Everyday and prospective memory deficits in ecstasy/polydrug users

The impact of ecstasy/polydrug use on real-world memory (i.e. everyday memory, cognitive failures and prospective memory [PM]) was investigated in a sample of 42 ecstasy/polydrug users and 31 non-ecstasy users. Laboratory-based PM tasks were administered along with self-reported measures of PM to test whether any ecstasy/polydrug-related impairment on the different aspects of PM was present. Self-reported measures of everyday memory and cognitive failures were also administered. Ecstasy/polydrug associated deficits were observed on both laboratory and self-reported measures of PM and everyday memory. The present study extends previous research by demonstrating that deficits in PM are real and cannot be simply attributed to self-misperceptions. The deficits observed reflect some general capacity underpinning both time- and event-based PM contexts and are not task specific. Among this group of ecstasy/polydrug users recreational use of cocaine was also prominently associated with PM deficits. Further research might explore the differential effects of individual illicit drugs on real-world memory

Prospective memory functioning among ecstasy/polydrug users: evidence from the Cambridge Prospective Memory Test (CAMPROMPT)

Rationale: Prospective memory (PM) deficits in recreational drug users have been documented in recent years. However, the assessment of PM has largely been restricted to self-reported measures that fail to capture the distinction between event-based and time-based PM. The aim of the present study is to address this limitation. Objectives: Extending our previous research, we augmented the range laboratory measures of PM by employing the CAMPROMPT test battery to investigate the impact of illicit drug use on prospective remembering in a sample of cannabis only, ecstasy/polydrug and non-users of illicit drugs, separating event and time-based PM performance. We also administered measures of executive function and retrospective memory in order to establish whether ecstasy/polydrug deficits in PM were mediated by group differences in these processes. Results: Ecstasy/polydrug users performed significantly worse on both event and time-based prospective memory tasks in comparison to both cannabis only and non-user groups. Furthermore, it was found that across the whole sample, better retrospective memory and executive functioning was associated with superior PM performance. Nevertheless, this association did not mediate the drug-related effects that were observed. Consistent with our previous study, recreational use of cocaine was linked to PM deficits. Conclusions: PM deficits have again been found among ecstasy/polydrug users, which appear to be unrelated to group differences in executive function and retrospective memory. However, the possibility that these are attributable to cocaine use cannot be excluded

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Article Prospective memory functioning among ecstasy/polydrug users: evidence from the Cambridge Prospective Memory Test (CAMPROMPT) Prospective Memory Functioning among Ecstasy/Polydrug users: Evidence from the Cambridge Prospective Memory Test (CAMPROMP

Abstract Rationale: Prospective memory (PM) deficits in recreational drug users have been documented in recent years. However the assessment of PM has largely been restricted to self report measures that fail to capture the distinction between event based and time based PM. The aim of the present study is to address this limitation. Objectives: Extending our previous research we augmented the range laboratory measures of PM by employing the CAMPROMPT test battery to investigate the impact of illicit drug use on prospective remembering in a sample of cannabis only, ecstasy/polydrug and non users of illicit drugs, separating event and time based PM performance. We also administered measures of executive function and retrospective memory in order to establish whether ecstasy/polydrug deficits in PM were mediated by group differences in these processes. Results: Ecstasy/polydrug users performed significantly worse on both event and time based prospective memory tasks in comparison to both cannabis only and non user groups. Furthermore, it was found that across the whole sample, better retrospective memory and executive functioning was associated with superior PM performance. Nevertheless, this association did not mediate the drug-related effects that were observed. Consistent with our previous study, recreational use of cocaine was linked to PM deficits. Conclusions: PM deficits have again been found among ecstasy/polydrug users which appear to be unrelated to group differences in executive function and retrospective memory. However, the possibility that these are attributable to cocaine use cannot be excluded. Prospective memory (PM) involves remembering to execute a particular behaviour at some future point in time which may be in the short or long term, for example remembering to turn off the lights when leaving a room or remembering to attend a meeting, meet a friend or pass on a message. Self report measures of this construct have been developed (e.g., Crawford et al., 2005; Unsurprisingly, given their role in supporting memory functions in general, evidence suggests that PM is dependent on medial temporal-hippocampal processes. For example, in a clinical group with medial temporal sclerosis, Aside from its reliance on medial temporal structures, PM is known to utilise prefrontal executive processes including the working memory system. Neuroimaging studies have revealed the involvement of the frontopolar cortex (Brodmann area 10) and neighbouring prefrontal areas during the performance of PM tasks It is worthy of note that prospective memory functions may be defined as either eventbased or time-based. For example, some predefined external event may trigger the retrieval of the intention to act, or alternatively the trigger may be the elapse of a given period of time. There is evidence to suggest that the two classes utilise neural processes that are at least in part separable. For example, Cannabis users were found to be impaired on both of these measures. A popular recent addition to laboratory measures of PM is the 'virtual week' paradigm. This PM test is a board game completed in the laboratory in which the participant is required to execute previously learned tasks at specified points as they progress around the board at specific times or in conjunction with specific events. This measure has featured in a number of studies. For example, deficits were observed on this measure among currently abstinent ecstasy users including those who used infrequently Nonetheless it must be acknowledged that there was no statistically significant interaction between user group and task type with users demonstrating a significant deficit overall. Thus while group differences in learning may partially account for the Thus the role of learning in accounting for the virtual week results remains unclearthe outcomes obtained are nonetheless consistent with an ecstasy-related PM deficit.. In our previous study (Hadjiefthyvoulou et al., in press) in order to minimise the learning requirement we used a small number of more simple PM tasks, for each of which only a single stimulus-response paring needed to be learned. We also used the Rivermead Behavioural Memory Test (RBMT; Method Design and Analytical Strategy A between participants design was employed with drug using group with three levels (ecstasy/polydrug, cannabis-only, and nonusers of illicit drugs) as the independent variable. The dependent variables were the CAMPROMPT time and event based PM scores. Background variables and the executive and recall measures were also assessed for grou

Sex differences in the actions of psychoactive agents and progesterone on anxiety-related behaviour in the Mongolian gerbil (Meriones unguiculatus), and the effects of corticosterone on the hippocampal morphology of Wistar rats (Rattus Norvegicus)

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Sex differences in the actions of psychoactive agents and progesterone on anxiety-related behaviour in the mongolian gerbil (meriones unguiculatus) and the effects of corticosterone on the hippocampal morphology of wistar rats (rattus norvegicus)

Many anxiety and stress-related disorders exhibit definitive sex differences in their prevalence, symptomology, response to treatment and prognosis. Animal studies have increased the understanding of these disorders, but much of the current research in this area has been conducted using only male rats or mice. Thus, the investigation of sex differences, especially within other rodent species is still relatively ignored. There is much evidence to implicate the involvement of steroid hormones in the response to anxiety and stress. The neuroactive steroid progesterone has been associated with the regulation of anxiety behaviour in rodents, whilst the steroid corticosterone has been related to the damaging effects of stress, especially within the hippocampus. However, current investigations have failed to examine the influence of gender on these findings. The initial aim of this thesis was to evaluate the suitability of the elevated plus-maze and black-white box tests of anxiety for male and female Mongolian gerbils. The second part of this thesis then evaluates the behavioural effects of progesterone treatment and withdrawal in this species. Finally, this thesis evaluates the influence of chronic corticosterone treatment on hippocampal volume and astrocyte cell numbers in male and female rats. Pharmacological validation of the elevated plus-maze and blackwhite box revealed that diazepam produced similar anxiolysis in male and female gerbils. Buspirone appeared to modulate motor activity rather that anxiety-specific behaviours in both sexes, but to a greater extent in males. Caffeine administration induced anxiety in both tests, but was more prominent in male gerbils. FG7142 also demonstrated some anxiogenic activity, however, this increase in anxiety was represented by different behavioural alterations in each sex. Investigation of the behavioural effects of progesterone treatment revealed that acute and chronic administration produced only weak effects on anxiety-related behaviour. Even so, acute progesterone appeared to produce greater anxiolysis in females, whereas these sex differences in treatment response were abolished by chronic treatment. Withdrawal of chronic progesterone appeared to increase anxiety in both the elevated plus-maze and black-white box, and was comparable for males and females. Examination of the effects of chronic corticosterone in rats revealed no significant alteration in the volume of the hippocampus in either sex, although male rats had larger hippocampal volume than females. Prolonged corticosterone treatment did produce increases in hippocampal astrocyte numbers in specific hippocampal regions. The findings of these investigations are discussed in relation to the aetiology of anxiety disorders and stress-related hippocampal damage

The effects of chronic corticosterone on hippocampalastrocyte numbers: A comparison of male and female Wistar rats

Chronic stress and/or glucocorticoid administration produces atrophy of hippocampal neurons. However, evidence of the impact of glucocorticoids on glial cells, especially in both males and females, is limited. In the present study, we investigated the total percentage body weight, hippocampal volume and hippocampal astrocyte numbers following chronic corticosterone treatment in male and female Wistar rats. Males had greater left and right hippocampal volumes overall, but no effect on hippocampal volume was seen after corticosterone treatment. Total body weight was dose-dependently lower in both sexes, but the decrease was more prominent in male rats. Corticosterone treatment dose-dependently increased astrocyte numbers in the CA1 region, but not in the lateral and medial CA3 hippocampal regions. This increase was similar in both male and female rats. The astrogliosis observed following chronic corticosterone may have implications for extrasynaptic communication and neuron-glia interactions and is similar to changes in the astrocytic population observed in aged rats

Survival : mind and brain

It is possible that you might face a life-threatening situation today – modern life is full of risks from crossing the road, to being involved in a large-scale terrorist attack. How would you react? Could your reactions influence your chances of survival? Or is survival just down to luck? It is true that some factors affecting your survival, such as blocked fire exits or the lack of working safety equipment are out of your personal control. However, it is also true that individual psychological and physiological responses to threat can greatly influence your survival chances. This article considers what goes on in mind and brain when we strive to survive

The effects of acute, chronic and withdrawn progesterone in male and female Mongolian gerbils (Meriones unguiculatus) in two tests of anxiety

Progesterone generally produces anxiolytic effects in rats and mice. However, sex differences in response to this neuroactive steroid have not been systematically investigated. Thus, this study investigated the anxiety-modulating actions of acute, chronic and withdrawn progesterone treatment in male and female Mongolian gerbils (Meriones unguiculatus) in the elevated plus-maze (EPM) and black–white box (BWB). Gerbils were tested after receiving vehicle, 0.5, 2.5, 7.5 or 15 mg/kg progesterone administered acutely, chronically (14 days) or after a 24-h withdrawal period following chronic treatment. Data analyses showed that overall the effects of progesterone were similar in males and females. Progesterone produced few behavioural alterations in the EPM following any of the treatment regimes. However, acute and chronic progesterone reduced anxiety in the BWB (as shown by increased exploration, locomotion and entries into the white compartment). In contrast, withdrawal of progesterone produced minimal effects in the EPM and BWB. This study suggests that the BWB maybe the most suitable test for detecting the anxiolytic effects of neuroactive steroids in gerbils. However, further research is needed to clarify the behavioural effects of progesterone in this species