3,715 research outputs found

    The relationship between internet addiction, attention deficit hyperactivity symptoms and online activities in adults

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    Aim: The objective of this study was to examine the relationship between Internet Addiction (IA), Attention Deficit Hyperactivity Disorder (ADHD) symptoms and online activities in an adult population. Methods: A sample of 400 individuals aged 18 to 70 completed the Adult ADHD Self-Report Scale (ASRS), Young's Internet Addiction Test, and their preferred online activities. Results: A moderate association was found between higher levels of ADHD symptoms and IA. The best predictors of IA scores were ADHD symptoms, age, playing online games and spending more time online. Conclusion: Our findings further support a positive relationship between ADHD symptoms and excessive internet use

    Enhancing the efficacy of 5-HT uptake inhibitors in the treatment of attention deficit hyperactivity disorder

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    Attention Deficit Hyperactivity Disorder (ADHD) is one of the most common childhood behavioural disorders, the frontline treatments for which are drugs with abuse potential. As a consequence, there is an urgent need to develop non addictive drug treatments with equivalent efficacy. Preclinical evidence suggests that selective serotonin uptake inhibitors (SSRIs) are likely to be effective in ADHD, however clinical reports suggest that SSRIs are of limited therapeutic value for the treatment of ADHD. We propose that this disconnect can be explained by the pattern of drug administration in existing clinical trials (administration for short periods of time, or intermittently) leading to inadequate control of the autoregulatory processes which control 5-HT release, most notably at the level of inhibitory 5-HT1A somatodendritic autoreceptors. These autoreceptors reduce the firing rate of 5-HT neurons (limiting release) unless they are desensitised by a long term, frequent pattern of drug administration. As such, we argue that the participants in earlier trials were not administered SSRIs in a manner which realises any potential benefits of targeting 5-HT in the pharmacotherapy of ADHD. In light of this, we hypothesise that there may be under-researched potential to exploit 5-HT transmission therapeutically in ADHD, either through changing the administration regime, or by pharmacological means. Recent pharmacological research has successfully potentiated the effects of SSRIs in acute animal preparations by antagonising inhibitory 5-HT1A autoreceptors prior to the administration of the SSRI fluoxetine. We suggest that combination therapies linking SSRIs and 5-HT1A antagonists are a potential way forward in the development of efficacious non-addictive pharmacotherapies for ADHD

    Developmental and individual differences in conditional reasoning: The role of contradiction training and cognitive style

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    Previous research has suggested that logical competence may not always be reflected in task performances but is influenced by various moderator variables that affect the actual application of competence. The present research examines the development of conditional reasoning from the perspective of a competencemoderator-performance approach (Overton, 1985; Overton & Newman, 1982). The effects of task interpretation and cognitive style as moderator variables for conditional reasoning were examined with 8th, 10th, and 12th grade students. Half of the students at each grade received training with contradictory evidence to alert them to faulty task interpretations. Generalization of training was assessed with a second conditional reasoning task. Cognitive style was assessed with the Matching Familiar Figures test. Results indicate that only the 12th graders benefit from training and training generalized to the subsequent task. It was also found that a reflective style enhanced performance at each grade level for the initial task. However, the beneficial effects of a reflective style were restricted on the generalization task to 12th graders who had received contradiction training. Conditional reasoning has been a central concern of recent research on logical though

    On the action potential as a propagating density pulse and the role of anesthetics

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    The Hodgkin-Huxley model of nerve pulse propagation relies on ion currents through specific resistors called ion channels. We discuss a number of classical thermodynamic findings on nerves that are not contained in this classical theory. Particularly striking is the finding of reversible heat changes, thickness and phase changes of the membrane during the action potential. Data on various nerves rather suggest that a reversible density pulse accompanies the action potential of nerves. Here, we attempted to explain these phenomena by propagating solitons that depend on the presence of cooperative phase transitions in the nerve membrane. These transitions are, however, strongly influenced by the presence of anesthetics. Therefore, the thermodynamic theory of nerve pulses suggests a explanation for the famous Meyer-Overton rule that states that the critical anesthetic dose is linearly related to the solubility of the drug in the membranes.Comment: 13 pages, 8 figure

    Drug therapies for attentional disorders alter the signal-to-noise ratio in the superior colliculus

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    Despite high levels of use, the mechanism of action of effective pharmacotherapies in attention deficit hyperactivity disorder (ADHD) is unknown. It has recently been hypothesized that one site of therapeutic action is the midbrain superior colliculus, a structure traditionally associated with visual processing, but also strongly implicated in distractibility, a core symptom of ADHD. We used male juvenile Wistar rats to examine the effects of therapeutically relevant doses of methylphenidate and d-amphetamine on collicular activity in vitro. Here we report a novel shared mechanism of the two drugs whereby they enhance the signal-to-noise ratio in the superior colliculus. The effects on the signal-to-noise ratio were mediated by serotonin (5-HT) via a pre-synaptic mechanism. This modulatory action would bias the system towards salient events and lead to an overall decrease in distractibility

    Electron Positron Annihilation Radiation from SgrA East at the Galactic Center

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    Maps of the Galactic electron-positron annihilation radiation show evidence for three distinct and significant features: (1) a central bulge source, (2) emission in the Galactic plane, and (3) an enhancement of emission at positive latitudes above the Galactic Center. In this paper, we explore the possibility that Sgr A East, a very prominent radio structure surrounding the Galactic nucleus, may be a significant contributer to the central bulge feature. The motivation for doing so stems from a recently proposed link between this radio object and the EGRET gamma-ray source 2EG J1746-2852. If this association is correct, then Sgr A East is also expected to be a source of copious positron production. The results presented here show that indeed Sgr A East must have produced a numerically significant population of positrons, but also that most of them have not yet had sufficient time to thermalize and annihilate. As such, Sgr A East by itself does not appear to be the dominant current source of annihilation radiation, but it will be when the positrons have cooled sufficiently and they have become thermalized. This raises the interesting possibility that the bulge component may be due to the relics of earlier explosive events like the one that produced Sgr A East.Comment: This manuscript was prepared with the AAS Latex macros v4.0 It is 37 pages long and has 16 figure

    Prosthesis use is associated with reduced physical self-disgust in limb amputees

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    Self-disgust is an emotion schema negatively affecting people’s body image and is triggered by bodily imperfections and deviations from the “normal” body envelope. In this study, we explore the idea that “normalising” the body in those with limb amputations via the prosthesis would be linked to reduced self-directed disgust. An international clinical community sample (N = 83) with mostly lower limb amputations completed measures about their demographics, prosthesis, adjustment, body image disturbance, psychological distress, and self-directed disgust in a survey design. Consistent with the “normalising” hypothesis, correlation and bootstrapped regression models revealed, first, that frequency of prosthesis use was significantly and negatively associated with physical self-disgust. Second, prosthesis use significantly mediated the exogenous effect of time since amputation on physical self-disgust. These results emphasise the psychological value of the prosthesis beyond its functional use, and stress its importance in normalising the body envelope in those with limb amputations, which may in turn promote psychological well-being

    The Impact of Length of Stay on Adjudicated Male Youths;\u27 Language Use: Focusing on Linguistic Analysis of Verbal Samples

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    The primary purpose of the study was to examine the impact of the length of juvenile offenders’ stay in a residential facility on attitudinal changes, measured by language use of 22 participants’ interviews analyzed by using a computerized text tool called Linguistic Inquiry and Word Count (LIWC) to obtain a measure of language use. A series of one-way ANOVA (SPSS 18.0 version) were used to examine the differences between the groups identified by the length of stay and interview interval. The results indicate that the length of stay significantly impacts language use regarding the language categories of affective process words and personal concerns. Participants with shorter residence (less than 1 month) expressed a higher rate of negative and money-related words while the group with longer residence (more than 5 months) tended to yield a higher rate of cognitive process words. Findings demonstrate how language expressions may provide a concrete indicator of adjudicated adolescents’ own cognitive or attitudinal changes over time

    Segregated anatomical input to sub-regions of the rodent superior colliculus associated with approach and defense

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    The superior colliculus (SC) is responsible for sensorimotor transformations required to direct gaze toward or away from unexpected, biologically salient events. Significant changes in the external world are signaled to SC through primary multisensory afferents, spatially organized according to a retinotopic topography. For animals, where an unexpected event could indicate the presence of either predator or prey, early decisions to approach or avoid are particularly important. Rodents’ ecology dictates predators are most often detected initially as movements in upper visual field (mapped in medial SC), while appetitive stimuli are normally found in lower visual field (mapped in lateral SC). Our purpose was to exploit this functional segregation to reveal neural sites that can bias or modulate initial approach or avoidance responses. Small injections of Fluoro-Gold were made into medial or lateral sub-regions of intermediate and deep layers of SC (SCm/SCl). A remarkable segregation of input to these two functionally defined areas was found. (i) There were structures that projected only to SCm (e.g., specific cortical areas, lateral geniculate and suprageniculate thalamic nuclei, ventromedial and premammillary hypothalamic nuclei, and several brainstem areas) or SCl (e.g., primary somatosensory cortex representing upper body parts and vibrissae and parvicellular reticular nucleus in the brainstem). (ii) Other structures projected to both SCm and SCl but from topographically segregated populations of neurons (e.g., zona incerta and substantia nigra pars reticulata). (iii) There were a few brainstem areas in which retrogradely labeled neurons were spatially overlapping (e.g., pedunculopontine nucleus and locus coeruleus). These results indicate significantly more structures across the rat neuraxis are in a position to modulate defense responses evoked from SCm, and that neural mechanisms modulating SC-mediated defense or appetitive behavior are almost entirely segregated
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