Showing papers on "Time perception published in 2000"

Cross-modal and cross-temporal association in neurons of frontal cortex

Abstract: The prefrontal cortex is essential for the temporal integration of sensory information in behavioural and linguistic sequences. Such information is commonly encoded in more than one sense modality, notably sight and sound. Connections from sensory cortices to the prefrontal cortex support its integrative function. Here we present the first evidence that prefrontal cortex cells associate visual and auditory stimuli across time. We gave monkeys the task of remembering a tone of a certain pitch for 10 s and then choosing the colour associated with it. In this task, prefrontal cortex cells responded selectively to tones, and most of them also responded to colours according to the task rule. Thus, their reaction to a tone was correlated with their subsequent reaction to the associated colour. This correlation faltered in trials ending in behavioural error. We conclude that prefrontal cortex neurons are part of integrative networks that represent behaviourally meaningful cross-modal associations. The orderly and timely activation of neurons in such networks is crucial for the temporal transfer of information in the structuring of behaviour, reasoning and language.

Duration Tuning in the Mouse Auditory Midbrain

Abstract: Temporal cues, including sound duration, are important for sound identification. Neurons tuned to the duration of pure tones were first discovered in the auditory system of frogs and bats and were discussed as specific adaptations in these animals. More recently duration sensitivity has also been described in the chinchilla midbrain and the cat auditory cortex, indicating that it might be a more general phenomenon than previously thought. However, it is unclear whether duration tuning in mammals is robust in face of changes of stimulus parameters other than duration. Using extracellular single-cell recordings in the mouse inferior colliculus, we found 55% of cells to be sensitive to stimulus duration showing long-pass, short-pass, or band-pass filter characteristics. For most neurons, a change in some other stimulus parameter, (e.g., intensity, frequency, binaural conditions, or using noise instead of pure tones) altered and sometimes abolished duration-tuning characteristics. Thus in many neurons duration tuning is interdependent with other stimulus parameters and, hence, might be context dependent. A small number of inferior colliculus neurons, in particular band-pass neurons, exhibited stable filter characteristics and could therefore be referred to as "duration selective." These findings support the idea that duration tuning is a general phenomenon in the mammalian auditory system.

ERPs and PET Analysis of Time Perception: Spatial and Temporal Brain Mapping During Visual Discrimination Tasks

Abstract: ERPs were recorded from 12 subjects performing duration and intensity visual discrimination tasks which have been previously used in a PET study. PET data showed that the same network was activated in both tasks (P. Maquet et al., NeuroImage 3:119 -126, 1996). Different ERP waveforms were observed for the late latency components depending on the dimension of the stimulus to be processed: frontal negativity (CNV) for the duration task and parieto-occipital positivity (P300) for the intensity task. Using BESA software, the sources were first modelled with a "PET dipolar model" (right prefrontal, right parietal, anterior cingulate, left and right fusiforms). To obtain a better fit for ERPs recorded in each task, two sources (cuneus, left prefrontal area) had to be added. Consistently with PET findings, dipole modelling indicates that duration and intensity dimensions of a visual stimulus are processed in the same areas. However, ERPs also reveal prominent differences between the time course of the dipole activations for each task, particularly for sources contributing to the late latency ERP components. In the intensity task, dipoles located in the cuneus, the anterior cingulate, and the left prefrontal area yield largest activity within the P300 interval, then activity diminishes rapidly as the stimulus ends, whereas in the duration task, the cuneus and anterior cingulate are still active several hundred milliseconds following stimulus offset. Moreover, in the duration task, the activity of the right frontal dipole parallels the CNV waveform, whereas in the intensity task, this dipole is largely inactive. We assume that the right frontal area plays a specific role in the formation of temporal judgments. Hum. Brain Mapping 10:49 - 60, 2000. © 2000 Wiley-Liss, Inc.

Visual feedback about time estimation is related to a right hemisphere activation measured by PET.

Abstract: In previous EEG experiments we have presented a time estimation task to our subjects, who had to press a button with either the left or right index finger 3 s after an auditory warning stimulus (WS). Two seconds later a visual Knowledge of Results (KR) stimulus was presented on a screen in front, informing them about whether the movement had been made in the correct time window (a vertical line), whether it was too early (a minus sign) or too late (a plus sign). The potential distribution underlying the anticipatory attention for the KR stimulus suggested a right hemisphere network in which the prefrontal cortex, the insula Reili and the parietal cortex were involved. In the present positron emission tomography (PET) activation study we aimed to further localize the exact positions of these regions, using the same paradigm. Two conditions were compared in which the WS had to be followed by a button press with the left index finger. In experimental condition A, subjects received true information about their performance, while in condition B false information was given, utilizing the same stimuli, but randomly, thus without any relation to the actual performance. In both conditions identical stimuli were presented and identical movements were made. Therefore we applied statistical parameter mapping (SPM) for comparison of condition A with B in order to identify regional increases in perfusion related to the anticipation and use of the KR. We found in line with our predictions a right hemisphere activation of (1) BA45, (2) the junction of the posterior insula with the temporal transverse gyrus and (3) the posterior part of the parietal cortex. This activation pattern was accompanied by a better performance due to KR. A second, though not predicted, effect was the increase in correct responses during the last two sessions compared to the first two sessions, independent of KR. This learning effect was accompanied by an activation of BA46 and the supplementary motor area (SMA), again in the right hemisphere. Summarizing, two different prefrontal areas in the right hemisphere were activated: a more ventral area, related to the use of external stimuli providing feedback about a past performance, in order to produce movements in time, and another mid-dorsal one, related to temporal programming on the basis of internal cues.

Rhythm Perception and Production

Abstract: Part I: Mental Timekeepers Internal Clocks, Oscillators and Complex Dynamics 1. Timekeepers versus nonlinear oscillators: How the approaches differ 2. Considerations regarding a comprehensive model of (poly)rhythmic movement 3. Limitations of the scanning procedure in assessing changes in coordination dynamics due to learning 4. The learning and transfer of multifrequency patterns Part II: Tapping and Synchronization 5. On the nature of variability in isochronous serial interval production 6. Synchronization error: An error in time perception 7. Subliminal temporal discrimination revealed in sensorimotor coordination 8. Tempo change: Timing of simple temporal ratios 9. Dynamics and embodiment in beat induction Part III: Time Perception and Estimation 10. Demonstrations of time-shrinking 11. Spatial attention deficits and the perception of interaural rhythmic sequences - a preliminary analysis 12. Information processing in the central executive: Effects of concurrent temporal production and memory updating tasks Part IV: Expressive Timing in Music 13. Rhythmic aspects of vibrato 14. On time: The influence of tempo, structure and style on the timing of grace notes in skilled musical performance 15. Rhythm in music performance and perceived structure Part V: Rhythm and Meter in Music and Speech 16. Complexity measures of musical rhythms 17. Why musicians tap slower than nonmusicians 18. Effects of delayed auditory feedback on speech: Just a problem of displaced rhythm? 19. Preliminary investigations of French and English speech rhythm: Are cross-linguistic differences in rhythmic organisation primarily metrical in origin?

Conscious and preconscious adaptation to rhythmic auditory stimuli: a magnetoencephalographic study of human brain responses.

Abstract: This study was triggered by the experimental evidence that subjects required to tap in synchrony with a heard rhythm spontaneously time their tapping to variations in rhythm frequency even when these variations are so small that they are not consciously detectable. We performed a series of magnetoencephalographic (MEG) measurements, aimed at investigating whether the response of the auditory cortex discriminates randomly administered series of brief tones differing from each other only by their interstimulus intervals (ISI). Moreover, by combining psychophysical measurements, conscious and preconscious adjustments of tapping to rhythm variations were compared with brain cortical responses. The ISIs were varied by 2% or 20% from a “central” value of 500 ms. Subjects always consciously detected the 20% ISI changes and easily adjusted their tapping accordingly, whereas they never consciously detected the 2% ISI changes, even though they always correctly adjusted their tapping to them. Analysis of the auditory evoked fields (AEFs) showed that the intensity of the M100 component decreased with decreasing ISI both for 20% and 2% variations in a statistically significant manner, despite the fact that the 2% variation was not consciously perceived. The M100 behavior indicated that connections between auditory and motor cortexes may exist that are able to use the information on rhythm variations in the stimuli even when these are not consciously identified by the subject. The ability of the auditory cortex to discriminate different time characteristics of the incoming rhythmic stimuli is discussed in this paper in relation to the theories regarding the physiology of time perception and discrimination.

Time perception in boys with attention-deficit/hyperactivity disorder according to time duration, distraction and mode of presentation.

Abstract: In a recent theoretical model of attention-deficit/hyperactivity disorder (ADHD), Barkley (1997a) predicted that ADHD children experience impairments in their psychological sense of time. This was demonstrated in a series of experiments by Barkley, Koplowicz, Anderson, and McMurray (1997). The present study sought to investigate the effects of ADHD subtype, stimulus duration, mode of presentation (visual versus auditory) and distractors on the performance of a simple time reproduction task. Data were obtained from 44 ADHD children (14 predominantly inattentive and 30 combined type) and 44 age-matched Controls using the Time Perception Application version 1.0 (Barkley, University of Massachusetts Medical Center, 1998). Results revealed that the ADHD children made significantly larger errors on Visual time reproduction tasks than the Controls, regardless of ADHD subtype or the presence of distractors. Furthermore, ADHD children were more likely to overestimate the shorter time intervals (0.5 and 2 s) and underestimate the longer time intervals (3, 4 and 6 s) relative to Controls. No group differences were observed on the auditory time reproduction task, with both ADHD and Control groups consistently underestimating the durations to be reproduced. The results of this study provide further support for the prediction that children with ADHD have an impaired sense of time.

Hemispheric equivalence and age-related differences in judgments of simultaneity to somatosensory stimuli.

Abstract: Hemispheric asymmetries, interhemispheric transfer time (IHTT), and age-related differences in judgments of simultaneity to tactile stimulation were examined. Two mechanical stimulators were employed to: (1) Determine whether both cerebral hemispheres are equally capable of processing fine tactile temporal information; (2) determine whether there is an age-related differential hemispheric decline in judgments of simultaneity, and (3) determine if simultaneity thresholds for tactile stimuli increase with advanced age. Tactile simultaneity thresholds were measured by using a modified parameter estimation by sequential testing algorithm. Participants judged whether pairs of tactile stimulation to index and middle fingers were delivered simultaneously. Results of both bimanual and unimanual conditions supported a model of hemispheric equivalence in that both hemispheres were equally capable of making judgments of simultaneity to fine tactile stimuli. The results further suggested that the hemispheric equivalence for judgments of simultaneity remains stable across adulthood. However, IHTTs of older adults were more than double that of younger adults, indicating a significant decrease in the speed of neural conduction. As well, relative to younger adults, older adults had significantly higher simultaneity thresholds.

Does time-shrinking take place in visual temporal patterns?

Abstract: The duration of a short empty time interval (typically shorter than 300 ms) is often underestimated when it is immediately preceded by a shorter time interval. This illusory underestimation—time-sh...

L'estimation du temps: perspective développementale

Abstract: Psychologists ceased debating the subjective and objective experience of time 10 years ago due to the findings of experiments suggesting that an internal clock is devoted to the treatment of temporal information in animals as well as human adults. Nevertheless, in the face of 1- to 6-year-old children's inaccurate temporal judgements, this discussion continued in developmental psychology. In particular, a dissociation has been established between the first forms of temporal experience in infants (temporal discrimination, temporal conditioning) and the adult-like representation of time. Recent studies reveal that 3-year-olds are also able to judge precisely time, but only under particular experimental conditions (filled duration, simultaneous imitation...) . Thus, 3-year-olds representation of time differs clearly from older children's notion of time. It appears that 3-year-olds possess a highly concrete sense of time that is specific to each action or experienced event.

A model of the effects of cognitive load on the subjective estimation and production of time intervals.

Abstract: How and where the brain calculates elapsing time is not known, and one or more internal pacemakers or others timekeeping systems have been suggested. Experiments have shown that the accuracy in estimating or producing time intervals depends on many factors and, in particular, both on the length of the intervals to be estimated and on the additional, and unrelated, cognitive load required during the task. The psychological ‘attentional approach’ is able to explain the experimental data in terms of perturbations of a cognitive timer. However, the basic biophysical mechanisms that could be involved at the single neuron level are still not clear. Here we propose a computational model suggesting how the process to focus the attention on a non-temporal task could alter the perception of time intervals as observed in the experiments. The model suggests that an attention-based excitatory and/or inhibitory background synaptic noise, impinging on the pacemaker circuit, could represent both qualitative and quantitative features of the cognitive load. These effects are predicted to be independent of the number, location or specific implementations of the internal timing systems.

The mental clock model

Abstract: All scholars who have investigated psychological time have stressed its elusive nature. On the one hand, we have a “smooth” or “effortless” experience of the flow of events. On the other hand, in spite of its familiarity, the temporal perception is hard to grasp. According to Gibson, “there is no such thing as the perception of time, but only the perception of events and locomotions”. In a quite similar way, Michonl has suggested that time should not be considered as “a property of the existential mode of things”, but as the “conscious experiential product” of the processes that allow human beings to maintain a dynamic, interactive relation with the flow of events in the external world.

On the perceived speed of time over time

Abstract: "I don't believe it: another year has flown by-it seems that time is going by at an ever-faster rate"" This often expressed perception of time, the speed of time, is both qualitatively and quantitatively explored While the speed of time is clearly invariant (at least on earth and at traveling speeds that are orders of magnitude below the speed of light), there is ample and plausible evidence that serves to contribute to our perception of a faster moving time More specifically, it seems that both nature and nurture impact or influence our perception of time and the speed of time In this exploratory study, we have briefly reviewed the cognition and related literature to understand why the older we get, the more we perceive the speed of time to increase - there is a clinical reason for this aging phenomenon We then showed that environmental or experiential factors can also effect our perceived speed of time Indeed, although the results should be considered preliminary, our analysis suggests that the nurture-related experience may have a stronger impact on our perceived speed of time than the nature-related perception (ie, due to aging)