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The temporal bisection task has long been used to study time perception as well as measure individual differences in time perception ability. The task involves training participants on short and long reference durations before presenting intermediate durations and asking participants to classify them as ‘short’ or ‘long’. However, there is little information about how well the bisection task measures individual differences in timing ability. To bridge this gap, we assessed the psychometric properties of measures obtained from a classic temporal bisection task: Weber ratio and percent correct. Because measures with binary responses tend to require many trials to reach adequate reliability, we also assessed the psychometric properties of a modified bisection task which used a continuous response format. In this task, participants represented intermediate durations on a visual analogue scale. Estimation error was used as the outcome measure. Participants (n = 46) completed the classic and modified bisection tasks twice across two sessions approximately one week apart. The modified bisection task had excellent internal consistency and test–retest reliability, while the classic task had fair to good internal consistency and good test–retest reliability. Overall, estimation error had the highest reliability, followed by percent correct, and then Weber ratio. In terms of validity, there was excellent convergent validity between the classic and modified bisection tasks. As an exploratory analysis, we assessed how the number of trials affected the reliability of each outcome measure across the two tasks. Based on this, we make recommendations on how to optimize reliability for both tasks in future research. [ABSTRACT FROM AUTHOR]

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Discriminating between temporal features in sensory stimuli is critical to complex behavior and decision-making. However, how sensory cortical circuit mechanisms contribute to discrimination between subsecond temporal components in sensory events is unclear. To elucidate the mechanistic underpinnings of timing in primary visual cortex (V1), we recorded from V1 using two-photon calcium imaging in awake-behaving mice performing a go/no-go discrimination timing task, which was composed of patterns of subsecond audiovisual stimuli. In both conditions, activity during the early stimulus period was temporally coordinated with the preferred stimulus. However, while network activity increased in the preferred condition, network activity was increasingly suppressed in the nonpreferred condition over the stimulus period. Multiple levels of analyses suggest that discrimination between subsecond intervals that are contained in rhythmic patterns can be accomplished by local neural dynamics in V1.

Buonomano and Rovelli (unpubl. manuscript, 2021) and Gruber, Block, and Montemayor (Front. Psychol. , 2022 , 13, art. 718505) grapple with the problem that we experience both a present moment and a flow of time, yet neither of those things seems to be recognised in physics. This paper makes three points about that. The present moment in perception is not the same as the present moment in physics because they occupy radically different time scales, 10–44 s in physics and something in the millisecond range in perception. The information about what is currently being perceived is experienced as in the present not because it is but because it is all labelled with time markers saying that it is the present; there are similar time markers identifying still active historical information as in the past. The flow of time is not generated by actual change over time but by an information structure existing at a single moment of time that represents change over connected time markers. Whether there is an actual present and an actual flow of time in the universe or not, the experienced present and experienced flow of time are perceptual constructs and nothing more. [ABSTRACT FROM AUTHOR]

Video game play has been suggested to improve visual and attention processing. Nevertheless, while action video game play is highly dynamic, there is scarce research on how information is temporally discriminated at the millisecond level. This cross-sectional study investigates whether temporal discrimination at the millisecond level in vision varies across action video game players (VGPs; N = 23) and non-video game players (NVGPs; N = 23). Participants discriminated synchronous from asynchronous onsets of two visual targets in virtual reality, while their EEG and oculomotor movements were recorded. Results show an increased sensitivity to short asynchronies (11, 33 and 66 ms) in VGPs compared with NVGPs, which was especially marked at the start of the task, suggesting better temporal discrimination abilities. Pre-targets oculomotor freezing – the inhibition of small fixational saccades – was associated with correct temporal discrimination, probably revealing attentional preparation. However, this parameter did not differ between groups. EEG and reconstruction analyses suggest that the enhancement of temporal discrimination in VGPs during temporal discrimination is related to parieto-occipital processing, and a reduction of alpha-band (8–14 Hz) power and inter-trial phase coherence. Overall, the study reveals an enhanced ability in action video game players to discriminate in time visual events in close temporal proximity combined with reduced alpha-band oscillatory activities. Consequently, playing action video games is associated with an improved temporal resolution of vision.

[Display omitted] • Parkinson's Disease impacts audiovisual temporal discrimination, reflecting altered multisensory integration. • The order of stimuli presentation influences temporal discrimination in Parkinson's Disease, with auditory-first trials showing enhanced performance over visual-first trials. • Parkinson's Disease significantly affects reaction times in audiovisual temporal discrimination tasks. Cognitive deficits are prevalent in Parkinson's disease (PD), ranging from mild deficits in perception and executive function to severe dementia. Multisensory integration (MSI), the ability to pool information from different sensory modalities to form a combined, coherent perception of the environment, is known to be impaired in PD. This study investigated the disruption of audiovisual MSI in PD patients by evaluating temporal discrimination ability between auditory and visual stimuli with different stimulus onset asynchronies (SOAs). The experiment was conducted with Fifteen PD patients and fifteen age-matched healthy controls where participants were requested to report whether the audiovisual stimuli pairs were temporal simultaneous. The temporal binding window (TBW), the time during which sensory modalities are perceived as synchronous, was adapted as the comparison index between PD patients and healthy individuals. Our results showed that PD patients had a significantly wider TBW than healthy controls, indicating abnormal audiovisual temporal discrimination. Furthermore, PD patients had more difficulty in discriminating temporal asynchrony in visual-first, but not in auditory-first stimuli, compared to healthy controls. In contrast, no significant difference was observed for auditory-first stimuli. PD patients also had shorter reaction times than healthy controls regardless of stimulus priority. Together, our findings point to abnormal audiovisual temporal discrimination, a major component of MSI irregularity, in PD patients. These results have important implications for future models of MSI experiments and models that aim to uncover the underlying mechanism of MSI in patients afflicted with PD. [ABSTRACT FROM AUTHOR]

State-dependent network models of sub-second interval timing propose that duration is encoded in states of neuronal populations that need to reset prior to a novel timing operation to maintain optimal timing performance. Previous research has shown that the approximate boundary of this reset interval can be inferred by varying the inter-stimulus interval between two to-be-timed intervals. However, the estimated boundary of this reset interval is broad (250–500 ms) and remains under-specified with implications for the characteristics of state-dependent network dynamics sub-serving interval timing. Here, we probed the interval specificity of this reset boundary by manipulating the inter-stimulus interval between standard and comparison intervals in two sub-second auditory duration discrimination tasks (100 and 200 ms) and a control (pitch) discrimination task using adaptive psychophysics. We found that discrimination thresholds improved with the introduction of a 333 ms inter-stimulus interval relative to a 250 ms inter-stimulus interval in both duration discrimination tasks, but not in the control task. This effect corroborates previous findings of a breakpoint in the discrimination performance for sub-second stimulus interval pairs as a function of an incremental inter-stimulus delay but more precisely localizes the minimal inter-stimulus delay range. These results suggest that state-dependent networks sub-serving sub-second timing require approximately 250–333 ms for the network to reset to maintain optimal interval timing. [ABSTRACT FROM AUTHOR]

Previous studies showed that humans and mice can maximize their rewards in two alternative temporal discrimination tasks by incorporating exogenous probabilities and endogenous timing uncertainty into their decisions. The current study investigated if the probabilistic relations modulated the temporal discrimination performance in scenarios with more than two temporal options. In order to address this question, we tested humans (Experiment 1) and mice (Experiment 2) in the dual-switch task, which required subjects to discriminate three time intervals (short, medium, and long durations) in a sequential fashion. The latencies of switches from short to medium and from medium to long option were the main units of analysis. The results revealed that the timing of switches between the first two options (short-to-medium) were sensitive to probabilistic information in both humans and mice. However, mice but not humans adapted the timing of their subsequent switches between the last two options (medium-to-long) based on the probabilistic information associated with these latter options. These results point at a suboptimal tendency in the temporal decisions of humans with multiple options.

Humans and rats can discriminate different fixed intervals (FIs) that are signaled by different stimuli. With only a few pairings of stimuli with intervals, temporal performance becomes a function of the stimuli, with responding increasing earlier for stimuli that signal shorter FIs compared to stimuli that signal longer FIs. As predicted by timing and conditioning models, the amount of training with the different stimuli and intervals determines the development of such stimulus control. This study reviews some earlier work from our group suggesting that the amount of training is necessary, but not sufficient, to account for the development of stimulus-controlled performance. Moreover, it describes an experiment in which participants were trained in a computerized shooting task with three FIs (target speeds) signaled by three stimuli (different background colors). In the first phase, the number of trials trained with each FI was held constant (60 trials each) across five experimental groups, but the order in which these trials were trained differed between groups, from a randomly determined FI in each trial (intermixed) to three consecutive blocks of 60 trials each (blocked). Intermediate groups had blocks of 10, 20, and 30 consecutive trials of each FI. Results showed that, although the amount of training was held constant across groups, the longer the training block the fewer the participants who demonstrated stimulus-controlled performance. In Phase 2, another 60 trials of each FI were trained, but intermixed for all groups. Results showed stimulus-controlled performance for all participants. These results represent another instance in which the amount of training is necessary, but not sufficient, for the development of stimulus control in temporal discriminations, and describe the effect of the number of consecutive trials within a block of training on temporal discriminations.

Video anomaly detection is an important task for public security in the multimedia field. It aims to distinguish events that deviate from normal patterns. As important semantic representation, the textual information can effectively perceive different contents for anomaly detection. However, most existing methods primarily rely on visual modality, with limited incorporation of textual modality in anomaly detection. In this paper, a cross-modality integration framework (CIForAD) is proposed for anomaly detection, which combines both textual and visual modalities for prediction, perception and discrimination. Firstly, a feature fusion prediction (FUP) module is designed to predict the target regions by fusing the visual features and textual features for prompting, which can amplify the discriminative distance. Then an image-text semantic perception (ISP) module is developed to judge semantic consistency by associating the fine-grained visual features with textual features, where a strategy of local training and global inference is introduced to perceive local details and global semantic correlation. Finally, a self-supervised time attention discrimination (TAD) module is built to explore the inter-frame relation and further distinguish abnormal sequences from normal sequences. Extensive experiments on the three challenging benchmarks indicate that our CIForAD obtains state-of-the-art anomaly detection performance. • Cross-modality integration framework (CIForAD) for unsupervised anomaly detection. • Prompts for frame prediction by fusing visual and textual features. • Semantic correlation maintained by image-text semantic perception module. • Time attention strategy on inter-frame relation for distinguishing time differences. • Extensive evaluations show outstanding anomaly detection performance. [ABSTRACT FROM AUTHOR]

A vital component of episodic memory is the ability to determine the temporal order of remembered events. Although it has been demonstrated that the hippocampus plays a crucial role in this ability, the details of its contributions are not yet fully understood. One proposed contribution of the hippocampus is the reduction of mnemonic interference through pattern separation. Prior studies have used behavioral paradigms designed to assess this function in the temporal domain by evaluating the ability to determine the order of remembered events as a function of proximity in time. Results from these paradigms in older adults (OA) have been mixed, possibly due to limitations in controlling elapsed time and narrow range of temporal lags. Here, we introduce a novel behavioral paradigm designed to overcome these limitations. We report that OAs are impaired relative to younger adults at moderate and high temporal lags but not at low lags (where performance approached floor). We evaluated OAs' ability to benefit from primacy (enhanced order judgment on the first few items of any given sequence) and found two distinct subgroups: one group was on par with young adults [aged-unimpaired (AU)] and the other group was two standard deviations below the mean of young adults [aged-impaired (AI)]. Temporal discrimination performance in AU adults was consistent with a pattern separation deficit, while performance in AI adults was consistent with a generalized temporal processing deficit. We propose that the task introduced is a sensitive marker for episodic memory deficits with age, and may have diagnostic value for early detection of age-related pathology.

Abstract The hippocampus has been known to process temporal information as part of memory formation. While time cells have been observed in the hippocampus and medial entorhinal cortex, a number of the behavioral tasks used present potential confounds that may cause some contamination of time cell observations due to animal movement. Here, we report the development of a novel nose poke-based temporal discrimination task designed to be used with in vivo calcium imaging for the analysis of hippocampal time cells in freely moving mice. First, we developed a ten second held nose poke paradigm for use in mice to deliver a purer time metric for the analysis of time cell activity in hippocampus CA1. Second, we developed a temporal discrimination task that involves the association of held nose poke durations of differing lengths with differential spatial cues presented in arms on a linear I-maze. Four of five mice achieved successful temporal discrimination within three weeks. Calcium imaging has been successfully performed in each of these tasks, with time cell activity being detected in the 10s nose poke task, and calcium waves being observed in discrete components of the temporal discrimination task. The newly developed behavior tasks in mice serve as novel tools to accelerate the study of time cell activity and examine the integration of time and space in episodic memory formation.

Background: Dystonia may have different neuroanatomical substrates and pathophysiology. This is supported by studies on the motor system showing, for instance, that plasticity is abnormal in idiopathic dystonia, but not in dystonia secondary to basal ganglia lesions.Objective: The aim of this study was to test whether somatosensory inhibition and plasticity abnormalities reported in patients with idiopathic dystonia also occur in patients with dystonia caused by basal ganglia damage.Methods: Ten patients with acquired dystonia as a result of basal ganglia lesions and 12 healthy control subjects were recruited. They underwent electrophysiological testing at baseline and after a single 45-minute session of high-frequency repetitive somatosensory stimulation. Electrophysiological testing consisted of somatosensory temporal discrimination, somatosensory-evoked potentials (including measurement of early and late high-frequency oscillations and the spatial inhibition ratio of N20/25 and P14 components), the recovery cycle of paired-pulse somatosensory-evoked potentials, and primary motor cortex short-interval intracortical inhibition.Results: Unlike previous reports of patients with idiopathic dystonia, patients with acquired dystonia did not differ from healthy control subjects in any of the electrophysiological measures either before or after high-frequency repetitive somatosensory stimulation, except for short-interval intracortical inhibition, which was reduced at baseline in patients compared to control subjects.Conclusions: The data show that reduced somatosensory inhibition and enhanced cortical plasticity are not required for the clinical expression of dystonia, and that the abnormalities reported in idiopathic dystonia are not necessarily linked to basal ganglia damage. © 2020 International Parkinson and Movement Disorder Society. [ABSTRACT FROM AUTHOR]

It is proposed that the perceived present is not a moment in time, but an information structure comprising an integrated set of products of perceptual processing. All information in the perceived present carries an informational time marker identifying it as "present". This marker is exclusive to information in the perceived present. There are other kinds of time markers, such as ordinality ("this stimulus occurred before that one") and duration ("this stimulus lasted for 50 ms"). These are different from the "present" time marker and may be attached to information regardless of whether it is in the perceived present or not. It is proposed that the perceived present is a very short-term and very high-capacity holding area for perceptual information. The maximum holding time for any given piece of information is ~100 ms: This is affected by the need to balance the value of informational persistence for further processing against the problem of obsolescence of the information. The main function of the perceived present is to facilitate access by other specialized, automatic processes. [ABSTRACT FROM AUTHOR]

Background: Unilateral or very asymmetric upper limb tremors with a jerky appearance are poorly investigated. Their clinical classification is an unsolved problem because their classification as essential tremor versus dystonic tremor is uncertain. To avoid misclassification as essential tremor or premature classification as dystonic tremor, the term indeterminate tremor was suggested.Objectives: The aim of this study was to characterize this tremor subgroup electrophysiologically and evaluate whether diagnostically meaningful electrophysiological differences exist compared to patients with essential tremor and dystonic tremor.Methods: We enrolled 29 healthy subjects and 64 patients with tremor: 26 with dystonic tremor, 23 with essential tremor, and 15 patients with upper limb tremor resembling essential tremor but was unusually asymmetric and jerky (indeterminate tremor). We investigated the somatosensory temporal discrimination threshold, the short-interval intracortical inhibition, and the cortical plasticity by paired associative stimulation.Results: Somatosensory temporal discrimination threshold was significantly increased in patients with dystonic tremor and indeterminate tremor, but it was normal in the essential tremor patients and healthy controls. Significant differences in short-interval intracortical inhibition and paired associative stimulation were not found among the three patient groups and controls.Conclusion: These results indicate that indeterminate tremor, as defined in this study, shares electrophysiological similarities with dystonic tremor rather than essential tremor. Therefore, we propose that indeterminate tremor should be considered as a separate clinical entity from essential tremor and that it might be dystonic in nature. Somatosensory temporal discrimination appears to be a useful tool in tremor classification. © 2019 International Parkinson and Movement Disorder Society. [ABSTRACT FROM AUTHOR]

The temporal aspect of somesthesia is a feature of any somatosensory process and a pre-requisite for the elaboration of proper behavior. Time processing in the milliseconds range is crucial for most of behaviors in everyday life. The somatosensory temporal discrimination threshold (STDT) is the ability to perceive two successive stimuli as separate in time, and deals with time processing in this temporal range. Herein, we focus on the physiology of STDT, on a background of the anatomophysiology of somesthesia and the neurobiological substrates of timing. A review of the literature through PubMed & Cochrane databases until March 2023 was performed with inclusion and exclusion criteria following PRISMA recommendations. 1151 abstracts were identified. 4 duplicate records were discarded before screening. 957 abstracts were excluded because of redundancy, less relevant content or not English-written. 4 were added after revision. Eventually, 194 articles were included. STDT encoding relies on intracortical inhibitory S1 function and is modulated by the basal ganglia-thalamic-cortical interplay through circuits involving the nigrostriatal dopaminergic pathway and probably the superior colliculus. • STDT is the ability to perceive two successive stimuli as separate in time. • It deals with time processing in the tens of milliseconds range. • It has been found pathologically raised in Parkinson´s disease and dystonia. • It has been found normal in essential tremor. • It is encoded in S1 intracortical inhibitory activity and modulated by dopaminergic activity. [ABSTRACT FROM AUTHOR]

In the field of time psychology, the functional significance of the contingent negative variation (CNV) component in time perception and whether the processing mechanisms of sub- and supra-second are similar or different still remain unclear. In the present study, event-related potential (ERP) technology and classical temporal discrimination tasks were used to explore the neurodynamic patterns of sub- and supra-second time perception. In Experiment 1, the standard interval (SI) was fixed at 500 ms, and the comparison interval (CI) ranged from 200 ms to 800 ms. In Experiment 2, the SI was fixed at 2000 ms, and the CI ranged from 1400 ms to 2600 ms. Participants were required to judge whether the CI was longer or shorter than the SI. The ERP results showed similar CNV activity patterns in the two experiments. Specifically, CNV amplitude would be more negative when the CI was longer or closer to the memorized SI. CNV peak latency increased significantly until the CI reached the memorized SI. We propose that CNV amplitude might reflect the process of temporal comparison, and CNV peak latency might represent the process of temporal decision-making. To our knowledge, it is the first ERP task explicitly testing the two temporal scales, sub- and supra-second timing, in one study. Taken together, the present study reveals a similar functional significance of CNV between sub- and supra-second time perception.

How interval timing is affected by aging constitutes one of the contemporary research questions. There is however a limited number of studies that investigate this research question in animal models of aging. The current study investigated how temporal decision-making is affected by aging. Initially, we trained young (2–3 month-old) and old C57BL/6J male mice (18–19 month-old) independently with short (3 s) and long (9 s) intervals by signaling, in each trial, the hopper associated with the interval that is in effect in that trial. The probability of short and long trials was manipulated (0.25 or 0.75) for different animals in each age group. During testing, both hoppers were illuminated, and thus active trial type was not differentiated. We expected mice to spontaneously combine the independently acquired time interval-location-probability information to adaptively guide their timing behavior in test trials. This adaptive ability and the resultant timing behavior were analyzed and compared between the age groups. Both young and old mice indeed adjusted their timing behavior in an abrupt fashion based on the independently acquired temporal-spatial-probabilistic information. The core timing ability of old mice was also intact. However, old mice had difficulty in terminating an ongoing timed response when the probability for the short trial was higher and this difference disappeared in the group that was exposed to a lower probability of short trials. These results suggest an inhibition problem in old mice as reflected through the threshold modulation process in timed decisions, which is cognitively penetrable to the probabilistic information.

Background: An abnormal temporal discrimination threshold in cervical dystonia (CD) is considered to be a mediational endophenotype; in unaffected relatives it is hypothesized to indicate non-manifesting gene carriage. The pathogenesis underlying this condition remains unknown. Investigation of the neural networks involved in disordered temporal discrimination may highlight its pathomechanisms.Objective: To examine resting state brain function in unaffected relatives of CD patients with normal and abnormal temporal discrimination. We hypothesized that the endophenotype, an abnormal temporal discrimination, would manifest as altered connectivity in relatives in regions associated with CD, thereby illuminating the neural substrates of the link between temporal discrimination and CD.Methods: Rs-fMRI data was analyzed from two sex- and age-matched cohorts: 16 unaffected relatives of CD patients with normal temporal discrimination and 16 with abnormal temporal discrimination. Regional and whole brain functional connectivity measures were extracted via Independent Component Analysis (ICA), Regional Homogeneity (ReHo), and Amplitude of Low Frequency (ALFF) analyses.Results: Our ICA analysis revealed increased connectivity within both the executive control and cerebellar networks and decreased connectivity within the sensorimotor network in relatives with abnormal temporal discrimination when compared to relatives with normal temporal discrimination. The ReHo and ALFF analyses complimented these results and demonstrated connectivity differences in areas corresponding to motor planning, movement coordination, visual information processing, and eye movements in unaffected relatives with abnormal temporal discrimination.Conclusion: Disordered connectivity in unaffected relatives with abnormal temporal discrimination illuminates neural substrates underlying endophenotype expression and supports the hypothesis that genetically determined aberrant connectivity, when later coupled with unknown environmental triggers, may lead to disease penetrance.

How interval timing is affected by aging constitutes one of the contemporary research questions. There is however a limited number of studies that investigate this research question in animal models of aging. The current study investigated how temporal decision-making is affected by aging. Initially, we trained young (2–3 month-old) and old C57BL/6J male mice (18–19 month-old) independently with short (3 s) and long (9 s) intervals by signaling, in each trial, the hopper associated with the interval that is in effect in that trial. The probability of short and long trials was manipulated (0.25 or 0.75) for different animals in each age group. During testing, both hoppers were illuminated, and thus active trial type was not differentiated. We expected mice to spontaneously combine the independently acquired time interval-location-probability information to adaptively guide their timing behavior in test trials. This adaptive ability and the resultant timing behavior were analyzed and compared between the age groups. Both young and old mice indeed adjusted their timing behavior in an abrupt fashion based on the independently acquired temporal-spatial-probabilistic information. The core timing ability of old mice was also intact. However, old mice had difficulty in terminating an ongoing timed response when the probability for the short trial was higher and this difference disappeared in the group that was exposed to a lower probability of short trials. These results suggest an inhibition problem in old mice as reflected through the threshold modulation process in timed decisions, which is cognitively penetrable to the probabilistic information. [ABSTRACT FROM AUTHOR]

Background: An abnormal temporal discrimination threshold in cervical dystonia (CD) is considered to be a mediational endophenotype; in unaffected relatives it is hypothesized to indicate non-manifesting gene carriage. The pathogenesis underlying this condition remains unknown. Investigation of the neural networks involved in disordered temporal discrimination may highlight its pathomechanisms. Objective: To examine resting state brain function in unaffected relatives of CD patients with normal and abnormal temporal discrimination. We hypothesized that the endophenotype, an abnormal temporal discrimination, would manifest as altered connectivity in relatives in regions associated with CD, thereby illuminating the neural substrates of the link between temporal discrimination and CD. Methods: Rs-fMRI data was analyzed from two sex- and age-matched cohorts: 16 unaffected relatives of CD patients with normal temporal discrimination and 16 with abnormal temporal discrimination. Regional and whole brain functional connectivity measures were extracted via Independent Component Analysis (ICA), Regional Homogeneity (ReHo), and Amplitude of Low Frequency (ALFF) analyses. Results: Our ICA analysis revealed increased connectivity within both the executive control and cerebellar networks and decreased connectivity within the sensorimotor network in relatives with abnormal temporal discrimination when compared to relatives with normal temporal discrimination. The ReHo and ALFF analyses complimented these results and demonstrated connectivity differences in areas corresponding to motor planning, movement coordination, visual information processing, and eye movements in unaffected relatives with abnormal temporal discrimination. Conclusion: Disordered connectivity in unaffected relatives with abnormal temporal discrimination illuminates neural substrates underlying endophenotype expression and supports the hypothesis that genetically determined aberrant connectivity, when later coupled with unknown environmental triggers, may lead to disease penetrance. [ABSTRACT FROM AUTHOR]

Background: Movement execution in healthy individuals increases the somatosensory temporal discrimination threshold. These changes are a result of mechanisms of sensory gating at the subcortical level. Although the somatosensory temporal discrimination threshold is abnormally increased in patients with focal dystonias, the effect of movement execution on somatosensory temporal discrimination in dystonic patients is unknown.Objectives: The objective of this study was to determine whether somatosensory temporal discrimination threshold modulation induced by voluntary movement is normal in different forms of focal dystonia.Methods: We enrolled 71 dystonic patients (24 with blepharospasm, 31 with cervical dystonia, and 16 with focal hand dystonia) and 39 age-matched healthy participants. Paired stimuli for the somatosensory temporal discrimination threshold were triggered by movement execution at movement onset and at various time intervals thereafter. We analyzed the kinematic features of the motor task to ascertain whether tactile input induces changes in movement parameters.Results: Movement execution led to greater and longer lasting increases in somatosensory temporal discrimination threshold values, both upon movement onset and at various time intervals thereafter, in patients with cervical dystonia and focal hand dystonia than in those with blepharospasm or the healthy participants. Somatosensory temporal discrimination testing did not induce any changes in the mean velocity of index finger movements in either patients or healthy participants.Conclusions: Somatosensory temporal discrimination threshold changes induced by movement execution are abnormal in focal dystonias. This abnormality is related to the type of dystonia. Abnormal gating of sensory information is likely involved in movement-induced triggering or worsening of different forms focal dystonia. © 2018 International Parkinson and Movement Disorder Society. [ABSTRACT FROM AUTHOR]

Background: Apart from motor symptoms, multiple deficits of sensory processing have been demonstrated in dystonia. The most consistent behavioural measure of this is abnormal somatosensory temporal discrimination threshold, which has recently been associated with physiological measures of reduced inhibition within the primary somatosensory area. High-frequency repetitive sensory stimulation is a patterned electric stimulation applied to the skin through surface electrodes that has been recently reported to shorten somatosensory temporal discrimination in healthy subjects and to increase the resting level of excitability in several different types of inhibitory interaction in the somatosensory and even motor areas.Objectives: We tested whether high-frequency repetitive sensory stimulation could augment cortical inhibition and, in turn, ameliorate somatosensory temporal discrimination in cervical dystonia.Methods: Somatosensory temporal discrimination and a number of electrophysiological measures of sensorimotor inhibition and facilitation were measured before and after 45 minutes of high-frequency repetitive sensory stimulation.Results: As compared with a group of healthy volunteers of similar age, in whom high-frequency repetitive sensory stimulation increased inhibition and shortened somatosensory temporal discrimination, patients with cervical dystonia showed a consistent, paradoxical response: they had reduced suppression of paired-pulse somatosensory evoked potentials, as well as reduced high-frequency oscillations, lateral inhibition, and short interval intracortical inhibition. Somatosensory temporal discrimination deteriorated after the stimulation protocol, and correlated with reduced measures of inhibition within the primary somatosensory cortex.Conclusions: We suggest that patients with dystonia have abnormal homeostatic inhibitory plasticity within the sensorimotor cortex and that this is responsible for their paradoxical response to high-frequency repetitive sensory stimulation. © 2018 International Parkinson and Movement Disorder Society. [ABSTRACT FROM AUTHOR]

Abstract This study explored the relationship between response cost and the responding maintained by free-operant schedules of reinforcement for participants with lower and higher levels of schizotypy. The ‘discounting’ hypothesis suggests that those with higher levels of schizotypy should be less sensitive to the negative consequences of their behavior. This predicts that participants with higher-schizotypy scores would have higher response levels on any given schedule, and that the effect of increasing response cost would not be as noticeable for this group. Participants responded via a computer keyboard on random interval (RI) 30-s, 60-s, and 120-s schedules of reinforcement for points (60 points), and experienced response costs of either low (1-point deduction) or high (10-point deduction) response costs. The UE subscale of the O-LIFE(B) was used to measure schizotypy levels. Response rates were higher with low-costs compared to high-costs for those with higher-UE scores, but not for those with lower-UE scores. That response cost differentially affected higher-UE scorers, suggesting that a ‘disconfirmation’ view of these data does not explain free-operant performance well. [ABSTRACT FROM AUTHOR]

Although a number of theoretical accounts of proactive interference (PI) in episodic memory have been proposed, existing empirical evidence does not support conclusively a single view yet. In two experiments we tested the predictions of the temporal discrimination theory of PI against alternative accounts by manipulating the presentation schedule of study materials (lists blocked by category vs. interleaved). In line with the temporal discrimination theory, we observed a clear buildup of (and release from) PI in the blocked condition, in which all the lists of the same category were presented sequentially. In the interleaved condition, with alternating lists of different categories, a more gradual and smoother buildup of PI was observed. When participants were left free to choose their presentation schedule, they spontaneously adopted an interleaved schedule, resulting again in more gradual PI. After longer delays, we observed recency effects at the list level in overall recall and, in the blocked condition, PI-related effects. The overall pattern of findings agrees with the predictions of the temporal discrimination theory of PI, complemented with categorical processing of list items, but not with alternative accounts, shedding light on the dynamics and underpinnings of PI under diverse presentation schedules and over different time scales. [ABSTRACT FROM AUTHOR]

In this paper, we consider the use of permanent implanted magnets inserted into an individual’s fingers as a form of human computer interface, the magnets being excited by an external coil. Tests involving amplitude detection, amplitude discrimination, frequency discrimination, temporal discrimination, and temporal gap detection were performed on implanted subjects. As a comparison the same tests were performed on individuals who had identical magnets attached to the outside of their skin. Results indicated that much smaller stimulation currents were required to achieve a sensitivity response in the implanted subjects. It is apparent that different corpuscles are affected by complex signals at different frequencies and this has a considerable effect on the results obtained and hence on the type of stimulation that can best be applied. [ABSTRACT FROM AUTHOR]

Objective Idiopathic adult onset cervical dystonia (IAOCD) is considered to be a partially penetrant autosomal dominant genetic condition. Dystonia may result from genetic and environmental factors. In this view, part of the physiology should be an endophenotype stemming from the genetic background. We assessed the most discriminative test to separate patients with IAOCD and healthy controls for further endophenotyping in non-affected 1st degree relatives. Methods We included patients with IAOCD, their 1st degree relatives and healthy controls. Tests performed: (1) Sensory temporal discrimination (visual, tactile, visuo-tactile), (2) Paired pulse paradigms using transcranial magnetic stimulation (TMS), (3) Mental rotation paradigms. Results 45 patients with IAOCD, 23 healthy controls and 14 non-affected 1st degree relatives were recruited. Visuo-tactile temporal discrimination separated best between controls and patients as well as between controls and 1st degree relatives. 36% of the latter had an abnormal visuo-tactile temporal discrimination. No difference between patients and healthy controls was found for the other paradigms. Conclusions Visuo-tactile temporal discrimination separates controls from patients with IAOCD and its 1st degree relatives. 36% of the latter had abnormal visuo-tactile thresholds supporting the role of visuo-tactile temporal discrimination as an endophenotype for IAOCD. Significance Even though the study was of exploratory design, our findings expand the understanding of endophenotypes in IAOCD. [ABSTRACT FROM AUTHOR]

Chemotherapy induced cognitive impairment (i.e. chemobrain) involves acute and long-term deficits in memory, executive function, and processing speed. Animal studies investigating these cognitive deficits have had mixed results, potentially due to variability in the complexity of behavioral tasks across experiments. Further, common chemotherapy treatments such as 5-fluorouracil (5-FU) break down myelin integrity corresponding to hippocampal neurodegenerative deficits and mitochondrial dysfunction. There is little evidence, however, of pharmacological treatments that may target mitochondrial dysfunction. Using a differential reinforcement of low rates (DRL) task combining spatial and temporal components, the current study evaluated the preventative effects of the pharmacological agent KU32 on the behavior of rats treated with 5-FU (5-FU + Saline vs. 5FU + KU32). DRL performance was analyzed the day after the first set of injections (D1), the day after the second set of injections (D7) and the last day of the experiment (D14). The 5FU + KU32 group earned significantly more reinforcers on the DRL task at D7 and D14 than the 5FU + Saline group. Further, the 5FU + KU32 group showed significantly better temporal discrimination. The 5FU + KU32 showed within-group improvement in temporal discrimination from D7 to D14. No significant differences were observed in spatial discrimination, however, those in the 5FU + Saline group responded more frequently on T3 compared to the 5FU + KU32 group, highlighting temporal discrimination differences between groups. The current data suggest that KU32 shows promise in the prevention of chemotherapy induced impairments in temporal discrimination. [ABSTRACT FROM AUTHOR]

It has been proposed that the retrosplenial cortex forms part of a 'where/when' information network. The present study focussed on the related issue of whether retrosplenial cortex also contributes to 'what/when' information, by examining object recency memory. In Experiment 1, rats with retrosplenial lesions were found to be impaired at distinguishing the temporal order of objects presented in a continuous series ('Within-Block' condition). The same lesioned rats could, however, distinguish between objects that had been previously presented in one of two discrete blocks ('Between-Block' condition). Experiment 2 used intact rats to map the expression of the immediate-early gene c -fos in retrosplenial cortex following performance of a between-block, recency discrimination. Recency performance correlated positively with levels of c- fos expression in both granular and dysgranular retrosplenial cortex (areas 29 and 30). Expression of c -fos in the granular retrosplenial cortex also correlated with prelimbic cortex and ventral subiculum c -fos activity, the latter also correlating with recency memory performance. The combined findings from both experiments reveal an involvement of the retrosplenial cortex in temporal order memory, which includes both between-block and within-block problems. The current findings also suggest that the rat retrosplenial cortex comprises one of a group of closely interlinked regions that enable recency memory, including the hippocampal formation, medial diencephalon and medial frontal cortex. In view of the well-established importance of the retrosplenial cortex for spatial learning, the findings support the notion that, with its frontal and hippocampal connections, retrosplenial cortex has a key role for both what/when and where/when information. [ABSTRACT FROM AUTHOR]

Objective High frequency repetitive somatosensory stimulation (HF-RSS), which is a patterned electric stimulation applied to the skin through surface electrodes, improves two-point discrimination, somatosensory temporal discrimination threshold (STDT) and motor performance in humans. However, the mechanisms which underlie these changes are still unknown. In particular, we hypothesize that refinement of inhibition might be responsible for the improvement in spatial and temporal perception. Methods Fifteen healthy subjects underwent 45 min of HF-RSS. Before and after the intervention several measures of inhibition in the primary somatosensory area (S1), such as paired-pulse somatosensory evoked potentials (pp-SEP), high-frequency oscillations (HFO), and STDT were tested, as well as tactile spatial acuity and short intracortical inhibition (SICI). Results HF-RSS increased inhibition in S1 tested by pp-SEP and HFO; these changes were correlated with improvement in STDT. HF-RSS also enhanced bumps detection, while there was no change in grating orientation test. Finally there was an increase in SICI, suggesting widespread changes in cortical sensorimotor interactions. Conclusions These findings suggest that HF-RSS can improve spatial and temporal tactile abilities by increasing the effectiveness of inhibitory interactions in the somatosensory system. Moreover, HF-RSS induces changes in cortical sensorimotor interaction. Significance HF-RSS is a repetitive electric stimulation technique able to modify the effectiveness of inhibitory circuitry in the somatosensory system and primary motor cortex. [ABSTRACT FROM AUTHOR]

• Action video game players and controls underwent a simultaneity judgement task. • EEG and eye-tracking data were recorded in virtual reality during the task. • Perceptual sensitivity to asynchronies is better in action video game players. • Behavioral benefits are accompanied by reduced parieto-occipital alpha activities. • Overall, the temporal resolution of vision appears enhanced in video game players. Video game play has been suggested to improve visual and attention processing. Nevertheless, while action video game play is highly dynamic, there is scarce research on how information is temporally discriminated at the millisecond level. This cross-sectional study investigates whether temporal discrimination at the millisecond level in vision varies across action video game players (VGPs; N = 23) and non-video game players (NVGPs; N = 23). Participants discriminated synchronous from asynchronous onsets of two visual targets in virtual reality, while their EEG and oculomotor movements were recorded. Results show an increased sensitivity to short asynchronies (11, 33 and 66 ms) in VGPs compared with NVGPs, which was especially marked at the start of the task, suggesting better temporal discrimination abilities. Pre-targets oculomotor freezing – the inhibition of small fixational saccades – was associated with correct temporal discrimination, probably revealing attentional preparation. However, this parameter did not differ between groups. EEG and reconstruction analyses suggest that the enhancement of temporal discrimination in VGPs during temporal discrimination is related to parieto-occipital processing, and a reduction of alpha-band (8–14 Hz) power and inter-trial phase coherence. Overall, the study reveals an enhanced ability in action video game players to discriminate in time visual events in close temporal proximity combined with reduced alpha-band oscillatory activities. Consequently, playing action video games is associated with an improved temporal resolution of vision. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine whether the progressive disappearance of short-latency conditioned responses, or inhibition of delay, observed in Pavlovian conditioning with long inter-stimulus intervals, could be reverted by the presentation of a novel stimulus. In one experiment, two groups of rabbits received extensive training with a short (250 ms) or a long (1500 ms) tone that overlapped and terminated with a periorbital shock unconditioned stimulus. After training, the presentation of an extraneous stimulus prior to tone onset produced a reinstatement of short latency CRs in the group trained with the long CS, but did not affect CR latency in the group trained with the short CS. This finding is consistent with Pavlov's (1927) view that conditioning with long conditioned stimuli involves the acquisition of response tendencies in the early portion of the stimulus that are subsequently suppressed by the development of an inhibitory process.

Background: Adult onset isolated focal dystonia presenting in early adult life is more frequent in men whereas in middle age it is female predominant. Temporal discrimination, an endophenotype of adult onset idiopathic isolated focal dystonia, shows evidence of sexual dimorphism in healthy participants. Objectives: We assessed the distinctive features of age-related sexual dimorphism of (i) sex ratios in dystonia phenotypes and (ii) sexual dimorphism in temporal discrimination in unaffected relatives of cervical dystonia patients. Methods: We performed (i) a meta-regression analysis of the proportion of men in published cohorts of phenotypes of adult onset dystonia in relation to their mean age of onset and (ii) an analysis of temporal discrimination thresholds in 220 unaffected first-degree relatives (125 women) of cervical dystonia patients. Results: In 53 studies of dystonia phenotypes the proportion of men showed a highly significant negative association with mean age of onset (p < 0.0001, pseudo-R2 = 59.6%), with increasing female predominance from 40 years of age. Age of onset and phenotype together explained 92.8% of the variance in proportion of men. Temporal discrimination in relatives under the age of 35 years is faster in women than men but the age-related rate of deterioration in women is twice that of men; after 45 years of age men have faster temporal discrimination than women. Conclusions: Temporal discrimination in unaffected relatives of cervical dystonia patients and sex-ratios in adult onset dystonia phenotypes show similar patterns of age-related sexual dimorphism. Such age-related sexual dimorphism in temporal discrimination and adult onset focal dystonia may reflect common underlying mechanisms. Cerebral GABA levels have been reported to show similar age-related sexual dimorphism in healthy participants and may be the mechanism underlying the observed age-related sexual dimorphism in temporal discrimination and the sex ratios in adult onset isolated focal dystonia.

The temporal discrimination threshold is the shortest time interval at which two sensory stimuli presented sequentially are detected as asynchronous by the observer. Temporal discrimination thresholds are known to increase with age. Having previously observed shorter thresholds in young women than in men, in this work we sought to sytematically examine the effect of sex and age on temporal discrimination. The aims of this study were to examine, in a large group of men and women aged 20 to 65 years, the distribution of temporal discrimination thresholds with an analysis of the individual participant’s responses, assessing the point of subjective equality (PSE) and the just noticeable difference (JND). These respectively assess sensitivity and accuracy of an individual’s response. In 175 participants (88 women) aged 20-65 years, temporal discrimination was faster in women than in men under the age of 40 years by a mean of approximately 13ms. However age-related decline in temporal discrimination was three times faster in women so that, in the age group of 40-65 years, the female superiority was reversed. The point of subjective equality showed a similar advantage in younger women and more marked age-related decline in women than men, as the temporal discrimination threshold. Just noticeable difference values declined equally in both sexes showing no sexual dimorphism. This observed sexual dimorphism in temporal discrimination is important for both a) future clinical research assessing disordered mid-brain covert attention in basal-ganglia disorders and b) understanding the biology of this sexual dimorphism which may be genetic or hormonal.

There is evidence that impulsive decision-making is associated with errors in timing. However, there has been little attempt to identify the putative mechanism responsible for impulsive animals' timing errors. One means of manipulating impulsivity in non-human animals is providing different levels of access to conspecifics. These preclinical models have revealed that social isolation increases impulsive responding across a wide range of tasks. The goal of the present study was to determine whether social isolation modulates time perception in pigeons by inducing more variability or a bias to underestimate the passage of time in temporal judgments. A temporal bisection task was used to characterize time perception. One group of pigeons performed the bisection following social enrichment, and the remaining half of the pigeons were tested following social isolation. Results revealed pigeons in the social isolation condition categorized a temporal stimulus sample as 'long' at shorter durations than pigeons in the social enrichment condition. These data highlight the mechanism(s) thought to underlie timing-based interventions aimed at reducing impulsivity in humans. Future work should consider whether impulsivity is produced by misperceptions of time or a reduced threshold for a response. [ABSTRACT FROM AUTHOR]

Behavior and events distributed in time can serve as markers that signal delays to future events. The majority of timing research has focused on how behavior changes as the time to some event, usually food availability, decreases. The primary objective of the two experiments presented here was to assess how behavior changes as time passes between two time markers when the first time marker was manipulated but the second, food delivery, was held constant. Pigeons were exposed to fixed-interval, response-initiated fixed-interval, and signaled response-initiated fixed-interval 15- and 30-s schedules of reinforcement. In Experiment 1, first-response latencies were systematically shorter in the signaled response-initiated schedules than response-initiated schedules, suggesting that the first response was a more effective time marker when it was signaled. In Experiment 2, responding in no-food (i.e. 'peak') trials indicated that timing accuracy was equivalent in the three schedule types. Compared to fixed interval schedules, timing precision was reduced in the signaled response-initiated schedules and was lowest in response-initiated schedules. Results from Experiments 1 and 2 coupled with previous research suggest that the overall 'informativeness' of a time marker relative to other events and behaviors in the environment may determine its efficacy. [ABSTRACT FROM AUTHOR]

Rapid behavioral adaptation is advantageous to the survival of a species, in that it aids in the continued attainment of resources, and in the avoidance of adverse consequences. Adaptation occurs rapidly when disparities between resources obtained at different locations are large, and appears enhanced when resources are obtained more frequently. These effects may result because such conditions make the relation between location and resource availability more discriminable, and hence the structure of the environment less ambiguous. We investigated whether differences in the discriminability of environmental stimuli that signaled differences in the likely location of resources had the same effect on the speed of adaptation. Adaptation occurred more rapidly, and behavior came under stronger control by the relation between stimuli, responses and resources, when the stimulus conditions following a change were more discriminable. Adaptation appeared attenuated when multiple stimuli signaled the likely availability of food with differing degrees of apparent reliability. We suggest that these effects of stimulus conditions on adaptation result from differences in the perceived relation between events in the environment. [ABSTRACT FROM AUTHOR]

Rattat and Picard (2012) reported that the coding of temporal information in short-term memory is modality-specific, that is, temporal information received via the visual (auditory) modality is stored as a visual (auditory) code. This conclusion was supported by modality-specific interference effects on visual and auditory duration discrimination, which were induced by secondary tasks (visual tracking or articulatory suppression), presented during a retention interval. The present study assessed the stability of these modality-specific interference effects. Our study did not replicate the selective interference pattern but rather indicated that articulatory suppression not only impairs short-term memory for auditory but also for visual durations. This result pattern supports a crossmodal or an abstract view of temporal encoding. [ABSTRACT FROM AUTHOR]