Pursuit Rotor Task Research Articles

Implicit learning in individuals with autism spectrum disorders: a meta-analysis.

Individuals with autism spectrum disorders (ASDs) are characterized by social communication difficulties and behavioural rigidity. Difficulties in learning from others are one of the most devastating features of this group of conditions. Nevertheless, the nature of learning difficulties in ASDs is still unclear. Given the relevance of implicit learning for social and communicative functioning, a link has been hypothesized between ASDs and implicit learning deficit. However, studies that have employed formal testing of implicit learning in ASDs provided mixed results. We undertook a systematic search of studies that examined implicit learning in ASDs using serial reaction time (SRT), alternating serial reaction time (ASRT), pursuit rotor (PR), and contextual cueing (CC) tasks, and synthesized the data using meta-analysis. A total of 11 studies were identified, representing data from 407 individuals with ASDs and typically developing comparison participants. The results indicate that individuals with ASDs do not differ in any task considered [SRT and ASRT task: standardized mean difference (SMD) -0.18, 95% confidence interval (CI) -0.71 to 0.36; PR task: SMD -0.34, 95% CI -1.04 to 0.36; CC task: SMD 0.27, 95% CI -0.07 to 0.60]. Based on our synthesis of the existing literature, we conclude that individuals with ASDs can learn implicitly, supporting the hypothesis that implicit learning deficits do not represent a core feature in ASDs.

Altered synaptic plasticity in Tourette's syndrome and its relationship to motor skill learning.

Gilles de la Tourette syndrome is a neuropsychiatric disorder characterized by motor and phonic tics that can be considered motor responses to preceding inner urges. It has been shown that Tourette patients have inferior performance in some motor learning tasks and reduced synaptic plasticity induced by transcranial magnetic stimulation. However, it has not been investigated whether altered synaptic plasticity is directly linked to impaired motor skill acquisition in Tourette patients. In this study, cortical plasticity was assessed by measuring motor-evoked potentials before and after paired associative stimulation in 14 Tourette patients (13 male; age 18–39) and 15 healthy controls (12 male; age 18–33). Tic and urge severity were assessed using the Yale Global Tic Severity Scale and the Premonitory Urges for Tics Scale. Motor learning was assessed 45 minutes after inducing synaptic plasticity and 9 months later, using the rotary pursuit task. On average, long-term potentiation-like effects in response to the paired associative stimulation were present in healthy controls but not in patients. In Tourette patients, long-term potentiation-like effects were associated with more and long-term depression-like effects with less severe urges and tics. While motor learning did not differ between patients and healthy controls 45 minutes after inducing synaptic plasticity, the learning curve of the healthy controls started at a significantly higher level than the Tourette patients' 9 months later. Induced synaptic plasticity correlated positively with motor skills in healthy controls 9 months later. The present study confirms previously found long-term improvement in motor performance after paired associative stimulation in healthy controls but not in Tourette patients. Tourette patients did not show long-term potentiation in response to PAS and also showed reduced levels of motor skill consolidation after 9 months compared to healthy controls. Moreover, synaptic plasticity appears to be related to symptom severity.

Procedural Learning and Individual Differences in Language

The aim of the current study was to examine different aspects of procedural memory in young adults who varied with regard to their language abilities. We selected a sample of procedural memory tasks, each of which represented a unique type of procedural learning, and has been linked, at least partially, to the functionality of the corticostriatal system. The findings showed that variance in language abilities is associated with performance on different domains of procedural memory, including the motor domain (as shown in the pursuit rotor task), the cognitive domain (as shown in the weather prediction task), and the linguistic domain (as shown in the nonword repetition priming task). These results implicate the corticostriatal system in individual differences in language.

Resting-state cortical connectivity predicts motor skill acquisition

Many studies have examined brain states in an effort to predict individual differences in the capacity for learning, with overall moderate results. The present study investigated how measures of cortical network function acquired at rest using dense-array EEG (256 leads) predict subsequent acquisition of a new motor skill. Brain activity was recorded in 17 healthy young subjects during 3min of wakeful rest prior to a single motor skill training session on a digital version of the pursuit rotor task. Practice was associated with significant gains in task performance (% time on target increased from 24% to 41%, p<0.0001). Using a partial least squares regression (PLS) model, coherence with the region of the left primary motor area (M1) in resting EEG data was a strong predictor of motor skill acquisition (R2=0.81 in a leave-one-out cross-validation analysis), exceeding the information provided by baseline behavior and demographics. Within this PLS model, greater skill acquisition was predicted by higher connectivity between M1 and left parietal cortex, possibly reflecting greater capacity for visuomotor integration, and by lower connectivity between M1 and left frontal–premotor areas, possibly reflecting differences in motor planning strategies. EEG coherence, which reflects functional connectivity, predicts individual motor skill acquisition with a level of accuracy that is remarkably high compared to prior reports using EEG or fMRI measures.

Reduction in Cortical Activation in the Sensorimotor Cortex during Motor Skill Learning of a Pursuit Rotor Task: A Functional Near-Infrared Spectroscopy Study

To investigate the cerebral mechanisms underlying learning of motor skills, we assessed serial changes of brain activation patterns during a pursuit rotor (PR) task in 12 right-handed healthy subjects using functional near-infrared spectroscopy (fNIRS). The subjects performed the task with their right hand for 15-s, alternated with a 30-s rest period, for 18 repetitions (cycles 1 to 18). Gains in motor skill were evaluated by recording the time for which the stylus remained on the target. Performance improved with repetition of the task. Task-related increases of oxygenated hemoglobin (oxy-Hb) were observed around the predicted location of the sensorimotor cortices on both hemispheres. The increased oxy-Hb levels appeared to reduce with repetition of the task in the channels covering the left sensorimotor area. Furthermore, there was a significant correlation between PR task performance gain and the oxy-Hb signal in the left and right sensorimotor areas. Our results suggest that cortical activation in the sensorimotor cortex reflects changes in a number of factors including sensory feedback processing, correct motor commands, and perceptual or cognitive function during learning of a PR task. Therefore, changes in contralateral sensorimotor cortical activation may serve as a motor sequence learning biomarker for rehabilitation purposes or the prediction of recovery.

An investigation of the effects of antiretroviral central nervous system penetration effectiveness on procedural learning in HIV+ drug users

Treatment with combination antiretroviral therapy (cART) regimens with a high capacity to penetrate the blood–brain barrier has been associated with lower levels of human immunodeficiency virus (HIV) in the central nervous system (CNS). This study examined neurocognitive performance among a sample of 118 HIV+ substance-dependent individuals (SDIs) and 310 HIV– SDIs. HIV+ participants were prescribed cART regimens with varying capacity to penetrate the CNS as indexed by the revised CNS Penetration Effectiveness (CPE) scale. Participants completed the Rotary Pursuit Task (RPT) and the Weather Prediction Task (WPT)—two measures of procedural learning (PL) with known sensitivity to HIV infection—and a control task of sustained attention. HIV+ SDIs prescribed cART with relatively high CNS penetrance performed significantly more poorly on both tasks than HIV– controls. Task performance of HIV+ SDIs prescribed cART with relatively low CNS penetrance did not differ significantly from either HIV– controls or the HIV+/high CPE group, although a trend toward lower RPT performance than that of HIV– participants was observed. Between-group differences were not seen on a control task of motor impulsivity (Immediate Memory Task), indicating that the observed deficits among HIV+/high CPE SDIs may have some specificity.

Cerebellar Morphology and Procedural Learning Impairment in Neuroleptic-Naive Youth at Ultrahigh Risk of Psychosis.

Despite evidence suggesting a role for cerebellar abnormalities in the pathogenesis of psychosis, the structure has yet to receive attention in individuals at ultrahigh risk for psychosis (UHR). Accumulating research has suggested that the cerebellum helps modulate cognition and movement, domains in which UHR individuals show impairment; understanding putative markers of risk, such as structural abnormalities and behavioral correlates, is essential. In this study, participants underwent a high-resolution structural brain scan and participated in a pursuit rotor experiment. Cerebellar regions associated with movement (anterior cerebellum) and cognition (crus I) were subsequently analyzed. UHR participants showed impaired performance on the pursuit rotor task, learned at a slower rate, and showed smaller cerebellar volumes compared with control participants. Left crus I volume was significantly associated with poor rate of learning. The present results suggest that cerebellar abnormalities and their behavioral correlates (poor learning and motor control) precede the onset of psychosis.

Visual delayed recall as a predictor of conversion to Alzheimer's disease in patients with amnestic mild cognitive impairment

Background:Amyloid imaging studies have shown early and focal deposition in preclinical PS1 and PS2 carriers among ADAD families. We investigated whether amyloid burden was associated with performance on cognitive tests, includingmeasures putatively sensitive to cognitive functions.Methods:We studied n1⁄411 cognitively normal (CN) ADAD family participants (age 22-44 years) and n1⁄43 with MCI (age 35-48). Participants included 8 PS-1 and 4 APP mutation-carriers, and 2 non-carriers. Participants completed PiB-PET imaging and standard neuropsychological tests, including measures of episodic memory, visuospatial construction, language, attention and executive functions. As well, participants completed a striatal cognitive battery including measures tapping 1) procedural learning (serial reaction time task of implicit learning; Rotary Pursuit task; mirror reading task); 2) risk-reward decision making (Iowa Gambling Task); and 3) psychomotor speed/dexterity (finger tapping; grooved pegboard). PiB-PET imaging data were acquired 50-70minutes after injection. Striatal PiB bindingwas computed as the SUVR (cerebellum reference) of a hand-drawn anterior-ventral striatum region of interest. Precuneus was a comparison ROI.Results: PiB SUVR in the anterior-ventral striatum ranged from 1.01 to 3.41 (mean 1.83; SD 0.78); in the precuneus PiB SUVR range from 1.26 to 3.31 (mean 1.76; SD 0.53). Age was correlatedwith PiB (r1⁄4.67, p<.01) but not in the precuneus. AmongCN participants only, partial correlations (age-controlled) between PiB and cognitive measures were significant (p .05, two-tailed) for finger tapping (r1⁄4.65); mirror reading (r1⁄4.79) and Iowa Gambling Task (r1⁄4.74). Traditional neuropsychological tests also correlated with PiB in CN participants, including MMSE, Boston Naming Test, Block Design and CERAD Word List Learning (partial r’s .63 to .78). In CN and MCI participants combined (n1⁄414), only finger tapping (non-dominant hand) and the IowaGambling Task were correlated with PiB (see Figure). A similar pattern of correlations was observed between precuneus PiB SUVR and cognitive measures, as well as with traditional neuropsychological measures. Corresponding analyses using pons as reference are underway and will be presented. Conclusions: Cognitive measures tapping behavioral functions of the striatum may be useful to explore in larger studies of preclinical AD.

Neuroplasticity in Depressed Individuals Compared with Healthy Controls

Several lines of evidence suggest that neuroplasticity is impaired in depression. This study aimed to compare neuroplasticity in 23 subjects with DSM-IV major depressive episode and 23 age- and gender-matched healthy controls, using an objective test that is independent of subject effort and motivation. Neuroplasticity was assessed in the motor cortex using a brain stimulation paradigm known as paired associative stimulation (PAS), which induces transient changes in motor cortical function. Motor cortical excitability was assessed before and after PAS using single-pulse transcranial magnetic stimulation (TMS) to induce motor evoked potentials (MEPs) in a hand muscle. After PAS, MEP amplitudes significantly increased in healthy controls compared with depressed subjects (P=0.002). The functional significance of motor cortical changes was assessed using a motor learning task-a computerized version of the rotor pursuit task. Healthy controls also performed better on motor learning (P=0.02). BDNF blood levels and genotype were assayed to determine any relationship with motor cortical plasticity. However, PAS results did not correlate with motor learning, nor appear to be related to BDNF measures. The significance of these findings is that it provides one of the first direct demonstrations of reduced neuroplasticity in depressed subjects, using an objective test.

1867 – Motor procedural learning in individuals with mild and moderate alzheimer's disease compared to healthy subjects

There are cognitive and motor impairments in individuals with Alzheimer's disease, which are related to their ability to learn the new procedures, skills and activities. The aim of the study is to compare motor procedural learning in individuals with mild and moderate Alzheimer's disease with motor procedural learning in older subjects without dementia. 32 individuals with mild and moderate Alzheimer's dementia (AD) (F.00.0, F.00.1, F.00.2) (MMSE> 15) (25 women, mean age 76.8 ± 6.41 and 7 men, mean age 79.1 ± 5.21), and 32 individuals without symptoms of dementia (healthy controls- HC) matched for sex, age and education level were examined. Motor procedural learning was assessed by the Pursuit Rotor Task (PRT). The time [ms] of keeping cursor within the moving round object-dot during every 4 trials was measured (after training session). The average time [ ms ] of keeping cursor within object in particular trials is as follows: - AD: 857, 1035, 1060, 1098 - HC: 1014, 1068, 1316, 1681 Statistically significant difference was found in parameters from fourth trial between examined groups (U Manna-Whitneya: Z=- 1,962; p=0,05). It was found that mild and moderate AD patients are able to procedural learn motor task although they achieve worse scores than older persons without dementia.

2880 – Sensory-motor coordination and procedural memory in HIV- and HIV+ opioid addicts

Introduction Various psychomotor dysfunctions are observed in opioid addicts and HIV- and HIV+ persons. Finding markers and methods for accurately determining the psychomotor functioning has practical importance in the diagnosis, monitoring and modification of treatment. Objectives The aim of the study is to evaluate the sensory-motor coordination, procedural memory and motor learning in HIV- and HIV+ opioid addicts during methadone maintenance treatment. Methods 28 HIV- (19 men and 9 women) and 39 HIV+ (23 men and 16 women) addicts treated with opioid replacement therapy (ORT) were examined. The mean age of participants: 40.1 years HIV-, 38.4 years HIV+, the mean daily dose of methadone: 69.82 ml HIV-, 69.95 ml HIV+, the average duration of addiction: 23.2 years HIV -, 20.4 years HIV+. To evaluate the hand-eye coordination and motor learning Pursuit Rotor Task (PRT) was used. Results It was found that HIV+ addicts are more than 25% lower psychomotor performance for hand-eye coordination as compared to HIV- addicts and 50% lower efficiency compared to healthy ones. In HIV+ addicts compared to the HIV- addicts and the healthy ones were more tremor with high amplitude and low frequency and less tremor with small amplitude and high frequency. Conclusions The HIV+ opioid addicts have worse motor coordination compared to HIV- addicts and healthy ones but no impairment of motor learning.

Differential Effect of Alcoholism and HIV Infection on Visuomotor Procedural Learning and Retention

Selective declarative memory processes are differentially compromised in chronic alcoholism (ALC) and HIV infection (HIV) and likely reflect neuropathology associated with each condition: frontocerebellar dysfunction in ALC and frontostriatal dysfunction in HIV infection. Evidence for disease overlap derives from observed exacerbated impairments in these declarative memory processes in ALC-HIV comorbidity. Less is known about nondeclarative memory processes in these disease conditions. Examination of visuomotor learning in chronic ALC and HIV infection could provide insight into the differential and combined contribution of selective disease-related injury to visuomotor procedural memory processes. We examined component processes of visuomotor learning and retention on the rotary pursuit task in 29 ALC, 23 HIV, 28 ALC+HIV, and 20 control subjects. Participants were given 4 rotary pursuit learning sessions over 2 testing days, typically separated by 1week, to assess visuomotor learning and retention patterns. Ancillary measures of simple motor, psychomotor, explicit memory, and balance abilities were administered to test which component processes independently predicted visuomotor learning. All clinical groups showed visuomotor learning across rotary pursuit testing sessions, despite impairment in visuomotor speed in the HIV groups and impairment in explicit memory and psychomotor speed in the alcohol groups. The 2 alcoholic groups showed retention and consolidation over time (i.e., improved performance without further training), whereas the HIV-infected group showed learning and retention but no consolidation effect. The comorbid group shared impairments associated with the ALC-only group (explicit memory and psychomotor speed) and the HIV-only group (visuomotor speed), although there was no clear compounded effect of alcohol and HIV infection on visuomotor learning performance. This study supports the hypothesis that ALC and HIV infection exert differential effects on components of visuomotor procedural learning. Further, the results provide behavioral evidence for dissociable influences of frontocerebellar and frontostriatal disruption to visuomotor procedural learning and retention.

Paired associative stimulation increases motor cortex excitability more effectively than theta-burst stimulation

ObjectiveTo examine the effects of theta burst stimulation (TBS) and paired associative stimulation (PAS) on excitability in the human motor cortex. MethodsSixteen healthy young participants received intermittent TBS (iTBS) or PAS to the primary motor cortex on two testing occasions, at least a week apart. Ten of the participants also received iTBS or PAS after conditioning with continuous TBS on two other occasions. Cortical excitability was assessed with single TMS pulses to the motor cortex. Motor evoked potentials (MEPs) were measured from the first dorsal interosseus (FDI) muscle before TBS or PAS stimulation, and every 10min for 60min after stimulation. Changes in excitability were compared against the potential for motor learning, assessed with the rotor pursuit task. ResultsAfter the PAS protocol MEP amplitudes were significantly increased. This increase was greater than after intermittent TBS, which did not change MEPs significantly. Conditioning with continuous TBS showed no significant effect. Participants’ responses were not correlated across protocols and were not correlated with rotor pursuit learning. ConclusionsPAS was the only protocol which induced significant increases in MEP amplitude. SignificancePAS is robust in inducing excitatory cortical change. This makes it a suitable protocol for testing plasticity in healthy and patient groups.

P-1121 - Effect of a single therapeutic dose of methadone on hand-eye coordination and motor learning in opioid-addicted subjects

Introduction Various psychomotor dysfunction are observed in opioid-addicted patients. Therefore it is important to determine the effect of psychoactive substance administered therapeutically in substitution therapy. Aims This study aims to assess the impact of a single therapeutic dose of methadone on hand-eye coordination and motor learning in opioid-addicted patients treated in substitution therapy. Methods Was examined 72 patients and 60 healthy subjects. The Pursuit Rotor Task (PRT) was used. The PRT was conducted twice: before and about 1 hour after administration of methadone in the opioid-addicted patients and at an about 1 hour interval in the control group. The study was performed for both the dominant and non-dominant hand. Results The statistical significantly (p Conclusions Administration of a single therapeutic dose of methadone in opioid-addicted patients may reduce high amplitude tremor and improve hand-eye coordination.

Impaired Motor Learning by a Pursuit Rotor Test Reduces Functional Outcomes During Rehabilitation of Poststroke Ataxia

Background. Motor learning is essential to gain skills with neurorehabilitation. Objective. To investigate whether capacity for motor learning affects rehabilitation outcome and its relevant brain activation in ataxic patients with stroke. Methods. Twelve patients presenting with ataxia admitted for inpatient rehabilitation 2 to 3 months after infratentorial stroke and 6 control subjects performed 8 repetitions of 30-second pursuit rotor (PR) task. Cortical oxygenated hemoglobin (oxyHb) signals were measured using functional near-infrared spectroscopy. Results. Both patients and controls learned the PR skill, although the gains in PR performance were significantly lower in patients. In patients, the less learning significantly correlated with smaller rehabilitation gains assessed by the Functional Independence Measure. The Fugl-Meyer score for coordination and balance did not change. Center of task-related increase of cortical oxyHb signals shifted from the presupplementary motor area (preSMA) to the supplementary motor area (SMA) with task repetitions in controls but not in patients. Accordingly, serial changes of ratio of oxyHb increase in the preSMA to SMA (preSMA/SMA ratio) were significantly different between the groups. In patients and controls, gains in PR performance and changes of the preSMA/SMA ratio correlated. Conclusions. Impaired motor sequence learning by the PR task was correlated with reduced rehabilitation gains for ataxic patients with stroke.

Impact of HIV and a history of marijuana dependence on procedural learning among individuals with a history of substance dependence

Marijuana (MJ) use and HIV infection are both associated with neurocognitive deficits, yet there is little research to date examining their interactions, specifically how they pertain to procedural learning (PL). We examined a sample of 86 individuals with a history of dependence for multiple substances who underwent a comprehensive evaluation including measures of mental health, substance use history, and three measures of PL: the photoelectric Rotary Pursuit Task (RPT), the Star Mirror Tracing Task (SMT), and the Weather Prediction Task (WPT). We found that a positive HIV serostatus and a history of marijuana dependence were both independently associated with overall poorer performance on the SMT and RPT in this sample of individuals with a history of dependence for multiple substances. Rate of improvement across trial blocks did not differ as a function of HIV serostatus or history of marijuana dependence. Although we found no significant HIV × MJ interaction for any of the PL tasks, we did observe evidence of additive negative effects from HIV and a history of marijuana dependence on overall performance on the SMT and RPT, but not the WPT. The findings suggest that complex motor skills are adversely affected among abstinent polysubstance users with a history of marijuana dependence and that such deficits are compounded by HIV.

Age, handedness, and sex contribute to fine motor behavior in children

The original rotor pursuit test requires that the subject attempts to keep a metal stylus in contact with a small metal disk that was placed in the surface of a turntable that rotated at a constant speed. The present study evaluated the Psychology Experiment Building Language (PEBL) pursuit rotor task. Children (N=427, ages 9–13, 44.4% females) completed a handedness inventory followed by four pursuit rotor trials with each hand. The total time on target increased with age with the dominant as well as non-dominant hands. A small, but significant, sex difference favoring males was also observed. Dextrals spent more time on target than sinistrals with their dominant hand but the reverse pattern was observed for the non-dominant hand. These group differences were independent of prior computer experience. These findings indicate that the freely downloadable PEBL pursuit rotor task is a useful measure of psychomotor function (http://pebl.sf.net) in children and adolescents.

Exploring the effect of inducing long-term potentiation in the human motor cortex on motor learning

Paired-associative stimulation (PAS) represents a neurophysiologic paradigm that involves peripheral nerve stimulation (PNS) of the median nerve, followed by the transcranial magnetic stimulation (TMS) of the contralateral motor cortex. PAS has been shown to result in long-term potentiation-like activity (PAS-LTP) if PNS precedes TMS by 25 milliseconds (PAS-25). PAS-LTP has also been shown to relate to simple motor performance. However, to date, no studies have directly investigated whether the induction of PAS-LTP is associated with enhanced motor learning. The objective of this study was to assess the short- and long-term effect of PAS-25 on motor learning. This was a randomized controlled pilot study in which the control condition was PAS-10, whereby PNS precedes TMS by 10 milliseconds. Motor learning was assessed using the rotary pursuit task at baseline prior to PAS-25 or PAS-10 and 45 minutes and 1 week post-PAS. As expected PAS-25 but not PAS-10 was associated with PAS-LTP as indexed by a significant potentiation of the motor evoked potential. Also, PAS-25 resulted in enhanced motor learning at 1 week post-PAS (F (2, 44) = 3.441, P = .041). This is the first PAS study showing long-term behavioral effect and suggests, albeit indirectly, that PAS-25 can trigger slowly manifesting cellular and structural changes that result in long-term improvement in motor performance. Larger studies with neurophysiologic or neuroimaging outcomes are needed to confirm such preliminary findings.

P.1.c.001 Acute psychomotor, memory and subjective effects of MDMA and THC (co-) administration over time in healthy volunteers

Introduction: In Western societies a considerable percentage of young people expose themselves to the combination of 3,4-methylenedioxymethamphetamine (MDMA or “ecstasy”). Cannabis (main active compound D9-tetrahydrocannabinol or THC) is frequently co-used with ecstasy (Parrott et al., 2007). Despite the prevalence of co-administration of MDMA and THC, the effects of combined use of these substances on behaviour in humans have so far not been investigated. The aim of the present study was to assess the acute effects of (co-) administration of MDMA and THC (the main psychoactive compound of cannabis) on pharmacokinetics, psychomotor performance, memory and subjective experience over time. Methods: We performed a four-way, double blind, randomized, crossover, placebo-controlled study in 16 healthy volunteers (12 male, 4 female) between the ages of 18 and 27. MDMA (100 mg) was given orally, THC (4, 6, and 6 mg, interval of 90 minutes) was vaporized and inhaled. Outcome measures were assessed repeatedly, i.e. before MDMA administration and at 15, 60, 105, 150, 240 and 300 minutes post drug administration, with the exception of the 18 word list memory task, which was performed 120 minutes after drug administration. Repeated measures consisted of blood sampling for analysis of study drug kinetics and assessments of postural stability (body sway), psychomotor function (eye movements and the Rotor Pusuit Task), memory (18 word list and N-back task), and subjective effects (VAS). Results: Body sway was increased, i.e. postural position was impaired, in all drug conditions compared to placebo. THC alone as well as co-administration of THC plus MDMA increased body sway compared to the MDMA alone condition. Eye movements were unaffected by THC, MDMA increased the peak velocity of eye movements. The Rotor Pursuit task (see Figure 1) performance was significantly impaired in the THC condition and the MDMA plus THC condition compared to the placebo and MDMA condition. MDMA alone did not affect the Rotor Pursuit task. Immediate recall of words was impaired in all drug conditions compared to placebo. Delayed recall and delayed recognition did not show a significant main effect of drug administration. The effects of (co-administration) of THC on the N-back working memory task were time- and dose dependent, where THC generally induced a robust but short-lived impairment of working memory. N-back performance was unaffected in the MDMA condition. Co-administration of THC and MDMA enhanced separate subjective drug effects: ratings of 'drug strength', 'internal and external perception', and 'feeling high' were increased compared to the MDMA condition. Conclusion: These results suggest that THC may exert much of its cognitive impairment via a common mechanism of reduced alertness. The stimulant effects of MDMA may attenuate this effect, but could not overcome THC induced impairments in the current study. Overall, THC induced more robust cognitive impairment compared to MDMA. Co-administration of THC with MDMA increased desired subjective drug effects and drug strength compared to the MDMA condition, which may explain the widespread use of this combination.

Separating specific from general learning in a napping paradigm on Multiple Object Tracking and Rotary Pursuit tasks

Separating specific from general learning in a napping paradigm on Multiple Object Tracking and Rotary Pursuit tasks