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PubMed2006

Residents' perceptions over time of pharmaceutical industry interactions and gifts and the effect of an educational intervention.

PURPOSE: To describe change in residents' attitudes toward gifts from and interactions with industry and to measure the effects of a formal educational workshop on changes in perceptions. METHOD: At the University of Chicago, 118 internal medicine residents completed an observational survey and took part in a controlled intervention across three years (2001-2004) of residency. Four cohorts of residents completing the program in 2004-2007 participated. The intervention was an interactive educational workshop, including reviews of literature and guidelines, and three videos demonstrating routine resident interactions with pharmaceutical representatives. Residents graduating in 2005 were the intervention group and residents graduating in 2004 the comparison group. Analysis of variance and linear regression models were used to determine the relationship between variables. RESULTS: Residents perceived "lunch sponsored at noon conference" and "pharmaceutical representative brief talk at noon conference" as increasingly appropriate over their training period (p < .02). Residents perceived "pens, notepads, pocket antibiotic guides" as increasingly appropriate and "tickets to sporting events," "round of golf," and "travel/registration for national conference" as increasingly inappropriate (p < .05). The intervention group was more likely to rate only one item, "lunch at noon conference," as less appropriate (p = .042). CONCLUSIONS: Residents' perceptions toward industry gifts and interactions changed modestly during their training to reflect institutional policy. "Appropriate" gifts of minimal value were generally perceived as increasingly appropriate, whereas "inappropriate" gifts were perceived as increasingly inappropriate over time. An educational workshop alone may not significantly alter residents' perceptions toward industry without the implementation of broad and consistent institutional policy.

Advertising↗
PubMed1978

The clinical utility of the hand-held tachistoscope.

A hand-held tachistoscope for use at the bedside was constructed and used to examine 40 normal controls and 170 psychiatric and neurological patients. This instrument quickly provided an index (perception time) which distinguished between idiopathic psychiatric illness and delirium, and between cortical and subcortical neuropathology. Slow perception time was seen in patients with delirium or cortical neuropathology.

Adolescent↗
PubMed1993

Acute effects of pentobarbital in a monkey operant behavioral test battery.

The effects of acute pentobarbital treatment were assessed using a complex operant test battery containing five tasks in which correct performance is thought to depend upon processes associated with short-term memory and attention [delayed-matching-to-sample (DMTS)], color and position discrimination [conditioned position responding (CPR)], motivation [progressive ratio (PR)], time perception [temporal response differentiation (TRD)], and learning [incremental repeated acquisition (IRA)]. Adult, male rhesus monkeys were tested 15 min after IV injection of saline or pentobarbital (1, 3, 5.6, 10, or 15 mg/kg). Behavioral endpoints measured included percent task completed, response rate or latency, and response accuracy. The order of task sensitivity to disruption by PBT was TRD > IRA = DMTS = PR > CPR, in which sensitivity was defined as a significant disruption in any aspect of task performance. PBT slowed response rates at 10.0 and/or 15.0 mg/kg in all tasks. Accuracy was decreased in the TRD task at > or = 5.6 mg/kg but doses of > or = 10.0 mg/kg were required to decrease accuracy in the IRA, DMTS, and CPR tasks. Thus, behavior thought to model time perception (TRD) was more sensitive than behavior modeling learning (IRA), short-term memory and attention (DMTS), and motivation (PR). CPR was the least sensitive behavior. Because pentobarbital exerts its effects at least in part via GABA systems, the effects in the current study were compared with those of a previous study of the acute effects of diazepam. The two compounds exerted fundamentally different effects on operant test battery performance.

Animals↗
PubMed2006

Delay period activity of monkey prefrontal neurones during duration-discrimination task.

Evidence from brain imaging studies has indicated involvement of the prefrontal cortex (PFC) in time perception; however, the role of this area remains unclear. To address this issue, we recorded single neuronal activity from the PFC of two monkeys while they performed a duration-discrimination task. In the task, two visual cues (a blue or red square) were presented consecutively followed by delay periods and subjects then chose the cue presented for the longer duration. Durations of both cues, order of cue duration [long-short (LS) or short-long (SL)] and order of cue colour (blue-red or red-blue) were randomized on a trial-by-trial basis. We found that subjects responded differently between LS and SL trials and that most prefrontal neurones showed significantly different activity during either the first or the second delay period when comparing activity in LS and SL trials. The present result offers new insights into neural mechanisms of time perception. It appears that, during the delay periods, the PFC contributes to implement a strategic process in temporal processing associated with a trial type (LS or SL) such as representation of the trial type, retention of cue information and anticipation of the forthcoming cue.

Animals↗
PubMed2001

Measuring maximum holding times and perception of static elevated work and forward bending in healthy young adults.

The objectives of this study were to investigate the maximum holding times (MHT) of two highly stressful postures: standing in a forward bend position and performing elevated work in a standing position. The relationship between perceived exertion and MHT was also studied. Subjects were 44 young adults, age 20-29 years (25 female, 19 male). A test-retest design was used to establish reliability. Mean maximum holding times for forward bending and elevated work were respectively 14.51 and 16.18 min with large interindividual variations. A logarithmic rather than a linear relation between perceived exertion and performance is found. It is not possible to reliably predict MHTs from subjective data. Test-retest correlation is high (n = 19, r = 0.716 and 0.813, p < 0.001), and the scores did not differ significantly (p < 0.005), indicating a reliable procedure. The average holding times of the population studied are higher than expected from literature. Neither generic formulas, curve estimations, or predictions can reliably predict an individual's MHT. An individual's MHTs are best tested through performance based testing.

Adult↗
PubMed2004

Memory for time intervals is impaired in left hemi-Parkinson patients.

The basal ganglia have been proposed as one of the neural correlates of timekeeping functions. Both encoding and memory retrieval components for time perception are impaired in Parkinson's disease (PD). The aim of our study was to investigate in hemi-Parkinsonian patients the existence of a specific alteration in memory for time depending on the affected side, to better understand the contribution of the left or right basal ganglia circuits in different components of time perception. Right and left hemi-PD patients performed a time reproduction task in which they were required to reproduce in the same session short (5 s) and long (15 s) time intervals, in off- and on-therapy condition. While the right hemi-PD patients overestimated the shorter interval, only the left hemi-PD group showed the memory migration effect, overestimating the shorter and underestimating the longer time intervals. These results argue for a critical involvement of the right basal ganglia in memory retrieval for time intervals, in the range of seconds.

Aged↗
PubMed2000

Changes of the neurotransmitter serotonin but not of hormones during short time music perception.

We studied the impact of the perception of pleasant and unpleasant music, as rated by healthy subjects with a psychometric scale, on the hormones prolactin and ACTH. In addition, the neurotransmitter serotonin (5-HT) was studied using the platelet model for central neurotransmission of 5-HT. We did not observe any significant changes of prolactin and ACTH during the perception of different kinds of music. The 5-HT content of platelets, however, was higher during the perception of pleasant music as compared to the perception of unpleasant music indicating an increased release of 5-HT during unpleasant music (748 ng/10(9) platelets vs. 699 ng/10(9) platelets; p<0.014). The difference of the 5-HT level was significantly correlated to the score of unpleasantness as rated by the subjects. Our data suggest that perception of unpleasant music induces increased release and decreased peripheral and possibly also central intracellular content of 5-HT.

Adrenocorticotropic Hormone↗
PubMed1986

Regularity, exposure time and perception of numerosity.

Two experiments are described. In Exp. 1, subjects compared the apparent numerosity of two kinds of dot patterns, regular vs irregular, with two different exposures (160 vs 2000 msec.). In Exp. 2, the subjects had to estimate the numerosity of the same patterns, presented one at a time. Analysis showed a relative overestimation of the regular patterns in Exp. 1 but not in Exp. 2. In general an overestimation occurred with an increase in exposure. Such results support our hypothesis of two separate processes as the basis of the two kinds of performance (estimating vs comparison).

Attention↗
PubMed1978

Methadone maintenance: an assessment of potential fluctuations in behavior between doses.

Thirty methadone maintenance outpatients were measured 1 and 25 hours after ingestion of methadone on auditory threshold, distance perception, simple and differential reaction time, time perception, attention span, and short-term memory. The results revealed a small but statistically significant difference between the two tests for distance perception. In addition, treatment interacted with preparatory interval on differential reaction time and with sex on attention span.

Adolescent↗
PubMed1996

Ethnic differences in temporal orientation and its implications for hypertension management.

Research indicates that health beliefs and perceptions are shaped and organized by life experiences. Time perception, also structured by life experiences, can systematically alter individuals' perceptions of disease and evaluations of treatment options. Using the Health Belief Model (HBM), this study examines the effects of ethnicity and hypertension temporal orientation on the health perceptions of 300 African Americans and White Americans with hypertension. Results revealed that African Americans were more present-oriented than White Americans regarding their daily experiences with managing hypertension. Compared to more future-oriented respondents, present-oriented people perceived themselves to be less susceptible to the consequences of hypertension, believed more in the benefits of home remedies and negative aspects of prescribed medication, and believed less in the benefits of prescribed medication and negative aspects of home remedies. We concluded that ethnicity influences hypertension temporal orientation and that hypertension temporal orientation affects perceptions about hypertension and its management. Implications for health and medical care are addressed.

Black or African American↗
PubMed2001

Interneurons, spike timing, and perception.

Rhythmic gamma oscillations at 30-70 Hz in cortical and hippocampal slices depend on a maintained excitation and on interactions between interneurons and pyramidal cells. These interactions include gap-junctional connections between inhibitory cells and fast excitatory and inhibitory chemical synapses. Spike timing with precision in the range of several ms may be assured by biphasic signaling mechanisms operating at these different connections. Such temporal precision may be important in cognitive processing.

Action Potentials↗
PubMed2004

Timing variations in music performance: musical communication, perceptual compensation, and/or motor control?

A perceptual performance paradigm was designed to disentangle the timing variations in music performance that are due to perceptual compensation, motor control, and musical communication. First, pianists perceptually adjusted the interonset intervals of three excerpts so that they sounded regular. These adjustments deviated systematically from regularity, highlighting two sources of perceptual biases in time perception: rhythmic grouping and a psychoacoustic intensity effect. Then the participants performed the excerpts on the piano in the same regular way. The intensity effect disappeared, and some variations due to motor constraints were observed in relation to rhythmic groups. Finally, the participants performed the excerpts musically. Variations due to musical communication involved additional group-final lengthening that reflected the hierarchical grouping structure of the excerpts. These results underline the nuclear role of grouping in musical time perception and production.

Adult↗
PubMed2001

Different spaces and different times for perception and action.

Separate, but interacting, visual systems have evolved in the primate brain for the perception of objects on the one hand and the control of actions directed at those objects on the other. This 'duplex' account of high-level vision suggests that 'reconstructive' approaches and 'purposive-animate-behaviorist' approaches need not be seen as mutually exclusive, but as complementary in their emphases on different aspects of visual function. Indeed, the limitations of one system are the strengths of the other. Perception (which is mediated by the ventral stream of visual projections in primate cortex) delivers a rich and detailed representation of the world, but does not compute the detailed metrics of the scene with respect to the observer. In contrast, the action system (which depends heavily on dorsal-stream projections) delivers accurate metrical information about an object in the required egocentric coordinates for action, but these computations are fleeting and are for the most part limited to the particular goal object that has been selected. Both systems work together in the production of purposive behavior--one system selects the goal object from the visual array, the other carries out the required metrical computations for the goal-directed action.

Animals↗
PubMed2000

High-speed memory scanning: a behavioral argument for a serial oscillatory model.

In order to account for the memory span [G.A. Miller, The magical number seven, plus minus two: some limits on our capacity for processing information, Psychol. Rev. 63 (1956) 81-97.], the magical number seven, plus minus two, and high-speed scanning in human memory ¿S. Sternberg, High speed scanning in human memory, Science 153 (1966) 652-654., Lisman and collaborators [O. Jensen, J.E. Lisman, An oscillatory short-term memory buffer model can account for data on the Sternberg task, J. Neurosci. 18 (1998) 10688-10699; J.E. Lisman, M.A.P. Idiart, Storage of 7+/-2 short-term memories in oscillatory subcycles, Science 267 (1995), 1512-1515.] proposed an oscillatory short-term memory buffer model. In this neurophysiological model: "a single brain network can separately maintain up to seven memories by a multiplexing mechanism that uses theta and gamma brain oscillations for clocking. A memory is represented by groups of neurons that fire in the same gamma cycle" ¿O. Jensen, J.E. Lisman, An oscillatory short-term memory buffer model can account for data on the Sternberg task, J. Neurosci. 18 (1998) 10688-10699, p. 10688. To test this model, we tried to modify the memory scanning time by shifting the gamma oscillation frequency. To this aim, we replicated the visual short-term memory scanning task ¿S. Sternberg, High speed scanning in human memory, Science 153 (1966) 652-654., and we simultaneously used the protocol that Treisman ¿M. Treisman, A. Faulkner, P.L.N. Naish, D. Brogan, The internal clock: evidence for a temporal oscillator underlying time perception with some estimates of its characteristics frequency, Perception 19 (1990) 705-743. designed to drive, slowing down or speeding up, a temporal oscillator acting in the gamma range ¿J.G.R. Jefferys, R.D. Traub, M.A. Whittington, Neuronal networks for induced "40 Hz rhythms, Trends Neurosci. 19 (1996) 202-208; W. MacKay, Synchronized neuronal oscillations and their role in motor processes, Trends Cog. Sci. 1 (1997) 176-183; M. Treisman, N. Cook, P.L.N. Naish, J.K. MacCrone, The internal clock: electroencephalographic evidence for oscillatory processes underlying time perception, Q. J. Exp. Psychol. 47A (1994) 241-289.. In this protocol, an auditory periodic stimulus (click train) was delivered at various frequencies during the task. The reaction time (RT), the slope, and the intercept of the linear function associating RT to memorized list length showed systematic modulations according to the stimulation frequency. The predicted driving effects due to the click trains were obtained, consisting of localised modulations of performance on the stimulation frequency band. We argue that memory scanning is indeed paced by a temporal oscillator, thus providing behavioral arguments for the serial oscillatory model of Lisman.

Adult↗
PubMed1994

Acute behavioral toxicity of MK-801 and phencyclidine: effects on rhesus monkey performance in an operant test battery.

Monkey performance of operant tasks was used to model several brain functions and monitor the acute effects of MK-801 and phencyclidine (PCP). MK-801 is a relatively selective N-methyl-D-aspartate (NMDA) receptor antagonist, while PCP is an NMDA antagonist that is also active at sigma opiate receptors. A comparison of these drugs' effects may indicate the relative importance of certain neurotransmitter receptor systems for specific behaviors. Learning and time perception behaviors are more sensitive (affected at lower doses) to the disruptive effects of MK-801 than are behaviors that model short-term memory, motivation, and color and position discrimination. Such selective disruption was not obtained for PCP: learning, short-term memory and attention, time perception, and motivation tasks are all equally sensitive to disruption. These findings suggest that specific brain functions are differentially affected by modulation of the NMDA and sigma opiate systems.

Animals↗
PubMed1994

Time estimation and juvenile delinquency.

Certain empirical evidence suggests that subjects prone to delinquent activity may have faster internal clocks than others. To investigate the relationship between antisocial behavior and time perception and its dependence on the experimental time interval and method and on whether the subject is institutionalized we obtained verbal and production estimates of 5-, 15-, 30-, and 60-sec. intervals from 249 adolescents (156 school attenders and 93 institutionalized subjects) classified into 3 groups according to the intensity of their antisocial activity. Results provide no support for the hypothesis that overestimation of short time intervals is associated with either juvenile delinquency or institutionalization.

Adolescent↗