Expectancy, attention, and time

Rhythmic variance influences the speed but not the accuracy of complex averaging decisions

When a rhythm makes an event predictable, that event is perceived faster, and typically more accurately. However, the experiments showing this used simple tasks, and most manipulated temporal expectancy by using periodic or aperiodic precursors unrelated to stimulus and task. Three experiments tested the generality of these observations in a complex task in which rhythm was intrinsic to, rather than a precursor of, the information needed to respond: listeners averaged the laterality of a stream of noise bursts. We varied presentation rate, degree of periodicity, and average lateralisation. Decisions following a probe tone were fastest after periodic stimuli, and slowest after the most aperiodic stimuli. Without a probe tone, listeners responded sooner during periodic sequences, thus hearing less information. Periodicity did not benefit accuracy overall. This gain in speed but not accuracy for less information is not reported for simpler tasks. Neural entrainment supplemented by cognitive factors provide a tentative explanation. When the task is inherently complex and demands high attention over long durations, both expected-periodic and unexpected-aperiodic stimuli can increase response amplitude, enhancing stimulus representation, but periodicity increases confidence to respond early. Drift diffusion modelling supports this proposal: aperiodicity modulated the decision threshold, but not the drift rate or non-decision time. Together, these new data and the literature point towards task-dependent effects of temporal expectation on decision-making, showing interactions between rhythmic variance, task complexity, and sources of expectation about stimuli. We suggest the implications are worth exploring to extend understanding of rhythmicity on decision-making to everyday situations.

Cerebellar Direct Current Stimulation Reveals the Causal Role of the Cerebellum in Temporal Prediction

Temporal prediction (TP) influences our perception and cognition. The cerebellum could mediate this multi-level ability in a context-dependent manner. We tested whether a modulation of the cerebellar neural activity, induced by transcranial Direct Current Stimulation (tDCS), changed the TP ability according to the temporal features of the context and the duration of target interval. Fifteen healthy participants received anodal, cathodal, and sham tDCS (15 min × 2 mA intensity) over the right cerebellar hemisphere during a TP task. We recorded reaction times (RTs) to a target during the task in two contextual conditions of temporal anticipation: rhythmic (i.e., interstimulus intervals (ISIs) were constant) and single-interval condition (i.e., the estimation of the timing of the target was based on the prior exposure of the train of stimuli). Two ISIs durations were explored: 600 ms (short trials) and 900 ms (long trials). Cathodal tDCS improved the performance during the TP task (shorter RTs) specifically in the rhythmic condition only for the short trials and in the single-interval condition only for the long trials. Our results suggest that the inhibition of cerebellar activity induced a different improvement in the TP ability according to the temporal features of the context. In the rhythmic context, the cerebellum could integrate the temporal estimation with the anticipatory motor responses critically for the short target interval. In the single-interval context, for the long trials, the cerebellum could play a main role in integrating representation of time interval in memory with the elapsed time providing an accurate temporal prediction.

Effects of Metrical Context on the P1 Component

BACKGROUND AND OBJECTIVES

The temporal structure of sound, characterized by regular patterns, plays a crucial role in optimizing the processing of auditory information. The meter, representing a well-organized sequence of evenly spaced beats in music, exhibits a hierarchical arrangement, with stronger beats occupying higher metrical positions. Moreover, the meter has been shown to influence behavioral and neural processing, particularly the N1, P2, and mismatch negativity components. However, the role of the P1 component in the context of metrical hierarchy remains unexplored. This study aimed to investigate the effects of metrical hierarchy on the P1 component and compare the responses between musicians and non-musicians.

SUBJECTS AND METHODS

Thirty participants (15 musicians and 15 non-musicians) were enrolled in the study. Auditory stimuli consisted of a synthesized speech syllable presented together with a repeating series of four tones, establishing a quadruple meter. Electrophysiological recordings were performed to measure the P1 component.

RESULTS

The results revealed that metrical position had a significant effect on P1 amplitude, with the strongest beat showing the lowest amplitude. This contrasts with previous findings, in which enhanced P1 responses were typically observed at on-the-beat positions. The reduced P1 response on the strong beat can be interpreted within the framework of predictive coding and temporal prediction, where a higher predictability of pitch changes at the strong beat leads to a reduction in the P1 response. Furthermore, higher P1 amplitudes were observed in musicians compared to non-musicians, suggesting that musicians have enhanced sensory processing.

CONCLUSIONS

This study demonstrates the effects of metrical hierarchy on the P1 component, thereby enriching our understanding of auditory processing. The results suggest that predictive coding and temporal prediction play important roles in shaping sensory processing. Further, they suggest that musical training may enhance P1 responses.

A novel method for estimating properties of attentional oscillators reveals an age-related decline in flexibility

Dynamic attending theory proposes that the ability to track temporal cues in the auditory environment is governed by entrainment, the synchronization between internal oscillations and regularities in external auditory signals. Here, we focused on two key properties of internal oscillators: their preferred rate, the default rate in the absence of any input; and their flexibility, how they adapt to changes in rhythmic context. We developed methods to estimate oscillator properties (Experiment 1) and compared the estimates across tasks and individuals (Experiment 2). Preferred rates, estimated as the stimulus rates with peak performance, showed a harmonic relationship across measurements and were correlated with individuals' spontaneous motor tempo. Estimates from motor tasks were slower than those from the perceptual task, and the degree of slowing was consistent for each individual. Task performance decreased with trial-to-trial changes in stimulus rate, and responses on individual trials were biased toward the preceding trial's stimulus properties. Flexibility, quantified as an individual's ability to adapt to faster-than-previous rates, decreased with age. These findings show domain-specific rate preferences for the assumed oscillatory system underlying rhythm perception and production, and that this system loses its ability to flexibly adapt to changes in the external rhythmic context during aging.

Enhancing rhythmic temporal expectations: The dominance of auditory modality under spatial uncertainty

To effectively process the most relevant information, the brain anticipates the optimal timing for allocating attentional resources. Behavior can be optimized by automatically aligning attention with external rhythmic structures, whether visual or auditory. Although the auditory modality is known for its efficacy in representing temporal information, the current body of research has not conclusively determined whether visual or auditory rhythmic presentations have a definitive advantage in entraining temporal attention. The present study directly examined the effects of auditory and visual rhythmic cues on the discrimination of visual targets in Experiment 1 and on auditory targets in Experiment 2. Additionally, the role of endogenous spatial attention was also considered. When and where the target was the most likely to occur were cued by unimodal (visual or auditory) and bimodal (audiovisual) signals. A sequence of salient events was employed to elicit rhythm-based temporal expectations and a symbolic predictive cue served to orient spatial attention. The results suggest a superiority of auditory over visual rhythms, irrespective of spatial attention, whether the spatial cue and rhythm converge or not (unimodal or bimodal), and regardless of the target modality (visual or auditory). These findings are discussed in terms of a modality-specific rhythmic orienting, while considering a single, supramodal system operating in a top-down manner for endogenous spatial attention.

Randomness impacts the building of specific priors, visual exploration, and perception in object recognition

Recognising objects is a vital skill on which humans heavily rely to respond quickly and adaptively to their environment. Yet, we lack a full understanding of the role visual information sampling plays in this process, and its relation to the individual's priors. To bridge this gap, the eye-movements of 18 adult participants were recorded during a free-viewing object-recognition task using Dots stimuli1. Participants viewed the stimuli in one of three orders: from most visible to least (Descending), least visible to most (Ascending), or in a randomised order (Random). This dictated the strength of their priors along the experiment. Visibility order influenced the participants' recognition performance and visual exploration. In addition, we found that while orders allowing for stronger priors generally led participants to visually sample more informative locations, this was not the case of Random participants. Indeed, they appeared to behave naïvely, and their use of specific object-related priors was fully impaired, while they maintained the ability to use general, task-related priors to guide their exploration. These findings have important implications for our understanding of perception, which appears to be influenced by complex cognitive processes, even at the basic level of visual sampling during object recognition.

Syncopation as structure bootstrapping: the role of asymmetry in rhythm and language

Syncopation - the occurrence of a musical event on a metrically weak position preceding a rest on a metrically strong position - represents an important challenge in the study of the mapping between rhythm and meter. In this contribution, we present the hypothesis that syncopation is an effective strategy to elicit the bootstrapping of a multi-layered, hierarchically organized metric structure from a linear rhythmic surface. The hypothesis is inspired by a parallel with the problem of linearization in natural language syntax, which is the problem of how hierarchically organized phrase-structure markers are mapped onto linear sequences of words. The hypothesis has important consequences for the role of meter in music perception and cognition and, more particularly, for its role in the relationship between rhythm and bodily entrainment.

Tapping to drumbeats in an online experiment changes our perception of time and expressiveness

Bodily movements along with music, such as tapping, are not only very frequent, but may also have a profound impact on our perception of time and emotions. The current study adopted an online tapping paradigm to investigate participants' time experiences and expressiveness judgements when they tapped and did not tap to a series of drumming performances that varied in tempo and rhythmic complexity. Participants were asked to judge durations, passage of time (PoT), and the expressiveness of the performances in two conditions: (1) Observing only, (2) Observing and tapping regularly to the perceived beats. Results show that tapping trials passed subjectively faster and were partially (in slow- and medium-tempo conditions) perceived shorter compared to the observing-only trials. Increases in musical tempo (in tapping trials) and in complexity led to faster PoT, potentially due to distracted attentional resources for the timing task. Participants' musical training modulated the effects of complexity on the judgments of expressiveness. In addition, increases in tapping speed led to duration overestimation among the less musically trained participants. Taken together, tapping to music may have altered the internal clock speed, affecting the temporal units accumulated in the pacemaker-counter model.

Contribution of speech rhythm to understanding speech in noisy conditions: Further test of a selective entrainment hypothesis

Previous work by McAuley et al. Attention, Perception, & Psychophysics, 82, 3222-3233, (2020), Attention, Perception & Psychophysics, 83, 2229-2240, (2021) showed that disruption of the natural rhythm of target (attended) speech worsens speech recognition in the presence of competing background speech or noise (a target-rhythm effect), while disruption of background speech rhythm improves target recognition (a background-rhythm effect). While these results were interpreted as support for the role of rhythmic regularities in facilitating target-speech recognition amidst competing backgrounds (in line with a selective entrainment hypothesis), questions remain about the factors that contribute to the target-rhythm effect. Experiment 1 ruled out the possibility that the target-rhythm effect relies on a decrease in intelligibility of the rhythm-altered keywords. Sentences from the Coordinate Response Measure (CRM) paradigm were presented with a background of speech-shaped noise, and the rhythm of the initial portion of these target sentences (the target rhythmic context) was altered while critically leaving the target Color and Number keywords intact. Results showed a target-rhythm effect, evidenced by poorer keyword recognition when the target rhythmic context was altered, despite the absence of rhythmic manipulation of the keywords. Experiment 2 examined the influence of the relative onset asynchrony between target and background keywords. Results showed a significant target-rhythm effect that was independent of the effect of target-background keyword onset asynchrony. Experiment 3 provided additional support for the selective entrainment hypothesis by replicating the target-rhythm effect with a set of speech materials that were less rhythmically constrained than the CRM sentences.

Just a phase? Causal probing reveals spurious phasic dependence of sustained attention

For over a decade, electrophysiological studies have reported correlations between attention / perception and the phase of spontaneous brain oscillations. To date, these findings have been interpreted as evidence that the brain uses neural oscillations to sample and predict upcoming stimuli. Yet, evidence from simulations have shown that analysis artefacts could also lead to spurious pre-stimulus oscillations that appear to predict future brain responses. To address this discrepancy, we conducted an experiment in which visual stimuli were presented in time to specific phases of spontaneous alpha and theta oscillations. This allowed us to causally probe the role of ongoing neural activity in visual processing independent of the stimulus-evoked dynamics. Our findings did not support a causal link between spontaneous alpha / theta rhythms and behaviour. However, spurious correlations between theta phase and behaviour emerged offline using gold-standard time-frequency analyses. These findings are a reminder that care should be taken when inferring causal relationships between neural activity and behaviour using acausal analysis methods.

Predictability awareness rather than mere predictability enhances the perceptual benefits for targets in auditory rhythms over targets following temporal cues

Sounds following a cue or embedded in a periodic rhythm are processed more effectively than sounds that are part of an aperiodic rhythm. One might also expect that a sound embedded in a periodic rhythm is processed more effectively than a sound following a single temporal cue. Such a finding would follow the theory that the entrainment of neural rhythmic activity by periodic stimuli renders the prediction of upcoming stimuli more efficient. We conducted a psychophysical experiment in which we tested the behavioral elements of this idea. Targets in periodic and aperiodic rhythms, if they occurred, always appeared at the same moment in time, and thus were fully predictable. In a first condition, participants remained unaware of this. In a second condition, an explicit instruction on the temporal location of the targets embedded in rhythms was provided. We assessed sensitivity and reaction times to the target stimuli in a difficult temporal detection task, and contrasted performance in this task to that obtained for targets temporally cued by a single preceding cue. Irrespective of explicit information about target predictability, target detection performance was always better in the periodic and temporal cue conditions, compared to the aperiodic condition. However, we found that the mere predictability of an acoustic target within a periodic rhythm did not allow participants to detect the target any better than in a condition where the target's timing was predicted by a single temporal cue. Only when participants were made aware of the specific moment in the periodic rhythm where the target could occur, did sensitivity increase. This finding suggests that a periodic rhythm is not automatically sufficient to provide perceptual benefits compared to a condition predictable yet not rhythmic condition (a cue). In some conditions, as shown here, these benefits may only occur in interaction with other factors such as explicit instruction and directed attention.

The effect of rhythm on selective listening in multiple-source environments for young and older adults

Understanding continuous speech with competing background sounds is challenging, particularly for older adults. One stimulus property that may aid listeners understanding of to-be-attended (target) material is temporal regularity (rhythm). In the context of speech-in-noise understanding, McAuley and colleagues recently showed a target rhythm effect whereby recognition of target speech was better when natural speech rhythm of a target talker was intact than when it was temporally altered. The current study replicates the target rhythm effect using a synthetic vowel sequence paradigm in young adults (Experiment 1) and then uses this paradigm to investigate potential age-related changes in the effect of rhythm on recognition (Experiment 2). Listeners identified the last three vowels of temporally regular (isochronous) and irregular (anisochronous) synthetic vowel sequences in quiet and with a competing background sequence of vowel-like harmonic tone complexes presented at various tempos. The results replicated the target rhythm effect whereby temporal regularity in the vowel sequences improved identification accuracy of young listeners compared to irregular vowel sequences. The magnitude of the effect was not found to be influenced by background tempo, but faster background tempos led to greater vowel identification accuracy independent of regularity. Older listeners also demonstrated a target rhythm effect but received less benefit from the temporal regularity of the target sequences than did young listeners. This study highlights the importance of rhythm for understanding age-related differences in selective listening in complex environments and provides a novel paradigm for investigating effects of rhythm on perception.

Dynamic models for musical rhythm perception and coordination

Rhythmicity permeates large parts of human experience. Humans generate various motor and brain rhythms spanning a range of frequencies. We also experience and synchronize to externally imposed rhythmicity, for example from music and song or from the 24-h light-dark cycles of the sun. In the context of music, humans have the ability to perceive, generate, and anticipate rhythmic structures, for example, "the beat." Experimental and behavioral studies offer clues about the biophysical and neural mechanisms that underlie our rhythmic abilities, and about different brain areas that are involved but many open questions remain. In this paper, we review several theoretical and computational approaches, each centered at different levels of description, that address specific aspects of musical rhythmic generation, perception, attention, perception-action coordination, and learning. We survey methods and results from applications of dynamical systems theory, neuro-mechanistic modeling, and Bayesian inference. Some frameworks rely on synchronization of intrinsic brain rhythms that span the relevant frequency range; some formulations involve real-time adaptation schemes for error-correction to align the phase and frequency of a dedicated circuit; others involve learning and dynamically adjusting expectations to make rhythm tracking predictions. Each of the approaches, while initially designed to answer specific questions, offers the possibility of being integrated into a larger framework that provides insights into our ability to perceive and generate rhythmic patterns.

Individual neurophysiological signatures of spontaneous rhythm processing

When sensory input conveys rhythmic regularity, we can form predictions about the timing of upcoming events. Although rhythm processing capacities differ considerably between individuals, these differences are often obscured by participant- and trial-level data averaging procedures in M/EEG research. Here, we systematically assessed neurophysiological variability displayed by individuals listening to isochronous (1.54Hz) equitone sequences interspersed with unexpected (amplitude-attenuated) deviant tones. Our approach aimed at revealing time-varying adaptive neural mechanisms for sampling the acoustic environment at multiple timescales. Rhythm tracking analyses confirmed that individuals encode temporal regularities and form temporal expectations, as indicated in delta-band (1.54Hz) power and its anticipatory phase alignment to expected tone onsets. Zooming into tone- and participant-level data, we further characterized intra- and inter-individual variabilities in phase-alignment across auditory sequences. Further, individual modelling of beta-band tone-locked responses showed that a subset of auditory sequences was sampled rhythmically by superimposing binary (strong-weak; S-w), ternary (S-w-w) and mixed accentuation patterns. In these sequences, neural responses to standard and deviant tones were modulated by a binary accentuation pattern, thus pointing towards a mechanism of dynamic attending. Altogether, the current results point toward complementary roles of delta- and beta-band activity in rhythm processing and further highlight diverse and adaptive mechanisms to track and sample the acoustic environment at multiple timescales, even in the absence of task-specific instructions.

Little fast, little slow, should I stay or should I go? Adapting cognitive control to local-global temporal prediction across typical development

Adaptive cognitive control (CC), the ability to adjust goal-directed behavior according to changing environmental demand, can be instantiated bottom-up by implicit knowledge, including temporal predictability of task-relevant events. In S1-S2 tasks, either local (trial-by-trial hazard expectation) or global (block-by-block expectation) temporal information can induce prediction, allowing for proactive action control. Recent developmental evidence showed that adaptive CC based on global temporal prediction emerges earlier than when it is based on the local one only. However, very little is known about how children learn to dynamically adjust behavior on the fly according to changing global predictive information. Addressing this issue is nevertheless crucial to unravel the mechanisms underlying adaptive CC flexibility. Here we used a modified version of the Dynamic Temporal Prediction task to investigate how typically developing younger (6-8 years) and older children (9-11 years), adolescents (12-15 years) and adults (21-31 years) use global prediction to shape adaptive CC over time. Specifically, the short-long percentage of S2 preparatory intervals was manipulated list-wide to create a slow-fast-slow-fast fixed block sequence and test how efficiently the response speed adapted accordingly. Overall, results revealed that in all groups behavioral performance is successfully adjusted as a function of global prediction in the late phase of the task (block 3 to 4). Remarkably, only adolescents and adults exhibit an early adaptation of adaptive CC (block 1 to 2), while children younger than 11 show sluggish ability in inferring implicit changes in global predictive rules. This age-related dissociation suggests that, although being present from an early age, adaptive CC based on global predictive information needs more developmental space to become flexible in an efficient way. In the light of a neuroconstructivist approach, we suggest that bottom-up driven implicit flexibility may represent a key prerequisite for the development of efficient explicit cognitive control.

Sustained responses and neural synchronization to amplitude and frequency modulation in sound change with age

Perception of speech requires sensitivity to features, such as amplitude and frequency modulations, that are often temporally regular. Previous work suggests age-related changes in neural responses to temporally regular features, but little work has focused on age differences for different types of modulations. We recorded magnetoencephalography in younger (21-33 years) and older adults (53-73 years) to investigate age differences in neural responses to slow (2-6 Hz sinusoidal and non-sinusoidal) modulations in amplitude, frequency, or combined amplitude and frequency. Audiometric pure-tone average thresholds were elevated in older compared to younger adults, indicating subclinical hearing impairment in the recruited older-adult sample. Neural responses to sound onset (independent of temporal modulations) were increased in magnitude in older compared to younger adults, suggesting hyperresponsivity and a loss of inhibition in the aged auditory system. Analyses of neural activity to modulations revealed greater neural synchronization with amplitude, frequency, and combined amplitude-frequency modulations for older compared to younger adults. This potentiated response generalized across different degrees of temporal regularity (sinusoidal and non-sinusoidal), although neural synchronization was generally lower for non-sinusoidal modulation. Despite greater synchronization, sustained neural activity was reduced in older compared to younger adults for sounds modulated both sinusoidally and non-sinusoidally in frequency. Our results suggest age differences in the sensitivity of the auditory system to features present in speech and other natural sounds.

A corticostriatal projection for sound-evoked and anticipatory motor behavior following temporal expectation

The ability to form predictions based on recent sensory experience is essential for behavioral adaptation to our ever-changing environment. Predictive encoding represented by neuronal activity has been observed in sensory cortex, but how this neuronal activity is transformed into anticipatory motor behavior remains unclear. Fiber photometry to investigate a corticostriatal projection from the auditory cortex to the posterior striatum during an auditory paradigm in mice, and pharmacological experiments in a task that induces a temporal expectation of upcoming sensory stimuli. We find that the auditory corticostriatal projection relays both sound-evoked stimulus information as well as predictive signals in relation to stimulus timing following rhythmic auditory stimulation. Pharmacological experiments suggest that this projection is required for the initiation of both sound-evoked and anticipatory licking behavior in an auditory associative-learning behavioral task, but not for the general recognition of presented auditory stimuli. This auditory corticostriatal projection carries predictive signals, and the posterior striatum is critical to the anticipatory stimulus-driven motor behavior.

Forward entrainment: Psychophysics, neural correlates, and function

We define forward entrainment as that part of behavioral or neural entrainment that outlasts the entraining stimulus. In this review, we examine conditions under which one may optimally observe forward entrainment. In Part 1, we review and evaluate studies that have observed forward entrainment using a variety of psychophysical methods (detection, discrimination, and reaction times), different target stimuli (tones, noise, and gaps), different entraining sequences (sinusoidal, rectangular, or sawtooth waveforms), a variety of physiological measures (MEG, EEG, ECoG, CSD), in different modalities (auditory and visual), across modalities (audiovisual and auditory-motor), and in different species. In Part 2, we describe those experimental conditions that place constraints on the magnitude of forward entrainment, including an evaluation of the effects of signal uncertainty and attention, temporal envelope complexity, signal-to-noise ratio (SNR), rhythmic rate, prior experience, and intersubject variability. In Part 3 we theorize on potential mechanisms and propose that forward entrainment may instantiate a dynamic auditory afterimage that lasts a fraction of a second to minimize prediction error in signal processing.

A critical analysis of Lin et al.'s (2021) failure to observe forward entrainment in pitch discrimination

Forward entrainment refers to that part of the entrainment process that outlasts the entraining stimulus. Several studies have demonstrated psychophysical forward entrainment in a pitch-discrimination task. In a recent paper, Lin et al. (2021) challenged these findings by demonstrating that a sequence of 4 entraining pure tones does not affect the ability to determine whether a frequency modulated pulse, presented after termination of the entraining sequence, has swept up or down in frequency. They concluded that rhythmic sequences do not facilitate pitch discrimination. Here, we describe several methodological and stimulus design flaws in Lin et al.'s study that may explain their failure to observe forward entrainment in pitch discrimination.

Expectations of the timing and intensity of a stimulus propagate to the auditory periphery through the medial olivocochlear reflex

Expectations concerning the timing of a stimulus enhance attention at the time at which the event occurs, which confers significant sensory and behavioral benefits. Herein, we show that temporal expectations modulate even the sensory transduction in the auditory periphery via the descending pathway. We measured the medial olivocochlear reflex (MOCR), a sound-activated efferent feedback that controls outer hair cell motility and optimizes the dynamic range of the sensory system. MOCR was noninvasively assessed using otoacoustic emissions. We found that the MOCR was enhanced by a visual cue presented at a fixed interval before a sound but was unaffected if the interval was changing between trials. The MOCR was also observed to be stronger when the learned timing expectation matched with the timing of the sound but remained unvaried when these two factors did not match. This implies that the MOCR can be voluntarily controlled in a stimulus- and goal-directed manner. Moreover, we found that the MOCR was enhanced by the expectation of a strong but not a weak, sound intensity. This asymmetrical enhancement could facilitate antimasking and noise protective effects without disrupting the detection of faint signals. Therefore, the descending pathway conveys temporal and intensity expectations to modulate auditory processing.

Effect of Tempo on Temporal Expectation Driven by Rhythms in Dual-Task Performance

Temporal expectation is the ability to focus attention at a particular moment in time to optimize performance, which has been shown to be driven by regular rhythms. However, whether the rhythm-based temporal expectations rely upon automatic processing or require the involvement of controlled processing has not been clearly established. Furthermore, whether the mechanism is affected by tempo remains unknown. To investigate this research question, the present study used a dual-task procedure. In a single task, the participants were instructed to respond to a visual target preceded by a regular or an irregular visual rhythm under a fast (500 ms) or slow (3,500 ms) tempo. The dual-task simultaneously combined a working memory (WM) task. The results showed temporal expectation effects in which the participants responded faster to the regular than to the irregular conditions in a single task. Moreover, this effect persisted under dual-task interference in the fast tempo condition but was impaired in the slow tempo condition. These results revealed that rhythmic temporal expectation induced by fast tempo was dependent on automatic processing. However, compared with the faster tempo, temporal expectation driven by a slower tempo might involve more controlled processing.

Oscillatory entrainment mechanisms and anticipatory predictive processes in children with autism spectrum disorder

Anticipating near-future events is fundamental to adaptive behavior, whereby neural processing of predictable stimuli is significantly facilitated relative to nonpredictable events. Neural oscillations appear to be a key anticipatory mechanism by which processing of upcoming stimuli is modified, and they often entrain to rhythmic environmental sequences. Clinical and anecdotal observations have led to the hypothesis that people with autism spectrum disorder (ASD) may have deficits in generating predictions, and as such, a candidate neural mechanism may be failure to adequately entrain neural activity to repetitive environmental patterns, to facilitate temporal predictions. We tested this hypothesis by interrogating temporal predictions and rhythmic entrainment using behavioral and electrophysiological approaches. We recorded high-density electroencephalography in children with ASD and typically developing (TD) age- and IQ-matched controls, while they reacted to an auditory target as quickly as possible. This auditory event was either preceded by predictive rhythmic visual cues or was not preceded by any cue. Both ASD and control groups presented comparable behavioral facilitation in response to the Cue versus No-Cue condition, challenging the hypothesis that children with ASD have deficits in generating temporal predictions. Analyses of the electrophysiological data, in contrast, revealed significantly reduced neural entrainment to the visual cues and altered anticipatory processes in the ASD group. This was the case despite intact stimulus-evoked visual responses. These results support intact behavioral temporal prediction in response to a cue in ASD, in the face of altered neural entrainment and anticipatory processes.NEW & NOTEWORTHY We examined behavioral and EEG indices of predictive processing in children with ASD to rhythmically predictable stimuli. Although behavioral measures of predictive processing and evoked neural responses were intact in the ASD group, neurophysiological measures of preparatory activity and entrainment were impaired. When sensory events are presented in a predictable temporal pattern, performance and neuronal responses in ASD may be governed more by the occurrence of the events themselves and less by their anticipated timing.

A primer on rhythm quantification for fish sounds: a Mediterranean case study

We have used a lately established workflow to quantify rhythms of three fish sound types recorded in different areas of the Mediterranean Sea. So far, the temporal structure of fish sound sequences has only been described qualitatively. Here, we propose a standardized approach to quantify them, opening the path for assessment and comparison of an often underestimated but potentially critical aspect of fish sounds. Our approach is based on the analysis of inter-onset-intervals (IOIs), the intervals between the start of one sound element and the next. We calculate exact beats of a sequence using Fourier analysis and IOI analysis. Furthermore, we report on important parameters describing the variability in timing within a given sound sequence. Datasets were chosen to depict different possible rhythmic properties: Sciaena umbra sounds have a simple isochronous-metronome-like-rhythm. The /Kwa/ sound type emitted by Scorpaena spp. has a more complex rhythm, still presenting an underlying isochronous pattern. Calls of Ophidion rochei males present no rhythm, but a random temporal succession of sounds. This approach holds great potential for shedding light on important aspects of fish bioacoustics. Applications span from the characterization of specific behaviours to the potential discrimination of yet not distinguishable species.

The influence of auditory rhythms on the speed of inferred motion

The present research explored the influence of isochronous auditory rhythms on the timing of movement-related prediction in two experiments. In both experiments, participants observed a moving disc that was visible for a predetermined period before disappearing behind a small, medium, or large occluded area for the remainder of its movement. In Experiment 1, the disc was visible for 1 s. During this period, participants were exposed to either a fast or slow auditory rhythm, or they heard nothing. They were instructed to press a key to indicate when they believed the moving disc had reached a specified location on the other side of the occluded area. The procedure measured the (signed) error in participants' estimate of the time it would take for a moving object to contact a stationary one. The principal results of Experiment 1 were main effects of the rate of the auditory rhythm and of the size of the occlusion on participants' judgments. In Experiment 2, the period of visibility was varied with size of the occlusion area to keep the total movement time constant for all three levels of occlusion. The results replicated the main effect of rhythm found in Experiment 1 and showed a small, significant interaction, but indicated no main effect of occlusion size. Overall, the results indicate that exposure to fast isochronous auditory rhythms during an interval of inferred motion can influence the imagined rate of such motion and suggest a possible role of an internal rhythmicity in the maintenance of temporally accurate dynamic mental representations.

Temporal prediction elicits rhythmic preactivation of relevant sensory cortices

Being able to anticipate events before they happen facilitates stimulus processing. The anticipation of the contents of events is thought to be implemented by the elicitation of prestimulus templates in sensory cortex. In contrast, the anticipation of the timing of events is typically associated with entrainment of neural oscillations. It is so far unknown whether and in which conditions temporal expectations interact with feature‐based expectations, and, consequently, whether entrainment modulates the generation of content‐specific sensory templates. In this study, we investigated the role of temporal expectations in a sensory discrimination task. We presented participants with rhythmically interleaved visual and auditory streams of relevant and irrelevant stimuli while measuring neural activity using magnetoencephalography. We found no evidence that rhythmic stimulation induced prestimulus feature templates. However, we did observe clear anticipatory rhythmic preactivation of the relevant sensory cortices. This oscillatory activity peaked at behaviourally relevant, in‐phase, intervals. Our results suggest that temporal expectations about stimulus features do not behave similarly to explicitly cued, nonrhythmic, expectations, yet elicit a distinct form of modality‐specific preactivation.

Rhythmic and speech rate effects in the perception of durational cues

Listeners' perception of temporal contrasts in spoken language is highly sensitive to contextual information, such as variation in speech rate. The present study tests how rate-dependent perception is also mediated by distal (i.e., temporally removed) rhythmic patterns. In four experiments the role of rhythmic alternations and their interaction with speech rate effects are tested. Experiment 1 shows proximal speech rate (contrast) effects obtain based on changes in local context. Experiment 2 shows that these effects disappear with the addition of distal rhythmic alternations, indicating that rhythmic grouping shifts listeners' perception, even when proximal context conflicts. Experiments 3 and 4 explore how orthogonal variation in overall speech rate impacts these effects and finds that trial-to-trial (i.e., global) speech rate variation eliminates rhythmic grouping effects, both with and without variation in proximal (immediately preceding) context. Together, these results suggest a role for rhythmic patterning in listeners' processing of durational cues in speech, which interacts in various ways with proximal, distal, and global rate contexts.

Effects of speech-rhythm disruption on selective listening with a single background talker

Recent work by McAuley et al. (Attention, Perception, & Psychophysics, 82, 3222-3233, 2020) using the Coordinate Response Measure (CRM) paradigm with a multitalker background revealed that altering the natural rhythm of target speech amidst background speech worsens target recognition (a target-rhythm effect), while altering background speech rhythm improves target recognition (a background-rhythm effect). Here, we used a single-talker background to examine the role of specific properties of target and background sound patterns on selective listening without the complexity of multiple background stimuli. Experiment 1 manipulated the sex of the background talker, presented with a male target talker, to assess target and background-rhythm effects with and without a strong pitch cue to aid perceptual segregation. Experiment 2 used a vocoded single-talker background to examine target and background-rhythm effects with envelope-based speech rhythms preserved, but without semantic content or temporal fine structure. While a target-rhythm effect was present with all backgrounds, the background-rhythm effect was only observed for the same-sex background condition. Results provide additional support for a selective entrainment hypothesis, while also showing that the background-rhythm effect is not driven by envelope-based speech rhythm alone, and may be reduced or eliminated when pitch or other acoustic differences provide a strong basis for selective listening.

The impact of phase entrainment on auditory detection is highly variable: Revisiting a key finding

Ample evidence shows that the human brain carefully tracks acoustic temporal regularities in the input, perhaps by entraining cortical neural oscillations to the rate of the stimulation. To what extent the entrained oscillatory activity influences processing of upcoming auditory events remains debated. Here, we revisit a critical finding from Hickok et al. (2015) that demonstrated a clear impact of auditory entrainment on subsequent auditory detection. Participants were asked to detect tones embedded in stationary noise, following a noise that was amplitude modulated at 3 Hz. Tonal targets occurred at various phases relative to the preceding noise modulation. The original study (N = 5) showed that the detectability of the tones (presented at near-threshold intensity) fluctuated cyclically at the same rate as the preceding noise modulation. We conducted an exact replication of the original paradigm (N = 23) and a conceptual replication using a shorter experimental procedure (N = 24). Neither experiment revealed significant entrainment effects at the group level. A restricted analysis on the subset of participants (36%) who did show the entrainment effect revealed no consistent phase alignment between detection facilitation and the preceding rhythmic modulation. Interestingly, both experiments showed group-wide presence of a non-cyclic behavioural pattern, wherein participants' detection of the tonal targets was lower at early and late time points of the target period. The two experiments highlight both the sensitivity of the task to elicit oscillatory entrainment and the striking individual variability in performance.

What you hear first, is what you get: Initial metrical cue presentation modulates syllable detection in sentence processing

Auditory rhythms create powerful expectations for the listener. Rhythmic cues with the same temporal structure as subsequent sentences enhance processing compared with irregular or mismatched cues. In the present study, we focus on syllable detection following matched rhythmic cues. Cues were aligned with subsequent sentences at the syllable (low-level cue) or the accented syllable (high-level cue) level. A different group of participants performed the task without cues to provide a baseline. We hypothesized that unaccented syllable detection would be faster after low-level cues, and accented syllable detection would be faster after high-level cues. There was no difference in syllable detection depending on whether the sentence was preceded by a high-level or low-level cue. However, the results revealed a priming effect of the cue that participants heard first. Participants who heard a high-level cue first were faster to detect accented than unaccented syllables, and faster to detect accented syllables than participants who heard a low-level cue first. The low-level-first participants showed no difference between detection of accented and unaccented syllables. The baseline experiment confirmed that hearing a low-level cue first removed the benefit of the high-level grouping structure for accented syllables. These results suggest that the initially perceived rhythmic structure influenced subsequent cue perception and its influence on syllable detection. Results are discussed in terms of dynamic attending, temporal context effects, and implications for context effects in neural entrainment.

Sub-optimal construction of an auditory profile from temporally distributed spectral information

When spectral components of a complex sound are presented not simultaneously but distributed over time, human listeners can still, to a degree, perceptually recover the spectral profile of the sound. This capability of integrating spectral information over time was investigated using a cued informational masking paradigm. Listeners detected a 1-kHz pure tone in a simultaneous masker composed of six random-frequency tones drawn on every trial. The spectral profile of the masker was cued using a precursor sound that consisted of a sequence of 50-ms bursts, separated by inter-burst intervals of 100 ms. Each burst in the precursor consisted of pure tones at the masker frequencies with tones appearing at each of the masker frequencies at different presentation probabilities. As the presentation probability increased in different conditions, the detectability of the target improved, indicating reliable precursor cuing regarding the spectral content of the masker. For many listeners, performance did not significantly improve as the number of precursor bursts increased from 2 to 16, indicating inefficient integration of information beyond 2 bursts. Additional analyses suggest that when intensity of the bursts is relatively constant, the contribution of the precursor is dominated by information in the initial burst.

Neural signatures of temporal regularity and recurring patterns in random tonal sound sequences

The auditory system is highly sensitive to recurring patterns in the acoustic input - even in otherwise unstructured material, such as white noise or random tonal sequences. Electroencephalography (EEG) research revealed a characteristic negative potential to periodically recurring auditory patterns - a response, which has been interpreted as memory trace-related and specific, rather than as a sign of periodicity-driven entrainment. Here, we aim to disentangle these two possible contributions by investigating the influence of a periodic sound sequence's inherent temporal regularity on event-related potentials. Participants were presented continuous sequences of short tones of random pitch, with some sequences containing a recurring pattern, and asked to indicate whether they heard a repetition. Patterns were either spaced equally across the random sequence (isochronous condition) or with a temporal jitter (jittered condition), which enabled us to differentiate between event-related potentials (and thus processing operations associated with a memory trace for a repeated pattern) and the periodic nature of the repetitions. A negative recurrence-related component could be observed independently of temporal regularity, was pattern-specific, and modulated by across trial repetition of the pattern. Critically, isochronous pattern repetition induced an additional early periodicity-related positive component, which started to build up already before the pattern onset and which was elicited undampedly even when the repeated pattern was occasionally not presented. This positive component likely reflects a sensory driven entrainment process that could be the foundation of a behavioural benefit in detecting temporally regular repetitions.

Adaptive Changes in the Dynamics of Visual Attention With Extended Practice

Previous research indicates that visual attention can adapt to temporal stimulus patterns utilizing the rapid serial visual presentation (RSVP) task. However, how the temporal dynamics of an attentional pulse adapt to temporal patterns has not been explored. We addressed this question by conducting an attentional component analysis on RSVP performance and explored whether changes in attentional dynamics were accompanied by explicit learning about predictable target timing. We utilized an RSVP task in which a target letter appeared either in two possible RSVP positions in fixed-timing conditions or in random positions over 1, 2, or 3 days of training. In a transfer phase, the target appeared in previously presented or new positions. Over 3 days of practice the target identification rate, efficacy, and precision of a putative attentional pulse increased. These changes reflected general learning in the RSVP task resulting in attentional dynamics more efficiently focused on the target. Although group performance effects did not support learning of fixed target positions, target identification rates and the measure of the efficacy of an attentional pulse at these positions were positively associated with explicit learning. The current study is the first to provide a detailed description of practice related adaptation of attentional dynamics and suggests that timing specific changes might be mediated by explicit temporal learning.

Temporal expectation driven by rhythmic cues compared to that driven by symbolic cues provides a more precise attentional focus in time

Temporal expectation is the ability to select the precise point in time for doing something to produce an optimal effect. Two sources of information that humans use to generate temporal expectations are rhythmic and symbolic cues. Both types of cues have been proven effective in directing attention to a future point in time resulting in improved performance. However, the temporal precision of the two forms of temporal expectation have rarely been compared. In the current study, 17 participants performed two temporal expectation tasks in which either a rhythmic cue or a symbolic cue indicated that a future target would appear after a 500-ms (short) or 1,500-ms (long) interval; the target appeared at the expected time in 54% of trials and at an unexpected earlier or later interval in 36% of trials. In both tasks, we observed that the reaction time (RT) curves were U-shaped, with a slower RT for the earlier and later unexpected intervals and a faster RT for intervals approaching the expected point in time. Furthermore, we found a significant interaction between task and the quadratic term of temporal expectation, which indicates that the U-shaped RT curves for the rhythmic cue task are steeper than those for the symbolic cue task. Thus, the current results revealed that compared with symbolic cues, temporal expectation driven by rhythmic cues provides a more precise attentional focus in time.

Meter enhances the subcortical processing of speech sounds at a strong beat

The temporal structure of sound such as in music and speech increases the efficiency of auditory processing by providing listeners with a predictable context. Musical meter is a good example of a sound structure that is temporally organized in a hierarchical manner, with recent studies showing that meter optimizes neural processing, particularly for sounds located at a higher metrical position or strong beat. Whereas enhanced cortical auditory processing at times of high metric strength has been studied, there is to date no direct evidence showing metrical modulation of subcortical processing. In this work, we examined the effect of meter on the subcortical encoding of sounds by measuring human auditory frequency-following responses to speech presented at four different metrical positions. Results show that neural encoding of the fundamental frequency of the vowel was enhanced at the strong beat, and also that the neural consistency of the vowel was the highest at the strong beat. When comparing musicians to non-musicians, musicians were found, at the strong beat, to selectively enhance the behaviorally relevant component of the speech sound, namely the formant frequency of the transient part. Our findings indicate that the meter of sound influences subcortical processing, and this metrical modulation differs depending on musical expertise.

Spectro-temporal glimpsing of speech in noise: Regularity and coherence of masking patterns reduces uncertainty and increases intelligibility

Adverse listening conditions involve glimpses of spectro-temporal speech information. This study investigated if the acoustic organization of the spectro-temporal masking pattern affects speech glimpsing in "checkerboard" noise. The regularity and coherence of the masking pattern was varied. Regularity was reduced by randomizing the spectral or temporal gating of the masking noise. Coherence involved the spectral alignment of frequency bands across time or the temporal alignment of gated onsets/offsets across frequency bands. Experiment 1 investigated the effect of spectral or temporal coherence. Experiment 2 investigated independent and combined factors of regularity and coherence. Performance was best in spectro-temporally modulated noise having larger glimpses. Generally, performance also improved as the regularity and coherence of masker fluctuations increased, with regularity having a stronger effect than coherence. An acoustic glimpsing model suggested that the effect of regularity (but not coherence) could be partially attributed to the availability of glimpses retained after energetic masking. Performance tended to be better with maskers that were spectrally coherent as compared to temporally coherent. Overall, performance was best when the spectro-temporal masking pattern imposed even spectral sampling and minimal temporal uncertainty, indicating that listeners use reliable masking patterns to aid in spectro-temporal speech glimpsing.

Spectro-temporal glimpsing of speech in noise: Regularity and coherence of masking patterns reduces uncertainty and increases intelligibility

Adverse listening conditions involve glimpses of spectro-temporal speech information. This study investigated if the acoustic organization of the spectro-temporal masking pattern affects speech glimpsing in "checkerboard" noise. The regularity and coherence of the masking pattern was varied. Regularity was reduced by randomizing the spectral or temporal gating of the masking noise. Coherence involved the spectral alignment of frequency bands across time or the temporal alignment of gated onsets/offsets across frequency bands. Experiment 1 investigated the effect of spectral or temporal coherence. Experiment 2 investigated independent and combined factors of regularity and coherence. Performance was best in spectro-temporally modulated noise having larger glimpses. Generally, performance also improved as the regularity and coherence of masker fluctuations increased, with regularity having a stronger effect than coherence. An acoustic glimpsing model suggested that the effect of regularity (but not coherence) could be partially attributed to the availability of glimpses retained after energetic masking. Performance tended to be better with maskers that were spectrally coherent as compared to temporally coherent. Overall, performance was best when the spectro-temporal masking pattern imposed even spectral sampling and minimal temporal uncertainty, indicating that listeners use reliable masking patterns to aid in spectro-temporal speech glimpsing.

Altering the rhythm of target and background talkers differentially affects speech understanding

Three experiments investigated listeners' ability to use speech rhythm to attend selectively to a single target talker presented in multi-talker babble (Experiments 1 and 2) and in speech-shaped noise (Experiment 3). Participants listened to spoken sentences of the form "Ready [Call sign] go to [Color] [Number] now" and reported the Color and Number spoken by a target talker (cued by the Call sign "Baron"). Experiment 1 altered the natural rhythm of the target talker and background talkers for two-talker and six-talker backgrounds. Experiment 2 considered parametric rhythm alterations over a wider range, altering the rhythm of either the target or the background talkers. Experiments 1 and 2 revealed that altering the rhythm of the target talker, while keeping the rhythm of the background intact, reduced listeners' ability to report the Color and Number spoken by the target talker. Conversely, altering the rhythm of the background talkers, while keeping the target rhythm intact, improved listeners ability to report the Color and Number spoken by the target talker. Experiment 3, which embedded the target talker in speech-shaped noise rather than multi-talker babble, similarly reduced recognition of the target sentence with increased alteration of the target rhythm. This pattern of results favors a dynamic-attending theory-based selective-entrainment hypothesis over a disparity-based segregation hypothesis and an increased salience hypothesis.

Behavioral effects of rhythm, carrier frequency and temporal cueing on the perception of sound sequences

Regularity of acoustic rhythms allows predicting a target embedded within a stream thereby improving detection performance and reaction times in spectral detection tasks. In two experiments we examine whether temporal regularity enhances perceptual sensitivity and reduces reaction times using a temporal shift detection task. Participants detected temporal shifts embedded at different positions within a sequence of quintet-sounds. Narrowband quintets were centered around carrier frequencies of 200 Hz, 1100 Hz, or 3100 Hz and presented at presentation rates between 1-8 Hz. We compared rhythmic sequences to control conditions where periodicity was reduced or absent and tested whether perceptual benefits depend on the presentation rate, the spectral content of the sounds, and task difficulty. We found that (1) the slowest rate (1 Hz) led to the largest behavioral effect on sensitivity. (2) This sensitivity improvement is carrier-dependent, such that the largest improvement is observed for low-frequency (200 Hz) carriers compared to 1100 Hz and 3100 Hz carriers. (3) Moreover, we show that the predictive value of a temporal cue and that of a temporal rhythm similarly affect perceptual sensitivity. That is, both the cue and the rhythm induce confident temporal expectancies in contrast to an aperiodic rhythm, and thereby allow to effectively prepare and allocate attentional resources in time. (4) Lastly, periodic stimulation reduces reaction times compared to aperiodic stimulation, both at perceptual threshold as well as above threshold. Similarly, a temporal cue allowed participants to optimally prepare and thereby respond fastest. Overall, our results are consistent with the hypothesis that periodicity leads to optimized predictions and processing of forthcoming input and thus to behavioral benefits. Predictable temporally cued sounds provide a similar perceptual benefit to periodic rhythms, despite an additional uncertainty of target position within periodic sequences. Several neural mechanisms may underlie our findings, including the entrainment of oscillatory activity of neural populations.

Synchronisation of Neural Oscillations and Cross-modal Influences

At any given moment, we receive multiple signals from our different senses. Prior research has shown that signals in one sensory modality can influence neural activity and behavioural performance associated with another sensory modality. Recent human and nonhuman primate studies suggest that such cross-modal influences in sensory cortices are mediated by the synchronisation of ongoing neural oscillations. In this review, we consider two mechanisms proposed to facilitate cross-modal influences on sensory processing, namely cross-modal phase resetting and neural entrainment. We consider how top-down processes may further influence cross-modal processing in a flexible manner, and we highlight fruitful directions for further research.

Spatial Attention and Temporal Expectation Exert Differential Effects on Visual and Auditory Discrimination

Anticipation of an impending stimulus shapes the state of the sensory systems, optimizing neural and behavioral responses. Here, we studied the role of brain oscillations in mediating spatial and temporal anticipations. Because spatial attention and temporal expectation are often associated with visual and auditory processing, respectively, we directly contrasted the visual and auditory modalities and asked whether these anticipatory mechanisms are similar in both domains. We recorded the magnetoencephalogram in healthy human participants performing an auditory and visual target discrimination task, in which cross-modal cues provided both temporal and spatial information with regard to upcoming stimulus presentation. Motivated by prior findings, we were specifically interested in delta (1-3 Hz) and alpha (8-13 Hz) band oscillatory state in anticipation of target presentation and their impact on task performance. Our findings support the view that spatial attention has a stronger effect in the visual domain, whereas temporal expectation effects are more prominent in the auditory domain. For the spatial attention manipulation, we found a typical pattern of alpha lateralization in the visual system, which correlated with response speed. Providing a rhythmic temporal cue led to increased postcue synchronization of low-frequency rhythms, although this effect was more broadband in nature, suggesting a general phase reset rather than frequency-specific neural entrainment. In addition, we observed delta-band synchronization with a frontal topography, which correlated with performance, especially in the auditory task. Combined, these findings suggest that spatial and temporal anticipations operate via a top-down modulation of the power and phase of low-frequency oscillations, respectively.

The influence of rhythm on detection of auditory and vibrotactile asynchrony

The perception of an event is strongly influenced by the context in which it occurs. Here, we examined the effect of a rhythmic context on detection of asynchrony in both the auditory and vibrotactile modalities. Using the method of constant stimuli and a two-alternative forced choice (2AFC), participants were presented with pairs of pure tones played either simultaneously or with various levels of stimulus onset asynchrony (SOA). Target stimuli in both modalities were nested within either: (i) a regularly occurring, predictable rhythm (ii) an irregular, unpredictable rhythm, or (iii) no rhythm at all. Vibrotactile asynchrony detection had higher thresholds and showed greater variability than auditory asynchrony detection in general. Asynchrony detection thresholds for auditory targets but not vibrotactile targets were significantly reduced when the target stimulus was embedded in a regular rhythm as compared to no rhythm. Embedding within an irregular rhythm produced no such improvement. The observed modality asymmetries are interpreted with regard to the superior temporal resolution of the auditory system and specialized brain circuitry supporting auditory-motor coupling.

The developing predictive brain: How implicit temporal expectancy induced by local and global prediction shapes action preparation across development

Human behavior is continuously shaped not just as a function of explicitly responding to external world events but also by internal biases implicitly driven by the capacity to extract statistics from complex sensory patterns. Two possible sources of predictability engaged to generate and update temporal expectancy are the implicit extraction of either local or global statistical contingencies in the events' temporal structure. In the context of action preparation the local prediction has been reported to be stable from the age of 6. However, there is no evidence about how the ability to extract and use global statistical patterns to establish temporal expectancy changes across development. Here we used a new, child-friendly reaction time task purposely designed to investigate how local (within-trial expectancy bias) and global (between-block expectancy bias) prediction interplay to generate temporal expectancy and consequently shape action preparation in young (5- to 6-year-old), middle-aged (7- to 8-year-old) and old (9- to 10-year-old) typically developing children. We found that while local temporal prediction showed stable developmental trajectories, the ability to use a global rule to action preparation in terms of both accuracy and speed becomes stable after the age of seven. These findings are discussed by adopting a neuroconstructivist-inspired theoretical account, according to which the developmental constraints on learning from hierarchically nested levels of sensory complexity may constitute a necessary prerequisite for mastering complex domains.

Induced Beta Power Modulations during Isochronous Auditory Beats Reflect Intentional Anticipation before Gradual Tempo Changes

Induced beta-band power modulations in auditory and motor-related brain areas have been associated with automatic temporal processing of isochronous beats and explicit, temporally-oriented attention. Here, we investigated how explicit top-down anticipation before upcoming tempo changes, a sustained process commonly required during music performance, changed beta power modulations during listening to isochronous beats. Musicians’ electroencephalograms were recorded during the task of anticipating accelerating, decelerating, or steady beats after direction-specific visual cues. In separate behavioural testing for tempo-change onset detection, such cues were found to facilitate faster responses, thus effectively inducing high-level anticipation. In the electroencephalograms, periodic beta power reductions in a frontocentral topographic component with seed-based source contributions from auditory and sensorimotor cortices were apparent after isochronous beats with anticipation in all conditions, generally replicating patterns found previously during passive listening to isochronous beats. With anticipation before accelerations, the magnitude of the power reduction was significantly weaker than in the steady condition. Between the accelerating and decelerating conditions, no differences were found, suggesting that the observed beta patterns may represent an aspect of high-level anticipation common before both tempo changes, like increased attention. Overall, these results indicate that top-down anticipation influences ongoing auditory beat processing in beta-band networks.

A stimulus-brain coupling analysis of regular and irregular rhythms in adults with dyslexia and controls

When listening to temporally regular rhythms, most people are able to extract the beat. Evidence suggests that the neural mechanism underlying this ability is the phase alignment of endogenous oscillations to the external stimulus, allowing for the prediction of upcoming events (i.e., dynamic attending). Relatedly, individuals with dyslexia may have deficits in the entrainment of neural oscillations to external stimuli, especially at low frequencies. The current experiment investigated rhythmic processing in adults with dyslexia and matched controls. Regular and irregular rhythms were presented to participants while electroencephalography was recorded. Regular rhythms contained the beat at 2 Hz; while acoustic energy was maximal at 4 Hz and 8 Hz. These stimuli allowed us to investigate whether the brain responds non-linearly to the beat-level of a rhythmic stimulus, and whether beat-based processing differs between dyslexic and control participants. Both groups showed enhanced stimulus-brain coherence for regular compared to irregular rhythms at the frequencies of interest, with an overrepresentation of the beat-level in the brain compared to the acoustic signal. In addition, we found evidence that controls extracted subtle temporal regularities from irregular stimuli, whereas dyslexics did not. Findings are discussed in relation to dynamic attending theory and rhythmic processing deficits in dyslexia.

Certain non-isochronous sound trains are perceived as more isochronous when they start on beat

Perceiving the duration of neighboring time intervals is vital for rhythm perception. We discovered a phenomenon in which the perceived equality/inequality of neighboring time intervals in a sound sequence is changed by its metrical interpretation. The target sound sequence consisted of eight short sound bursts marking seven neighboring time intervals, which were repetitions of two durations (T1 and T2) presented in alternation (T1-T2-T1-T2 …). There were three tempos, which corresponded to T1 + T2 being 210, 420, and 630 ms. The physical difference between T1 and T2 (T1 - T2) was varied systematically for each tempo in the ranges of -100 to 100 ms (when T1 + T2 was 210 or 420 ms) or -150 to 150 ms (when T1 + T2 was 630 ms). Participants reported the level of perceived equality/inequality of these neighboring time intervals. For each target sequence, four isochronous lower-pitched preceding sounds were added at different phases so that the beginning of either T1 (Beat-on-T1 condition) or T2 (Beat-on-T2 condition) coincided with the beat induced by these preceding sounds. When T2 was longer than T1 by up to 60 ms, the neighboring time intervals of the same target sequence were perceived as more "equal" in the Beat-on-T1 condition compared with the Beat-on-T2 condition. Such a difference in the perceived equality/inequality appeared significantly only at the intermediate tempo of T1 + T2 = 420 ms. The difference in equality/inequality perception at limited temporal conditions could be accounted for by the occurrence of an illusion in time perception called time-shrinking.

Word Recall is Affected by Surrounding Metrical Context

It has been claimed that English has a metrical structure, or rhythm, in which stressed and unstressed syllables alternate. In previous research regular, alternating patterns have been shown to facilitate online language comprehension. Expanding these findings to downstream processing would lead to the prediction that metrical regularity enhances memory. Research from the memory literature, however, indicates that regular patterns are less salient and therefore less well remembered, and also that strings of similar sounds are harder to remember. This work suggests that, like lists of words with similar sounds, lists of words with similar metrical patterns are less accurately remembered than comparable metrically irregular patterns. The present study tests these conflicting predictions by examining the effects of metrical regularity in a recall task. We find that words are better recalled when they do not match their metrical context, suggesting that a regular metrical structure may not be beneficial in all contexts.

Auditory-motor coupling affects phonetic encoding

Recent studies have shown that moving in synchrony with auditory stimuli boosts attention allocation and verbal learning. Furthermore rhythmic tones are processed more efficiently than temporally random tones ('timing effect'), and this effect is increased when participants actively synchronize their motor performance with the rhythm of the tones, resulting in auditory-motor synchronization. Here, we investigated whether this applies also to sequences of linguistic stimuli (syllables). We compared temporally irregular syllable sequences with two temporally regular conditions where either the interval between syllable onsets (stimulus onset asynchrony, SOA) or the interval between the syllables' vowel onsets was kept constant. Entrainment to the stimulus presentation frequency (1 Hz) and event-related potentials were assessed in 24 adults who were instructed to detect pre-defined deviant syllables while they either pedaled or sat still on a stationary exercise bike. We found larger 1 Hz entrainment and P300 amplitudes for the SOA presentation during motor activity. Furthermore, the magnitude of the P300 component correlated with the motor variability in the SOA condition and 1 Hz entrainment, while in turn 1 Hz entrainment correlated with auditory-motor synchronization performance. These findings demonstrate that acute auditory-motor coupling facilitates phonetic encoding.

Evidence for the Rhythmic Perceptual Sampling of Auditory Scenes

Converging results suggest that perception is controlled by rhythmic processes in the brain. In the auditory domain, neuroimaging studies show that the perception of sounds is shaped by rhythmic activity prior to the stimulus, and electrophysiological recordings have linked delta and theta band activity to the functioning of individual neurons. These results have promoted theories of rhythmic modes of listening and generally suggest that the perceptually relevant encoding of acoustic information is structured by rhythmic processes along auditory pathways. A prediction from this perspective-which so far has not been tested-is that such rhythmic processes also shape how acoustic information is combined over time to judge extended soundscapes. The present study was designed to directly test this prediction. Human participants judged the overall change in perceived frequency content in temporally extended (1.2-1.8 s) soundscapes, while the perceptual use of the available sensory evidence was quantified using psychophysical reverse correlation. Model-based analysis of individual participant's perceptual weights revealed a rich temporal structure, including linear trends, a U-shaped profile tied to the overall stimulus duration, and importantly, rhythmic components at the time scale of 1-2 Hz. The collective evidence found here across four versions of the experiment supports the notion that rhythmic processes operating on the delta time scale structure how perception samples temporally extended acoustic scenes.