Putting memory in context: dissociating memories by distinguishing the nature of context.

In recent years, spontaneous recognition tasks have become commonplace methods of assessing memory in animals. Adaptations of these tasks allow us to look at the role of objects, contexts and spatial locations in memory. Recent findings have highlighted that not all types of contexts in these tasks rely on the same neural systems. Similarly, asking different questions about the same types of context can allow the dissociation of neural systems underlying these memories. Here we review the current position in how context is used in such tasks, and we consider the fundamental importance of clearly defining both the nature of the context being used, and the questions asked of it in order to fully appreciate the neural and cognitive mechanisms being studied in such tasks.

Exotic species of zooplankton in the Upper Paraná River floodplain, Daphnia lumholtzi Sars, 1885 (Crustacea: Branchiopoda).

The integrity of aquatic ecosystems is being challenged worldwide by invading species, which has been one of the frequent causes of biodiversity loss. The invader may cause extinctions of vulnerable native species through predation, grazing, competition and habitat alteration. Daphnia lumholtzi G. O. Sars, 1885, a native cladoceran from Australia, Southwestern Asia and North Africa, has recently been found in the Neotropical region. The D. lumholtzi records from the Upper Paraná River floodplain were restricted to the Pombas floodplain lake (22 degrees 47' 55.92" S and 53 degrees 21' 32.58" W) and Pau Véio Backwater (22 degrees 44' 50.76' S and 53 degrees 15' 11.16' W), in 2003 and 2008, respectively. This species can be distinguished from the other Daphnia species registered in Brazil by the conspicuous pointed fornix, the sizes of the tail spine and helmet, and a carapace ventral margin with strong spines. The high temperatures in the tropical region, as well as the increase in water transparency and the decrease in nutrient concentration observed in the environments of the Upper Paraná River floodplain due to the upstream retention by dams, may favor the development of D. lumholtzi populations. The development of populations of D. lumholtzi in natural environments of the Upper Paraná River floodplain may suggest that this species is establishing in the Neotropical region.

Exotic species of zooplankton in the Upper Paraná River floodplain, Daphnia lumholtzi Sars, 1885 (Crustacea: Branchiopoda) / Espécie exótica de zooplâncton na planície de inundação do Alto Rio Paraná, Daphnia lumholtzi Sars, 1885 (Crustacea: Branchiopoda)

The integrity of aquatic ecosystems is being challenged worldwide by invading species, which has been one of the frequent causes of biodiversity loss. The invader may cause extinctions of vulnerable native species through predation, grazing, competition and habitat alteration. Daphnia lumholtzi G. O. Sars, 1885, a native cladoceran from Australia, Southwestern Asia and North Africa, has recently been found in the Neotropical region. The D. lumholtzi records from the Upper Paraná River floodplain were restricted to the Pombas floodplain lake (22º 47' 55.92" S and 53º 21' 32.58" W) and Pau Véio Backwater (22º 44' 50.76" S and 53º 15' 11.16" W), in 2003 and 2008, respectively. This species can be distinguished from the other Daphnia species registered in Brazil by the conspicuous pointed fornix, the sizes of the tail spine and helmet, and a carapace ventral margin with strong spines. The high temperatures in the tropical region, as well as the increase in water transparency and the decrease in nutrient concentration observed in the environments of the Upper Paraná River floodplain due to the upstream retention by dams, may favor the development of D. lumholtzi populations. The development of populations of D. lumholtzi in natural environments of the Upper Paraná River floodplain may suggest that this species is establishing in the Neotropical region.

A integridade dos ecossistemas aquáticos está sendo desafiada no mundo inteiro por espécies invasoras, as quais tem sido uma das causas freqüentes de perda de biodiversidade. Um invasor pode causar extinções de espécies nativas vulneráveis através de predação, herbivoría, competição e alteração de habitat. Daphnia lumholtzi G. O. Sars, 1885, cladócero nativo da Austrália, sudeste da Ásia e norte da África, recentemente tem sido registrado na região neotropoical. Os registros de D. lumholtzi na planície de inundação do Alto Rio Paraná foram restritos a lagoa das Pombas (22º 47' 55.92" S e 53º 21' 32.58" O) e Ressaco do Pau Véio (22º 44' 50.76" S e 53º 15' 11.16" O), em 2003 e 2008, respectivamente. Esta espécie pode ser diferenciada das demais espécies de Daphnia encontradas no Brasil pelos conspícuos fórnices pontiagudos, tamanho dos espinhos caudal e elmo, e margem ventral com espinhos fortes. As elevadas temperaturas na região tropical, o aumento da transparência da água e a redução das concentrações de nutrientes nos ambientes da planície de inundação do alto rio Paraná, devido aos represamentos a montante, podem estar favorecendo o desenvolvimento de populações de D. lumholtzi. O desenvolvimento de populações de D. lumholtzi em ambientes naturais da planície de inundação do alto rio Paraná pode representar o estabelecimento desta espécie na região neotropical.

The working memory capabilities of the spontaneously hypertensive rat.

This study addresses the working memory capabilities of the male spontaneously hypertensive rat (SHR) strain as compared to the normotensive inbred strain, Wistar Kyoto (WKY), and the out bred Sprague Dawley (SD) rat as a normal control. The objective was to use two working memory tasks in the water maze with different strategic demands: forced alternation (FA) which allows the use of either an allocentric ("place") or egocentric ("response") localisation strategy and delayed matching-to-place (DMP) which requires an allocentric strategy. In the FA task, SHR reached criterion at the same rate as WKY and SD controls and were impaired to the same extent as WKY at the long (1 h) delay. Furthermore, both SHR and WKY were impaired relative to SD when the memory load was increased through the use of massed trials. In the DMP task, the performance of SHR did not differ from that of either of the control strains, either during training or in response to delay. These findings do not provide evidence of short-term memory impairments in the SHR, which is a commonly-used animal model of Attention Deficit Hyperactivity Disorder (ADHD) in humans.

The role of cervical dysfunction in migraine: a systematic review.

This systematic review evaluates the strength of the evidence for the role of cervical musculoskeletal dysfunction in migraine. In this review, cervical musculoskeletal dysfunction will refer to the abnormal sensory afferentation from cervical region structures contained within the receptive field of the trigeminocervical nucleus. Electronic database searches using MEDLINE, PubMed and CINAHL were performed, and 17 studies investigating cervical musculoskeletal dysfunction in people with migraine were selected for review. The methodological quality of the included studies was assessed by two independent reviewers using a customized checklist. The review found that intersubject differences were inadequately reported and controlled, which resulted in grouping of participants with varying pathologies and symptoms. A diverse range of assessment procedures was used by the reviewed studies, which made comparison of their findings difficult. The assessment procedures were mainly used to quantify the degree of cervical musculoskeletal dysfunction, rather than to identify a cause and effect relationship between cervical structure and migrainous pain. Although animal study evidence proposes a role for cervical musculoskeletal dysfunction in migraine, this systematic review of the literature found that there is currently no convincing evidence to confirm this phenomenon in humans.

Spontaneously hypertensive, Wistar Kyoto and Sprague-Dawley rats differ in their use of place and response strategies in the water radial arm maze.

This study further characterises the use of mnemonic systems in the spontaneously hypertensive rat (SHR), which is frequently used as a rodent model of attention deficit hyperactivity disorder. The objective of this study was to assess the preference of male SHR, Wistar-Kyoto (WKY) and Sprague-Dawley (SD) rats for a place or response strategy when trained on an ambiguous T-maze task, and also to examine whether all strains acquired information about both strategies during ambiguous training, regardless of their preferred strategy. In the first experiment, SHR and WKY showed a preference for a response strategy on the ambiguous T-maze task; in contrast, SD displayed a preference for a place strategy. In the second experiment, all strains demonstrated that they learned information about both the response and place strategies during ambiguous training. However, on a conditioned place preference test SHR did not display as strong a preference for the place arm as WKY and SD. This finding supports previous research in a conditioned cue preference test, in which SHR did not display a preference for the cue associated with the platform. These observations that the strains differ with respect to behavioural strategy in a learning task suggest that they differ in the underlying neural circuitry that serves goal-directed behaviour, and are consistent with SHR having deficits associated with the nucleus accumbens.

The phenomenology of personality change due to traumatic brain injury in children and adolescents.

The authors aimed to contribute a clinically rich description of personality change due to traumatic brain injury (PC) in children. The sample consisted of consecutively injured children. Ninety-four subjects ages 5 to 14 years were assessed at the time of hospitalization after a traumatic brain injury (TBI). A standardized psychiatric interview, the Neuropsychiatric Rating Schedule, was used to elicit symptoms of PC. PC occurred in 59% of severe (22/37) and 5% of mild/moderate (3/57) TBI subjects. Among the 37 severe TBI subjects, the labile subtype of PC was the most common (49%), followed by the aggressive and disinhibited subtypes (38% each), apathy (14%), and paranoia (5%). Also frequent in severe TBI was perseveration (35%). A detailed case example, numerous clinical vignettes of PC symptoms, and a tabulation of their frequencies provide clinicians a broader frame of reference for eliciting symptoms of PC.

A model for estimating mental health service needs in South Africa.

OBJECTIVE: To develop a model for estimating the services and human resources needed to care for people with severe psychiatric conditions in a hypothetical population of 100,000 people in South Africa. METHOD: Annual mental health service needs were estimated in terms of numbers of daily patient visits (DPV) in ambulatory care, the number of beds required, and staffing. Developed within a spreadsheet format, the model allows for the adjustment of key service variables according to estimated or existing service data. RESULTS: At 100% coverage, 87 DPV, 28 acute beds, and 10 medium-long stay beds are necessary for a population of 100,000 people. This would require 35.2 full-time equivalent mental health staff: 21.3 for inpatient care, 12.0 for ambulatory care, and 1.9 for management. CONCLUSION: Because the model can produce a range of service recommendations, the assumptions that inform it should be clearly stated and justified. This method makes the assumptions on which services are planned explicit and allows for a rational approach to decision making.

Performance of the Diagnostic Interview Schedule for Children Version 2.3 (DISC-2.3) in an informal settlement area in South Africa.

OBJECTIVE: To investigate the performance of the Xhosa Diagnostic Interview Schedule for Children Version 2.3 (DISC-2.3) in a community study of African children and adolescents in Khayelitsha, a largely informal settlement area in Cape Town, South Africa. METHOD: A cross-sectional community study of 500 youths aged 6 to 16 years was undertaken using a systematic sampling strategy based on random starting points in the community. Three trained Xhosa-speaking lay interviewers administered the DISC-2.3 to youths and their parents in their homes. Additional questions included degree of impairment, selected risk factors, and service use. RESULTS: The administration of the Xhosa DISC-2.3 in an informal settlement area was both feasible and acceptable to respondents. Psychiatric disorder with impairment was recorded for 76 (15.2%) of the children and adolescents. Consultation had been sought in only 20 cases, mostly from medical doctors, except for 3 who had attended indigenous healers. Rates of disorder were significantly higher among respondents who were living in unserviced areas or who came from homes where food was needed. CONCLUSIONS: The DISC is a potentially useful instrument even in the presence of major constraints on conducting epidemiological research.

Expression of schizophrenia in black Xhosa-speaking and white English-speaking South Africans.

OBJECTIVE: To investigate whether schizophrenia manifests itself differently in Xhosa-speaking South Africans, compared with English-speaking white South Africans. DESIGN: A comparative study of the presentation of schizophrenia in two groups of patients. SETTINGS AND SUBJECTS: A sample of 63 patients (43 Xhosa-speaking and 20 English-speaking) admitted to a large psychiatric hospital for the first time with a diagnosis of schizophrenia. OUTCOME MEASURES: The Present State Examination (PSE) was used to confirm the clinical diagnosis of schizophrenia. The Relatives' Rating of Symptoms and Social Behaviour (KAS-R) was used to obtain information on the behavioural and emotional expression of schizophrenia. RESULTS: A significantly higher prevalence of aggressive and disruptive behaviour was reported by relatives of Xhosa-speaking patients with schizophrenia of recent onset compared with English-speaking patients. The PSE elicited significantly more delusions of persecution, sexual and fantastic delusions, self-neglect and irritability in the Xhosa-speaking patients. CONCLUSION: Significant differences in the presentation of schizophrenia, but not its core symptoms, were identified in Xhosa-speaking blacks and English-speaking whites.

A survey of professional activities of psychiatrists in South Africa.

To obtain information about practicing psychiatrists in South Africa, a questionnaire was mailed in 1993 to all 378 registered psychiatrists, of whom 210 (55.6 percent) responded. After selected data for nonrespondents were obtained, information was available for 357, or 94.4 percent of registered psychiatrists. Of the 261 psychiatrists practicing in South Africa, 147 (56.3 percent) were in full-time private practice. There were 6.4 psychiatrists per million population, with large discrepancies between provinces. Only 7 percent of psychiatrists spent any time working in rural areas, and only 10.8 percent could communicate in one or more African languages. These findings emphasize the magnitude of the challenge of developing a primary mental health care system in postapartheid South Africa.

Post-traumatic stress disorder in children exposed to violence.

OBJECTIVES: To investigate to what extent local children exposed to community violence develop post-traumatic stress disorder (PTSD), whether the symptom profile is typical or atypical, and how detection can be improved. DESIGN: A cross-sectional study of two samples of children with a high risk of past exposure to violence. SETTING AND SUBJECTS: Sixty Xhosa-speaking children aged 10-16 years; 30 from the Children's Home which serves Khayelitsha, and 30 from a school in a violent area of Khayelitsha. OUTCOME MEASURES: A shortened version of the Survey of Exposure to Community Violence (SECV) was administered to determine exposure to violence. Structured questionnaires and a clinical assessment were used to elicit symptoms and make psychiatric diagnoses. RESULTS: All 60 children reported exposure to indirect violence, 57 (95%) had witnessed violence, and 34 (56%) had experienced violence themselves. Twenty-four (40%) met the criteria for on or more DSM-III-R diagnoses and 13 (21.7%) met the criteria for PTSD. CONCLUSIONS: Community violence places children at a high risk of developing serious psychiatric disorders and many children develop PTSD. None of the children in the school sample had received intervention prior to the study, pointing towards an urgent need for increased community and professional awareness of children at risk.

Conduct disorder among children in an informal settlement. Evaluation of an intervention programme.

OBJECTIVES: This study aimed to evaluate the effectiveness of a 12-week intervention programme for conduct-disordered boys aged 10-16 years. DESIGN: A descriptive study comparing a group of boys who participated in an intervention programme with a non-participant group. SETTING: All the participants were resident in Khayelitsha and the programme was conducted at Empilweni, a community mental health project in Site C, Khayelitsha. SUBJECTS: Nine of the 15 boys who were referred to Empilweni for serious conduct problems participated in the intervention; the remaining 6 were non-participants. OUTCOME MEASURES: The New York Teacher Rating Scale (NYTRS) and selected modules of the Diagnostic Interview Schedule for Children (DISC) were administered before and immediately after the treatment programme, and again after a 6-month interval. RESULTS: Six months after the intervention, the treatment group showed a significant reduction in defiance, physical and delinquent aggression, as well as additional conduct problems. The non-treatment group only showed a significant reduction in defiance. CONCLUSIONS: The study results suggest that short-term community-based group therapy may be effective in treating delinquent behaviour among boys in an informal settlement. The feasibility of promoting such interventions as part of national violence prevention programmes requires serious consideration.

A qualitative investigation of alcohol drinking among male high school students from three communities in the cape peninsula, South Africa.

This article reports on a qualitative study using focus group discussions about alcohol binge drinking with tenth grade male high-school students. Groups were run separately with binge drinking and non-binge drinking adolescents in three different communities. The Theory of Planned Behaviour with two additional constructs was used to provide a theoretical framework for the semi-structured discussions and for the analysis of the data. Although the findings are complex some clear differences did emerge between binge drinkers and non-binge drinkers and between participants from the three different communities. The binge drinkers perceived positive outcomes from binge drinking, were embedded within a peer group culture of binge drinking, and found few obstacles of obtaining alcohol. The non-binge drinkers were more concerned with longer term life goals and were motivated to comply with family pressures not to drink excessively. The implications of these findings for preventive programs and for future research are discussed.

Alcohol misuse in South african male adolescents: a qualitative investigation.

Previous investigations of risk behaviors among high-school students in the Cape Peninsula, South Africa, revealed a high prevalence of binge drinking among boys. Qualitative methods were used to identify and gain insights into the social context of alcohol misuse in male adolescents. Two focus groups were held with eight adolescent binge drinkers. The content of the discussions were analyzed using the grounded theory method. Three key findings emerged. First, adolescents drink because they derive benefits from the use or misuse of alcohol, such as increased self-confidence and adult status. Factors which facilitate the use of alcohol include the alleviation of boredom, experimentation, peer pressure, and parental influences. Second, participants attributed negative characteristics to teetotallers such as being conservative and immature. Binge drinkers were attributed negative characteristics such as lacking self-control and self-respect. Moderate drinkers were attributed with positive characteristics such as being mature and socially adept. Finally, the influential role of alcohol promoting advertising was highlighted. Although participants minimized the effects of advertising it was clear that it played a role in their perception of themselves and of their peers especially with respect to drinking behaviors. The findings suggest some useful prevention strategies among adolescent males at risk for alcohol misuse.

Risk-taking behaviour of Cape Peninsula high-school students. Part IX. Evidence for a syndrome of adolescent risk behaviour.

OBJECTIVES: To ascertain whether the notion of a syndrome of adolescent risk behaviour (which includes problem drinking, marijuana use, having experienced sexual intercourse, 'general deviance' and cigarette smoking) is valid for this setting; and to investigate whether suicidal behaviour and behaviour that exposes the adolescent to injury should be included in this syndrome. DESIGN: Cross-sectional survey utilising a self-completed questionnaire; for both sexes, relationships between behaviours were documented as odds ratios. SETTING: High schools in the Cape Peninsula, South Africa. SUBJECTS: 7,340 students from 16 schools in the three major education departments. OUTCOME MEASURES: Participation in the following behaviours: alcohol bingeing, cannabis smoking, sexual intercourse, knife-carrying at school, cigarette smoking, attempting suicide, failure to use a seat belt, and walking home at night from beyond the neighbourhood. RESULTS: All the odds ratios were greater than 1. There were statistically significant odds ratios between all the pairs of risk behaviours included in the 'original' syndrome of risk behaviour except for cigarette smoking and having had sexual intercourse in the case of girls. There were statistically significant relationships between all these risk behaviours, suicidal behaviour, and behaviours that exposed the adolescent to risk of physical injury, except for failure to use a seat belt and: (i) suicidal behaviour for both sexes; and (ii) walking home alone at night and having had sexual intercourse in the case of girls. CONCLUSION: The notion of a syndrome of adolescent risk behaviour is valid for this population, and both suicidal behaviour and behaviour that exposes the adolescent to injury should be included in this syndrome.

Risk-taking behaviour of Cape Peninsula high-school students. Part X. Multivariate relationships among behaviours.

OBJECTIVE: To investigate the relationship between adolescent risk behaviours, taking into account their influence upon one another. DESIGN: Cross-sectional survey utilising a self-completed questionnaire; stepwise logistic regression analyses were carried out, stratified for gender. SETTING: High schools in the Cape Peninsula, South Africa SUBJECTS: 7,340 students from 16 schools in the three major education departments. OUTCOME MEASURES: The outcome variables for each regression model were: cigarette smoking, cannabis smoking, alcohol bingeing, sexual intercourse, knife-carrying at school, walking home at night from beyond the neighbourhood, attempting suicide, and failure to use a seat belt. For each model, 26 risk behaviours served as independent variables. RESULTS: For each model, between 3 and 9 variables qualified for inclusion for each gender. There was a substantial association between many forms of substance abuse. In the previous 12 months, suicidal thoughts or statements of suicidal intent were predictors of a suicide attempt. Several variables involving injury were predictors of exposure to danger in getting home at night, and this was a predictor of substance abuse. Cannabis smoking, alcohol bingeing and exposure to danger in getting home at night were predictors of and were predicted by having had sexual intercourse. CONCLUSION: There are significant relationships between many adolescent risk behaviours, even when the influence of other risk behaviours is taken into account. The probability of adverse sequelae of risk behaviours, such as exposure to danger in getting home at night and sexual intercourse, is increased by the presence of selected other risk behaviours.

Informed consent--a survey of doctors' practices in South Africa.

OBJECTIVE: To examine doctors' practices with regard to informed consent. DESIGN: Cross-sectional, descriptive survey. PARTICIPANTS AND SETTING: All full-time consultants and registrars in the Departments of Medicine, Obstetrics and Gynaecology, Paediatrics and Child Health, Paediatric Surgery and Surgery at the University of Cape Town were included. The overall response rate was 63% (160/254). MEASUREMENT: Data were collected by means of self-administered, semi-structured questionnaires. RESULTS: Most doctors (79%) felt it was their responsibility to ensure that patients and parents were fully informed about diagnostic and therapeutic interventions. Many (62%) supported a patient-centred standard for determining the type and amount of information to disclose. Doctors disclose most of the legally required information except for information about alternative forms of treatment and remote serious risks. They almost never provide information on medical costs. The most common reasons for not obtaining informed consent were the doctors' tendency to 'tell' patients/parents what they intend doing and their belief that patients/parents expect doctors to know what is medically best for them. Language, inadequate communication skills and lack of time were, surprisingly, seldom viewed as obstacles to the obtaining of informed consent. Findings were independent of discipline (medical or surgical) and doctors' status (consultant or registrar). Doctors who treat children were significantly less likely to obtain consent for certain interventions. CONCLUSION: Doctors meet many, but not all, of the legal requirements for informed consent. The findings question whether informed consent as envisioned by the law exists in reality. Cross-cultural research is needed to clarify patients' and parents' expectations of informed consent.

Risk-taking behaviour of Cape Peninsula high-school students. Part I. Introduction and methods.

In this study, risk-taking behaviour of Cape Peninsula high-school students was investigated. Suicidal behaviour, cigarette smoking, alcohol consumption, drug use, road-related behaviour, violent behaviour and sexual behaviour were included. This article, the first in a series, describes the rationale and methodology of the project. Sixteen schools were selected so as to yield a representative sample of schools in the three major education departments in the Cape Peninsula (administered by the Department of Education and Training and the Houses of Assembly and Representatives). The final sample size was 7,340 school students. A self-administered questionnaire was completed in a normal school period. Estimates for each education department were weighted to produce an overall estimate. The results are presented by standard and home language(s), and gender. Limitations of the study include its cross-sectional nature; the possibility of under- and over-reporting; the exclusion of important groups of adolescents such as absentees and dropouts, and those attending specialised and private schools; and not being able to present the results separately for each education department.