Oscillatory neural activity is a fundamental characteristic of the mammalian brain spanning multiple levels of spatial and temporal scale. Current theories of neural oscillations and analysis ...techniques employed to investigate their functional significance are based on an often implicit assumption: In the absence of experimental manipulation, the spectral content of any given EEG- or MEG-recorded neural oscillator remains approximately stationary over the course of a typical experimental session (∼1 h), spontaneously fluctuating only around its dominant frequency. Here, we examined this assumption for ongoing neural oscillations in the alpha-band (8–13 Hz). We found that alpha peak frequency systematically decreased over time, while alpha-power increased. Intriguingly, these systematic changes showed partial independence of each other: Statistical source separation (independent component analysis) revealed that while some alpha components displayed concomitant power increases and peak frequency decreases, other components showed either unique power increases or frequency decreases. Interestingly, we also found these components to differ in frequency. Components that showed mixed frequency/power changes oscillated primarily in the lower alpha-band (∼8–10 Hz), while components with unique changes oscillated primarily in the higher alpha-band (∼9–13 Hz). Our findings provide novel clues on the time-varying intrinsic properties of large-scale neural networks as measured by M/EEG, with implications for the analysis and interpretation of studies that aim at identifying functionally relevant oscillatory networks or at driving them through external stimulation.
•Oscillatory neural activity is increasingly being linked to cognitive functions.•α-band activity (8:13 Hz) often dominates the EEG signal during wakefulness.•We investigated systematic changes in alpha power and frequency over time.•Over 1 hour of visual task performance, α-frequency decreased and α-power increased•Multiple non-stationary processes occur in endogenous α-band activity over time.
Selection mechanisms that dynamically gate only relevant perceptual information for further processing and sustained representation in working memory are critical for goal-directed behavior. We ...examined whether this gating process can be modulated by transcranial direct current stimulation (tDCS) over left dorsolateral prefrontal cortex (lDLPFC)—a region known to play a key role in working memory and conscious access. Specifically, we examined the effects of tDCS on the magnitude of the “attentional blink” (AB), a deficit in identifying the second of two targets presented in rapid succession. Thirty-four participants performed an AB task before (baseline), during and after 20 min of 1-mA anodal and cathodal tDCS in two separate sessions. On the basis of previous reports linking individual differences in AB magnitude to individual differences in DLPFC activity and on the basis of suggestions that effects of tDCS depend on baseline brain activity levels, we hypothesized that anodal tDCS over lDLPFC would modulate the magnitude of the AB as a function of individual baseline AB magnitude. Behavioral results did not provide support for this hypothesis. At the group level, we also did not observe any significant effects of tDCS, and a Bayesian analysis revealed strong evidence that tDCS to lDLPFC did not affect AB performance. Together, these findings do not support the idea that there is an optimal level of prefrontal cortical excitability for cognitive function. More generally, they add to a growing body of work that challenges the idea that the effects of tDCS can be predicted from baseline levels of behavior.
Pre‐stimulus electroencephalogram (EEG) oscillations, especially in the alpha range (8–13 Hz), can affect the sensitivity to temporal lags between modalities in multisensory perception. The effects ...of alpha power are often explained in terms of alpha's inhibitory functions, whereas effects of alpha frequency have bolstered theories of discrete perceptual cycles, where the length of a cycle, or window of integration, is determined by alpha frequency. Such studies typically employ visual detection paradigms with near‐threshold or even illusory stimuli. It is unclear whether such results generalize to above‐threshold stimuli. Here, we recorded EEG, while measuring temporal discrimination sensitivity in a temporal‐order judgement task using above‐threshold auditory and visual stimuli. We tested whether the power and instantaneous frequency of pre‐stimulus oscillations predict audiovisual temporal discrimination sensitivity on a trial‐by‐trial basis. By applying a jackknife procedure to link single‐trial pre‐stimulus oscillatory power and instantaneous frequency to psychometric measures, we identified a posterior cluster where lower alpha power was associated with higher temporal sensitivity of audiovisual discrimination. No statistically significant relationship between instantaneous alpha frequency and temporal sensitivity was found. These results suggest that temporal sensitivity for above‐threshold multisensory stimuli fluctuates from moment to moment and is indexed by modulations in alpha power.
In an audiovisual temporal‐order judgement task, we employed a novel jackknife procedure to quantify temporal sensitivity derived from a psychometric function at the single‐trial level. We found that higher pre‐stimulus alpha power predicted a lower temporal sensitivity, while instantaneous alpha frequency was not predictive of temporal sensitivity. Individual peak‐alpha frequency did not correlate significantly with temporal sensitivity across participants nor did individual peak‐alpha power.
Selection mechanisms that dynamically gate only relevant perceptual information for further processing and sustained representation in working memory are critical for goal-directed behavior. We ...examined whether this gating process can be modulated by anodal transcranial direct current stimulation (tDCS) over left dorsolateral pFC (DLPFC)—a region known to play a key role in working memory and conscious access. Specifically, we examined the effects of tDCS on the magnitude of the so-called “attentional blink” (AB), a deficit in identifying the second of two targets presented in rapid succession. Thirty-four participants performed a standard AB task before (baseline), during, and after 20 min of 1-mA anodal and cathodal tDCS in two separate sessions. On the basis of previous reports linking individual differences in AB magnitude to individual differences in DLPFC activity and on suggestions that effects of tDCS depend on baseline brain activity levels, we hypothesized that anodal tDCS over left DLPFC would modulate the magnitude of the AB as a function of individual baseline AB magnitude. Indeed, individual differences analyses revealed that anodal tDCS decreased the AB in participants with a large baseline AB but increased the AB in participants with a small baseline AB. This effect was only observed during (but not after) stimulation, was not found for cathodal tDCS, and could not be explained by regression to the mean. Notably, the effects of tDCS were not apparent at the group level, highlighting the importance of taking individual variability in performance into account when evaluating the effectiveness of tDCS. These findings support the idea that left DLPFC plays a critical role in the AB and in conscious access more generally. They are also in line with the notion that there is an optimal level of prefrontal activity for cognitive function, with both too little and too much activity hurting performance.
•Memorizing more features significantly impacts visual working memory capacity.•Both object load and feature load affected change detection separately.•CDA amplitude increased with increasing object ...load.•Findings suggest that both objects and features contribute to limitations in visual working memory capacity.
An ongoing debate in visual working memory research is concentrated on whether visual working memory capacity is determined solely by the number of objects to be memorized, or additionally by the number of relevant features contained within objects. Using a novel change detection task that contained multi-feature objects we examined the effect of both object number and feature number on visual working memory capacity, change detection sensitivity, and posterior slow wave event-related brain potential (ERP) activity. Behaviorally, working memory capacity and sensitivity were modulated as a function of both the number of objects and the number of features memorized per object. However, the Contralateral Delay Activity (CDA) was only sensitive to the number of objects, but not to the number of features. This suggests that while both objects and features contribute to limitations in visual working memory capacity, the CDA is an insufficient mechanism to account for feature level representations.
The present paper is the mission statement of the Control of Impulsive Action (Ctrl-ImpAct) Lab regarding Open Science. As early-career researchers (ECRs) in the lab, we first state our personal ...motivation to conduct research based on the principles of Open Science. We then describe how we incorporate four specific Open Science practices (i.e., Open Methodology, Open Data, Open Source, and Open Access) into our scientific workflow. In more detail, we explain how Open Science practices are embedded into the so-called ‘co-pilot’ system in our lab. The ‘co-pilot’ researcher is involved in all tasks of the ‘pilot’ researcher, that is designing a study, double-checking experimental and data analysis scripts, as well as writing the manuscript. The lab has set up this co-pilot system to increase transparency, reduce potential errors that could occur during the entire workflow, and to intensify collaborations between lab members. Finally, we discuss potential solutions for general problems that could arise when practicing Open Science.
Although our sensory experience is mostly multisensory in nature, research on working memory representations has focused mainly on examining the senses in isolation. Results from the multisensory ...processing literature make it clear that the senses interact on a more intimate manner than previously assumed. These interactions raise questions regarding the manner in which multisensory information is maintained in working memory. We discuss the current status of research on multisensory processing and the implications of these findings on our theoretical understanding of working memory. To do so, we focus on reviewing working memory research conducted from a multisensory perspective, and discuss the relation between working memory, attention, and multisensory processing in the context of the predictive coding framework. We argue that a multisensory approach to the study of working memory is indispensable to achieve a realistic understanding of how working memory processes maintain and manipulate information.
Preserved ratio impaired spirometry (PRISm) is defined as a forced expiratory volume in 1 s (FEV
) <80% predicted and FEV
/forced vital capacity ≥0.70. PRISm is associated with respiratory symptoms ...and comorbidities. Our objective was to discover novel genetic signals for PRISm and see if they provide insight into the pathogenesis of PRISm and associated comorbidities.
We undertook a genome-wide association study (GWAS) of PRISm in UK Biobank participants (Stage 1), and selected single nucleotide polymorphisms (SNPs) reaching genome-wide significance for replication in 13 cohorts (Stage 2). A combined meta-analysis of Stage 1 and Stage 2 was done to determine top SNPs. We used cross-trait linkage disequilibrium score regression to estimate genome-wide genetic correlation between PRISm and pulmonary and extrapulmonary traits. Phenome-wide association studies of top SNPs were performed.
22 signals reached significance in the joint meta-analysis, including four signals novel for lung function. A strong genome-wide genetic correlation (r
) between PRISm and spirometric COPD (r
=0.62, p<0.001) was observed, and genetic correlation with type 2 diabetes (r
=0.12, p=0.007). Phenome-wide association studies showed that 18 of 22 signals were associated with diabetic traits and seven with blood pressure traits.
This is the first GWAS to successfully identify SNPs associated with PRISm. Four of the signals, rs7652391 (nearest gene
), rs9431040 (
), rs62018863 (
) and rs185937162 (
), have not been described in association with lung function before, demonstrating the utility of using different lung function phenotypes in GWAS. Genetic factors associated with PRISm are strongly correlated with risk of both other lung diseases and extrapulmonary comorbidity.
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