Showing papers on "Time perception published in 2005"

A representation of the hazard rate of elapsed time in macaque area LIP

Abstract: The capacity to anticipate the timing of environmental cues allows us to allocate sensory resources at the right time and prepare actions. Such anticipation requires knowledge of elapsed time and of the probability that an event will occur. Here we show that neurons in the parietal cortex represent the probability, as a function of time, that a salient event is likely to occur. Rhesus monkeys were trained to make eye movements to peripheral targets after a light dimmed. Within a block of trials, the 'go' times were drawn from either a bimodal or unimodal distribution of random numbers. Neurons in the lateral intraparietal area showed anticipatory activity that revealed an internal representation of both elapsed time and the probability that the 'go' signal was about to occur (termed the hazard rate). The results indicate that the parietal cortex contains circuitry for representing the time structure of environmental cues over a range of seconds.

Neural network involved in time perception: an fMRI study comparing long and short interval estimation.

Abstract: In this study, long ( approximately 1,300 ms) and short duration ( approximately 450 ms) estimation trials in an event-related functional MRI (fMRI) study were contrasted in order to reveal the regions within a time estimation network yielding increased activation with the increase of the duration to be estimated. In accordance with numerous imaging studies, our results showed that the presupplementary motor area (preSMA), the anterior cingulate, the prefrontal and parietal cortices, and the basal ganglia were involved in the estimation trials whatever the duration to be estimated. Moreover, only a subset of the regions within this distributed cortical and subcortical network yielded increased activation with increasing time, namely, the preSMA, the anterior cingulate cortex, the right inferior frontal gyrus (homolog to Broca's area), the bilateral premotor cortex, and the right caudate nucleus. This suggests that these regions are directly involved in duration estimation. We propose that the caudate-preSMA circuit, the anterior cingulate, and the premotor-inferior frontal regions may support a clock mechanism, decision and response-related processes, and active maintenance of temporal information, respectively.

Age Effects in Perception of Time

Abstract: Despite the widespread belief that the subjective speed of the passage of time increases with age, empirical results are controversial. In this study, a combination of questionnaires was employed to assess subjective time perception by 499 subjects, ages 14 to 94 years. Pearson correlations and nonlinear regression analyses on a variety of questionnaires and the age of the participants show that the momentary perception of the passage of time and the retrospective judgment of past periods of time are a function of chronological age; however, small-to-moderate effects accounted for at most 10% of the variance. Results generally support the widespread perception that the passage of time speeds up with age. These results are discussed in the context of models of prospective and retrospective time judgment, but interpretations have to be treated with caution given methodological limitations.

Time perception: modality and duration effects in attention-deficit/hyperactivity disorder (ADHD).

Abstract: Time perception performance was systematically investigated in adolescents with and without attention-deficit/hyperactivity disorder (ADHD). Specifically, the effects of manipulating modality (auditory and visual) and length of duration (200 and 1000 ms) were examined. Forty-six adolescents with ADHD and 44 controls were administered four duration discrimination tasks and two control tasks, and a set of standardized measures. Participants with ADHD had higher thresholds than controls on all of the duration discrimination tasks, with the largest effect size obtained on the visual 1000 ms duration discrimination task. No group differences were observed on the control tasks. Visual-spatial memory was found to be a significant predictor of visual and auditory duration discrimination at longer intervals (1000 ms) in the ADHD sample, whereas auditory verbal working memory predicted auditory discrimination at longer intervals (1000 ms) in the control sample. These group differences suggest impairments in basic timing mechanisms in ADHD.

Timing the brain: mental chronometry as a tool in neuroscience.

Abstract: How do we relate human thought processes to measurable events in the brain? Mental chronometry, which has origins that date back more than a century, seeks to measure the time course of mental operations in the human nervous system [1]. From the late 1800s until 1950, the field was built almost entirely around a single method: measuring and comparing people's reaction times during simple cognitive tasks. As far back as 1868, Franciscus Donders [2] subtracted the time taken to make a single response to an unvarying stimulus—what he called an instructed reflex—from the time it took to make the same response to one of two events, obtaining the time required to discriminate between the two stimuli. Further, he subtracted the time to discriminate two stimuli from a situation in which there were also two possible responses in order to obtain the time required for choice.

Simultaneity constancy: detecting events with touch and vision

Abstract: What are the consequences of visual and tactile neural processing time differences when combining multisensory information about an event on the body’s surface? Visual information about such events reaches the brain at a time that is independent of the location of the event. However, tactile information about such events takes different amounts of time to be processed depending on the distance between the stimulated surface and the brain. To investigate the consequences of these differences, we measured reaction times to touches and lights on different parts of the body and the perceived subjective simultaneity (PSS) for various combinations. The PSSs for pairs of stimuli were predicted by the differences in reaction times. When lights and touches were on different body parts (i.e. the hand and foot) a trend towards compensation for any processing time differences was found, such that simultaneity was veridically perceived. When stimuli were both on the foot, subjects perceived simultaneity when the light came on significantly earlier than the touch, despite similar processing times for these stimuli. When the stimuli were both on the hand, however, there was complete compensation for the significant processing time differences between the light and touch such that simultaneity was correctly perceived, a form of simultaneity constancy. To identify if there was a single simultaneity constancy mechanism or multiple parallel mechanisms, we altered the PSS of an auditory-visual stimulus pair and looked for effects on the PSS of a visual-touch pair. After repeated exposure to a light/sound pair with a fixed time lag between them, there was no effect on the PSS of a touch-light pair, suggesting multiple parallel simultaneity constancy mechanisms.

The right parietal cortex and time perception: back to Critchley and the Zeitraffer phenomenon.

Abstract: We investigated the involvement of the posterior parietal cortex in time perception by temporarily disrupting normal functioning in this region, in subjects making prospective judgements of time or pitch. Disruption of the right posterior parietal cortex significantly slowed reaction times when making time, but not pitch, judgements. Similar interference with the left parietal cortex and control stimulation over the vertex did not significantly change performance on either pitch or time tasks. The results show that the information processing necessary for temporal judgements involves the parietal cortex, probably to optimise spatiotemporal accuracy in voluntary action. The results are in agreement with a recent neuroimaging study and are discussed with regard to a psychological model of temporal processing and a recent proposal that time is part of a parietal cortex system for encoding magnitude information relevant for action.

Overloading temporal memory.

Abstract: This study tested the hypothesis that memory is a major source of variance in temporal processing. Participants categorized intervals as short or long. The number of base durations and interval types mixed within blocks of trials varied from 1 session to another. Results revealed that mixing 2 base durations within blocks increased categorization errors, but mixing 2 marker types did not. Results are attributed to the involvement of more than 1 memory representation, which is argued to show the critical role of memory in temporal processing. Because mixing modalities has no such effect, it was argued that modalities share a common representation in memory. Finally, there was no difference in the perceived duration of auditory and visually marked intervals, which is inconsistent with most reports on this effect.

Time estimation ability and distorted perception of sleep in insomnia.

Abstract: Although it is an established finding that people with insomnia characteristically overestimate the time they have taken to get to sleep and underestimate the total amount of time they have slept, little is known about the mechanisms that underpin this phenomenon. Accordingly, this study sought to investigate whether the tendency to misperceive sleep among patients with insomnia is accounted for by (a) a general deficit in time estimation ability or (b) the context in which the time estimates are made. Twenty individuals with insomnia and 20 individuals who did not have insomnia were asked to perform two time estimation tasks; one in the laboratory during the day and one in the participant's own bedroom during the night. The two groups were compared with respect to the accuracy of their performance in estimating unfilled temporal intervals of various lengths. The results indicated that the performance of the insomnia group was no different from that of the noninsomnia group, regardless of the context in which the time estimates were made. Time overestimation correlated positively with cognitive and physiological arousal experienced during the time estimation tasks. These findings argue against the hypothesis that individuals with insomnia misperceive their sleep simply because they are poor estimators of time. Future research is required to test the hypothesis that increased cognitive arousal (worry) and physiological arousal are candidate mechanisms that underpin sleep misperception.

Behavioral and electrophysiological indices of temporal processing dysfunction in schizophrenia.

Abstract: Timing deficits in schizophrenia have been noted in several behavioral studies. However, the involvement of mediating factors, such as inattention, has not been ruled out as contributing to these effects. Mismatch negativity (MMN), an electrophysiological measure, may provide a more direct index of stimulus processing ability in individuals with schizophrenia. The current study explored the relationship between behavioral time judgments and a time-based MMN paradigm. Participants were administered two MMN paradigms consisting of an “easy” or “difficult” deviant and an analogous behavioral measure of time processing. Matched against a healthy comparison group, patients exhibited decreased MMN amplitude on the “difficult” deviant interval only. However, on the behavioral paradigm, the patients made significantly more errors across all conditions. These results suggest that behavioral measures of time processing may reflect different processes than those captured by preattentive physiological measures in thi...

Cumulative blood oxygenation-level-dependent signal changes support the 'time accumulator' hypothesis.

Abstract: We studied time-related changes in the blood oxygenation-level-dependent signal during a time reproduction task. Nine healthy study participants retained and reproduced stimuli of varying durations in the multi-second range. During the encoding phase of the task, activity in the left dorsolateral prefrontal cortex inversely correlated with the interval duration, while an adjacent region in the dorsolateral prefrontal cortex showed positive correlation with duration in the reproduction phase. Cumulative signal increase during the reproduction phase, as found in the primary motor and supplementary motor areas, may also reflect the time-sensitive behavior. Signal accumulation in the right caudate nucleus is in agreement with presumed role of basal ganglia in time perception. These results support the 'time accumulator' hypothesis.

Altered subjective time of events in schizophrenia

Abstract: Time perception has long been known to be impaired in schizophrenia. Moreover, recent neuropsychological theories have postulated abnormalities of cognitive motor control in schizophrenia. However, the intersection of these two topics has rarely been studied, and it is unclear what role subjects' own actions may play in the construction of subjective time representation. The present experiment compared the performance of 19 patients with schizophrenia and 24 normal controls in a timing judgment task. The results show that patients bind two consecutive movements more strongly than controls. This anomaly could play a role in the subjective pathological experiences of patients.

Prefrontal brain activity predicts temporally extended decision-making behavior

Abstract: Although functional neuroimaging studies of human decision-making processes are increasingly common, most of the research in this area has relied on passive tasks that generate little individual variability. Relatively little attention has been paid to the ability of brain activity to predict overt behavior. Using functional magnetic resonance imaging (fMRI), we investigated the neural mechanisms underlying behavior during a dynamic decision task that required subjects to select smaller, short-term monetary payoffs in order to receive larger, long-term gains. The number of trials over which the longterm gains accrued was manipulated experimentally (2 versus 12). Event-related neural activity in right lateral prefrontal cortex, a region associated with high-level cognitive processing, selectively predicted choice behavior in both conditions, whereas insular cortex responded to fluctuations in amount of reward but did not predict choice behavior. These results demonstrate the utility of a functional neuroimaging approach in behavioral psychology, showing that (a) highly circumscribed brain regions are capable of predicting complex choice behavior, and (b) fMRI has the ability to dissociate the contributions of different neural mechanisms to particular behavioral tasks.

Chronometric evidence for entrained attention.

Abstract: Recent theories of dynamic attention have renewed the interest in temporal context as a determinant of attention. The mechanism of dynamic attention remains unclear, and both stochastic time perception processes and deterministic oscillators are possible. The results of Experiment 1 demonstrate that attention can be guided by isochronous series of warning stimuli and that elapsed time cannot fully account for this effect. Experiment 2 indicates that temporal structure can be used over a limited range of time. The results of Experiment 3 indicate that temporal pattern, rather than variability, is a determinant of temporally focused attention. The results of Experiment 4 demonstrate that a coupled oscillator is a better predictor of reaction time than a stochastic timing mechanism is, under certain assumptions.

The relationship between behavioral inhibition and time perception in children.

Abstract: PURPOSE: To test one component of Barkley's (1997) model of executive functions by examining the relationship between behavioral inhibition and time perception in children. METHOD: Correlation analysis was used to determine the relationships between measures of behavioral inhibition and time perception for the entire sample, and for boys (n = 34) and girls (n = 26) separately. FINDINGS: For both parent and child measures, behavioral inhibition and time perception scores were correlated for the total group and for girls. Child measure of behavioral inhibition and time perception were not correlated for boys. CONCLUSIONS: The findings of this study support Barkley's theory and indicate a relationship between poor behavioral inhibition and poor time perception in children.

Time Perception in Migraine Sufferers: An Experimental Matched-Pairs Study

Abstract: Despite occasional case reports, the influence of migraine on time perception has not been systematically investigated. We used an experimental technique to study the estimation of auditory duration in 40 migraineurs at different tone intervals in the ms and in the 1-s range and compared their performance with 40 matched normal subjects. With a time awareness questionnaire we also evaluated the subjective experience of elapsing time for long durations involving long-term memory processes. Migraine did not influence temporal judgements in either of the tests, suggesting that migraineurs do not generally over- or underestimate temporal events. The subgroup of migraineurs with a depressive disorder, however, showed a marked speeding up of their internal timekeeping mechanisms, pointing to depression as an important covariable in time perception.

Chronostasis without voluntary action

Abstract: In a previous study we explored auditory chronostasis and suggested an arousal account of this temporal illusion rather than one dependent on backdating actions to the onset of a motor event. Here we present three experiments designed to distinguish between two competing accounts of the mechanisms underlying the illusion. Experiment 1 investigated whether voluntary movements are necessary for the illusion to occur. Experiment 2 sought to clarify whether auditory chronostasis occurs when the intervals to be judged are continuous (temporally contiguous) rather than separate events. Experiment 3 was designed to establish whether increased task demands account for the illusion. Together the results from these experiments show that chronostasis is an illusion that is not dependent on voluntary action, can occur without a change in the spatial location of the stimulus (thus precluding an account based on spatial attention), occurs with discrete as well as continuous events, and is affected by the salience of the termination of the event to be timed rather than the onset. Collectively these findings suggest that the mechanisms underlying chronostasis are best explained by an arousal hypothesis since neither attention nor backdating to action can account for the commonalities between chronostasis in the auditory, visual and tactile domains.