Influence of caffeine, cold and exercise on multiple choice reaction time

RATIONALE: The effects of caffeine on psychomotor performance have been evaluated under resting conditions and in a thermoneutral environment. Our hypothesis was that these effects could be modified by factors enhancing the level of alertness, such as exercise and cold exposure. OBJECTIVE: The purpose of this study was to follow up changes in the multiple choice reaction time (RT) during exercise at room and low ambient temperatures after caffeine or placebo administered in a double blind manner. METHODS: Nine soccer players performed multistage, incremental exercise until volitional exhaustion on a bicycle ergometer at 22 degrees C or 4 degrees C, 1 h after ingestion of coffee with caffeine (CAF) or without it (PL). Immediately before exercise and at the end of each workload, RT and blood lactate (LA) were measured. Oxygen uptake (VO2) and heart rate (HR) were recorded continuously. Blood LA threshold and the workload associated with the shortest RT were determined. RESULTS: During exercise at 22 degrees C, RT was significantly shorter in CAF than in the PL test, while at 4 degrees C there were no differences in RT between CAF and PL trials. Cold exposure did not affect RT either at rest or during exercise. Neither caffeine nor cold exposure influenced the maximal VO2, the maximal HR and LA threshold. CONCLUSION: In the thermoneutral environment, caffeine ingestion improved psychomotor performance during exercise, whilst at low ambient temperature this effect was blunted. These findings suggest that the stimulating action of caffeine depends on the level and source of arousal.     

Alcohol Effects on Mood, Equilibrium, and Simulated Driving

BACKGROUND: The effects of alcohol on simple versus complex psychomotor performance were compared in 18 adults. METHODS: Subjects received ethanol doses of 0.0, 0.5, and 0.8 g/kg in a randomized, double-blind, within-subject design. Forty minutes after finishing their drinking, the subjects completed a 60-min battery of tests that included: 1) a sensory organization posturography test (EquiTest); 2) latency to apply the brake after appearance of a barrier in a driving simulator (brake reaction time); 3) visual analog subjective-effects scales (VAS); 4) the Profile of Mood States (POMS); 5) critical flicker fusion (CFF); and 6) choice reaction time (CRT). RESULTS: Alcohol dose dependently reduced composite equilibrium scores and increased brake reaction time. On the CRT task, total reaction time was significantly increased after the high dose but not the low dose. Alcohol dose dependently increased VAS "dizzy," "high," and "drug effect" ratings. The POMS and CFF were not significantly affected by alcohol. CONCLUSIONS: These data suggest that an ethanol dose that neither influences certain mood states nor impairs simple psychomotor task performance nonetheless may impair equilibrium and complex psychomotor tasks (e.g., driving).     

Modulation of morphine sensitization in the rat by contextual stimuli

Rationale: The repeated administration of addictive drugs, such as amphetamine, cocaine, and morphine, produces a progressive enhancement (sensitization) of their psychomotor activating effects. We have previously shown that administration of amphetamine or cocaine in a distinct test environment promotes more robust psychomotor sensitization than if they are given at home. No information is available, however, on whether this environmental manipulation has a similar effect on sensitization to morphine, a drug that enhances dopamine (DA) release in the striatum indirectly by disinhibiting midbrain DA neurons. Objectives: The main goal of present study was to determine whether exposure to a distinct environmental context facilitates morphine sensitization. Methods: As an index of psychomotor activation, we used rotational behavior in rats with a uni- lateral 6-hydroxydopamine lesion of the mesostriatal DA system. There are inconsistencies in the literature regarding the ability of morphine to elicit rotational behavior. Therefore, in experiment 1 we determined the effect of 2.0, 3.0, 4.0, 6.0, and 8.0 mg/kg, IP, of morphine on rotational behavior. In experiment 2, we studied the effect of five consecutive IV infusions of saline or morphine (2.0 mg/kg) in rats treated either in their home cage or in a distinct and relatively novel test environment. After 5 days of withdrawal, all rats received an IV infusion of 2.0 mg/kg morphine (Morphine challenge). The following day all rats received an IV infusion of saline (Saline challenge). Results: Morphine produced a dose-dependent increase in rotational behavior. Environmental novelty enhanced both the acute psychomotor response to morphine and its ability to induce psychomotor sensitization. Furthermore, a conditioned rotational response was seen only in animals treated in the novel environment. Conclusions: Environmental novelty can facilitate the development of sensitization to the psychomotor activating effects of major addictive drugs, such as amphetamine, cocaine, and morphine. Received: 29 November 1999 / Accepted: 14 March 2000     

Comparing the subjective, psychomotor, and physiological effects of intravenous hydromorphone and morphine in healthy volunteers

RATIONALE: The psychopharmacological profile of hydromorphone, an opioid that has been used extensively for many years for post-operative pain management, has not been adequately characterized in non-drug abusers. OBJECTIVES: To characterize the subjective, psychomotor, and physiological effects of a range of single doses of hydromorphone in non-drug-abusing volunteers and to compare the effects of hydromorphone with that of morphine, a benchmark mu opioid agonist. METHODS: Subjects in a six-session study were injected in an upper extremity vein with 0, 0.33, 0.65, 1.3 mg/70 kg hydromorphone, and 5 and 10 mg/70 kg morphine, using a randomized, double-blind, crossover design. RESULTS: Hydromorphone increased scores on the pentobarbital-chlorpromazine-alcohol group and lysergic acid diethylamide scales and decreased scores on the benzedrine group scale of the Addiction Research Center Inventory, increased adjective checklist ratings of ("dry mouth", "flushing", and "nodding", and increased visual analog scale ratings indicative of both pleasant (e.g., drug liking) and unpleasant (e.g., "feel bad") effects. The subjective effects of morphine at putatively equianalgesic doses to those of hydromorphone were similar to those of hydromorphone, but in some cases of lesser magnitude. Psychomotor impairment was modest with hydromorphone and absent with morphine. Both opioids produced dose-dependent decreases in pupil size. A relative potency analysis indicated that hydromorphone was 10 times as potent as morphine (1 mg hydromorphone=10 mg morphine). CONCLUSIONS: The results of this study demonstrate that 0.33-1.3 mg hydromorphone had orderly, dose-related effects on subjective, psychomotor, and physiological variables, and similar effects to those of a benchmark mu opioid agonist, morphine.     

Administration of triazolam prior to recovery sleep: effects on sleep architecture,subsequent alertness and performance

The effects of triazolam (0.125, 0.25, and 0.5 mg) versus placebo on recovery sleep staging, subsequent alertness and psychomotor performance were evaluated in humans. Forty-five healthy male subjects were deprived of sleep for 24 h, then administered a single dose of triazolam or placebo using a double-blind procedure. Subjects then attempted to obtain recovery sleep under non-sleep-conducive conditions (sitting upright in a well-lit, crowded chamber) for the next 6 h, followed by 18 more hours of sleep deprivation. During all sleep deprivation periods subjects were tested bihourly on a performance assessment battery which included symbol digit modalities tests (SDMT), four-letter search (FLS), logical reasoning (LR), time estimation (TE), visual vigliance (VV), and short term memory (STM) tasks. Sleepiness levels were measured objectively with multiple sleep latency tests (MSLT) and subjectively with the Stanford Sleepiness Scale (SSS). Compared to placebo, all doses of triazolam resulted in increased amounts of stage 3–4 sleep, and the 0.5 mg dose significantly reduced awakenings (Ps<0.05). Although subjects receiving triazolam averaged 21–42 min more total sleep time (TST) than subjects receiving placebo, differences in TST were not statistically significant. Apparent triazolam-mediated benefits to sleep quality resulted in no obvious improvements in performance or alertness levels during subsequent sleep deprivation. It was concluded that the increases in stage 3–4 sleep amouts were most likely due to triozolam-mediated increases arousal thresholds, and the triazolam mediated changes in sleep parameters obtained in the present study were not indicative of substantial changes in the recuperative value of sleep.This material has been reviewed by the Walter Reed Army Institute of Research, and there is no objection to its presentation and/or publication. The opinions or assertions contained herein are the private views of the author and are not to be construed as official or as reflecting the position of the Department of the Army or the Department of Defense     

The adenosine A<Subscript>2A</Subscript> antagonist MSX-3 reverses the effects of the dopamine antagonist haloperidol on effort-related decision making in a T-maze cost/benefit procedure

Rationale  Mesolimbic dopamine (DA) is a critical component of the brain circuitry regulating behavioral activation and effort-related processes. Research involving choice tasks has shown that rats with impaired DA transmission reallocate their instrumental behavior away from food-reinforced tasks with high response requirements and instead select less effortful food-seeking behaviors. Objective  Previous work showed that adenosine A_2A antagonism can reverse the effects of the DA antagonist haloperidol in an operant task that assesses effort-related choice. The present work used a T-maze choice procedure to assess the effects of adenosine A_2A and A₁ antagonism. Materials and methods  With this task, the two arms of the maze have different reinforcement densities (four vs. two food pellets), and a vertical 44 cm barrier is positioned in the arm with the higher density, presenting the animal with an effort-related challenge. Untreated rats strongly prefer the arm with the high density of food reward and climb the barrier in order to obtain the food. Results  Haloperidol produced a dose-related (0.05–0.15 mg/kg i.p.) reduction in the number of trials in which the rats chose the high-barrier arm. Co-administration of the adenosine A_2A receptor antagonist MSX-3 (0.75, 1.5, and 3.0 mg/kg i.p.), but not the A₁ antagonist 8-cyclopentyl-1,3-dipropylxanthine (0.75, 1.5, and 3.0 mg/kg i.p.), reversed the effects of haloperidol on effort-related choice and latency. Conclusions  Adenosine A_2A and D2 receptors interact to regulate effort-related decision making, which may have implications for the treatment of psychiatric symptoms such as psychomotor slowing or anergia that can be observed in depression, parkinsonism, and other disorders.     

学习障碍儿童精神运动能力及其影响因素的研究

目的:探讨学习障碍儿童精神运动能力及其影响因素。方法:以36名学习障碍儿童为研究对象,与之配对选出学习中等、学习优良儿童各36名作对照组,对他们进行精神运动能力,Conner行为量表等项调查。结果:由单因素分析发现,学习障碍儿童精神运动能力等方面较其他两组儿童差。对儿童精神运动能力进行多元回归分析,结果表明:数字符号、组别、心身问题、冲动多动、视觉保持等是影响儿童精神运动能力的重要因素。     

Interstitial Deletion of Long Arm of Chromosome 2(q3 lq33)

We describe the case of a 4-month-old girl with interstitial deletion of the long arm of chromosome 2(46,XX,del(2) (q31 q33)). Clinical features included intrauterine growth retardation, psychomotor delay, antimongoloid slanting of the palpebral fissures, hypertelorism, low set ears, cleft palate, micrognathia, luxatio coxae and pes varus. It is suggested that the gene for soluble isocitrate dehydrogenase (IDH₁) is located on 2q33.3. The activity of serum IDH₁ was in the normal range in this patient.     

RETRACTED ARTICLE: Perinatal and first year outcomes of spontaneous versus assisted twins: a single center experience

OBJECTIVE: The aim is to compare naturally conceived twins with twins conceived by assisted reproductive techniques (ART) by means of perinatal outcome, behavioural patterns and psychomotor development. MATERIAL AND METHODS: Three hundred and five spontaneous and 119 assisted twins were compared in aspects of behavioural patterns, mental and psychomotor development, as well as maternal and gestational age, foetal presentation, birth weight, sex, Apgar scores, perinatal complications, delivery route, and admission to neonatal intensive care unit (NICU) RESULTS: Although the maternal age was higher in assisted twins, the mean gestational age and birth weight of assisted twins were significantly less than those of spontaneous twins. The assisted twins did not differ from the naturally conceived twins in aspects of presentation, Apgar scores, admission to NICU and perinatal complications. However, caesarean section rate and the delivery rate of male foetuses were significantly higher in assisted twins. During the first year of life, retardation in mental and psychomotor development was more pronounced in assisted twins. Also assisted twins experienced behavioural problems and difficulties in parent-child interactions more frequently. CONCLUSIONS: Although twins born to assisted pregnancies had significantly shorter duration of gestation and thus less birth weight, their perinatal outcome was similar to that of spontaneous twins. The mothers of assisted twins may be keener on getting intensive prenatal care, which might in turn help to diminish any possible maternal and foetal risks. However, assisted twins showed significantly retarded psychomotor and mental development and experienced problems with environmental factors more frequently during their first year.