Rhythmic sampling of information is thought to be an important aspect of explorative behaviour. This review presents an overview on experimental conditions that are used to study rhythmic sampling and associated oscillatory brain activity during attentive vision. It provides guidelines to efficiently quantify behavioural rhythms, compares results from human and non-human primate studies and argues that the underlying neural mechanisms of sampling can co-occur in both sensory and high-level areas.

Visual perception operates in an oscillatory fashion at an alpha frequency, such that perceptual snapshots are taken at favorable phases of the rhythm. Visual attention also seems to operate rhythmically, albeit at a theta frequency. We provide evidence for distinct roles of the perceptual alpha and the attentional theta rhythm, suggesting that sampling is characterized by fluctuating spatial resolution rather than a strict succession of blind gaps and perceptual snapshots.

We probed visual detection capability of human participants (N = 22) while they had to maintain a variable number of items in visual working memory (VWM). A dense sampling approach allowed to disclose different rhythms associated with different VWM loads: Low load was associated with an oscillation in detection at ~7.5 Hz, whereas an oscillation at ~5 Hz was observed in higher VWM load. This pattern of results is consistent with a central sampling attentional rhythm that allocates shared attentional resources both to the flow of external visual stimulation and to the internal maintenance of visual information.

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Employing an audio-visual detection task, we confirm that attention rhythmically oscillates between two objects at ~4–8 Hz and in counter-phase to each other. The effect was present in both the visual and the auditory modality and was also reflected in counter-phasic theta-modulations of frontal alpha power in the EEG.

We asked participants to discriminate the ear-of-origin of a brief pure tone embedded in dichotic white noise and manipulated stimulus expectation by presenting the target with unequal probability to the two ears (80% vs. 20%). Our results show that even under high stimulus expectation, auditory perceptual priors are propagated via ear-specific reverberations, manifested as rhythmic fluctuations of decision bias at alpha frequencies (~9 Hz).

Here, we aimed to replicate recent work that showed rhythmic attention in a visual attention task. Also, we aimed show that rhythmic attention at the cued spatial location depended on the behavioural relevance of the cue. We nor found evidence for rhythmic attention at the cued location, neither found that rhythmic attention depended on the location's behavioural relevance.

We employed a multiple-alternative forced-choice (m-AFC) discrimination task to study the single-trial EEG predictors of subjective reports of level of visual awareness, as well as accuracy. Our results replicate findings from a 2-AFC task, showing an inverse relationship between pre-stimulus alpha-power and visual awareness, but no link to discrimination accuracy. This confirms a dissociation between subjective and objective measures of performance, with pre-stimulus EEG power predicting the former.

During an electroencephalography recording, participants were asked to distinguish upright from rotated visual gratings presented for up to 1,500 ms. The power of the individual alpha frequency at occipital electrodes influenced the perceptual accuracy. Reduced alpha power prior to stimulus onset resulted in more accurate perception.

Performance variability on a visual orientation perception task was best defined by a single distribution. Post-target 2- to 7-Hz electroencephalography (EEG) activity and the P3 event-related potential (ERP) varied with task performance in that more accurate trials had greater power and a more positive P3. These results suggest that perceptual quality can be characterised by a fixed range, and where it falls within that range is modulated by the post-target power in the lower-frequency bands and their analogous ERPs.

Pre-stimulus alpha-band oscillations influence the detection of visual stimuli (Hits vs. Misses) through both power differences and phase opposition. We report distinct brain sources for power and phase effects. Moreover pre-stimulus power, unlike phase opposition, alters the subsequent stimulus-evoked response. These results suggest that distinct neural mechanisms underlie the impact of alpha-band power and phase on perceptual outcome in visual detection tasks.

Decoding accuracy of grating orientation in MEG is modulated by the phase of ongoing brain activity in the theta/alpha range in the frontoparietal attention network.

According to the α-theories, visual sensitivity fluctuates with posterior alpha oscillations. We sought proof of applicability by measuring reaction times (RTs) to visual targets time-locked to the α-cycle using a real-time electroencephalography (EEG)-based brain–computer interface (BCI). Stimuli time locking to the α-cycle was successful, but RTs were not correlated with the α-phase. Although α-phase might play a role in the speed of visual processing from a theoretical perspective, we conclude that its potential impact for EEG-based BCI appears negligible.

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.

Recent advances in attention research have been propelled by the debate on target enhancement versus distractor suppression. A major neural correlate of attention is the modulation of alpha oscillatory power (~10 Hz), which signifies shifts of attention in time, space and between modalities. This opinion article reviews and critically examines conceptual and methodological key aspects that are indispensable for a mechanistic understanding of the role of neural alpha oscillations for attention.

This article summarizes some of the early research into brain rhythms, focusing on work using repetitive visual stimulation, also known as photic driving. Links to contemporary open research questions are highlighted, particularly between photic driving results and current entrainment studies, as well as general arguments for reading historical literature.

Predictability-based perceptual inferences increase entrainment to isochronous auditory sequences. Both temporal and spectral regularities contribute to sensory entrainment

Recording magnetoencephalography while presenting continuous speech under different levels of degradation shows that alpha power and speech tracking are differently affected. While alpha power declines with declining clarity speech tracking follows an inverted U-shape. Linear mixed models suggest that a combination of alpha power and tracking contribute to subjective speech understanding.

Here, we propose a novel clinical framework for non-invasively treating dementia-related disorders, called Gamma music-based interventions (Gamma-MBIs), that combines previous music-based interventions (MBIs) with current approaches employing Gamma-frequency sensory stimulation. We theorize that Gamma-MBIs could target multiple biomarkers of dementia, restore neural activity that underlies learning and memory (e.g., Gamma-frequency neural activity, Theta-Gamma coupling), and actively engage auditory and reward networks in the brain to promote behavioral change.

The brain extracts temporal regularities from the environment to anticipate upcoming events. Furthermore, with prior knowledge about their contents, the brain is thought to leverage this by instantiating anticipatory sensory templates. We investigated if sensory templates occur in response to a rhythmic stimulus stream with predictable temporal structure. We found that temporal rhythmic predictions did not induce sensory templates but rather modulated the excitability in early sensory cortices.

Rhythmic visual stimulation at alpha frequency (‘entrainment’) has previously led to modulated visual processing over SOAs, implying entrained alpha-phase effects. What about alpha power? We here found no differential effects of rhythmic as compared with arrhythmic stimulation in a reaction time task inspired by attention studies, aiming to test whether rhythmic alpha stimulation might modulate attention-related alpha power.

In a series of auditory pitch discrimination tasks with 181 healthy human participants, we provide no evidence for the popular hypothesis that entrainment to external rhythms (cues) facilitates perception and behavior. Instead, we found that behavior (reaction time) correlates positively with the frequency of these external rhythms. Thus, in a rhythmic environment covert active sensing, rather than entrainment, might underlie behavioral or perceptual improvements.

Neural oscillations sample the environment rhythmically. Environmental rhythms entrain neural rhythms and lead to resampling the world. Regularly distributed salient events lead to more attentional resources allocated to them, thus enhancing the probability of perceiving them. We expected regular acoustic rhythms to facilitate performance in sound- and syllable-monitoring tasks (non-linguistic and linguistic material). Facilitatory effect of regular rhythm was only detected on linguistic material, suggesting that isochrony modulates attention to linguistic more than to non-linguistic stimuli.

The current study revisited the entrainment effect observed in Hickok et al. (2015) (N = 5), by conducting a conceptual replication (N = 24) and an exact replication (N = 23). The original study showed that the detection of an acoustic target presented across nine temporal positions (a: yellow lines) following a sequence of amplitude modulated noise (a: blue curve to the left of the dashed line) exhibited a bicyclic modulation pattern (b: red graph) across the five tested participants (individual effect size in c: red graph). Results from our two experiments with larger sample sizes revealed that this modulation effect was only present in a subset of participants (~36%; c: black dots enclosed in dark blue areas) and was not observed at the group level (b: blue graphs).

We conducted a behavioural experiment to investigate the psychological mechanisms of sensory–motor synchronisation by introducing a rhythmic structure using a subdivision in a tone sequence. Subdivided tones made synchronised tapping less variable than a simple repetition of a tone when the intertap interval was 900 ms or more. On the other hand, a shorter intertap interval of 600 ms caused synchronisation more variable.

It has long been debated whether neural oscillations may implement a discrete sampling process in perceptual systems of the brain. Rhythmic, non-invasive brain stimulation (rNIBS) is increasingly used to test this hypothesis. In this review, we introduce the basic concepts of rNIBS methods in the study of perception, overview different experimental approaches along with their findings, and discuss their methodological pitfalls and limitations.

We repeatedly measured electroencephalography (EEG) between- and within-sessions, during resting state and attention task, from two posterior electrodes. The ‘maximum’ method on average yielded the same individual alpha frequency (IAF) estimates as a ‘Gaussian fit’ method, but the latter was more consistent, and rest-IAF was more consistent than task-IAF. When calibrating rhythmic stimulation protocols to individual EEG markers, we thus recommend rest-EEG along with a Gaussian fit method.

Alpha oscillations (8–12 Hz) have been related to temporal sampling in vision. After estimating the individual alpha frequency (IAF) from the electroencephalogram, we delivered transcranial alternating current stimulation (tACS) at slightly slower and faster frequencies (±2 Hz), whereas the participants performed a temporal integration/segregation task. Contrarily to our hypothesis, right-parietal tACS did not increase/decrease the IAF and did not lead to a modulation of the integration/segregation performance. Nonetheless, we observed preliminary evidence for an influence of tACS phase on temporal integration.

Here we show that both older and younger adults are able to encode targets paired with distractors into long-term memory. Also, we demonstrate that older adults only modulated alpha power during high distraction. These results indicate that both younger and older adults are able to employ the same inhibitory control mechanisms successfully, but that older adults fail to call upon these when distraction is minimal.

Phase-amplitude coupling was studied in an auditory region of the frontal cortex and the auditory cortex of bats. Coupling profiles differed across structures, with prominent delta/high-gamma coupling in frontal regions, and strong delta-theta/low-gamma coupling in auditory cortex. Distinct profiles may represent different mechanisms for neuronal processing in frontal and auditory cortices, and might complement oscillatory interactions for sensory processing in fronto-auditory cortical networks.

Neural oscillations are ubiquitous features of neural field data, with great potential for informing our understanding of neural function and how it relates to cognition. However, there is a great degree of variability in methods for investigating them, and findings that are reported. In this piece, we explore methodological considerations for analysing neural oscillations that may underlie some potential misinterpretations and propose best practice guidelines for addressing them.

What aspects of discrete perception theories are addressed when brain wave findings are related to discrete perception? The first aspect we propose requires clarifying whether findings are about the content of consciousness or the temporal structure of consciousness per se. The second aspect requires specifying the choice of intermittency theory and its consequences on conscious and unconscious processing. The third aspect requires showing whether sampling in discrete perception is necessarily linked to specific brain rhythms and addressing the issue of multiple temporal resolutions.