Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “REACTION TIME”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1976

The effect of various levels of strenuous to exhaustive exercise on reaction time.

Reaction times and heart rates of 10 subjects walking and running on a motor-driven treadmill were recorded. The exercise consisted of four 3-min stages: Stage 1, 2.5 mph at 12% grade; Stage 2, 3.4 mpg at 14% grade; Stage 3, 4.2 mph at 16% grade; Stage 4 5.0 mph at 18% grade. Subjects were given three separate tests at 1-week intervals. There was an increase in reaction time with increased exercise, but this effect diminished significantly over days. Also, when heart rate was 80% of maximum during the post-test, reaction time was not significantly different from the pre-test. Optimum reaction time was obtained at approximately 40% of maximum heart rate.

Fatigue↗
PubMed2004

Systems-level integration of interval timing and reaction time.

Reaction time (RT) procedures are a prominent tool for the study of information processing by humans and other animals. The interpretation of how RT changes after manipulating the appropriate experimental variables has contributed to the contemporary understanding of a variety of cognitive constructs, including attention and memory. With the use of properly designed tasks, evaluating how RT is modified in response to various neural perturbations has become common within the realms of behavioral and cognitive neuroscience. One interesting observation made during both human and animal RT experiments is that the RT to a signal often speeds-up as more time is allotted to prepare for the signal's onset-referred to as the preparatory interval (PI) effect. In the human RT literature, the PI effect has been used as evidence for time estimation playing a fundamental role in the determination of RT. On the other hand, our theoretical understanding of time estimation remains largely divorced from the RT findings in the animal cognition literature. In order to bridge these different perspectives, we provide here a review of the behavioral parallels between RT and interval-timing experiments. Moreover, both the PI effect and interval timing are shown to be jointly influenced by neuropathologies such as Parkinson's disease in humans or dopamine-depleting brain lesions in experimental animals. The primary goal of this review is to consider human and animal RT experiments within the broader context of interval timing. This is accomplished by first integrating human RT theory with scalar timing theory-the leading model of interval timing. Following this, both RT and interval timing are discussed at a brain systems level insofar as these two processes share common neural substrates. Our conclusion is that interval timing and RT processes are in fact two sides of the same coin.

Animals↗
PubMed2003

Acute effect of Mukh bhastrika (a yogic bellows type breathing) on reaction time.

Reaction time (RT) is an index of the processing ability of central nervous system and a simple means of determining sensory-motor performance. It has been reported that yoga training improves human performance including central neural processing. Earlier studies from our laboratories have shown that yoga training produces a significant decrease in visual reaction time (VRT) and auditory reaction time (ART). The present work was planned to determine if mukh bhastrika (a yogic technique in which breath is actively blasted out in 'whooshes' following a deep inspiration) has any effect on central neural processing by studying its effect on RT. 22 healthy schoolboys who were practising yoga for the past three months were recruited for the present study. VRT and ART were recorded before and after nine rounds of mukh bhastrika. Mukh bhastrika produced a significant (P < 0.01) decrease in VRT as well as ART. A decrease in RT indicates an improved sensory-motor performance and enhanced processing ability of central nervous system. This may be due to greater arousal, faster rate of information processing, improved concentration and/ or an ability to ignore extraneous stimuli. This is of applied value in situations requiring faster reactivity such as sports, machine operation, race driving and specialised surgery. It may also be of value to train mentally retarded children and older sports persons who have prolonged RT.

Acoustic Stimulation↗
PubMed1982

The influence of transient distortion on reaction time.

Reaction times to acoustic stimuli (250 and 4000 Hz sine waves) varying in rise-decay time (50, 25, 10, 5.0, and 1.0 msec) were obtained from normal hearing listeners (N = 3). Findings indicate that decreasing rise-decay time systematically distorts the shape of the latency-intensity function. Data from the shortest rise-decay condition suggests that transient distortion may affect a relatively small change in signal detectabiliity across a signal intensity range of 75 dB.

Adult↗
PubMed2001

Timing and reaction time.

Because reaction time (RT) tasks are generally repetitive and temporally regular, participants may use timing strategies that affect response speed and accuracy. This hypothesis was tested in 3 serial choice RT experiments in which participants were presented with stimuli that sometimes arrived earlier or later than normal. RTs increased and errors decreased when stimuli came earlier than normal, and RTs decreased and errors increased when stimuli came later than normal. The results were consistent with an elaboration of R. Ratcliff's diffusion model (R. Ratcliff, 1978; R. Ratcliff & J. N. Rouder, 1998; R. Ratcliff, T. Van Zandt, & G. McKoon, 1999), supplemented by a hypothesis developed by D. Laming (1979a, 1979b), according to which participants initiate stimulus sampling before the onset of the stimulus at a time governed by an internal timekeeper. The success of this model suggests that timing is used in the service of decision making.

Adolescent↗
PubMed2004

Effect of stimulus intensity on manual and saccadic reaction time.

Reaction time (RT) decreases with stimulus intensity. Hughes and Kesley (1984) demonstrated, however, that the effect of stimulus intensity on simple RT is larger for manual than for saccadic responses. We reexamined this relation under various conditions. The dissociation occurred when the task enabled the generation of exogenous saccades. We found, however, no dissociation if endogenous saccades had to be executed. It is hypothesized that the different effects of intensity result from the simplified neuronal processing of exogenous saccades performed in the direct route from the retina to the superior colliculus.

Hand↗
PubMed2000

Repetition priming reveals sustained facilitation and transient inhibition in reaction time.

Reaction time (RT) in a detection or a location discrimination task increases when a target is repeatedly presented at the same location (inhibition), whereas RT decreases in feature (color or orientation) discrimination tasks (facilitation; Y. Tanaka & S. Shimojo, 1996a). Here, the time course of inhibition and facilitation was examined, using a repetition priming paradigm. Results indicate that inhibition occurred only in the immediately successive trial, whereas facilitation accumulated over several trials with location repetition. Moreover, inhibition and facilitation occurred in a task-relevant manner: Detection-location discrimination tasks produced transient RT increase, whereas feature discrimination tasks produced cumulative RT decrease. These results suggest a functional dissociation between spatial orienting and feature analysis, as well as top-down modulations by tasks leading to different types of visual memory.

Adult↗
PubMed2000

Effect of cold pressor test on visual reaction time and auditory reaction time.

Influence of stress (cold) on visual reaction time (VRT) for red, green and yellow colours and auditory reaction time (ART) for high and low pitched sounds was studied in 60 healthy subjects (17-19 years) by digital display response time apparatus. Pain threshold and pain tolerance time were 23.02 +/- 8.11 and 249.35 +/- 64.88 sec. respectively. During the standard cold pressor test (CPT), there was significant increase (P < 0.01) in VRT for all the three colours, the increase being the least for the red colour. There was significant increase (P < 0.01) in ART for both high and low pitched sounds. There was increase in heart rate and respiratory rate as compared to controls. This increase in VRT and ART with CPT was probably due to decreased conduction velocity of nerves, which could be due to vasoconstriction attributed to increased sympathetic activity caused by cold and pain.

Adolescent↗
PubMed1983

Relation between finger reaction time and voice reaction time in stuttering and nonstuttering children and adults.

Nine stutterers and nine nonstutterers at each of three age levels (5 years, 9 years, and 18 years and above) responded to the onset of 21 1-kHz tones by depressing the index finger of their preferred hand on a response key. Finger reaction times (FRTs) were measured to the nearest millisecond and compared to the voice reaction times (VRTs) obtained from the same subjects. Increased speed and stability of the finger reaction times were observed as an inverse function of age for both groups. The stutterers, as a group, exhibited mean FRTs which were significantly longer and more variable than those of the nonstutterers at each of the three age levels. High correlations also were found between the finger and voice reaction scores for both the stutterers and the nonstutterers. Results support the inference that some stutterers may exhibit difficulty in the consistent execution of motor control strategies common to both speech and nonspeech movements.

Acoustic Stimulation↗
PubMed1989

Perception time and reaction time.

Two experiments were performed in order to examine the possible contribution of visual perception time in motor response time under conditions of pursuit eye movements. Subjects had to follow with their eyes a light spot moving horizontally along a reference scale at a constant velocity of 14 degrees/s. Stimuli (the disappearance of the moving spot) were presented randomly at distances of 11.3, 17.7 and 24.2 angular degrees from the onset of motion. In Experiment 1 subjects had to report verbally the scale division at which the stimuli were presented. In Experiment 2 subjects had to press a button as quickly as possible after stimulus presentation. No relationship between visual perception time and motor reaction time was found.

Adult↗
PubMed2004

A genetic investigation of the covariation among inspection time, choice reaction time, and IQ subtest scores.

Information processing speed, as measured by elementary cognitive tasks, is correlated with higher order cognitive ability so that increased speed relates to improved cognitive performance. The question of whether the genetic variation in Inspection Time (IT) and Choice Reaction Time (CRT) is associated with IQ through a unitary factor was addressed in this multivariate genetic study of IT, CRT, and IQ subtest scores. The sample included 184 MZ and 206 DZ twin pairs with a mean age of 16.2 years (range 15-18 years). They were administered a visual (pi-figure) IT task, a two-choice RT task, five computerized subtests of the Multidimensional Aptitude Battery, and the digit symbol substitution subtest from the WAIS-R. The data supported a factor model comprising a general, three group (verbal ability, visuospatial ability, broad speediness), and specific genetic factor structure, a shared environmental factor influencing all tests but IT, plus unique environmental factors that were largely specific to individual measures. The general genetic factor displayed factor loadings ranging between 0.35 and 0.66 for the IQ subtests, with IT and CRT loadings of -0.47 and -0.24, respectively. Results indicate that a unitary factor is insufficient to describe the entire relationship between cognitive speed measures and all IQ subtests, with independent genetic effects explaining further covariation between processing speed (especially CRT) and Digit Symbol.

Adolescent↗
PubMed1997

Correlation between Bereitschaftspotential and reaction time measurements in patients with Parkinson's disease. Measuring the impaired supplementary motor area function?

For a long time, reaction time (RT) testing has been used for objective assessment of characteristics of the movement impairments in patients with Parkinson's disease (PD). On the other hand, it is supposed that Bereitschaftspotential (BP) reflects CNS preparatory activity for the execution of voluntary movements, and amplitudes of BP are generally smaller in PD. In order to analyze possible correlations between two methods, we studied 15 drug-naive patients with idiopathic PD (Hoehn and Yahr stage from 1 to 2.5). BP was recorded from three scalp locations: Cz, C3, and C4, and Lateralized Potential (LP) was additionally calculated as a C3-C4 difference waveform. We recorded amplitudes of the initial part of BP (at 650 ms before movement-NS1), the maximal amplitude immediately before movement onset (N1), and the N1-NS1 difference (NS2), from the Cz and LP recordings. Two RT testing paradigms were used: Simple Reaction Time (SRT) and Choice Reaction Time (ChRT). The only significant correlation between RT parameters and BP amplitudes from Cz was negative correlation between dT (difference time between Choice Reaction Time and Simple Reaction Time), on one hand, and NS1 (P = 0.006) and N1 (P = 0.026), on the other. However, Cz-NS2 did not correlate with any of the RT parameters. Our data suggest that PD patients with smaller difference between ChRT and SRT, that is presumably caused by the lesser capacity of the movement pre-programming, have smaller (i.e., less negative) BP amplitudes. This association is especially pronounced for the earlier, NS1 amplitude that is supposed to reflect the activity of the supplementary motor area (SMA). The diminished capacity of SMA activation may be the cause of the both, smaller early BP amplitudes, and smaller ChRT-SRT difference, in PD patients.

Adolescent↗
PubMed2001

Evaluation of immunomagnetic separation method for detection of Giardia for different reaction times and reaction volumes.

Immunomagnetic separation (IMS) has been specified as a standard method for the measurement of Giardia. In this study, Dynal IMS was evaluated on the basis of recovery efficiencies of Giardia cysts for various IMS operational conditions. The average recoveries for Giardia in deionized, treated and raw water samples were 82.6 +/- 12.2% (n = 6), 75.6 +/- 15.2% (n = 3), and 70.6 +/- 18.2% (n = 3), respectively. Significant changes in recovery were observed by altering the debris ratio and the debris components of water samples. Changing the reaction volume within the same vessel had no significant effect on cyst recovery efficiencies. However, prolonging the reaction time did increase recovery efficiencies.

Animals↗
PubMed2001

An inaccurate-timing filter for reaction time measurement by JAVA applets implementing Internet-based experiments.

JAVA applets are not accurate enough to measure reaction time unless precautions are taken. A response-filtering technique is introduced that identifies inaccurate measurements by testing whether the client-side JAVA implementation produces false measurements of a time interval of known length during the measured reaction time. Reaction times that indicate such inaccuracy are discarded to increase the reliability of the remaining data. Three studies provide illustrative data on the effectiveness of the new technique, using 11 different computer systems. Study 1 showed differences in the accuracy of different clients and higher variability of the obtained means with applets than with native programs. Study 2 showed sharply increased variability when additional loads were imposed on the clients during reaction time measurement. The response-filtering technique diminishes this variability. Study 3 indicated more accurate measurement, with the new technique being able to reveal even smaller differences in difficult technical conditions.

Humans↗