scholarly journals Oscillatory correlates of selective restudy

2021 ◽  
Author(s):  
Michael Wirth ◽  
Bernhard Pastötter ◽  
Karl-Heinz Bäuml

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.

2021 ◽  
Vol 15 ◽  
Author(s):  
Michael Wirth ◽  
Bernhard Pastötter ◽  
Karl-Heinz T. Bäuml

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.


2005 ◽  
Vol 17 (3) ◽  
pp. 530-541 ◽  
Author(s):  
Marcel C.M. Bastiaansen ◽  
Marieke van der Linden ◽  
Mariken ter Keurs ◽  
Ton Dijkstra ◽  
Peter Hagoort

Oscillatory neuronal dynamics, observed in the human electroencephalogram (EEG) during language processing, have been related to the dynamic formation of functionally coherent networks that serve the role of integrating the different sources of information needed for understanding the linguistic input. To further explore the functional role of oscillatory synchrony during language processing, we quantified event-related EEG power changes induced by the presentation of open-class (OC) words and closed-class (CC) words in a wide range of frequencies (from 1 to 30 Hz), while subjects read a short story. Word presentation induced three oscillatory components: a theta power increase (4–7 Hz), an alpha power decrease (10– 12 Hz), and a beta power decrease (16–21 Hz). Whereas the alpha and beta responses showed mainly quantitative differences between the two word classes, the theta responses showed qualitative differences between OC words and CC words: A theta power increase was found over left temporal areas for OC words, but not for CC words. The left temporal theta increase may index the activation of a network involved in retrieving the lexical semantic properties of the OC items.


eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Nathan Weisz ◽  
Nadine Gabriele Kraft ◽  
Gianpaolo Demarchi

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.


2021 ◽  
Author(s):  
Hesham A. ElShafei ◽  
Ying Joey Zhou ◽  
Saskia Haegens

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


2003 ◽  
Vol 17 (4) ◽  
pp. 195-202 ◽  
Author(s):  
Vanessa K. Lim ◽  
John L. Bradshaw ◽  
Michael E.R. Nicholls ◽  
Ian J. Kirk ◽  
Jeff P. Hamm ◽  
...  

AbstractSimple tapping and complex movements (Luria finger apposition task) were performed unimanually and bimanually by two groups of professional guitarists while EEG was recorded from electrodes over the sensorimotor cortex. One group had a task-specific movement disorder (focal dystonia or musicians' cramp), while the other group did not (controls). There were no significant group interactions in the task-related power (TRPow) within the alpha range of 8-10Hz (mu1). In contrast, there was a significant group interaction within the alpha range of 10-12Hz (mu2); these latter frequencies are associated with task-specific sensorimotor integration. The significant group interaction included task (simple and complex) by hand (left, right, and both) by electrodes (10 electrodes over the sensorimotor areas). In the rest conditions, the alpha power (10-12Hz) was comparable between the groups; during movement, however, compared to the controls, patients demonstrated the greatest TRPow (10-12Hz) over all conditions. This was particularly evident when patients used their affected hand and suggests that patients with musicians' cramp have impaired task-specific sensorimotor integration.


2021 ◽  
Vol 153 ◽  
pp. 107755
Author(s):  
Benjamin J. Griffiths ◽  
María Carmen Martín-Buro ◽  
Bernhard P. Staresina ◽  
Simon Hanslmayr ◽  
Tobias Staudigl

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fabio Masina ◽  
Giorgio Arcara ◽  
Eleonora Galletti ◽  
Isabella Cinque ◽  
Luciano Gamberini ◽  
...  

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.


2021 ◽  
Vol 37 (2) ◽  
Author(s):  
Przemysław Filipiak ◽  
Anna Jaskóła ◽  
Karolina Gattner

Objectives. Psoriasis makes a relative contraindication for lithium treatment which can exacerbate its symptoms or induce it itself. On the other hand, lithium exerts immuno-modulatory activity. Case study. In this paper, a case of a female patient is presented. The patient has been treated since 2012 for bipolar affective illness (bipolar disorder – BD) and psori­asis, which occurred for the first time during a depress­ive episode. Despite intensive pharmacological treatment, both as inpatient and outpatient, a satisfactory improvement of affective illness has not been obtained. After the introduction of lithium, a remission of BD was achieved as well as a reduction of psoriatic changes, which have been maintained until now (2021). Conclusion. The remission of Bipolar Disorder (BD) on lithium can suggest that the patient belongs to the group of the so-called excellent lithium responders. In the presen­ted case remission of psoriasis was observed during lithium treatment. This case report must be treated with caution because remission could be spontaneous and the patient needs further observation.


2019 ◽  
Author(s):  
Benjamin J. Griffiths ◽  
Stephen D. Mayhew ◽  
Karen J. Mullinger ◽  
João Jorge ◽  
Ian Charest ◽  
...  

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.


2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 396-397
Author(s):  
Juan Taboada ◽  
Wilfido Briñez ◽  
José E Miranda ◽  
Alfredo Marin

Abstract El objetivo de este estudio fue evaluar el posible efecto probiótico del sustrato de residuos agroindustriales fermentado con BAL y levaduras sobre los indicadores productivos, reproductivos y de salud de cobayas primíparas y su descendencia. Se utilizaron 80 cuyes nulíparas distribuidas en 4 grupos de 20 hembras nulíparas cada uno, de 120 ± 5 días de edad, 1450 ± 25 g de peso vivo, todas sometidas al mismo sistema de manejo y alimentación actual de la granja. Se aplicaron con una dosis de 1 mL del bioaditivo / animal. Los tratamientos suministrados fueron las siguientes variantes: T1. control. T2, Sustrato (residuos agroindustriales) fermentado con L. acidophilus ATCC® 4356 ™. T3, sustrato más Kluyveromyces fragilis L4 (UCLV). T4, sustrato fermentado con microorganismos T2 y T3.En el experimento se utilizó un diseño completamente al azar, donde se evaluaron los indicadores reproductivos, productivos y de salud. Weight gain in pregnancy was greater (P < 0.05) in T4 in this same group, weight loss was less (P < 0.05) in lactation; the age at first conception and at delivery decreased (P < 0.05) in T4; fertility, the number of live-born animals and the weight at birth and at weaning were higher (P < 0.05) in T4 compared to the other groups; Likewise, blood parameters notably improved in the animals of treatment 4. The treaties with bioaditive were the ones whit the best behavior as reflected in table 1. In the experiment, the beneficial effect as a probiotic was confirmed by the treatments (T2, T3 and T4) of these with the best performance was T4. The inclusion of substrates fermented with LAB and yeasts significantly improves the productive, reproductive and health indicators of primiparous guinea pigs and their offspring.


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