated data.