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PubMed2002

Short-term memory and time estimation: beyond the 2-second "critical" value.

We showed previously that when time intervals around two seconds (s) are reproduced concurrently with a memory task, intervals are positively related to duration of memory processing. However, some data in research on timing as well as in memory research suggest that 2 s might be a critical duration beyond which different mechanisms or structures would support performance. This implies that the interference observed between memory processing and 2-s productions could be specific to these durations, and would not be obtained with longer durations. In this experiment, intervals ranging from 1.85 to 6.45 s were reproduced by participants, who were searching simultaneously for a memory probe. At all durations, reproductions were positively related to memory set size. These findings have implications with regards to previous research indicating a discontinuity around 2-3 s in time perception. They suggest in particular that the role of memory is similar in reproduction of durations around 2 s and of longer durations.

Adult↗

PubMed2003

Smoking abstinence impairs time estimation accuracy in cigarette smokers.

Time estimation is used as an index of attention processes and may be sensitive to self-administration and withdrawal of psychoactive drugs such as nicotine, the primary addictive ingredient in tobacco. To test this hypothesis, 22 nonsmokers (12 male, 10 female) and 20 daily cigarette smokers (12 male, 8 female) were asked to estimate the duration of a 45-second period of time in a laboratory setting. Smokers participated in two sessions: once after smoking ad-lib and once after objectively confirmed 24-hour smoking abstinence. In smokers, time estimation accuracy was impaired after smoking abstinence compared to accuracy after ad-lib smoking (P<.01). Relative to nonsmokers, smokers' time estimation accuracy differed significantly after the abstinence period only (P=.05). Smokers reported feeling more stressed and unable to focus after abstinence relative to nonsmokers (P<.05). No gender differences were observed on any outcome measures. These results suggest that, in a controlled laboratory setting, smoking abstinence has a negative impact on time perception, which may contribute to the performance decrements and discomfort that smokers report during an attempt to quit.

Adolescent↗

PubMed2000

Conditioned and unconditioned behavioral-cognitive effects of a dopamine antagonist in rats.

Many drugs need to be taken multiple times to achieve a therapeutic effect. Researchers have identified several mechanisms to account for the slow onset of drug action, including drug accumulation and structural changes induced by drugs. This article provides an example of a new mechanism to account for this change in drug action. Stimuli that accompany drug administration may come to evoke conditioned responses (CRs), and these CRs may be the basis for changes in drug efficacy. Specifically, this research shows that a dopamine antagonist, pimozide, changes response rates through the direct action of the drug but changes time perception through the CRs elicited by drug administration.

Animals↗

PubMed1973

Objective assessment of hypnotically induced time distortion.

The objective precision of operant conditioning methodology validates the power of hypnosis to induce alterations in time perception. Personal tempo was systematically modified by instructions to trained hypnotic subjects, with significant behavioral effects observed on a variety of response rate measures.

Adult↗

PubMed1981

The influence of low-level, event-related DC-currents during time estimation in humans.

Two experiments were designed to investigate further the influence of low-level transcephalic DC currents on human reaction time and time perception. Thirty-two subjects participated in the experiments, with the second one a replication of the first. During a first trial series, subjects responded to the offset of a 6 second tone. Simultaneous to tone presentation a current was applied between vertex and collar bone electrodes. Current polarity varied randomly across trials. During a second trial series, subjects interrupted tone and current when they estimated a time interval of same length as the previously experienced had elapsed. In both studies subjects interrupted the tone/current after a shorter interval when the negative pole was applied as compared to vertex-positive trials. Results suggest that a vertex-negative external current suppresses an internally required state, whereas an external positive current supports internal SP-generation. The brain may tend to terminate the former state earlier than the latter.

Acoustic Stimulation↗

PubMed2006

Interval bisection in spontaneously hypertensive rats.

An interval bisection procedure was used to study time discrimination in spontaneously hypertensive rats (SHR), which have been proposed as an animal model for the attention deficit hyperactivity disorder (ADHD); Wistar Kyoto and Wistar rats were used as comparison groups. In this procedure, after subjects learn to make one response (S) following a short duration stimulus, and another (L) following a long duration stimulus, stimuli of intermediate durations are presented, and the percentage of L is calculated for each duration. A logistic function is fitted to these data, and different parameters that describe the time discrimination process are obtained. Four conditions, with different short and long durations (1-4, 2-8, 3-12, 4-16s) were used. The results indicate that time discrimination is not altered in SHR, given that no difference in any of the parameters obtained were significant. Given that temporal processing has been proposed as a fundamental factor in the development of the main symptoms of ADHD, and that deficits in time discrimination have been found in individuals with that disorder, the present results suggest the necessity of exploring time perception in SHR with other procedures and sensory modalities, in order to assess its validity as an animal model of ADHD.

Animals↗

PubMed1998

Timed active avoidance learning in lurcher mutant mice.

Lurcher mutant mice (+/Lc) which exhibit a massive loss of neurons in the cerebellar cortex and in the inferior olivary nuclei were subjected to an active avoidance learning task; the animals' avoidance response must occur within a small time window after a short or a long delay. The control mice needed a mean of 8.3 sessions of 10 trials (short delay group) and of 11.8 sessions (long delay group) and showed good retention after a 24 h interval. When subjected to the same number of sessions, the +/Lc mice were unable to learn the timing task. However, a subgroup of lurcher mutants was able to learn after a high number of sessions (25.4 sessions as a mean). There was no intergroup difference in the standard version of one-way active avoidance. These results indicate that the cerebellar cortex is involved in time processing during active avoidance. The cerebellum may be part of a loop including the cerebral cortex known to be involved in time perception. An alternative explanation is that the cerebellar mutant animals had persevering tendencies acquired during performance of the one-way avoidance task.

Animals↗

PubMed1997

Acceptability for temporal modification of consecutive segments in isolated words.

Perceptual sensitivity to temporal modification in two consecutive speech segments was measured in word contexts to explore the following two questions: (1) whether there is an interaction between multiple segmental durations, and (2) what aspect of the stimulus context determines the perceptually salient temporal markers? Experiment 1 obtained acceptability ratings for words with temporal modifications. The results showed that the compensatory change in duration of a vowel (V) and its adjacent consonant (C) is not perceptually so salient as expected for the simultaneous modifications in the two segments. This finding suggests the presence of a time perception range wider than a single segment (V or C). The results of experiment 1 also showed that rating scores for compensatory modification between V and C do not depend on the temporal order of modified pairs (VC or CV), but rather on the loudness difference between V and C; the acceptability decreased when the loudness difference between V and C became high. This suggests that perceptually salient markers locate around major jumps in loudness. The second finding, the dependence on the loudness jump, was replicated in experiment 2, which utilized a detection task for temporal modifications on nonspeech stimuli modeling the time-loudness features of the speech stimuli. Experiment 3 further investigated the influence of the temporal order of V and C by utilizing the detection task for the speech stimuli instead of the acceptability ratings.

Humans↗

PubMed1980

Filling time versus affective response to the activity that fills the time: independent effects on time judgment?

Previous time perception research has confounded manipulations intended to evoke different affective reactions to the task with different levels of nontemporal processing demands. An attempt was made to separate these dimensions by a social comparison procedure aimed at making the same concurrent task (card sorting) appear differentially interesting to two groups of college students. Response uncertainty varied within the task to that processing demands could be compared while reported interest in the task varied between groups. Magnitude of time estimates related inversely to response uncertainty, but reported interest in the task made no independent contribution to the variance of estimates.

Affect↗

PubMed1999

Behavioral evaluation of microwave irradiation.

Establishing safe exposure levels for microwave irradiation is important since new, more powerful emitters are developed and the potential for accidental exposure is increasing. Analysis of the behavior of exposed laboratory animals has proven to be an accurate and repeatable metric for assessing the effects of microwave irradiation. Determining the specific absorption rate (SAR) at which an animal will cease an ongoing behavior has proven useful in the development of safe exposure levels for humans. Behaviors that have been used are simple tasks, and the point at which behavior changes significantly or ceases has often been referred to as "work stoppage." The tasks have been used to evaluate the overwhelming effects of heating produced by microwave irradiation. Both whole-body exposures and partial-body exposures with hotspots have been evaluated. Recent studies have suggested that microwave effects on specific cognitive aspects of behavior such as attention, learning, memory, discrimination, and time perception may occur at SAR levels far below the SARs needed to cause work stoppage. New research studies are underway to evaluate microwave-induced cognitive effects.

Absorption↗

PubMed2000

Role of frontal cortex in memory for duration: an event-related potential study in humans.

Event-related potentials were recorded in order to determine how brain activity is lateralized during the encoding and the recognition of visual durations (700 and 2500 ms ranges). It is assumed in the Hemispheric Encoding Retrieval Asymmetry model that the encoding of words, faces and odours involves left frontal areas whereas their recognition involves right frontal areas. The present results indicate that, for temporal information, the hemispheric bias is different: a negativity developed over right frontal electrodes for both encoding and recognition, and for both duration ranges. Thus, the involvement of right frontal areas appears critical for time perception. Conversely to what was expected, contingent negative variation during recognition was large over both left and right frontal electrodes. These results suggest that the involvement of both hemispheres is necessary for recognition of temporal information.

Adult↗

PubMed2002

Cortical involvement in temporal reproduction: evidence for differential roles of the hemispheres.

Only few studies have addressed temporal processing for durations longer than 1 s, and even fewer studies have investigated cortical involvement in time perception, in particular temporal production and reproduction. The present study investigated temporal reproduction in healthy control subjects and patients with anterior or posterior cortical lesions in the left or right hemisphere, or with subcortical left-hemispheric lesions. The paradigm involved presentation of either auditory or visual stimuli of 10 different standard intervals ranging from 1 to 5.5 seconds duration. Participants were required to reproduce the duration of a stimulus. Our results show that: (1) temporal reproduction across this temporal range can be better described with two separate linear regressions (bilinear approach) than with one single linear regression, thus contrasting the scalar timing concept; (2) that patients can, regardless of the hemisphere lesioned, perform reproductions of durations smaller than 2-3 s with reasonable accuracy; and (3) that patients with right-hemispheric lesions appear to be impaired in reproductions of stimuli longer than 2-3 s. Since attention appeared not to be impaired in the patients tested, the findings suggest that the integrity of the right hemisphere seems to be critical for temporal reproduction of intervals longer than 2-3 s.

Adult↗

PubMed1993

Perception and allocation of time by dyslexic children.

The perception and allocation of time by individuals is closely associated with their observed behaviors in life. A dyslexic child presents unique and interesting problems to educational researchers, teachers, and parents since the information-processing style differs from that of normal children. This study examined not the cognitive understanding of time or problems in measuring time (dyschronometria), but the perception and allocation of time by 26 normal and 21 dyslexic children between the ages of 10 years and 17 years old. These findings were measured by a specifically designed time allocation and perception questionnaire and a circles test. The analysis indicated that the dyslexic children tended to be far more outer- and inner-directed with regard to their time allocations and generally perceived time as a linking of past, present, and future events.

Adolescent↗

PubMed2004

Association between cognitive performance and striatal dopamine binding is higher in timing and motor tasks in patients with schizophrenia.

The basal ganglia have received increasing attention with regard to their role in time pacing, motor function and other components of cognition. The aim of this study was to test whether the finer the motor activity and/or time perception performance were, the higher the striatal dopamine D(2) binding would be. Single photon emission computed tomography (SPECT) with [(123)I]iodobenzamide (IBZM) was performed to measure striatal D(2) receptor densities. A battery of neuropsychological tests, including the Wisconsin Card Sorting Test (WCST), the finger tapping test (FTT), and an attention test, was performed by patients with schizophrenia. Results indicated a strong correlation between the FTT score and striatal D(2) receptor binding. Neuroleptic dosage plays an important role in the relationship between cognitive tasks and striatal dopamine receptor densities. In addition, the striatal D(2) receptor density is more significantly correlated with attentional tests that consider the time effect than those that do not. Among the three tests performed, the WCST was least significantly correlated with striatal D(2) receptor densities. A decrease in striatal dopamine D(2) receptor density seems to be associated with impaired performance on optimal timing tasks and motor processing in patients with schizophrenia.

Adult↗

PubMed2005

Towards an understanding of unique and shared pathways in the psychopathophysiology of ADHD.

Most attention deficit hyperactivity disorder (ADHD) research has compared cases with unaffected controls. This has led to many associations, but uncertainties about their specificity to ADHD in contrast with other disorders. We present a selective review of research, comparing ADHD with other disorders in neuropsychological, neurobiological and genetic correlates. So far, a specific pathophysiological pathway has not been identified. ADHD is probably not specifically associated with executive function deficits. It is possible, but not yet established, that ADHD symptoms may be more specifically associated with motivational abnormalities, motor organization and time perception. Recent findings indicating common genetic liabilities of ADHD and other conditions raise questions about diagnostic boundaries. In future research, the delineation of the pathophysiological mechanisms of ADHD needs to match cognitive, imaging and genetic techniques to the challenge of defining more homogenous clinical groups; multi-site collaborative projects are needed.

Attention Deficit Disorder with Hyperactivity↗

PubMed1977

Effects of degree of obesity, age of onset, and weight loss on responsiveness to sensory and external stimuli.

Four experiments tested responsiveness to external and sensory stimuli in female human subjects who differed in degree of overweight and in age of onset of their obesity. The effects of weight loss upon external responsiveness were assessed by testing subjects before and after weight reduction in order to determine the role of energy deficit and deprivation in mediating heightened responsiveness to external cues. There was no significant positive correlation between degree of overweight and degree of external responsiveness. In general, the age of onset of the obesity was also not a relevant factor in the degree of externality. Weight loss did not change responses to visual and cognitive cue salience manipulations in measures of feeding, emotionality, time perception, and short-term recall, whereas responsiveness to variations in palatability increased following weight reduction. While external cue responsiveness does not appear to result from adiposity per se or from deprivation, responsiveness to taste stimuli may reflect these parameters. The role of external and sensory cues in the development and maintenance of obesity is discussed.

Adolescent↗

PubMed2006

Convergent validity of measures of cognitive distortions, impulsivity, and time perspective with pathological gambling.

The present study investigated the convergent validity of the Gamblers' Beliefs Questionnaire (GBQ), Gambling Passion Scale (GPS), Eysenck Impulsivity Questionnaire (EIQ), and Stanford Time Perception Inventory (STPI) in reference to pathological gambling. The authors recruited 105 undergraduates representing categories of pathological gamblers, potential pathological gamblers, and nonpathological gamblers and administered the measures under neutral conditions. Both subscales of the GBQ and GPS and the Impulsivity subscale of the EIQ exhibited strong convergent validity, whereas the STPI showed weaker correspondence with symptoms of pathological gambling. Applications and limitations of these findings are discussed.

Adult↗

PubMedDate not supplied

Use of the NCTR Operant Test Battery in nonhuman primates.

A battery of behavioral tasks, designed to monitor complex "cognitive" functions in nonhuman primates, has been in use for several years at the National Center for Toxicological Research. Subjects performing in this Operant Test Battery (OTB) work for food reinforcers and correct performance in each task contained in the OTB is thought to depend upon a relatively specific brain function. The specific tasks and the functions that they are thought to model are: delayed matching-to-sample (DMTS), short-term memory and attention; incremental repeated acquisition (IRA), learning; temporal response differentiation (TRD), time perception; progressive ratio (PR), motivation; and conditioned position responding (CPR), color and position discrimination. Data from various studies indicate that, in general: 1) OTB responding between subjects follows a normal or near-normal distribution; 2) performance in one task does not correlate very highly with performance in any of the other tasks; 3) females acquire correct OTB responding more rapidly than do males; and 4) the profile of disruption of task performance by acute drug administration varies depending upon drug class.

Animals↗