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PubMedDate not supplied

Giving the older driver enough perception-reaction time.

Many types of behavior slow with age, and older drivers require more time to process information and make decisions. How greater response time requirements relate to the design of the highway environment and to features of new in-vehicle technologies is discussed. The design requirements for many different aspects of roadway geometrics and traffic control devices are based on design driver perception-reaction times. However, without knowing how much slower older drivers are than the design driver, it is difficult to determine whether they are adequately protected by current design practice and, if not, what the desired change in design should be. Attempts to address this have been hampered by the lack of directly relevant data, the situation-specific nature of certain findings, and the older driver's ability to compensate for declines in basic skills. Also discussed are the promise and problems of new in-vehicle technologies for providing the older driver with adequate time to act. These intelligent vehicle highway systems (IVHS) may speed navigational decision making and recognition of hazards and maneuver requirements. However, the possibility for interfering with quick responding also arises, and IVHS systems might disadvantage the older driver in other ways.

Aged↗
PubMed2006

An ERP study of temporal discrimination in rats.

In this study, we examined event-related potentials (ERPs) in rats performing a timing task. The ERPs were recorded during a timing task and a control task from five regions (frontal cortex, striatum, hippocampus, thalamus, and cerebellum) that are related to time perception. In the timing task, the rats were required to judge the interval between two tones. This interval could be either 500 or 2000 ms. In the control task, only the 500 ms interval between tones was presented and only one lever was available for responses. Any difference in ERPs between the two tasks was considered to reflect the processes that are related to temporal discrimination. The frontal cortex, striatum, and thalamus yielded concurrent differences in ERPs between the two tasks. The results suggest that these regions might play an important role in temporal discrimination.

Animals↗
PubMed2003

Effects of THC on behavioral measures of impulsivity in humans.

This study investigated the acute effects of delta(9)-tetrahydrocannabinol (THC) on four behavioral measures of impulsivity in recreational marijuana users. Although impulsive behavior has been studied using several different measures of impulsivity, few studies have utilized more than one of these measures on a single cohort. In this study, 37 healthy men and women participated in three sessions, in which they received capsules containing placebo, 7.5, or 15 mg THC in randomized order under double-blind conditions. Subjects were tested on the following four tasks: the Stop task, which measures the ability to inhibit a prepotent motor response; a Go/no-go task; a Delay discounting task, which measures the value of delayed or uncertain reinforcers; and a time estimation task, which measures alterations in time perception through a time reproduction procedure. Subjects also completed mood questionnaires and general measures of performance. THC produced its expected effects on subjective measures including increases in ARCI euphoria and marijuana scales. THC increased impulsive responding on the Stop task but did not affect performance on either the Go/no-go or Delay or Probability discounting tasks. On the time reproduction task, THC increased estimates of the duration of short intervals while not affecting estimates of longer intervals. There were no significant correlations between the four tasks either before or after drug administration. These results suggest that THC may increase certain forms of impulsive behavior while not affecting other impulsive behaviors. The dissociations between the four measures of impulsivity suggest that impulsivity is an assemblage of distinct components rather than a unitary process.

Adolescent↗
PubMed1992

Effects of atropine on operant test battery performance in rhesus monkeys.

The acute behavioral effects of atropine sulfate were assessed using a battery of complex food-reinforced operant tasks that included: temporal response differentiation (TRD, n = 7); delayed matching-to-sample (DMTS, n = 6), progressive ratio (PR, n = 8), incremental repeated acquisition (IRA, n = 8), and conditioned position responding (CPR, n = 8). Performance in these tasks is thought to depend primarily upon specific brain functions such as time perception, short-term memory and attention, motivation, learning, and color and position discrimination, respectively. Atropine sulfate (0.01-0.56 mg/kg iv), given 15-min pretesting, produced significant dose-dependent decreases in the number of reinforcers obtained in all tasks. Response rates decreased significantly at greater than or equal to 0.03 mg/kg for the learning and discrimination tasks, at greater than or equal to 0.10 mg/kg for the motivation and short-term memory and attention tasks, and at greater than or equal to 0.30 mg/kg for the time perception task. Response accuracies were significantly decreased at doses greater than or equal to 0.10 mg/kg for the learning, discrimination, and short-term memory and attention tasks, and at greater than or equal to 0.30 mg/kg for the time perception task. Thus, the order of task sensitivity to any disruption by atropine is learning = color and position discrimination greater than time perception = short-term memory and attention = motivation (IRA = CPR greater than TRD = DMTS = PR). Thus in monkeys, the rates of responding in operant tasks designed to model learning and color and position discrimination were the most sensitive measures to atropine's behavioral effects. Accuracy in these same task was also disrupted but at higher doses. These data support the hypothesis that cholinergic systems play a greater role in the speed (but not accuracy) of performance of our learning and discrimination tasks compared to all other tasks. Accuracy of responding in these and the short-term memory task, all of which involve the use of lights as visual stimuli, was more sensitive to disruption by atropine than those tasks which did not utilize such strong visual stimuli.

Animals↗
PubMed1991

Influence of age, gender, height and education on vibration sense. A study by tuning fork in 192 normal subjects.

We measured perception time of the vibratory stimulus from a 128 cps tuning fork in 96 male and 96 female normal subjects equally subdivided into 8 age decades. The following sites were examined: clavicula, olecranon, styloid apophysis of ulna and radius, anterosuperior spina of ilium, rotula (patella), internal and external malleolus. Reproducibility between different examiners and between tests by the same examiner on different days was good. There was a marked regional variation with longer perception times at the distal regions of upper limbs. A non linear age-related decrease in vibration sense was found in all regions. Males had longer perception times at clavicula, females at distal limbs; the latter finding might be explained by shorter stature in females. Perception times at distal limbs were longer in subjects with higher education levels. The study provides normative data for vibration sense in different regions and defines the effects on it of age, gender, height and education.

Adolescent↗
PubMedDate not supplied

[Development of the time conditioned reflex in various phases of the day cycle in rats].

Outbred rats (n = 60) were trained to count 20-s intervals (by the technique developed by J. Bures) with drinking reinforcement. The animals were divided in three groups, which were subjected to conditioning from 7.00 to 9.00 a.m, from 1.00 to 3.00 p.m., and from 8.00 to 10.00 p.m, respectively. Conditioning was most efficient in the morning and least efficient in the day-time. Thus, the better capability of rats for time perception and conditioning on the basis of time perception in transitional phases of a day (from light to darkness and on the contrary) is in agreement with circadian rhythm of locomotion of these nocturnal animals.

Animals↗
PubMed2002

Perception onset time during fixations in free viewing.

In this study, we investigated when visual perception begins in fixations. During picture viewing, the picture was degraded at the beginning of selected saccades and changed back to the original after varying intervals. Participants manually responded whenever they detected changes. The change-backs were undetected when they occurred <6 msec after the end of the saccade, marked by the peak of the overshoot in dual Purkinje image eyetracker data, and detection reached asymptote 32 msec after that marker. Eye velocity at the change-back time also affected detection likelihood. Apparently, perception begins around the time at which the eyes stop rotating at the end of a saccade, giving a psychological justification for measuring fixation durations from then. This also specifies the deadline for gaze-contingent display changes to occur without detectable image motion. Investigators using the dual Purkinje image eyetracker should consider the peak of the overshoot as the fixation onset time and measure intrafixational presentation times from then.

Fixation, Ocular↗
PubMed1996

Characterization of hydrotropism: the timing of perception and signal movement from the root cap in the agravitropic pea mutant ageotropum.

In recent years, experiments have demonstrated that the gravity response of roots can be separated from the hydrotropic response by using the agravitropic pea mutant ageotropum. Though this mutant has been a useful tool for demonstrating the existence of the hydrotropic response of roots, little is known about how perception, transduction, transmission, and the growth response is accomplished. In this study, we have used the ageotropum mutant to investigate both the threshold time for perception of an osmotic stimulation and the minimum time required for signal transduction and transmission in roots following an osmotic stimulation at the root cap. In addition, we have compared the threshold times and signal transmission times of hydrotropism in the ageotropum roots to the gravity response of Alaska pea roots.

Gravitropism↗
PubMed1988

[The function of the counting of time as the basis for the individual adaptive activity of the nervous system].

An important role of time factor in adaptive process of organisms is shown on the basis of great literary material. The time perception is a result of the interrelationship of the so-called "biological clock" and learning during the whole ontogenesis. The hypothetical mechanisms of time perception are discussed. In own experiments the authors revealed more distinct expressiveness of high-frequency components in electroencephalogram spectrum and less expressiveness of low-frequency components in subjects underestimating time intervals compared with subjects overestimating them. A conception on the role of individual characteristics of nervous system in time perception is developed.

Adaptation, Physiological↗
PubMed1992

The perception of time as a factor in Rogers' Science of Unitary Human Beings: a literature review.

This literature review examines an operationalization of Martha Rogers' Science of Unitary Human Beings. The principle of helicy and the theory of accelerating evolution has been used by a number of authors as a theoretical framework for the exploration of how patients, particularly those who are elderly, perceive the passage of time. Although there is no conclusive evidence to support the aspect of Rogers' theory of accelerating evolution that suggests that as people grow older they perceive time as passing more quickly, there is evidence that suggests that different elderly patients can have a variable perception of the passage of time. For example, some patients perceive the passage of time as rapid and will be happy to sit quietly. Others may perceive the passage of time as occurring more slowly and will require diversional therapy. A conclusion is reached that nurses should include individual assessments of the patients' perception of the passage of time in order to identify accurately the degree of need for diversional activities.

Aged↗
PubMed2002

First-time fathers: perceptions of preparedness for fatherhood.

Little is known about how men prepare to become fathers. The purpose of this phenomenological study was to describe first-time fathers' perceptions of preparedness for and the transition to parenthood. Nineteen prospective and new fathers participating in 4 focus groups described the unique experiences of men as they prepared to become fathers. A total of 15 themes emerged from the data. The authors discuss themes in the transition to fatherhood--the reality of the pregnancy; physical, emotional, and financial preparation; and relationships with friends, parents-in-law, and health professionals--and conclude that the participants actively prepared for fatherhood, attempted to adjust to the perceived expectations of their new role, and sought information on how to be a good father. These results contribute to our understanding of behaviour among new fathers and to the body of research on fathering. Appropriate preparation for fatherhood has the potential to enhance maternal, child, and family health.

Adaptation, Psychological↗
PubMed2004

A perceptive individual time trial performed by triathletes to estimate the anaerobic threshold. A preliminary study.

AIM: The aim of the study was to test the ability to estimate the power output (PO) and heart rate (HR) associated with ''anaerobic threshold'' levels for triathletes by means of a 30-min perceptive individual time trial (PITT30). METHODS: Thirteen triathletes (8 males and 5 females) performed an incremental exercise test to estimate maximal parameters such as oxygen uptake, power output and heart rate. From this incremental exercise test, the individual anaerobic threshold (IAT) and ventilatory threshold (VT) for all subjects were estimated. Then, the subjects completed a PITT30 at self-selected work intensity on a stationary ergometer equipped with the SRM Training System. Mean values of PO, HR, and pedalling cadence were recorded continuously between the 5th and the 30th min of the test. RESULTS: Significant correlations were observed between the mean PO recorded during PITT30 and PO measured at IAT (r=0.88; p<0.0001) and at VT (r=0.89; p<0.0001). Furthermore, bias and limits of agreement confirm the degree of association between the 3 METHODS: However, PITT30 over-estimated HR values compared to the values obtained at IAT and VT. CONCLUSION: It was concluded that, for triathletes, mean PO measured with PITT30 allows a partial valid estimation of PO associated with 2 known methods of ''anaerobic threshold'' determination. The application of PITT30 may offer a useful tool for athletes and coaches to estimate the ''anaerobic threshold'' in order to control accurately the training effects.

Adult↗
PubMed1992

Perception of timing of movement-onset in a simple reaction time task.

Subjects judged verbally on temporal order between pressing a switch and a marking sound (MS) in a simple reaction time paradigm. They were uncertain when sound preceded movement by less than about 60 ms or followed it by less than 130 ms (transient zone--TZ). The point of subjective equality (defined by 0.5 probability of correct judgements of temporal order of sound and switching onsets) and the median of TZ were shifted about 60 and 35 ms prior movement onset, respectively. Estimating mutual timing of movement preparation and execution and sensory delays, these shifts correspond to the simultaneity of onsets of MS and proprioceptive feedback in the brain. Thus the results suggest about proprioceptive origin of perception of active movement onset.

Adult↗
PubMed1996

Simple reaction time and perception of temporal order: dissociations and hypotheses.

Simple motor reaction time and judgment of temporal order are commonly recognized as two methods for estimation of perceptual latency. Unfortunately, the results obtained by the methods under the same conditions do not agree. We review hypotheses attempting to explain the disagreement. Although some of these seem to be promising, no one at present could be fully accepted.

Arousal↗
PubMed2001

Is patients' perception of time spent with the physician a determinant of ambulatory patient satisfaction?

BACKGROUND: Time management in ambulatory patient visits is increasingly critical. Do patients who perceive a longer visit with internists report increased satisfaction? METHODS: Prospective survey of 1486 consecutively encountered ambulatory visits to 16 primary care physicians (PCPs) in an academic primary care clinic. Patients were queried regarding demographics, health status, perception of time spent before and after ambulatory visits, whether the physician appeared rushed, and visit satisfaction. Physicians were queried regarding time spent, estimated patient satisfaction, and whether they felt rushed. RESULTS: In 69% of 1486 consecutive visits, patient previsit expectation of visit duration was 20 minutes or less. Patient and PCP postvisit estimates of time spent significantly exceeded patient previsit time expectation. Patients who estimated that they spent more time than expected with the PCP were significantly more satisfied with the visit. When patient postvisit estimate of time spent was less than the previsit expectation, visit satisfaction was significantly lower independent of time spent. Patient worry about health and lower self-perceived health status were significantly associated with patient expectation for longer visits. Primary care physicians felt rushed in 10% of encounters. Although PCPs estimated patient satisfaction was significantly lower when they felt rushed, patient satisfaction was identical when PCPs did and did not feel rushed. Patients indicated that PCPs appeared rushed in 3% of encounters, but this perception did not affect patient satisfaction. CONCLUSION: Perceived ambulatory visit duration and meeting or exceeding patient expectation of time needed to be spent with the physician are determinants of patient satisfaction in an ambulatory internal medicine practice.

Ambulatory Care↗
PubMed2004

[Dynamics of time intervals evaluation in heroin addicts].

An evaluation of time perception in drug addicts was carried out in 12 s intervals, using 10 attempts with up to 0.1 s precision. Eighty-two heroin addicts in abstinent and post abstinent periods have been observed, the results being compared to 52 healthy controls. During the first two days after admission to the hospital (abstinent syndrome development), time intervals values were lower in patients than in controls, reaching a precision of recalling 12s, with a following exceeding of this index. On day 15-16, time perception returned to precise level (post abstinent period). Depending on drug addiction duration and individual features of brain hemisphere asymmetry, changes in subjective time perception were revealed in the study.

Adolescent↗
PubMed2005

Patient and physician perceptions of timely access to care.

BACKGROUND: Timeliness of care is 1 of 6 dimensions of quality identified in Crossing the Quality Chasm. We compared patient and physician perceptions of appropriate timing of visits for common medical problems. METHODS: This study was conducted at 2 internal medicine clinics at the University of Colorado Health Sciences Center. Adult patients and companions, and outpatient General Internists were surveyed. The survey contained 11 clinical scenarios of varying urgency. Respondents indicated how soon the patient in each scenario should be seen. Responses ranged from that day to 1 to 3 months. Responses were analyzed using the Mann-Whitney U test. RESULTS: Two hundred and sixty-two patients and 46 of 61 physicians responded. For 8 of the 11 scenarios patients felt they should be seen significantly earlier than physicians. Scenarios involving chronic knee and stomach pain, routine diabetes care, and hyperlipidemia generated the greatest differences. Patients and physicians agreed on the urgency of scenarios concerning wheezing in an asthmatic, an ankle injury, and acute pharyngitis. CONCLUSIONS: Patients expected to be seen sooner than physicians thought necessary for many common chronic medical conditions, but are in agreement about timeliness for some acute problems. Understanding patient expectations may help physicians respond to requests for urgent evaluation of chronic conditions.

Adult↗