Home About us Contact
|
Home About us Contact | ||
|
|
||
Reaction Time Task (reaction + time_task)
Kinds of Reaction Time Task Selected AbstractsEvidence for implicit sequence learning in dyslexiaDYSLEXIA, Issue 1 2002Steve W. Kelly Abstract Nicolson and Fawcett (Cognition 1990; 35: 159,182) have suggested that a deficit in the automatization of skill learning could account for the general impairments found in dyslexia. Much of the evidence for their claims has been collected via a dual task paradigm, which might allow for alternative explanations of the data. The present study examines automatic skill learning in a single task paradigm and extends previous studies by independently examining the contribution of stimulus-based and response-based learning. The task replicates Mayr's (J. Exp. Psychol.: Learning Memory Cognition 1996; 22: 350,364) methodology in the Serial Reaction Time task by exposing participants to two structured displays, simultaneously. Learning is measured by comparing RT to the learned sequence against RT to a random display. This study demonstrates learning for both dyslexic and control groups for a spatial sequence which was observed and a concurrent non-spatial sequence which was responded to via a keypress. Learning of the sequence did not seem to depend on awareness of the sequence structure. These results suggest that automatic skill learning is intact in dyslexic individuals. Copyright © 2002 John Wiley & Sons, Ltd. [source] Acute neuropsychological effects of methylphenidate in stimulant drug-naïve boys with ADHD II , broader executive and non-executive domainsTHE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 11 2006Sinéad M. Rhodes Background:, Accumulating evidence supports methylphenidate-induced enhancement of neuropsychological functioning in attention deficit hyperactivity disorder (ADHD). The present study was designed to investigate the acute effects of the psychostimulant drug, methylphenidate (MPH), on neuropsychological performance in stimulant naïve boys with ADHD. Methods:, Seventy-three drug-naïve boys (age 7,15) with ADHD (combined type) completed neuropsychological tasks from the CANTAB battery under randomised, placebo controlled, double-blind conditions following an acute challenge with either placebo (n = 24), .3 (n = 25) or .6 (n = 24) mg/kg oral MPH. Results:, MPH did not impair performance on any task. MPH (.6 mg/kg) lengthened response latencies on a task of Spatial Recognition, shortened response times on a Reaction Time task and restored performance on a Delayed Matching to Sample visual, non-working memory task. Contrary to predictions, MPH did not enhance performance on tasks with a prominent executive component, including Go/NoGo, Spatial Working Memory, Stockings of Cambridge and Attentional Set shifting tasks. Conclusions:, Acute administration of MPH to drug-naïve boys with ADHD did not impair neuropsychological performance. Acute MPH enhanced performance on some aspects of non-executive functioning. MPH-induced slowing of responding on a relatively complex Spatial Recognition memory task and quickened responding on a reaction time task requiring less cognitive resources suggests that MPH may act by improving self-regulatory ability. MPH may not exert its effects on neuropsychological functioning by enhancing executive processes. [source] Serotonin transporter deficiency in rats improves inhibitory control but not behavioural flexibilityEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2007Judith R. Homberg Abstract Impulsivity and aggression have been suggested to inversely correlate with central serotonin (5-HT) levels in a trait-like manner. However, this relationship is far from straightforward. In the present study we addressed the effect of lifelong reduced or absent serotonin transporter (SERT) function, which is associated with constitutively increased extracellular 5-HT levels, on impulsivity and aggression. We used unique SERT knockout rats in a resident,intruder test, five-choice serial reaction time task and serial reversal learning task to assay aggression, inhibitory control and behavioural flexibility, respectively. Homozygous SERT knockout rats (SERT,,/,) displayed reduced aggression and improved inhibitory control, but unchanged behavioural flexibility. The behavioural phenotype of heterozygous SERT knockout rats (SERT,+/,) was not different from that of wild-type controls in any of the behavioural paradigms. We determined monoamine (metabolite) tissue levels in the medial prefrontal cortex, orbitofrontal cortex, lateral hypothalamus, raphe nuclei and cerebrospinal fluid, and found that the 5-HT levels, but not other monoamine tissue levels, were reduced in SERT,,/, rats. In addition, the 5-hydroxyindoleacetic acid (5-HIAA)/5-HT ratio in cerebrospinal fluid was increased in these rats. In conclusion, our data show that the absence of the SERT affects aggression and inhibitory control, but not behavioural flexibility, characteristics that may reflect the trait-like consequences of constitutive changes in central 5-HT levels. [source] Interactions between alcohol and caffeine in relation to psychomotor speed and accuracyHUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 3 2002Michelle Mackay Abstract Unlike other CNS depressants, alcohol intoxication can be associated with increased error rates, coupled with unaffected (or speeded) response rates during psychomotor and cognitive processing. The present study examined whether concurrent consumption of caffeine may differentially affect these aspects of alcohol and performance. A randomised, double-blind, placebo-controlled design was utilised in which 64 healthy young volunteers received either 0.66,g/kg alcohol, caffeine (110,120,mg), both or neither. Performance was assessed using a four choice reaction time task (FCRT) with elements of repetitive (predictable) and random stimuli sequences and the digit symbol substitution task (DSST). Individuals on alcohol made significantly more errors during both fixed and random FCRT sequences, and there was evidence of weak antagonism of these effects by caffeine on the latter measure. On the DSST test of psychomotor speed, alcohol was associated with a significant slowing, the caffeine group were significantly faster and there was clear antagonism of the effects of alcohol by caffeine. These findings confirm that alcohol consumption is associated a greater number of errors and provide some evidence for task-specific antagonism of alcohol's cognitive effects by caffeine. Copyright © 2002 John Wiley & Sons, Ltd. [source] Differentiating Type A behaviour and hyperactivity using observed motivation during a reaction time taskINFANT AND CHILD DEVELOPMENT, Issue 2 2003Lilianne Nyberg Abstract In light of the previously found overlap between Type A behaviour as measured by the Matthews Youth Test for Health (MYTH) and hyperactivity scales, the overall aim of this study was to clarify the standing of MYTH-defined Type A behaviour relative to hyperactivity and Attention-Deficit/Hyperactivity Disorder (ADHD), using observed task motivation and performance on a choice reaction-time task, the Complex Reaction Time (CRT) measure. This study included 21 boys exhibiting Type A behaviour, 22 ADHD boys, 20 non-clinically hyperactive boys, and 20 non-hyperactive boys, between the ages of 6 and 13 years. It was proposed that a differentiation of constructs would be possible using observed task motivation if the MYTH were a discriminantly valid measure of Type A behaviour. Results showed that the MYTH-defined Type A group differed from the clinically diagnosed ADHD group, although it was markedly similar to the non-clinical hyperactive group, displaying comparable CRT performance and low level of task motivation. Type A behaviour correlated to CRT performance and task motivation in a way which was conceptually more indicative of hyperactivity than of Type A behaviour, which questions the validity of the MYTH as a measure of the Type A construct. The MYTH Impatience subscale was found to be particularly impure with regard to hyperactivity. Copyright © 2003 John Wiley & Sons, Ltd. [source] Endogenous serotonin and serotonin2C receptors are involved in the ability of M100907 to suppress cortical glutamate release induced by NMDA receptor blockadeJOURNAL OF NEUROCHEMISTRY, Issue 2 2009Eleonora Calcagno Abstract Blockade of NMDA receptors by intracortical infusion of 3-(R)-2-carboxypiperazin-4-propyl-1-phosphonic acid (CPP) increases glutamate (GLU) and serotonin (5-HT) release in the medial prefrontal cortex and impairs attentional performance in the 5-choice serial reaction time task. These effects are prevented by the 5-HT2A receptor antagonist, (R)-(+)-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenyl)ethyl]-4-piperidine methanol (M100907). We explored the roles of endogenous 5-HT and 5-HT1A and 5-HT2C receptors in the mechanisms by which M100907 suppresses CPP-induced release of cortical GLU and 5-HT using in vivo microdialysis. CPP raised extracellular GLU and 5-HT by about 250% and 170% respectively. The 5-HT synthesis inhibitor, p -chlorophenylalanine (300 mg/kg), prevented M100907 suppressing CPP-induced GLU release. The effect of M100907 on these rises of GLU and 5-HT and attentional performance deficit was mimicked by the 5-HT2C receptor agonist, (S)-2-(6-chloro-5-fluoroindol-1-yl)-1-methylethylamine fumarate, (Ro60-0175, 30 ,g/kg) while intra-mPFC (SB242084, 6-chloro-5-methyl-1-[[2-[(2-methyl-3-pyridyl)oxy]-5-pyridyl]carbamoyl]-indoline, 0.1 ,M), a 5-HT2C receptor antagonist, prevented the effect of M100907 on extracellular GLU. The 5-HT1A receptor antagonist, N -[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]- N -(2-pyridinyl)cyclohexane carboxenide trihydrochloride (100 ,M) abolished the effect of M100907 on the CPP-induced 5-HT release. The data show that blockade of 5-HT2A receptors is not sufficient to suppress the CPP-induced rise of extracellular GLU and 5-HT and suggest that M100907 suppresses GLU release induced by CPP by enhancing the action of endogenous 5-HT on 5-HT2C receptors. [source] Pulsed radio-frequency electromagnetic fields: dose-dependent effects on sleep, the sleep EEG and cognitive performanceJOURNAL OF SLEEP RESEARCH, Issue 3 2007SABINE J. REGEL Summary To establish a dose,response relationship between the strength of electromagnetic fields (EMF) and previously reported effects on the brain, we investigated the influence of EMF exposure by varying the signal intensity in three experimental sessions. The head of 15 healthy male subjects was unilaterally exposed for 30 min prior to sleep to a pulse-modulated EMF (GSM handset like signal) with a 10 g-averaged peak spatial specific absorption rate of (1) 0.2 W kg,1, (2) 5 W kg,1, or (3) sham exposed in a double-blind, crossover design. During exposure, subjects performed two series of three computerized cognitive tasks, each presented in a fixed order [simple reaction time task, two-choice reaction time task (CRT), 1-, 2-, 3-back task]. Immediately after exposure, night-time sleep was polysomnographically recorded for 8 h. Sleep architecture was not affected by EMF exposure. Analysis of the sleep electroencephalogram (EEG) revealed a dose-dependent increase of power in the spindle frequency range in non-REM sleep. Reaction speed decelerated with increasing field intensity in the 1-back task, while accuracy in the CRT and N-back task were not affected in a dose-dependent manner. In summary, this study reveals first indications of a dose,response relationship between EMF field intensity and its effects on brain physiology as demonstrated by changes in the sleep EEG and in cognitive performance. [source] Dual task interference in psychogenic tremorMOVEMENT DISORDERS, Issue 14 2007Hatice Kumru MD Abstract Psychogenic tremor (PT) is visually indistinguishable from voluntarily mimicked tremor. Healthy volunteers have difficulties with carrying out simultaneously two tasks due to the phenomenon known as dual task interference. Therefore, performing voluntary rhythmic movements would be a burden for carrying out fast ballistic movements with the contralateral hand. We hypothesized that, similarly to healthy volunteers performing rhythmic movements, patients with PT should show the effects of dual task interference, and this may distinguish them from patients with other types of tremor. We studied 6 patients with PT, 9 with Parkinson's disease (PD) and predominantly unilateral tremor, 11 with essential tremor (ET), and 10 normal volunteers (NV) mimicking tremor. They were requested to perform a unilateral simple reaction time task (SRT) to a visual imperative signal in two different conditions: at rest (rSRT) and during contralateral hand tremor (tSRT). Reaction time was significantly longer in tSRT than in rSRT in PT and in NV groups (P < 0.01 for both groups). However, no significant differences were observed between rSRT and tSRT in PD and ET. The delay of unilateral tSRT with respect to rSRT suggests an effect of tremorlike oscillatory movements on reaction time that is consistent with the concept of dual-task interference in NV or PT patients but not in PD or ET. These observations may be useful in the evaluation of psychogenic movement disorders. © 2007 Movement Disorder Society [source] Optimal signal bandwidth for the recording of surface EMG activity of facial, jaw, oral, and neck musclesPSYCHOPHYSIOLOGY, Issue 1 2001A. van Boxtel Spontaneous pericranial electromyographic (EMG) activity is generally small and is contaminated by strong low-frequency artifacts. High-pass filtering should suppress artifacts but affect EMG signal power only minimally. In 24 subjects who performed a warned simple reaction time task, the optimal high-pass cut-off frequency was examined for nine different pericranial muscles. From four experimental conditions (visual and auditory reaction signals combined with hand and foot responses), 1-min EMG recordings were selected (bandwidth: 0.4,512 Hz) and divided into 60 1-s data segments. These segments were high-pass filtered, the ,3-dB cut-off frequency varying from 5 to 90 Hz, and subjected to power spectral analysis. Optimal high-pass filter frequencies were determined for the mean power spectra based on visual estimation or comparison with a theoretical spectrum of the artifact-free EMG signal. The optimal frequencies for the different muscles varied between 15 and 25 Hz and were not influenced by stimulus or response modality. For all muscles, a low-pass filter frequency between 400 and 500 Hz was appropriate. [source] Acute neuropsychological effects of methylphenidate in stimulant drug-naïve boys with ADHD II , broader executive and non-executive domainsTHE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 11 2006Sinéad M. Rhodes Background:, Accumulating evidence supports methylphenidate-induced enhancement of neuropsychological functioning in attention deficit hyperactivity disorder (ADHD). The present study was designed to investigate the acute effects of the psychostimulant drug, methylphenidate (MPH), on neuropsychological performance in stimulant naïve boys with ADHD. Methods:, Seventy-three drug-naïve boys (age 7,15) with ADHD (combined type) completed neuropsychological tasks from the CANTAB battery under randomised, placebo controlled, double-blind conditions following an acute challenge with either placebo (n = 24), .3 (n = 25) or .6 (n = 24) mg/kg oral MPH. Results:, MPH did not impair performance on any task. MPH (.6 mg/kg) lengthened response latencies on a task of Spatial Recognition, shortened response times on a Reaction Time task and restored performance on a Delayed Matching to Sample visual, non-working memory task. Contrary to predictions, MPH did not enhance performance on tasks with a prominent executive component, including Go/NoGo, Spatial Working Memory, Stockings of Cambridge and Attentional Set shifting tasks. Conclusions:, Acute administration of MPH to drug-naïve boys with ADHD did not impair neuropsychological performance. Acute MPH enhanced performance on some aspects of non-executive functioning. MPH-induced slowing of responding on a relatively complex Spatial Recognition memory task and quickened responding on a reaction time task requiring less cognitive resources suggests that MPH may act by improving self-regulatory ability. MPH may not exert its effects on neuropsychological functioning by enhancing executive processes. [source] Mapping of direction and muscle representation in the human primary motor cortex controlling thumb movementsTHE JOURNAL OF PHYSIOLOGY, Issue 9 2009W. J. Z'Graggen Larger body parts are somatotopically represented in the primary motor cortex (M1), while smaller body parts, such as the fingers, have partially overlapping representations. The principles that govern the overlapping organization of M1 remain unclear. We used transcranial magnetic stimulation (TMS) to examine the cortical encoding of thumb movements in M1 of healthy humans. We performed M1 mapping of the probability of inducing a thumb movement in a particular direction and used low intensity TMS to disturb a voluntary thumb movement in the same direction during a reaction time task. With both techniques we found spatially segregated representations of the direction of TMS-induced thumb movements, thumb flexion and extension being best separated. Furthermore, the cortical regions corresponding to activation of a thumb muscle differ, depending on whether the muscle functions as agonist or as antagonist for flexion or extension. In addition, we found in the reaction time experiment that the direction of a movement is processed in M1 before the muscles participating in it are activated. It thus appears that one of the organizing principles for the human corticospinal motor system is based on a spatially segregated representation of movement directions and that the representation of individual somatic structures, such as the hand muscles, overlap. [source] Motor-linked implicit learning in persons with autism spectrum disordersAUTISM RESEARCH, Issue 2 2010Brittany G. Travers Abstract Fifteen adolescents and young adults with high-functioning autism spectrum disorders (ASD) and 18 age- and IQ-matched adults with typical development (TD) completed a serial reaction time task (SRT) to examine possible motor-linked implicit learning impairments in persons with ASD. Measures were taken to decrease the role of explicit learning in the SRT. Results showed that participants with ASD demonstrated intact motor-linked implicit learning. Furthermore, the motor-linked implicit learning appeared to take place at a similar rate across trials in the group with ASD compared to the group with TD. These results suggest that persons with ASD are successful in implicit learning of motor-linked behavior. The results of this study, coupled with past findings, suggest that people with ASD may be able to learn motor movements without conscious awareness, especially if the individual is older and is learning fine motor sequences. [source] Histamine H1 receptor blockade predominantly impairs sensory processes in human sensorimotor performanceBRITISH JOURNAL OF PHARMACOLOGY, Issue 1 2009P Van Ruitenbeek Background and purpose:, Centrally active antihistamines impair cognitive performance, particularly sensorimotor performance. The aim of the present study was to further elucidate the scarcely studied subprocesses involved in sensorimotor performance, which may be affected by H1 receptor blockade. Better knowledge about the cognitive deficits associated with histamine dysfunction can contribute to better treatment of clinical disorders in which histamine hypofunction may be a contributing factor, such as in schizophrenia. Experimental approach:, Interactions of dexchlorpheniramine with specific task manipulations in a choice reaction time task were studied. Task demands were increased at the level of sensory subprocesses by decreasing stimulus quality, and at the level of motor subprocesses by increasing response complexity. A total of 18 healthy volunteers (9 female) aged between 18 and 45 years participated in a three-way, double-blind, crossover design. Treatments were single oral doses of 4 mg dexchlorpheniramine, 1 mg lorazepam and placebo. Behavioural effects were assessed by measuring reaction times and effects on brain activity by event-related potentials. Key results:, Dexchlorpheniramine significantly slowed reaction times, but did not significantly interact with task manipulations. However, it did significantly interact with stimulus quality, as measured by event-related potentials. Lorazepam slowed reaction times and interacted with perceptual manipulations, as shown by effects on reaction times. Conclusions and implications:, The results confirm that the histamine system is involved in sensory information processing and show that H1 blockade does not affect motoric information processing. Histamine hypofunction in clinical disorders may cause impaired sensory processing, which may be a drug target. [source] Relations between fatigue, neuropsychological functioning, and physical activity after treatment for breast carcinomaCANCER, Issue 9 2002Daily self-report, objective behavior Abstract BACKGROUND Previous research indicates that disease free breast carcinoma survivors who experienced severe fatigue also had many problems with regard to neuropsychological functioning and physical activity, measured with general self-report questionnaires. Both neuropsychological functioning and physical activity can be measured with daily self-report measures in addition to measures of objective behavior. The main objective of this study was to examine the relations between 1) fatigue and 2) daily self-reported and objective measures of neuropsychological functioning and physical activity. METHODS Disease free breast carcinoma survivors and age-matched women with no history of breast carcinoma filled out a daily self-observation list and wore an actometer during a period of 12 days. Furthermore, they performed two standardized tests to assess neuropsychological functioning. RESULTS No differences were found between severely fatigued disease free breast carcinoma survivors, nonseverely fatigued disease free breast carcinoma survivors, and women in a control group with regard to daily self-reported and objective physical activity. The severely fatigued disease free patients reported more impairment in neuropsychological functioning on daily questionnaires compared with nonseverely fatigued disease free patients and women in the control group. However, no differences were found between these three groups on a standardized concentration task. On a standardized reaction time task, no significant differences were found between the two groups of disease free breast carcinoma survivors: However, women in the severely fatigued group had a significantly longer reaction time compared with women in the control group. CONCLUSIONS Fatigue is correlated strongly with daily self-reported neuropsychological functioning, but not with objective neuropsychological functioning, in a laboratory setting. In the current study, fatigue was not correlated with daily self-reported and objective physical activity. Cancer 2002;95:2017,26. © 2002 American Cancer Society. DOI 10.1002/cncr.10891 [source] Maturation of action monitoring from adolescence to adulthood: an ERP studyDEVELOPMENTAL SCIENCE, Issue 6 2005Alexandra M. Hogan This study investigated the development of the frontal lobe action-monitoring system from late childhood and adolescence to early adulthood using ERP markers of error processing. Error negativity (ERN) and correct response negativity (CRN) potentials were recorded while adolescents and adults (aged 12,22 years, n = 23) performed two forced-choice visual reaction time tasks of differing complexity. Significant age differences were seen for behavioural and ERP responses to complex (infrequent, incompatible) trials: adolescents elicited an error negativity of reduced magnitude compared with adults. Furthermore, in contrast to adults, adolescents showed a non-significant differentiation between response-locked ERP components elicited by correct (CRN) and error responses (ERN). Behaviourally, adolescents corrected fewer errors in incompatible trials, and with increasing age there was greater post-error slowing. In conclusion, the neural systems underlying action-monitoring continue to mature throughout the second decade of life, and are associated with increased efficiency for fast error detection and correction during complex tasks. [source] What shields some can shackle others: the approach-related consequences of threat categorisations vary by agreeablenessEUROPEAN JOURNAL OF PERSONALITY, Issue 7 2005Michael D. Robinson It is common to think that threat categorisation tendencies (TCTs) should undermine a person's subjective well-being. However, recent research has suggested that the hedonic impact of such tendencies varies considerably according to a person's traits. The present research seeks to extend such a perspective by considering potential interactions between TCTs and the trait of agreeableness. TCTs were measured through the use of choice reaction time tasks contrasting the threat and non-threat categories. As expected, TCTs were not correlated with the trait of agreeableness, but interacted with this trait in predicting the dependent measures. Within three studies involving 184 undergraduates, TCTs were associated with the higher levels of approach-related behaviour and positive emotion among disagreeable individuals, but lower levels of these same variables among agreeable individuals. The authors suggest that threat categorisation tendencies psychologically protect or burden the individual, depending on the levels of agreeableness. Copyright © 2005 John Wiley & Sons, Ltd. [source] Resource allocation and fluid intelligence: Insights from pupillometryPSYCHOPHYSIOLOGY, Issue 1 2010Elke Van Der Meer Abstract Thinking is biological work and involves the allocation of cognitive resources. The aim of this study was to investigate the impact of fluid intelligence on the allocation of cognitive resources while one is processing low-level and high-level cognitive tasks. Individuals with high versus average fluid intelligence performed low-level choice reaction time tasks and high-level geometric analogy tasks. We combined behavioral measures to examine speed and accuracy of processing with pupillary measures that indicate resource allocation. Individuals with high fluid intelligence processed the low-level choice reaction time tasks faster than normal controls. The task-evoked pupillary responses did not differ between groups. Furthermore, individuals with high fluid intelligence processed the high-level geometric analogies faster, more accurately, and showed greater pupil dilations than normal controls. This was only true, however, for the most difficult analogy tasks. In addition, individuals with high fluid intelligence showed greater preexperimental pupil baseline diameters than normal controls. These results indicate that individuals with high fluid intelligence have more resources available and thus can solve more demanding tasks. Moreover, high fluid intelligence appears to be accompanied by more task-free exploration. [source] Psychomotor speed in hypertension: Effects of reaction time components, stimulus modality, and phase of the cardiac cyclePSYCHOPHYSIOLOGY, Issue 3 2007Louisa Edwards Abstract Hypertension is characterized by cognitive deficits. As evidence for impaired psychomotor speed, including slower reaction times, is mixed, we aimed to provide a detailed investigation of simple reaction time in hypertension. Pre-motor and motor reaction times were measured across the cardiac cycle in 30 hypertensives and 29 normotensives to determine the effects of phasic and tonic blood pressure on performance. Auditory, visual, and tactile simple reaction time tasks were completed with stimuli presented 0, 300, and 600 ms after the R-wave of the electrocardiogram. Reaction times did not differ between hypertensives and normotensives. Although pre-motor reaction times were faster during the late phase than the early phase of the cardiac cycle whereas motor reaction times were unchanged, this effect was similar for hypertensives and normotensives. No sensory-motor deficits were evident in these hypertensives regardless of baroreceptor activity. [source] | ||||||||||||||||