Neuroanatomical and neurochemical substrates of timing

Reward positivity affects temporal interval production in a continuous timing task

The neural circuits of reward processing and interval timing (including the perception and production of temporal intervals) are functionally intertwined, suggesting that it might be possible for momentary reward processing to influence subsequent timing behavior. Previous animal and human studies have mainly focused on the effect of reward on interval perception, whereas its impact on interval production is less clear. In this study, we examined whether feedback, as an example of performance-contingent reward, biases interval production. We recorded EEG from 20 participants while they engaged in a continuous drumming task with different realistic tempos (1728 trials per participant). Participants received color-coded feedback after each beat about whether they were correct (on time) or incorrect (early or late). Regression-based EEG analysis was used to unmix the rapid occurrence of a feedback response called the reward positivity (RewP), which is traditionally observed in more slow-paced tasks. Using linear mixed modeling, we found that RewP amplitude predicted timing behavior for the upcoming beat. This performance-biasing effect of the RewP was interpreted as reflecting the impact of fluctuations in reward-related anterior cingulate cortex activity on timing, and the necessity of continuous paradigms to make such observations was highlighted.

Goal-directed learning is multidimensional and accompanied by diverse and widespread changes in neocortical signaling

New tasks are often learned in stages with each stage reflecting a different learning challenge. Accordingly, each learning stage is likely mediated by distinct neuronal processes. And yet, most rodent studies of the neuronal correlates of goal-directed learning focus on individual outcome measures and individual brain regions. Here, we longitudinally studied mice from naïve to expert performance in a head-fixed, operant conditioning whisker discrimination task. In addition to tracking the primary behavioral outcome of stimulus discrimination, we tracked and compared an array of object-based and temporal-based behavioral measures. These behavioral analyses identify multiple, partially overlapping learning stages in this task, consistent with initial response implementation, early stimulus-response generalization, and late response inhibition. To begin to understand the neuronal foundations of these learning processes, we performed widefield Ca2+ imaging of dorsal neocortex throughout learning and correlated behavioral measures with neuronal activity. We found distinct and widespread correlations between neocortical activation patterns and various behavioral measures. For example, improvements in sensory discrimination correlated with target stimulus evoked activations of response-related cortices along with distractor stimulus evoked global cortical suppression. Our study reveals multidimensional learning for a simple goal-directed learning task and generates hypotheses for the neuronal modulations underlying these various learning processes.

Keeping the Time: The Impact of External Clock-Speed Manipulation on Time-Based Prospective Memory

Several studies have suggested that time monitoring is important for appropriate time-based prospective memory (TBPM). However, it is still unknown if people actively use internal timing processes to monitor the approaching target time, and whether they do so by tracking the duration between clock digits, or by counting and matching the numerical progression of clock ticks' digits with the target time. Therefore, in the present study, we investigated whether a manipulation of the external time affected time monitoring and TBPM performance. In two experiments, participants performed two identical TBPM tasks: a first TBPM block with no clock-speed manipulation followed by a second TBPM block, where the clock-speed was manipulated as faster or slower (experimental conditions) or normal (control condition). The results showed that only participants in the slower clock condition increased time monitoring in the second compared to the first TBPM block (d = 0.42 and 1.70); moreover, particularly in Experiment 2, participants in the faster clock condition checked the clock significantly less frequently than participants in the slower clock (d = -1.70) and in the control condition (d = -0.98), but only during the 4th minute. No effect was found for TBPM performance. Overall, results suggested that people tracked the target time by counting and matching the numerical progression of clock ticks' digits with the target time. The findings are discussed considering the most recent theoretical advancements about the relationship between time perception and TBPM.

Anticipation of sexually arousing visual event leads to overestimation of elapsed time

Subjective estimates of duration are affected by emotional expectations about the future. For example, temporal intervals preceding a threatening event such as an electric shock are estimated as longer than intervals preceding a non-threatening event. However, it has not been unequivocally shown that such temporal overestimation occurs also when anticipating a similarly arousing but appealing event. In this study, we examined how anticipation of visual erotic material influenced perceived duration. Participants did a temporal bisection task, where they estimated durations of visual cues relative to previously learned short and long standard durations. The color of the to-be-timed visual cue signalled either a chance of seeing a preferred erotic picture at the end of the interval or certainty of seeing a neutral grey bar instead. The results showed that anticipating an appealing event increased the likelihood of estimating the cue duration as long as compared to the anticipation of a grey bar. Further analyses showed that this temporal overestimation effect was stronger for those who rated the anticipated erotic pictures as more sexually arousing. The results thus indicate that anticipation of appealing events has a similar dilating effect on perceived duration as does the anticipation of aversive events.

Goal-Directed Learning is Multidimensional and Accompanied by Diverse and Widespread Changes in Neocortical Signaling

New tasks are often learned in stages with each stage reflecting a different learning challenge. Accordingly, each learning stage is likely mediated by distinct neuronal processes. And yet, most rodent studies of the neuronal correlates of goal-directed learning focus on individual outcome measures and individual brain regions. Here, we longitudinally studied mice from naïve to expert performance in a head-fixed, operant conditioning whisker discrimination task. In addition to tracking the primary behavioral outcome of stimulus discrimination, we tracked and compared an array of object-based and temporal-based behavioral measures. These behavioral analyses identify multiple, partially overlapping learning stages in this task, consistent with initial response implementation, early stimulus-response generalization, and late response inhibition. To begin to understand the neuronal foundations of these learning processes, we performed widefield Ca2+ imaging of dorsal neocortex throughout learning and correlated behavioral measures with neuronal activity. We found distinct and widespread correlations between neocortical activation patterns and various behavioral measures. For example, improvements in sensory discrimination correlated with target stimulus evoked activations of licking-related cortices along with distractor stimulus evoked global cortical suppression. Our study reveals multidimensional learning for a simple goal-directed learning task and generates hypotheses for the neuronal modulations underlying these various learning processes.

Insular and prelimbic cortices control behavioral accuracy and precision in a temporal decision-making task in rats

The anterior insular cortex (AIC) comprises a region of sensory integration. It appears to detect salient events in order to guide goal-directed behavior, code tracking errors, and estimate the passage of time. Temporal processing in the AIC may be instantiated by the integration of representations of interoception. Projections between the AIC and the medial prefrontal cortex (mPFC) - found both in rats and humans - also suggest a possible role for these structures in the integration of autonomic responses during ongoing behavior. Few studies, however, have investigated the role of AIC and mPFC in decision-making and time estimation tasks. Moreover, their findings are not consistent, so the relationship between temporal decision-making and those areas remains unclear. The present study employed bilateral inactivations to explore the role of AIC and prelimbic cortex (PL) in rats during a temporal decision-making task. In this task, two levers are available simultaneously (but only one is active), one predicting reinforcement after a short, and the other after a long-fixed interval. Optimal performance requires a switch from the short to the long lever after the short-fixed interval elapsed and no reinforcement was delivered. Switch behavior from the short to the long lever was dependent on AIC and PL. During AIC inactivation, switch latencies became more variable, while during PL inactivation switch latencies became both more variable and less accurate. These findings point to a dissociation between AIC and PL in temporal decision-making, suggesting that the AIC is important for temporal precision, and PL is important for both temporal accuracy and precision.

Atypical Time to Contact Estimation in Young Adults with Autism Spectrum Disorder

Individuals with Autism Spectrum Disorder (ASD) present atypical sensory processing in the perception of moving stimuli and biological motion. The present study aims to explore the performance of young adults with ASD in a time to contact (TTC) estimation task involving social and non-social stimuli. TTC estimation involves extrapolating the trajectory of a moving target concealed by an occluder, based on the visible portion of its path, to predict the target's arrival time at a specific position. Sixteen participants with a diagnosis of level-1 ASD (M = 19.2 years, SE = 0.54 years; 3 F, 13 M) and sixteen participants with TD (M = 22.3 years, SE = 0.44 years; 3 F, 13 M) took part in the study and underwent a TTC estimation task. The task presented two object types (a car and a point-light walker), different object speeds, occluder lengths, motion directions and motion congruency. For the car object, a larger overestimation of TTC emerged for ASDs than for TDs, whereas no difference between ASDs and TDs emerged for the point-light walker. ASDs exhibited a larger TTC overestimation for the car object than for the point-light walker, whereas no difference between object types emerged for TDs. Our results indicated an atypical TTC estimation process in young adults with ASD. Given its importance in daily life, future studies should further explore this skill. Significant effects that emerged from the analysis are discussed.

Effects of movement training based on rhythmic auditory stimulation in cognitive impairment: a meta-analysis of randomized controlled clinical trial

Objective

According to the World Alzheimer's Disease Report in 2015,there were 9.9 million new cases of dementia in the world every year. At present, the number of patients suffering from dementia in China has exceeded 8 million, and it may exceed 26 million by 2040.Mild cognitive impairment (MCI) refers to the pathological state of pre-dementia with the manifestation of the progressive decline of memory or other cognitive functions but without decline of activities of daily life. It is particularly important to prevent or prolong the development of MCI into dementia. Research showing effects of rhythmic auditory stimulation based-movement training(RASMT) interventions on cognitive function is also emerging. Therefore, the present meta-analysis briefly summarize findings regarding the impacts of RASMT programs on cognitive impairment.

Methods

Data from Pubmed, Embase, and Cochrane Library were utilized. The impact of RASMT on cognitive functions was evaluated using indicators such as overall cognitive status, memory, attention, and executive functions. The REVMAN5.3 software was employed to analyze bias risks integrated into the study and the meta-analysis results for each indicator.

Results

A total of 1,596 studies were retrieved, of which 1,385 non-randomized controlled studies and 48 repetitive studies were excluded. After reviewing titles and abstracts of the remaining 163 articles, 133 irrelevant studies were excluded, 30 studies were downloaded and read the full text. Among 30 articles, 18 articles that did not meet the inclusion criteria were excluded, the other 12 studies were included in this meta-analysis. Utilizing the Cochrane Collaborative Network Bias Risk Assessment Scale, it was found that 11 studies explained the method of random sequence generation, nine studies did not describe allocation concealment, four were single-blinded to all researchers, and eight reported single-blinding in the evaluation of experimental results. In the meta-analysis, the main outcomes showed statistically significant differences in overall cognitive status [MD = 1.19, 95%CI (0.09, 2.29), (p < 0.05)], attention [MD = -1.86, 95%CI (-3.53, -0.19), (p < 0.05)], memory [MD = 0.71, 95%CI (0.33, 1.09), (p < 0.01)], and executive function [MD = -0.23, 95% CI (-0.44, -0.02), (p < 0.05)]. Secondary outcomes indicated no statistically significant differences in verbal fluency [MD = -0.51, 95%CI (-1.30, 0.27), (p = 0.20)], while depression [MD = -0.29, 95% CI (-0.42, -0.16), (p < 0.01)] and anxiety [MD = 0.19, 95% CI (0.06, 0.32), (p < 0.01)] exhibited statistically significant differences. The GRADEpro GDT online tool assessed the quality of evidence for the outcome measures, revealing one low-quality outcome, two moderate-quality outcomes, and one high-quality outcome in this review.

Conclusion

This study shows that RASMT can improve the general cognitive status, memory, attention and executive function of patients with cognitive impairment. The quality of evidence revealed that MMSE was low, attention and memory were moderate, and executive function was high. The RAMST program (type of exercise: play percussion instruments; time of exercise: 30-60 min; frequency of exercise: 2-3 times/week; duration of exercise: more than 12 weeks) was proved to be more effective in improving cognitive function. However, the sample size is relatively insufficient, the future needs further study.

Systematic review registration

PROSPERO, identifier: CRD42023483561.

Syllabic rhythm and prior linguistic knowledge interact with individual differences to modulate phonological statistical learning

Phonological statistical learning - our ability to extract meaningful regularities from spoken language - is considered critical in the early stages of language acquisition, in particular for helping to identify discrete words in continuous speech. Most phonological statistical learning studies use an experimental task introduced by Saffran et al. (1996), in which the syllables forming the words to be learned are presented continuously and isochronously. This raises the question of the extent to which this purportedly powerful learning mechanism is robust to the kinds of rhythmic variability that characterize natural speech. Here, we tested participants with arhythmic, semi-rhythmic, and isochronous speech during learning. In addition, we investigated how input rhythmicity interacts with two other factors previously shown to modulate learning: prior knowledge (syllable order plausibility with respect to participants' first language) and learners' speech auditory-motor synchronization ability. We show that words are extracted by all learners even when the speech input is completely arhythmic. Interestingly, high auditory-motor synchronization ability increases statistical learning when the speech input is temporally more predictable but only when prior knowledge can also be used. This suggests an additional mechanism for learning based on predictions not only about when but also about what upcoming speech will be.

Sub-second timing irregularities in a simple motor task in autism spectrum disorder: Preliminary effects of intermittent light stimulation

Several authors have contributed extensively to the neurocognitive understanding of timing. In Autism Spectrum Disorder (ASD) on the contrary, internal timing and its functioning is not well understood. In this study, we have adapted a simple finger-tapping motor task, with a timing component, as we aim at understanding whether the processing of time is preserved in this population. We have tested a group of people on the autism spectrum without intellectual disabilities and a control sample recruited from the general population, matched for age, sex, schooling and general cognitive abilities on this task with a learning and testing phase. In the testing phase, we have added two exploratory conditions where participants were exposed to intermittent light stimulation of 4 and 8 Hz. Results show that both in the learning and testing phase, besides troubles in the motor component encountered by the people on the spectrum, their timing component performance was also problematic. This reveals to be especially true for time intervals below the 1 s range, as hypothesized, whereas performance in longer intervals is clearly preserved. It was also observed that the exposure to intermittent light stimulation specifically overcomes the difficulties observed in the autistic group, at the timing components at this millisecond time range. The observed timing difficulties in this group seem to be restricted to the system responsible for the processing of time intervals in the milliseconds range, which helps accommodate disparate findings in the literature.

The perceptual timescape: Perceptual history on the sub-second scale

There is a high-capacity store of brief time span (∼1000 ms) which information enters from perceptual processing, often called iconic memory or sensory memory. It is proposed that a main function of this store is to hold recent perceptual information in a temporally segregated representation, named the perceptual timescape. The perceptual timescape is a continually active representation of change and continuity over time that endows the perceived present with a perceived history. This is accomplished primarily by two kinds of time marking information: time distance information, which marks all items of information in the perceptual timescape according to how far in the past they occurred, and ordinal temporal information, which organises items of information in terms of their temporal order. Added to that is information about connectivity of perceptual objects over time. These kinds of information connect individual items over a brief span of time so as to represent change, persistence, and continuity over time. It is argued that there is a one-way street of information flow from perceptual processing either to the perceived present or directly into the perceptual timescape, and thence to working memory. Consistent with that, the information structure of the perceptual timescape supports postdictive reinterpretations of recent perceptual information. Temporal integration on a time scale of hundreds of milliseconds takes place in perceptual processing and does not draw on information in the perceptual timescape, which is concerned with temporal segregation, not integration.

Pre-supplementary Motor Cortex Mediates Learning Transfer from Perceptual to Motor Timing

When we intensively train a timing skill, such as learning to play the piano, we not only produce brain changes associated with task-specific learning but also improve our performance in other temporal behaviors that depend on these tuned neural resources. Since the neural basis of time learning and generalization is still unknown, we measured the changes in neural activity associated with the transfer of learning from perceptual to motor timing in a large sample of subjects (n = 65; 39 women). We found that intense training in an interval discrimination task increased the acuity of time perception in a group of subjects that also exhibited learning transfer, expressed as a reduction in inter-tap interval variability during an internally driven periodic motor task. In addition, we found subjects with no learning and/or generalization effects. Notably, functional imaging showed an increase in pre-supplementary motor area and caudate-putamen activity between the post- and pre-training sessions of the tapping task. This increase was specific to the subjects that generalized their timing acuity from the perceptual to the motor context. These results emphasize the central role of the cortico-basal ganglia circuit in the generalization of timing abilities between tasks.

Sub-second and multi-second dopamine dynamics underlie variability in human time perception

Timing behaviour and the perception of time are fundamental to cognitive and emotional processes in humans. In non-human model organisms, the neuromodulator dopamine has been associated with variations in timing behaviour, but the connection between variations in dopamine levels and the human experience of time has not been directly assessed. Here, we report how dopamine levels in human striatum, measured with sub-second temporal resolution during awake deep brain stimulation surgery, relate to participants' perceptual judgements of time intervals. Fast, phasic, dopaminergic signals were associated with underestimation of temporal intervals, whereas slower, tonic, decreases in dopamine were associated with poorer temporal precision. Our findings suggest a delicate and complex role for the dynamics and tone of dopaminergic signals in the conscious experience of time in humans.

Roles of the cerebellum and basal ganglia in temporal integration: Insights from a synchronized tapping task

OBJECTIVE

The aim of this study was to clarify the roles of the cerebellum and basal ganglia for temporal integration.

METHODS

We studied 39 patients with spinocerebellar degeneration (SCD), comprising spinocerebellar atrophy 6 (SCA6), SCA31, Machado-Joseph disease (MJD, also called SCA3), and multiple system atrophy (MSA). Thirteen normal subjects participated as controls. Participants were instructed to tap on a button in synchrony with isochronous tones. We analyzed the inter-tap interval (ITI), synchronizing tapping error (STE), negative asynchrony, and proportion of delayed tapping as indicators of tapping performance.

RESULTS

The ITI coefficient of variation was increased only in MSA patients. The standard variation of STE was larger in SCD patients than in normal subjects, especially for MSA. Negative asynchrony, which is a tendency to tap the button before the tones, was prominent in SCA6 and MSA patients, with possible basal ganglia involvement. SCA31 patients exhibited normal to supranormal performance in terms of the variability of STE, which was surprising.

CONCLUSIONS

Cerebellar patients generally showed greater STE variability, except for SCA31. The pace of tapping was affected in patients with possible basal ganglia pathology.

SIGNIFICANCE

Our results suggest that interaction between the cerebellum and the basal ganglia is essential for temporal processing. The cerebellum and basal ganglia and their interaction regulate synchronized tapping, resulting in distinct tapping pattern abnormalities among different SCD subtypes.

Rhythmic musical activities may strengthen connectivity between brain networks associated with aging-related deficits in timing and executive functions

Brain aging and common conditions of aging (e.g., hypertension) affect networks important in organizing information, processing speed and action programming (i.e., executive functions). Declines in these networks may affect timing and could have an impact on the ability to perceive and perform musical rhythms. There is evidence that participation in rhythmic musical activities may help to maintain and even improve executive functioning (near transfer), perhaps due to similarities in brain regions underlying timing, musical rhythm perception and production, and executive functioning. Rhythmic musical activities may present as a novel and fun activity for older adults to stimulate interacting brain regions that deteriorate with aging. However, relatively little is known about neurobehavioral interactions between aging, timing, rhythm perception and production, and executive functioning. In this review, we account for these brain-behavior interactions to suggest that deeper knowledge of overlapping brain regions associated with timing, rhythm, and cognition may assist in designing more targeted preventive and rehabilitative interventions to reduce age-related cognitive decline and improve quality of life in populations with neurodegenerative disease. Further research is needed to elucidate the functional relationships between brain regions associated with aging, timing, rhythm perception and production, and executive functioning to direct design of targeted interventions.

Estimating Time and Rhythm by Predicting External Stimuli

In this chapter, we present recent findings from our group showing that elapsed time, interval timing, and rhythm maintenance might be achieved by the well-known ability of the brain to predict the future states of the world. The difference between predictions and actual sensory evidence is used to generate perceptual and behavioral adjustments that help subjects achieve desired behavioral goals. Concretely, we show that (1) accumulating prediction errors is a plausible strategy humans could use to determine whether a train of consecutive stimuli arrives at regular or irregular intervals. By analyzing the behavior of human and non-human primate subjects performing rhythm perception tasks, we demonstrate that (2) the ability to estimate elapsed time and internally maintain rhythms is shared across primates and humans. Neurophysiological recordings show that (3) the medial premotor cortex engages in rhythm entrainment and maintains oscillatory activity that reveals an internal metronome's spatial and temporal characteristics. Finally, we demonstrate that (4) the amplitude of gamma oscillations within this cortex increases proportionally to the total elapsed time. In conjunction with our most recent experiments, our results suggest that timing might be achieved by an internal simulation of the sensory stimuli and the motor commands that define the timing task that needs to be performed.

Dopamine dysregulation in Parkinson's disease flattens the pleasurable urge to move to musical rhythms

The pleasurable urge to move to music (PLUMM) activates motor and reward areas of the brain and is thought to be driven by predictive processes. Dopamine in motor and limbic networks is implicated in beat-based timing and music-induced pleasure, suggesting a central role of basal ganglia (BG) dopaminergic systems in PLUMM. This study tested this hypothesis by comparing PLUMM in participants with Parkinson's disease (PD), age-matched controls, and young controls. Participants listened to musical sequences with varying rhythmic and harmonic complexity (low, medium and high), and rated their experienced pleasure and urge to move to the rhythm. In line with previous results, healthy younger participants showed an inverted U-shaped relationship between rhythmic complexity and ratings, with preference for medium complexity rhythms, while age-matched controls showed a similar, but weaker, inverted U-shaped response. Conversely, PD showed a significantly flattened response for both the urge to move and pleasure. Crucially, this flattened response could not be attributed to differences in rhythm discrimination and did not reflect an overall decrease in ratings. For harmonic complexity, PD showed a negative linear pattern for both the urge to move and pleasure while healthy age-matched controls showed the same pattern for pleasure and an inverted U for the urge to move. This contrasts with the pattern observed in young healthy controls in previous studies, suggesting that both healthy aging and PD also influence affective responses to harmonic complexity. Together, these results support the role of dopamine within cortico-striatal circuits in the predictive processes that form the link between the perceptual processing of rhythmic patterns and the affective and motor responses to rhythmic music.

Temporal Information Processing in the Cerebellum and Basal Ganglia

Temporal information processing in the range of a few hundred milliseconds to seconds involves the cerebellum and basal ganglia. In this chapter, we present recent studies on nonhuman primates. In the studies presented in the first half of the chapter, monkeys were trained to make eye movements when a certain amount of time had elapsed since the onset of the visual cue (time production task). The animals had to report time lapses ranging from several hundred milliseconds to a few seconds based on the color of the fixation point. In this task, the saccade latency varied with the time length to be measured and showed stochastic variability from one trial to the other. Trial-to-trial variability under the same conditions correlated well with pupil diameter and the preparatory activity in the deep cerebellar nuclei and the motor thalamus. Inactivation of these brain regions delayed saccades when asked to report subsecond intervals. These results suggest that the internal state, which changes with each trial, may cause fluctuations in cerebellar neuronal activity, thereby producing variations in self-timing. When measuring different time intervals, the preparatory activity in the cerebellum always begins approximately 500 ms before movements, regardless of the length of the time interval being measured. However, the preparatory activity in the striatum persists throughout the mandatory delay period, which can be up to 2 s, with different rate of increasing activity. Furthermore, in the striatum, the visual response and low-frequency oscillatory activity immediately before time measurement were altered by the length of the intended time interval. These results indicate that the state of the network, including the striatum, changes with the intended timing, which lead to different time courses of preparatory activity. Thus, the basal ganglia appear to be responsible for measuring time in the range of several hundred milliseconds to seconds, whereas the cerebellum is responsible for regulating self-timing variability in the subsecond range. The second half of this chapter presents studies related to periodic timing. During eye movements synchronized with alternating targets at regular intervals, different neurons in the cerebellar nuclei exhibit activity related to movement timing, predicted stimulus timing, and the temporal error of synchronization. Among these, the activity associated with target appearance is particularly enhanced during synchronized movements and may represent an internal model of the temporal structure of stimulus sequence. We also considered neural mechanism underlying the perception of periodic timing in the absence of movement. During perception of rhythm, we predict the timing of the next stimulus and focus our attention on that moment. In the missing oddball paradigm, the subjects had to detect the omission of a regularly repeated stimulus. When employed in humans, the results show that the fastest temporal limit for predicting each stimulus timing is about 0.25 s (4 Hz). In monkeys performing this task, neurons in the cerebellar nuclei, striatum, and motor thalamus exhibit periodic activity, with different time courses depending on the brain region. Since electrical stimulation or inactivation of recording sites changes the reaction time to stimulus omission, these neuronal activities must be involved in periodic temporal processing. Future research is needed to elucidate the mechanism of rhythm perception, which appears to be processed by both cortico-cerebellar and cortico-basal ganglia pathways.

Neural mechanisms for integrating time and visual velocity cues in a prediction motion task: An fNIRS study

Human beings use accurate estimates of the time-to-collision of moving objects effortlessly in everyday life. In the laboratory, researchers typically apply prediction motion (PM) tasks to investigate motion processing. In the PM tasks, time structure refers to the ratio of travel time between the visible segment (first segment) and occluded segment (second segment). The condition of T = 1.0, which indicates that the time spent moving is the same across the two segments, is called equal time structure. The present study investigated the neural mechanisms of time and visual velocity information in prediction motion using functional near-infrared spectroscopy (fNIRS). Experiment 1 showed that when visual velocity was not available, participants performed better in equal time structure conditions than in unequal time structure conditions. Moreover, the left inferior parietal lobe (IPL) showed higher activation under equal time structure conditions. Experiment 2 showed that participants also performed better in equal time structure conditions when visual velocity was available. Both the left IPL and superior parietal lobe (SPL) exhibited stronger activation under equal time structure conditions in Experiment 2. A comparison between the two experiments showed that participants integrated time structure and visual velocity to estimate arrival time of the moving object. The fNIRS data indicated that the left SPL could be involved in information integration when judging arrival time.

Dopamine precursor depletion affects performance and confidence judgements when events are timed from an explicit, but not an implicit onset

Dopamine affects processing of temporal information, but most previous work has tested its role in prospective tasks, where participants know in advance when the event to be timed starts. However, we are often exposed to events whose onset we do not know in advance. We can evaluate their duration after they have elapsed, but mechanisms underlying this ability are still elusive. Here we contrasted effects of acute phenylalanine and tyrosine depletion (APTD) on both forms of timing in healthy volunteers, in a within-subject, placebo-controlled design. Participants were presented with a disc moving around a circular path and asked to reproduce the duration of one full revolution and to judge their confidence in performance. The onset of the revolution was either known in advance (explicit onset) or revealed only at the end of the trial (implicit onset). We found that APTD shortened reproduced durations in the explicit onset task but had no effect on temporal performance in the implicit onset task. This dissociation is corroborated by effects of APTD on confidence judgements in the explicit task only. Our findings suggest that dopamine has a specific role in prospective encoding of temporal intervals, rather than the processing of temporal information in general.

Debates on the dorsomedial prefrontal/dorsal anterior cingulate cortex: insights for future research

The dorsomedial prefrontal cortex/dorsal anterior cingulate cortex (dmPFC/dACC) is a brain area subject to many theories and debates over its function(s). Even its precise anatomical borders are subject to much controversy. In the past decades, the dmPFC/dACC has been associated with more than 15 different cognitive processes, which sometimes appear quite unrelated (e.g. body perception, cognitive conflict). As a result, understanding what the dmPFC/dACC does has become a real challenge for many neuroscientists. Several theories of this brain area's function(s) have been developed, leading to successive and competitive publications bearing different models, which sometimes contradict each other. During the last two decades, the lively scientific exchanges around the dmPFC/dACC have promoted fruitful research in cognitive neuroscience. In this review, we provide an overview of the anatomy of the dmPFC/dACC, summarize the state of the art of functions that have been associated with this brain area and present the main theories aiming at explaining the dmPFC/dACC function(s). We explore the commonalities and the arguments between the different theories. Finally, we explain what can be learned from these debates for future investigations of the dmPFC/dACC and other brain regions' functions.

Both stronger and weaker cerebro-cerebellar functional connectivity patterns during processing of spoken sentences in autism spectrum disorder

Cerebellar differences have long been documented in autism spectrum disorder (ASD), yet the extent to which such differences might impact language processing in ASD remains unknown. To investigate this, we recorded brain activity with magnetoencephalography (MEG) while ASD and age-matched typically developing (TD) children passively processed spoken meaningful English and meaningless Jabberwocky sentences. Using a novel source localization approach that allows higher resolution MEG source localization of cerebellar activity, we found that, unlike TD children, ASD children showed no difference between evoked responses to meaningful versus meaningless sentences in right cerebellar lobule VI. ASD children also had atypically weak functional connectivity in the meaningful versus meaningless speech condition between right cerebellar lobule VI and several left-hemisphere sensorimotor and language regions in later time windows. In contrast, ASD children had atypically strong functional connectivity for in the meaningful versus meaningless speech condition between right cerebellar lobule VI and primary auditory cortical areas in an earlier time window. The atypical functional connectivity patterns in ASD correlated with ASD severity and the ability to inhibit involuntary attention. These findings align with a model where cerebro-cerebellar speech processing mechanisms in ASD are impacted by aberrant stimulus-driven attention, which could result from atypical temporal information and predictions of auditory sensory events by right cerebellar lobule VI.

Brain-imaging evidence for compression of binary sound sequences in human memory

According to the language-of-thought hypothesis, regular sequences are compressed in human memory using recursive loops akin to a mental program that predicts future items. We tested this theory by probing memory for 16-item sequences made of two sounds. We recorded brain activity with functional MRI and magneto-encephalography (MEG) while participants listened to a hierarchy of sequences of variable complexity, whose minimal description required transition probabilities, chunking, or nested structures. Occasional deviant sounds probed the participants' knowledge of the sequence. We predicted that task difficulty and brain activity would be proportional to the complexity derived from the minimal description length in our formal language. Furthermore, activity should increase with complexity for learned sequences, and decrease with complexity for deviants. These predictions were upheld in both fMRI and MEG, indicating that sequence predictions are highly dependent on sequence structure and become weaker and delayed as complexity increases. The proposed language recruited bilateral superior temporal, precentral, anterior intraparietal, and cerebellar cortices. These regions overlapped extensively with a localizer for mathematical calculation, and much less with spoken or written language processing. We propose that these areas collectively encode regular sequences as repetitions with variations and their recursive composition into nested structures.

Amodal population clock in the primate medial premotor system for rhythmic tapping

The neural substrate for beat extraction and response entrainment to rhythms is not fully understood. Here we analyze the activity of medial premotor neurons in monkeys performing isochronous tapping guided by brief flashing stimuli or auditory tones. The population dynamics shared the following properties across modalities: the circular dynamics of the neural trajectories form a regenerating loop for every produced interval; the trajectories converge in similar state space at tapping times resetting the clock; and the tempo of the synchronized tapping is encoded in the trajectories by a combination of amplitude modulation and temporal scaling. Notably, the modality induces displacement in the neural trajectories in the auditory and visual subspaces without greatly altering the time-keeping mechanism. These results suggest that the interaction between the medial premotor cortex's amodal internal representation of pulse and a modality-specific external input generates a neural rhythmic clock whose dynamics govern rhythmic tapping execution across senses.

Planning ahead: Predictable switching recruits task-active and resting-state networks

Switching is a difficult cognitive process characterised by costs in task performance; specifically, slowed responses and reduced accuracy. It is associated with the recruitment of a large coalition of task-positive regions including those referred to as the multiple demand cortex (MDC). The neural correlates of switching not only include the MDC, but occasionally the default mode network (DMN), a characteristically task-negative network. To unpick the role of the DMN during switching we collected fMRI data from 24 participants playing a switching paradigm that perturbed predictability (i.e., cognitive load) across three switch dimensions-sequential, perceptual, and spatial predictability. We computed the activity maps unique to switch vs. stay trials and all switch dimensions, then evaluated functional connectivity under these switch conditions by computing the pairwise mutual information functional connectivity (miFC) between regional timeseries. Switch trials exhibited an expected cost in reaction time while sequential predictability produced a significant benefit to task accuracy. Our results showed that switch trials recruited a broader activity map than stay trials, including regions of the DMN, the MDC, and task-positive networks such as visual, somatomotor, dorsal, salience/ventral attention networks. More sequentially predictable trials recruited increased activity in the somatomotor and salience/ventral attention networks. Notably, changes in sequential and perceptual predictability, but not spatial predictability, had significant effects on miFC. Increases in perceptual predictability related to decreased miFC between control, visual, somatomotor, and DMN regions, whereas increases in sequential predictability increased miFC between regions in the same networks, as well as regions within ventral attention/ salience, dorsal attention, limbic, and temporal parietal networks. These results provide novel clues as to how DMN may contribute to executive task performance. Specifically, the improved task performance, unique activity, and increased miFC associated with increased sequential predictability suggest that the DMN may coordinate more strongly with the MDC to generate a temporal schema of upcoming task events, which may attenuate switching costs.

Cathodal high-definition transcranial direct current stimulation (HD-tDCS) of the left ventral prefrontal cortex (vPFC) interferes with conscious error correction

Precise motor timing requires the ability to flexibly adapt one's own movements with respect to changes in the environment. Previous studies suggest that the correction of perceived as compared to non-perceived timing errors involves at least partially distinct brain networks. The dorsolateral prefrontal cortex (dPFC) has been linked to the correction of perceived timing errors and evidence for a contribution of the ventrolateral PFC (vPFC) specifically to the correction of non-perceived errors exists. The present study aimed at clarifying the functional contribution of the left vPFC for the correction of timing errors by adopting high-definition transcranial direct current stimulation (HD-tDCS). Twenty-one young healthy volunteers synchronized their right index finger taps with respect to an isochronous auditory pacing signal. Perceivable and non-perceivable step-changes of the metronome were interspersed, and error correction was analyzed by means of the phase-correction response (PCR). In subsequent sessions anodal and cathodal HD-tDCS was applied to the left vPFC to establish a brain-behavior relationship. Sham stimulation served as control condition. Synchronization accuracy as well as error correction were determined immediately prior to and after HD-tDCS. The analysis suggests a detrimental effect of cathodal HD-tDCS distinctively on error correction in trials with perceived timing errors. The data support the significance of the left vPFC for error correction in the temporal domain but contradicts the view of a role in the correction of non-perceived errors.

Neurophysiological correlates of altered time awareness in Alzheimer's disease and frontotemporal dementia

BACKGROUND

Alterations in time awareness have been reported in dementia, particularly in Alzheimer's disease (AD) and frontotemporal dementia (FTD). However, the neurophysiological correlates underlying these alterations remain largely unexplored. This study aimed to investigate the neurophysiological correlates of altered time awareness in AD and FTD patients.

METHODS

A total of 150 participants (50 AD patients, 50 FTD patients, and 50 healthy controls [HC]) underwent a standardized neuropsychological assessment, an altered time awareness survey, and transcranial magnetic stimulation (TMS) to assess cholinergic (short latency afferent inhibition-SAI), GABAergic (short interval intracortical inhibition-SICI), and glutamatergic (intracortical facilitation-ICF) circuits.

RESULTS

In AD patients, the most frequent symptom was difficulty in ordering past events (52.0%), while FTD patients primarily struggled with estimating temporal intervals between events (40.0%). Significant differences were observed between HC and both patient groups, as well as between AD and FTD patients in their tendency to re-live past events. Binomial logistic regression analysis revealed that impairments in glutamatergic and cholinergic circuits significantly predicted the likelihood of participants manifesting altered time awareness symptoms.

CONCLUSIONS

This study provides novel insights into the neurophysiological correlates of altered time awareness in AD and FTD patients, highlighting the involvement of specific neurotransmitter circuits, particularly glutamatergic and cholinergic circuits. Further research is needed to explore the potential clinical implications and therapeutic targets arising from these findings.

Hippocampal orchestration of associative and sequential memory networks for episodic retrieval

Episodic memory involves the recollection of contextual details replayed mentally across time. Here, we propose the association-sequence network (ASN) model, characterizing complementary cortico-hippocampal networks underlying the retrieval of simultaneously associated and sequentially ordered events. Participants viewed objects, presented singly or in pairs, and later reported whether two objects were shown simultaneously, consecutively, or farther apart in time. Behavioral results and hippocampal activation reveal a correlation between the two sequential conditions but not the simultaneous condition, despite the temporal proximity of consecutive pairs. We also find that anterior hippocampal activity is modulated by temporal distance. Distinct cortical networks are engaged during simultaneous and sequential memory (prefrontal cortex and angular gyrus for association; supplementary motor cortex and precuneus for sequence); notably, these regions show differential connectivity with the hippocampus. The ASN model provides a comprehensive framework for how we reconstruct memories that are both rich in associative detail and temporally dynamic in nature.

Glutamatergic neurometabolite levels in the caudate are associated with the ability of rhythm production

Introduction

Glutamatergic neurometabolites play important roles in the basal ganglia, a hub of the brain networks involved in musical rhythm processing. We aimed to investigate the relationship between rhythm processing abilities and glutamatergic neurometabolites in the caudate.

Methods

We aquired Glutamatergic function in healthy individuals employing proton magnetic resonance spectroscopy. We targeted the right caudate and the dorsal anterior cingulate cortex (dACC) as a control region. Rhythm processing ability was assessed by the Harvard Beat Assessment Test (H-BAT).

Results

We found negative correlations between the production part of the Beat Saliency Test in the H-BAT and glutamate and glutamine levels in the caudate (r = -0.693, p = 0.002) whereas there was no such association in the dACC.

Conclusion

These results suggest that higher glutamatergic neurometabolite levels in the caudate may contribute to rhythm processing, especially the ability to produce meter in music precisely.

Multiplexing working memory and time in the trajectories of neural networks

Working memory (WM) and timing are generally considered distinct cognitive functions, but similar neural signatures have been implicated in both. To explore the hypothesis that WM and timing may rely on shared neural mechanisms, we used psychophysical tasks that contained either task-irrelevant timing or WM components. In both cases, the task-irrelevant component influenced performance. We then developed recurrent neural network (RNN) simulations that revealed that cue-specific neural sequences, which multiplexed WM and time, emerged as the dominant regime that captured the behavioural findings. During training, RNN dynamics transitioned from low-dimensional ramps to high-dimensional neural sequences, and depending on task requirements, steady-state or ramping activity was also observed. Analysis of RNN structure revealed that neural sequences relied primarily on inhibitory connections, and could survive the deletion of all excitatory-to-excitatory connections. Our results indicate that in some instances WM is encoded in time-varying neural activity because of the importance of predicting when WM will be used.

Music Therapy for Gait and Speech Deficits in Parkinson's Disease: A Mini-Review

Parkinson's disease (PD) is a progressive central nervous system disease with a common motor symptom of gait disturbance in PD, which is more pronounced in the later stages. Although FDA-approved treatments, including dopaminergic pharmacotherapy, deep brain stimulation, and rehabilitation, have some benefits in improving gait dysfunction, a fair amount of advanced PD patients can develop a disability, social isolation, and high mortality and morbidity. Recently, clinicians and scientists have applied music to clinical therapy, namely music therapy. It has been used as a unique rehabilitation tool to improve PD-induced gait and speech disorders. Based on relevant studies in recent years, this paper reviews the published literature about music in treating gait disorders and speech problems in PD patients. Additionally, we discuss current studies' limitations and emphasize the future potential research fields.

Phylogenic evolution of beat perception and synchronization: a comparative neuroscience perspective

The study of music has long been of interest to researchers from various disciplines. Scholars have put forth numerous hypotheses regarding the evolution of music. With the rise of cross-species research on music cognition, researchers hope to gain a deeper understanding of the phylogenic evolution, behavioral manifestation, and physiological limitations of the biological ability behind music, known as musicality. This paper presents the progress of beat perception and synchronization (BPS) research in cross-species settings and offers varying views on the relevant hypothesis of BPS. The BPS ability observed in rats and other mammals as well as recent neurobiological findings presents a significant challenge to the vocal learning and rhythm synchronization hypothesis if taken literally. An integrative neural-circuit model of BPS is proposed to accommodate the findings. In future research, it is recommended that greater consideration be given to the social attributes of musicality and to the behavioral and physiological changes that occur across different species in response to music characteristics.

The role of cerebellum in timing processing: a contingent negative variation study

Time management is an important aspect of human behaviour and cognition. Several brain regions are thought to be involved in motor timing and time estimation tasks. However, subcortical regions such as the basal nuclei and cerebellum seem to play a role in timing control. The aim of this study was to investigate the role of the cerebellum in temporal processing. For this purpose, we transitorily inhibited cerebellar activity by means of cathodal transcranial direct current stimulation (tDCS) and studied the effects of this inhibition on contingent negative variation (CNV) parameters elicited during a S1-S2 motor task in healthy subjects. Sixteen healthy subjects underwent a S1-S2 motor task prior to and after cathodal and sham cerebellar tDCS in separate sessions. The CNV task consisted of a duration discrimination task in which subjects had to determine whether the duration of a probe interval trial was shorter (800 ms), longer (1600 ms), or equal to the target interval of 1200 ms. A reduction in total CNV amplitude emerged only after cathodal tDCS for short and target interval trials, while no differences were detected for the long interval trial. Errors were significantly higher after cathodal tDCS than at baseline evaluation of short and target intervals. No reaction time differences were found for any time interval after the cathodal and sham sessions. These results point to a role of the cerebellum in time perception. In particular, the cerebellum seems to regulate temporal interval discrimination for second and sub-second ranges.

Why the clock ticks differently in Parkinson's disease: Insights from motor imagery and resting-state functional magnetic resonance imaging

In Parkinson's disease (PD), an impaired perception of suprasecond time intervals has been reported. From a neurobiological perspective, dopamine is thought to be an important mediator of timing. Nevertheless, it is still unclear whether timing deficits in PD occur mainly in the motor context and are associated with corresponding striatocortical loops. This study attempted to fill this gap by investigating time reproduction in the context of a motor imagery task, and its neurobiological correlates in resting-state networks of basal ganglia substructures in PD. Nineteen PD patients and 10 healthy controls therefore underwent two time reproduction tasks. In a motor imagery task, subjects were asked to walk down a corridor for 10 s and reproduce the time spent walking during motor imagery afterwards. In an auditory task, the subjects had to reproduce an acoustically presented time interval of 10 s. Subsequently, resting-state functional magnetic resonance imaging was performed and voxel-wise regressions were conducted between striatal functional connectivity and performance in the individual task at group level and compared between groups. Patients significantly misjudged the time interval in the motor imagery task and an auditory task in comparison to controls. Seed-to-voxel functional connectivity analysis of basal ganglia substructures revealed a significant association between striatocortical connectivity and motor imagery performance. PD patients showed a different pattern of associated striatocortical connections as indicated by significantly different regression slopes for connections of the right putamen and left caudate nucleus. In accordance with previous findings, our data confirm an impaired time reproduction of suprasecond time intervals in PD patients. Our data imply that deficits in time reproduction tasks are not specific to motor context but reflect a general time reproduction deficit. According to our findings, impaired performance in context of motor imagery is accompanied by a different configuration of striatocortical resting-state networks responsible for timing.

Wrinkles in subsecond time perception are synchronized to the heart

The role of the heart in the experience of time has been long theorized but empirical evidence is scarce. Here, we examined the interaction between fine-grained cardiac dynamics and the momentary experience of subsecond intervals. Participants performed a temporal bisection task for brief tones (80-188 ms) synchronized with the heart. We developed a cardiac Drift-Diffusion Model (cDDM) that embedded contemporaneous heart rate dynamics into the temporal decision model. Results revealed the existence of temporal wrinkles-dilation or contraction of short intervals-in synchrony with cardiac dynamics. A lower prestimulus heart rate was associated with an initial bias in encoding the millisecond-level stimulus duration as longer, consistent with facilitation of sensory intake. Concurrently, a higher prestimulus heart rate aided more consistent and faster temporal judgments through more efficient evidence accumulation. Additionally, a higher speed of poststimulus cardiac deceleration, a bodily marker of attention, was associated with a greater accumulation of sensory temporal evidence in the cDDM. These findings suggest a unique role of cardiac dynamics in the momentary experience of time. Our cDDM framework opens a new methodological avenue for investigating the role of the heart in time perception and perceptual judgment.

Time perception reflects individual differences in motor and non-motor symptoms of Parkinson's disease

Dopaminergic signaling in the striatum has been shown to play a critical role in the perception of time. Decreasing striatal dopamine efficacy is at the core of Parkinson's disease (PD) motor symptoms and changes in dopaminergic action have been associated with many comorbid non-motor symptoms in PD. We hypothesize that patients with PD perceive time differently and in accordance with their specific comorbid non-motor symptoms and clinical state. We recruited patients with PD and compared individual differences in patients' clinical features with their ability to judge millisecond to second intervals of time (500ms-1100ms) while on or off their prescribed dopaminergic medications. We show that individual differences in comorbid non-motor symptoms, PD duration, and prescribed dopaminergic pharmacotherapeutics account for individual differences in time perception performance. We report that comorbid impulse control disorder is associated with temporal overestimation; depression is associated with decreased temporal accuracy; and PD disease duration and prescribed levodopa monotherapy are associated with reduced temporal precision and accuracy. Observed differences in time perception are consistent with hypothesized dopaminergic mechanisms thought to underlie the respective motor and non-motor symptoms in PD, but also raise questions about specific dopaminergic mechanisms. In future work, time perception tasks like the one used here, may provide translational or reverse translational utility in investigations aimed at disentangling neural and cognitive systems underlying PD symptom etiology.

One Sentence Summary

Quantitative characterization of time perception behavior reflects individual differences in Parkinson's disease motor and non-motor symptom clinical presentation that are consistent with hypothesized neural and cognitive mechanisms.

The neural representation of time distributed across multiple brain regions differs between implicit and explicit time demands

Animals appear to possess an internal timer during action, based on the passage of time. However, the neural underpinnings of the perception of time, ranging from seconds to minutes, remain unclear. Herein, we considered the neural representation of time based on mounting evidence on the neural correlates of time perception. The passage of time in the brain is represented by two types of neural encoding as follows: (i) the modulation of firing rates in single neurons and (ii) the sequential activity in neural ensembles. Time-dependent neural activity reflects the relative time rather than the absolute time, similar to a clock. They emerge in multiple regions, including the hippocampus, medial and lateral entorhinal cortices, medial prefrontal cortex, and dorsal striatum. Moreover, they involve different brain regions, depending on an implicit or explicit event duration. Thus, the two types of internal timers distributed across multiple brain regions simultaneously engage in time perception, in response to implicit or explicit time demands.

Brain networks for temporal adaptation, anticipation, and sensory-motor integration in rhythmic human behavior

Human interaction often requires the precise yet flexible interpersonal coordination of rhythmic behavior, as in group music making. The present fMRI study investigates the functional brain networks that may facilitate such behavior by enabling temporal adaptation (error correction), prediction, and the monitoring and integration of information about 'self' and the external environment. Participants were required to synchronize finger taps with computer-controlled auditory sequences that were presented either at a globally steady tempo with local adaptations to the participants' tap timing (Virtual Partner task) or with gradual tempo accelerations and decelerations but without adaptation (Tempo Change task). Connectome-based predictive modelling was used to examine patterns of brain functional connectivity related to individual differences in behavioral performance and parameter estimates from the adaptation and anticipation model (ADAM) of sensorimotor synchronization for these two tasks under conditions of varying cognitive load. Results revealed distinct but overlapping brain networks associated with ADAM-derived estimates of temporal adaptation, anticipation, and the integration of self-controlled and externally controlled processes across task conditions. The partial overlap between ADAM networks suggests common hub regions that modulate functional connectivity within and between the brain's resting-state networks and additional sensory-motor regions and subcortical structures in a manner reflecting coordination skill. Such network reconfiguration might facilitate sensorimotor synchronization by enabling shifts in focus on internal and external information, and, in social contexts requiring interpersonal coordination, variations in the degree of simultaneous integration and segregation of these information sources in internal models that support self, other, and joint action planning and prediction.

Neurophysiological mechanisms of error monitoring in human and non-human primates

Performance monitoring is an important executive function that allows us to gain insight into our own behaviour. This remarkable ability relies on the frontal cortex, and its impairment is an aspect of many psychiatric diseases. In recent years, recordings from the macaque and human medial frontal cortex have offered a detailed understanding of the neurophysiological substrate that underlies performance monitoring. Here we review the discovery of single-neuron correlates of error monitoring, a key aspect of performance monitoring, in both species. These neurons are the generators of the error-related negativity, which is a non-invasive biomarker that indexes error detection. We evaluate a set of tasks that allows the synergistic elucidation of the mechanisms of cognitive control across the two species, consider differences in brain anatomy and testing conditions across species, and describe the clinical relevance of these findings for understanding psychopathology. Last, we integrate the body of experimental facts into a theoretical framework that offers a new perspective on how error signals are computed in both species and makes novel, testable predictions.

Reward Processing Alters the Time Perception Networks in Patients with Major Depressive Disorder

Behavioral studies revealed that time perception is affected by the presence of a reward. Both the experience of time and the reward processing were shown to be distorted in major depressive disorder (MDD). We aimed to investigate how neural correlates of time perception and reward anticipation interact in patients with MDD. Participants (17 healthy, seven MDD) performed a time perception task during fMRI scanning that requires estimating the speed of a moving rectangle which was briefly occluded. In the control condition, participants attended to the change in color tone of the rectangle. Half of the runs were rewarded with a monetary payment per correctly done trial to evaluate the effect of a reward. The fMRI data were acquired with a 3T scanner and analyzed with repeated-measures analysis of variance (ANOVA) using SPM12. The activations related to the integration of time with reward were different between both groups in the supplementary motor area, intraparietal sulcus, thalamus, frontal eye field and caudate nucleus. Increased coupling between supplementary motor area and caudate/putamen region during timing was found in MDD patients more than in controls. Overall, our findings suggest that functional differences related to the interaction of time perception with reward anticipation in MDD occur via dysfunction of the cortico-striatal-thalamic network.

Intrinsic hippocampal connectivity is associated with individual differences in retrospective duration processing

The estimation of incidentally encoded durations of time intervals (retrospective duration processing) is thought to rely on the retrieval of contextual information associated with a sequence of events, automatically encoded in medial temporal lobe regions. "Time cells" have been described in the hippocampus (HC), encoding the temporal progression of events and their duration. However, whether the HC supports explicit retrospective duration judgments in humans, and which neural dynamics are involved, is still poorly understood. Here we used resting-state fMRI to test the relation between variations in intrinsic connectivity patterns of the HC, and individual differences in retrospective duration processing, assessed using a novel task involving the presentation of ecological stimuli. Results showed that retrospective duration discrimination performance predicted variations in the intrinsic connectivity of the bilateral HC with the right precentral gyrus; follow-up exploratory analyses suggested a role of the CA1 and CA4/DG subfields in driving the observed pattern. Findings provide insights on neural networks associated with implicit processing of durations in the second range.

It's time for attentional control: Temporal expectation in the attentional blink

The attentional blink (AB) reveals a limitation in conscious processing of sequential targets. Although it is widely held that the AB derives from a structural bottleneck of central capacity, how the central processing is constrained is still unclear. As the AB reflects the dilemma of deploying attentional resources in the time dimension, research on temporal allocation provides an important avenue for understanding the mechanism. Here we reviewed studies regarding the role of temporal expectation in modulating the AB performance primarily based on two temporal processing strategies: interval-based and rhythm-based timings. We showed that both temporal expectations can help to organize limited resources among multiple attentional episodes, thereby mitigating the AB effect. As it turns out, scrutinizing on the AB from a temporal perspective is a promising way to comprehend the mechanisms behind the AB and conscious cognition. We also highlighted some unresolved issues and discussed potential directions for future research.

Difference Between the Judgment of Short and Long Durations: Estimates of Durations and Judgment of the Passage of Time

This study aimed to examine intra-individual differences in both duration and passage of time (PoT) judgments, and the relationships between them, for a wide range of durations going from a few hundred milliseconds to several minutes. Participants performed a study with a within-subjects design with durations in the milliseconds (200–400 ms), seconds (2–4 s), tens of seconds (20–40 s) and minutes (2–4 min) ranges. For the duration judgments, the results revealed individual differences in temporal accuracy between short durations (<3 s) and long durations (>20 s). In contrast, positive relationships were observed for PoT judgments across the different time scales, except for the millisecond duration. Finally, a significant correlation between duration and PoT judgments appeared in our study only for durations longer than 1 s. Taken together, these results support the temporal taxonomy that distinguishes between the processing of short and long durations, with the latter likely being modulated by memory mechanisms and the awareness of the PoT.

Effects of motor pacing on frontal-hemodynamic responses during continuous upper-limb and whole-body movements

Advances in timing research advocate for the existence of two timing mechanisms (automatic vs. controlled) that are related to the level of cognitive control intervening for motor behavior regulation. In the present study, we used the functional near-infrared spectroscopy (fNIRS) cutting-edge technique to examine the hypothesis that prefrontal inhibitory control is needed to perform slow motor activities. Participants were asked to perform a sensorimotor-synchronization task at various paces (i.e., slow, close-to-spontaneous, fast). We contrasted upper-limb circle drawing to a more naturalistic behavior that required whole-body movements (i.e., steady-state walking). Results indicated that whole-body movements led to greater brain oxygenation over the motor regions when compared with upper-limb activities. The effect of motor pace was found in the walking task only, with more bilateral orbitofrontal and left dorsolateral activation at slow versus fast pace. Exploratory analyses revealed a positive correlation between the activation of the orbitofrontal and motor areas for the close-to-spontaneous pace in both tasks. Overall, results support the key role of prefrontal cognitive control in the production of slow whole-body movements. In addition, our findings confirm that upper-limb (laboratory-based) tasks might not be representative of those engaged during everyday-life motor behaviors. The fNIRS technique may be a valuable tool to decipher the neurocognitive mechanisms underlying naturalistic, adaptive motor behaviors.

Temporal judgments of actions following unilateral brain damage

Sense of time is a complex construct, and its neural correlates remain to date in most part unknown. To complicate the frame, physical attributes of the stimulus, such as its intensity or movement, influence temporal perception. Although previous studies have shown that time perception can be compromised after a brain lesion, the evidence on the role of the left and right hemispheres are meager. In two experiments, the study explores the ability of temporal estimation of multi-second actions and non-biological movements in 33 patients suffering from unilateral brain lesion. Furthermore, the modulatory role of induced embodiment processes is investigated. The results reveal a joint contribution of the two hemispheres depending not only on different durations but also on the presence of actions. Indeed, the left hemisphere damaged patients find it difficult to estimate 4500 ms or longer durations, while the right hemisphere damaged patients fail in 3000 ms durations. Furthermore, the former fail when a biological action is shown, while the latter fail in non-biological movement. Embodiment processes have a modulatory effect only after right hemisphere lesions. Among neuropsychological variables, only spatial neglect influences estimation of non-biological movement.

First few seconds for flow: A comprehensive proposal of the neurobiology and neurodynamics of state onset

Flow is a cognitive state that manifests when there is complete attentional absorption while performing a task. Flow occurs when certain internal as well as external conditions are present, including intense concentration, a sense of control, feedback, and a balance between the challenge of the task and the relevant skillset. Phenomenologically, flow is accompanied by a loss of self-consciousness, seamless integration of action and awareness, and acute changes in time perception. Research has begun to uncover some of the neurophysiological correlates of flow, as well as some of the state's neuromodulatory processes. We comprehensively review this work and consider the neurodynamics of the onset of the state, considering large-scale brain networks, as well as dopaminergic, noradrenergic, and endocannabinoid systems. To accomplish this, we outline an evidence-based hypothetical situation, and consider the flow state in a broader context including other profound alterations in consciousness, such as the psychedelic state and the state of traumatic stress that can induce PTSD. We present a broad theoretical framework which may motivate future testable hypotheses.

Neurocognitive analyses reveal that video game players exhibit enhanced implicit temporal processing

Winning in action video games requires to predict timed events in order to react fast enough. In these games, repeated waiting for enemies may help to develop implicit (incidental) preparation mechanisms. We compared action video game players and non-video game players in a reaction time task involving both implicit time preparations and explicit (conscious) temporal attention cues. Participants were immersed in virtual reality and instructed to respond to a visual target appearing at variable delays after a warning signal. In half of the trials, an explicit cue indicated when the target would occur after the warning signal. Behavioral, oculomotor and EEG data consistently indicate that, compared with non-video game players, video game players better prepare in time using implicit mechanisms. This sheds light on the neglected role of implicit timing and related electrophysiological mechanisms in gaming research. The results further suggest that game-based interventions may help remediate implicit timing disorders found in psychiatric populations.

A cross-sectional EEG study reveals that individuals who consistently play action video games exhibit improved performance in a reaction time task involving implicit time preparations, compared with participants who did not normally play video games

Moderate physical activity alters the estimation of time, but not space

Moderate physical activity can influence cognitive functions and visual cortical activity. However, little is known about the effects of exercise on fundamental perceptual domains, such as spatial and temporal representation. Here we tackled this issue by testing the impact of physical activity on a temporal estimation task in a group of adult volunteers in three different conditions: (1) in a resting condition (baseline), (2) during moderate physical activity (cycling in place – PA), and (3) approximately 15 to 20 min following the physical activity phase, in which participants were seated and returned to a regular heart rate (POST). We show that physical activity specifically impacts time perception, inducing a consistent overestimation for durations in the range of milliseconds. Notably, the effect persisted in the POST session, ruling out the main contribution of either heart rate or cycling rhythmicity. In a control experiment, we found that spatial perception (distance estimation) was unaffected by physical activity, ruling out a major contribution of arousal and fatigue to the observed temporal distortion. We speculate that physical exercise might alter temporal estimation either by up-regulating the dopaminergic system or modulating GABAergic inhibition.

Time-estimation process could cause the disappearence of readiness potential

Generally, the readiness potential (RP) is considered to be the scalp electroencephalography (EEG) activity preceding movement. In our previous study, we found early RP was absent among approximately half of the subjects during instructed action, but we did not identify the mechanism causing the disappearance of the RP. In this study, we investigated whether the time-estimation process could cause the disappearance of the RP. First, we designed experiments consisting of motor execution (ME), motor execution after time estimation (MEATE), and time estimation (TE) tasks, and we collected and preprocessed the EEG data of 16 subjects. Second, we compared the event related potential (ERP) waveform and scalp topography between ME and MEATE tasks. Then, to explore the influence of time-estimation, we analyzed the difference in ERP between MEATE and TE tasks. Finally, we used source imaging to probe the activation of brain regions during the three tasks, and we calculated the average activation amplitude of eight motor related brain regions. We found that the RP occurred in the ME task but not in the MEATE task. We also found that the waveform of the difference in ERP between the MEATE and TE tasks was similar to that of the ME task. The results of source imaging indicated that, compared to the ME task, the activation amplitude of the supplementary motor area (SMA) decreased significantly for the MEATE task. Our results suggested that the time estimation process could cause the disappearance of the RP. This phenomenon might be caused by the counteraction of neural electrical activity related to time estimation and motor preparation in the SMA.

mPFC catecholamines modulate attentional capture by appetitive distracters and attention to time in a peak-interval procedure in rats

The behavioral and neural mechanisms by which distracters delay interval timing behavior are currently unclear. Distracters delay timing in a considerable dynamic range: Some distracters have no effect on timing ("run"), whereas others seem to "stop" timing; some distracters restart ("reset") the entire timing mechanisms at their offset, whereas others seem to capture attentional resources long after their termination ("over-reset"). While the run-reset range of delays is accounted for by the Time-Sharing Hypothesis (Buhusi, 2003, 2012), the behavioral and neural mechanisms of "over-resetting" are currently uncertain. We investigated the role of novelty (novel/familiar) and significance (consequential/inconsequential) in the time-delaying effect of distracters and the role of medial prefrontal cortex (mPFC) catecholamines by local infusion of norepinephrine-dopamine reuptake inhibitor (NDRI) nomifensine in a peak-interval (PI) procedure in rats. Results indicate differences in time delay between groups, suggesting a role for both novelty and significance: inconsequential, familiar distracters "stopped" timing, novel distracters "reset" timing, whereas appetitively conditioned distracters "over-reset" timing. mPFC infusion of nomifensine modulated attentional capture by appetitive distracters in a "U"-shaped fashion, reduced the delay after novel distracters, but had no effects after inconsequential, familiar distracters. These results were not due to nomifensine affecting either timing accuracy, precision, or peak response rate. Results may help elucidate the behavioral and physiological mechanisms underlying interval timing and attention to time and may contribute to developing new treatment strategies for disorders of attention. (PsycInfo Database Record (c) 2022 APA, all rights reserved).