scholarly journals Auditory cortical alpha/beta desynchronization prioritizes the representation of memory items during a retention period

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Nathan Weisz ◽  
Nadine Gabriele Kraft ◽  
Gianpaolo Demarchi
Keyword(s):  
Superior Temporal Gyrus ◽  
Entire Group ◽  
Auditory Modality ◽  
Alpha Power ◽  
Retention Period ◽  
Beta Power ◽  
Functional Inhibition ◽  
Alpha Beta ◽  
Increased Strength ◽  
Sternberg Task

To-be-memorized information in working-memory could be protected against distracting influences by processes of functional inhibition or prioritization. Modulations of oscillations in the alpha to beta range in task-relevant sensory regions have been suggested to play an important role for both mechanisms. We adapted a Sternberg task variant to the auditory modality, with a strong or a weak distracting sound presented at a predictable time during the retention period. Using a time-generalized decoding approach, relatively decreased strength of memorized information was found prior to strong distractors, paralleled by decreased pre-distractor alpha/beta power in the left superior temporal gyrus (lSTG). Over the entire group, reduced beta power in lSTG was associated with relatively increased strength of memorized information. The extent of alpha power modulations within participants was negatively correlated with strength of memorized information. Overall, our results are compatible with a prioritization account, but point to nuanced differences between alpha and beta oscillations.

scholarly journals Oscillatory Correlates of Selective Restudy

2021 ◽  
Vol 15 ◽  
Author(s):  
Michael Wirth ◽  
Bernhard Pastötter ◽  
Karl-Heinz T. Bäuml
Keyword(s):  
Beneficial Effect ◽  
The Other ◽  
Alpha Power ◽  
Mental Context ◽  
Power Increase ◽  
Beta Power ◽  
Alpha Beta ◽  
Study Context

Prior behavioral work has shown that selective restudy of some studied items leaves recall of the other studied items unaffected when lag between study and restudy is short, but improves recall of the other items when lag is prolonged. The beneficial effect has been attributed to context retrieval, assuming that selective restudy reactivates the context at study and thus provides a retrieval cue for the other items (Bäuml, 2019). Here the results of two experiments are reported, in each of which subjects studied a list of items and then, after a short 2-min or a prolonged 10-min lag, restudied some of the list items. Participants' electroencephalography (EEG) was recorded during both the study and restudy phases. In Experiment 2, but not in Experiment 1, subjects engaged in a mental context reinstatement task immediately before the restudy phase started, trying to mentally reinstate the study context. Results of Experiment 1 revealed a theta/alpha power increase from study to restudy after short lag and an alpha/beta power decrease after long lag. Engagement in the mental context reinstatement task in Experiment 2 eliminated the decrease in alpha/beta power. The results are consistent with the view that the observed alpha/beta decrease reflects context retrieval, which became obsolete when there was preceding mental context reinstatement.

scholarly journals Shaping information processing: the role of oscillatory dynamics in a working-memory task

2021 ◽  
Author(s):  
Hesham A. ElShafei ◽  
Ying Joey Zhou ◽  
Saskia Haegens
Keyword(s):  
Information Processing ◽  
Information Flow ◽  
Alpha Power ◽  
Match To Sample ◽  
Beta Power ◽  
Phase Alignment ◽  
Alpha Beta ◽  
Comprehensive Framework ◽  
High Beta

AbstractNeural oscillations are thought to reflect low-level operations that can be employed for higher-level cognitive functions. Here, we investigated the role of brain rhythms in the 1–30 Hz range by recording MEG in participants performing a visual delayed match-to-sample paradigm in which orientation or spatial frequency of sample and probe gratings had to be matched. A cue occurring before or after sample presentation indicated the to-be-matched feature. We demonstrate that alpha/beta power decrease tracks the presentation of the informative cue and indexes faster responses. Moreover, these faster responses coincided with an augmented phase alignment of slow oscillations, as well as phase-amplitude coupling between slow and fast oscillations. Importantly, stimulus decodability was boosted by both low alpha power and high beta power. In summary, we provide support for a comprehensive framework in which different rhythms play specific roles: slow rhythms control input sampling, while alpha (and beta) gates the information flow, beta recruits task-relevant circuits, and the timing of faster oscillations is controlled by slower ones.Highlights- We test a comprehensive framework of rhythms as building blocks for information processing- Participants performed a visual delayed match-to-sample task with pre- & retro-cues- Phase alignment of slow rhythms, governing input sampling, indexes faster responses- Alpha/beta power, gating information flow, boost behavior & track informative cues- Low alpha (gating) & high beta (circuit-setup) power boost signal information content

scholarly journals Oscillatory correlates of selective restudy

2021 ◽  
Author(s):  
Michael Wirth ◽  
Bernhard Pastötter ◽  
Karl-Heinz Bäuml
Keyword(s):  
Beneficial Effect ◽  
The Other ◽  
Alpha Power ◽  
Mental Context ◽  
Power Increase ◽  
Beta Power ◽  
Alpha Beta ◽  
Study Context

Prior behavioral work has shown that selective restudy of some studied items leaves recall of the other studied items unaffected when lag between study and restudy is short, but improves recall of the other items when lag is prolonged. The beneficial effect has been attributed to context retrieval, assuming that selective restudy reactivates the context at study and thus provides a retrieval cue for the other items (Bäuml, 2019). Here the results of two experiments are reported, in each of which subjects studied a list of items and then, after a short 2-min or a prolonged 10-min lag, restudied some of the list items. Participants’ electroencephalography (EEG) was recorded during both the study and restudy phases. In Experiment 2, but not in Experiment 1, subjects engaged in a mental context reinstatement task immediately before the restudy phase started, trying to mentally reinstate the study context. Results of Experiment 1 revealed a theta/alpha power increase from study to restudy after short lag and an alpha/beta power decrease after long lag. Engagement in the mental context reinstatement task in Experiment 2 eliminated the decrease in alpha/beta power. The results are consistent with the view that the observed alpha/beta decrease reflects context retrieval, which became obsolete when there was preceding mental context reinstatement.

scholarly journals Alpha/beta power decreases during episodic memory formation predict the magnitude of alpha/beta power decreases during subsequent retrieval

2021 ◽  
Vol 153 ◽  
pp. 107755
Author(s):  
Benjamin J. Griffiths ◽  
María Carmen Martín-Buro ◽  
Bernhard P. Staresina ◽  
Simon Hanslmayr ◽  
Tobias Staudigl
Keyword(s):  
Episodic Memory ◽  
Memory Formation ◽  
Beta Power ◽  
Alpha Beta

scholarly journals Neurophysiological and behavioural effects of conventional and high definition tDCS

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fabio Masina ◽  
Giorgio Arcara ◽  
Eleonora Galletti ◽  
Isabella Cinque ◽  
Luciano Gamberini ◽  
...  
Keyword(s):  
Response Times ◽  
Power Reduction ◽  
Alpha Power ◽  
High Definition ◽  
Mixed Effect ◽  
State Dependency ◽  
Mixed Effect Models ◽  
Beta Power ◽  
Neurophysiological Data ◽  
Spectrum Density

AbstractHigh-definition transcranial direct current stimulation (HD-tDCS) seems to overcome a drawback of traditional bipolar tDCS: the wide-spread diffusion of the electric field. Nevertheless, most of the differences that characterise the two techniques are based on mathematical simulations and not on real, behavioural and neurophysiological, data. The study aims to compare a widespread tDCS montage (i.e., a Conventional bipolar montage with extracephalic return electrode) and HD-tDCS, investigating differences both at a behavioural level, in terms of dexterity performance, and a neurophysiological level, as modifications of alpha and beta power as measured with EEG. Thirty participants took part in three sessions, one for each montage: Conventional tDCS, HD-tDCS, and sham. In all the conditions, the anode was placed over C4, while the cathode/s placed according to the montage. At baseline, during, and after each stimulation condition, dexterity was assessed with a Finger Tapping Task. In addition, resting-state EEG was recorded at baseline and after the stimulation. Power spectrum density was calculated, selecting two frequency bands: alpha (8–12 Hz) and beta (18–22 Hz). Linear mixed effect models (LMMs) were used to analyse the modulation induced by tDCS. To evaluate differences among the montages and consider state-dependency phenomenon, the post-stimulation measurements were covariate-adjusted for baseline levels. We observed that HD-tDCS induced an alpha power reduction in participants with lower alpha at baseline. Conversely, Conventional tDCS induced a beta power reduction in participants with higher beta at baseline. Furthermore, data showed a trend towards a behavioural effect of HD-tDCS in participants with lower beta at baseline showing faster response times. Conventional and HD-tDCS distinctively modulated cortical activity. The study highlights the importance of considering state-dependency to determine the effects of tDCS on individuals.

scholarly journals Alpha/beta power decreases track the fidelity of stimulus-specific information

2019 ◽  
Author(s):  
Benjamin J. Griffiths ◽  
Stephen D. Mayhew ◽  
Karen J. Mullinger ◽  
João Jorge ◽  
Ian Charest ◽  
...  
Keyword(s):  
Information Processing ◽  
Memory Retrieval ◽  
Negative Relationship ◽  
Memory Task ◽  
Significant Negative Correlation ◽  
Neuronal Firing ◽  
Specific Information ◽  
Beta Power ◽  
Alpha Beta ◽  
Task Irrelevant

AbstractMassed synchronised neuronal firing is detrimental to information processing. When networks of task-irrelevant neurons fire in unison, they mask the signal generated by task-critical neurons. On a macroscopic level, mass synchronisation of these neurons can contribute to the ubiquitous alpha/beta (8-30Hz) oscillations. Reductions in the amplitude of these oscillations, therefore, may reflect a boost in the processing of high-fidelity information within the cortex. Here, we test this hypothesis. Twenty-one participants completed an associative memory task while undergoing simultaneous EEG-fMRI recordings. Using representational similarity analysis, we quantified the amount of stimulus-specific information represented within the BOLD signal on every trial. When correlating this metric with concurrently-recorded alpha/beta power, we found a significant negative correlation which indicated that as alpha/beta power decreased, our metric of stimulus-specific information increased. This effect generalised across cognitive tasks, as the negative relationship could be observed during visual perception and episodic memory retrieval. Further analysis revealed that this effect could be better explained by alpha/beta power decreases providing favourable conditions for information processing, rather than directly representing stimulus-specific information. Together, these results indicate that alpha/beta power decreases parametrically track the fidelity of both externally-presented and internally-generated stimulus-specific information represented within the cortex.

Cortical oscillations to measure anti-epileptic drug activity in clinical trials

2021 ◽  
Author(s):  
Andrea Biondi ◽  
Lorenzo Rocchi ◽  
Viviana Santoro ◽  
Gregory Beatch ◽  
Pierre Rossini ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Brain Activity ◽  
Systematic Evaluation ◽  
Alpha Power ◽  
Brain Oscillations ◽  
Cortical Oscillations ◽  
Anti Epileptic Drug ◽  
Beta Power ◽  
Gamma Power

Abstract The frequency analysis of electroencephalographic (EEG) activity, either spontaneous or evoked by transcranial magnetic stimulation (TMS-EEG), is a powerful tool to investigate changes in brain activity and excitability following the administration of antiepileptic drugs (AEDs). However, a systematic evaluation of the effect of AEDs on spontaneous and TMS-induced brain oscillations has not yet been provided. We studied the effects of lamotrigine, levetiracetam, and of a novel potassium channel opener (XEN1101) on TMS-induced and spontaneous brain oscillations in a group of healthy volunteers. Levetiracetam suppressed TMS-induced theta, alpha and beta power, whereas lamotrigine increased TMS-induced alpha power. XEN1101 decreased TMS-induced delta, theta and beta power. Resting-state EEG showed a decrease of theta band power after lamotrigine intake. Levetiracetam increased theta, beta and gamma power, while XEN1101 produced an increase of delta, theta, beta and gamma power. Different AEDs induce specific patterns of power changes in spontaneous and TMS-induced brain oscillations. Spontaneous and TMS-induced cortical oscillations represent a powerful tool to characterize the effect of AEDs on in vivo brain activity. Spectral fingerprints of specific AEDs should be further investigated to provide robust and objective biomarkers of biological effect in human clinical trials.

Emotion and Brain Oscillations: High Arousal is Associated with Decreases in Alpha- and Lower Beta-Band Power

2020 ◽  
Author(s):  
David Schubring ◽  
Harald T Schupp
Keyword(s):  
Stimulus Onset ◽  
Emotional Stimulus ◽  
Brain Oscillations ◽  
Beta Band ◽  
Viewing Condition ◽  
Stimulus Processing ◽  
Beta Power ◽  
Picture Presentation ◽  
Alpha Beta ◽  
Task Conditions

Abstract The study of brain oscillations associated with emotional picture processing has revealed conflicting findings. Although many studies observed a decrease in power in the alpha- and lower beta band, some studies observed an increase. Accordingly, the main aim of the present research series was to further elucidate whether emotional stimulus processing is related to an increase or decrease in alpha/beta power. In Study 1, participants (N = 16) viewed briefly presented (150 ms) high-arousing erotic and low-arousing people pictures. Picture presentation included a passive viewing condition and an active picture categorization task. Study 2 (N = 16) replicated Study 1 with negative valence stimuli (mutilations). In Study 3 (N = 18), stimulus materials of Study 1 and 2 were used. The main finding is that high-arousing pictures (erotica and mutilations) are associated with a decrease of power in the alpha/beta band across studies and task conditions. The effect peaked in occipitoparietal sensors between 400 and 800 ms after stimulus onset. Furthermore, a late (>1000 ms) alpha/beta power increase to mutilation pictures was observed, possibly reflecting top–down inhibitory control processes. Overall, these findings suggest that brain oscillations in the alpha/beta-band may serve as a useful measure of emotional stimulus processing.

scholarly journals The influence of induction speed on the frontal (processed) EEG

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
D. P. Obert ◽  
P. Sepúlveda ◽  
S. Kratzer ◽  
G. Schneider ◽  
M. Kreuzer
Keyword(s):  
Injection Rate ◽  
Alpha Power ◽  
Verbal Command ◽  
Spectral Edge Frequency ◽  
Induction Group ◽  
Power Spectral ◽  
Beta Power ◽  
Processed Eeg ◽  
Electroencephalogram Eeg ◽  
Slow Injection

Abstract The intravenous injection of the anaesthetic propofol is clinical routine to induce loss of responsiveness (LOR). However, there are only a few studies investigating the influence of the injection rate on the frontal electroencephalogram (EEG) during LOR. Therefore, we focused on changes of the frontal EEG especially during this period. We included 18 patients which were randomly assigned to a slow or fast induction group and recorded the frontal EEG. Based on this data, we calculated the power spectral density, the band powers and band ratios. To analyse the behaviour of processed EEG parameters we calculated the beta ratio, the spectral entropy, and the spectral edge frequency. Due to the prolonged induction period in the slow injection group we were able to distinguish loss of responsiveness to verbal command (LOvR) from loss of responsiveness to painful stimulus (LOpR) whereas in the fast induction group we could not. At LOpR, we observed a higher relative alpha and beta power in the slow induction group while the relative power in the delta range was lower than in the fast induction group. When concentrating on the slow induction group the increase in relative alpha power pre-LOpR and even before LOvR indicated that frontal EEG patterns, which have been suggested as an indicator of unconsciousness, can develop before LOR. Further, LOvR was best reflected by an increase of the alpha to delta ratio, and LOpR was indicated by a decrease of the beta to alpha ratio. These findings highlight the different spectral properties of the EEG at various levels of responsiveness and underline the influence of the propofol injection rate on the frontal EEG during induction of general anesthesia.

scholarly journals Elevations in EEG Power Spectra During the Recall of Sport Failure Amongst University Athletes

2020 ◽  
Author(s):  
Laura Ceccarelli ◽  
Ryan Jeffrey Giuliano
Keyword(s):  
Acute Stress ◽  
Power Spectra ◽  
Self Esteem ◽  
Recall Task ◽  
Alpha Power ◽  
Self Compassion ◽  
Beta Power ◽  
Eeg Power ◽  
High Beta ◽  
University Athletes

Previously, we showed that university athletes demonstrate cardiac reactivity resembling an acute stress response while recalling a previous sport failure. Athletes who reported higher levels of self- compassion showed greater elevation of parasympathetic nervous system reactivity during recall of failure, and also showed more adaptive behavioural reactions, less maladaptive thoughts, and less negative affect during the task. Here, we analyzed changes in power spectra of the electroencephalogram (EEG) before, during, and after the recall of a previous sports failure, and whether individual differences in self-compassion or related constructs impact EEG changes during recall. Significant reactivity to, and recovery from, the recall task was observed across all EEG bandwidths: delta power decreased, and theta, low alpha, high alpha, low beta, and high beta power all increased from baseline to recall. Analogous EEG power changes were observed during recovery: delta power increased, while theta, low alpha, high alpha, low beta, and high beta power all decreased to baseline levels. Large gender differences were observed, with females generally showing greater EEG power across bandwidths during all phases of the experiment. Higher levels of self-compassion were associated with reduced theta power at baseline and during the recovery phase. Reactivity and recovery scores of EEG power were associated with self-reported self-esteem in the low alpha band: individuals reporting higher self-esteem showed greater increases in low alpha power during the recall task and greater decreases in low alpha power during recovery. These results are amongst the first to examine EEG power changes during experiences of acute stress and may have implications for improving how athletes recover from failures in sporting events.

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