Altitudinal variation in behavioural thermoregulation: Local adaptation vs. plasticity in California grasshoppers

We investigated the adaptive significance of behavioural thermoregulation in univoltine populations of the grasshopper Melanoplus sanguinipes along an altitudinal gradient in California using laboratory tests of animals raised under different temperatures. Trials consisted of continuous body temperature measurements with semi-implanted microprobes in a test arena, and observation and simultaneous recording of behavioural responses. These responses included mobility, basking and orientation of the body axes (aspect angle) towards a radiation source. Mobility and basking are determined by the altitudinal origin of the parental generation and not by the temperature treatments. With increasing altitude, individuals tend increasingly to raise body temperatures via mobility and increased basking. In contrast, body orientation towards the radiation source is influenced by the temperature treatments but not by the altitude of origin. Individuals experiencing higher temperatures during rearing show a lower tendency to lateral flanking. We conclude that body orientation responses are not adapted locally. In contrast other components of the behavioural syndrome that increase body temperature, such as mobility and basking, are adaptive in response to local selection pressure. The thermoregulatory syndrome of these grasshoppers is an important contribution to life-history adaptations that appropriately match season lengths.

Freshwater pearl mussels show plasticity of responses to different predation risks but also show consistent individual differences in responsiveness

Animals often show behavioural plasticity with respect to predation risk but also show behavioural syndromes in terms of consistency of responses to different stimuli. We examine these features in the freshwater pearl mussel. These bivalves often aggregate presumably to reduce predation risk to each individual. Predation risk, however, will be higher in the presence of predator cues. Here we use dimming light, vibration and touch as novel stimuli to examine the trade-off between motivation to feed and motivation to avoid predation. We present two experiments that each use three sequential novel stimuli to cause the mussels to close their valves and hence cease feeding. We find that mussels within a group showed shorter closure times than solitary mussels, consistent with decreased vulnerability to predation in group-living individuals. Mussels exposed to the odour of a predatory crayfish showed longer closures than control mussels, highlighting the predator assessment abilities of this species. However, individuals showed significant consistency in their closure responses across the trial series, in line with behavioural syndrome theory. Our results show that bivalves trade-off feeding and predator avoidance according to predation risk but the degree to which this is achieved is constrained by behavioural consistency. © 2011 Elsevier B.V.

Étude du sommeil et de l’immunocompétence suite à un infarctus aigu du myocarde chez le rat

Plusieurs études ont montré que la perturbation des fonctions du système cardiovasculaire constitue un risque majeur de développement du trouble dépressif chez l'homme. De plus, suite à un infarctus du myocarde, 15-30% de la population développe la dépression majeure dans les 6 à 8 mois suivant cet événement suggérant un lien entre les maladies cardiovasculaires et la dépression. Cette dépression est caractérisée par une série de troubles du sommeil. Approximativement 80% des patients hospitalisés et 70% des malades en consultation externe avec une dépression majeure rapportent des difficultés d’initiation et de maintient du sommeil. Les travaux effectués dans les laboratoires de Roger Godbout et Guy Rousseau ont montré que suite à un infarctus aigu du myocarde chez le rat, on observait de l'anhédonie, de la détresse comportementale et de la mort cellulaire par apoptose dans le système limbique. Cette apoptose suivait un décours spatial et temporel et avait été prévenue par l’administration d’antidépresseurs. De plus, le facteur de nécrose tumorale alpha (TNF-α) serait un composant majeur dans l’activation de la voie extrinsèque conduisant à la mort cellulaire observée dans le système limbique. Les résultats de cette thèse montrent que les rats ayant subi un infarctus du myocarde (IM) présentaient à la fois des troubles du sommeil, de l'anhédonie et de la détresse comportementale comparables à ceux des autres modèles animaux de dépression. Les symptômes de dépression ont été prévenus par l'administration à la fois d'un antidépresseur (escitalopram) et d'un inhibiteur de la synthèse des cytokines proinflammatoires (pentoxifylline). Les troubles du sommeil et l'apoptose avaient aussi été prévenus par l'admistration respective de l'escitalopram et de la pentoxifylline. De plus, les animaux ayant subi un IM présentaient une diminution du nombre de cellules cholinergiques dans le générateur du sommeil paradoxal expliquant en partie la réduction de la durée du sommeil paradoxal observée dans cette thèse. Les animaux ayant subi un IM montraient une augmentation systémique du TNF-α, l'interleukine-1 (IL-1β), et la prostaglandine E2 (PGE2). Le traitement par l'escitalopram bloquait l'augmentation des niveaux plasmatiques du TNF-α, de l'IL-1β, et de la PGE2 sans affecter celui de la corticostérone et de l'IL-6. Finalement, pour la première fois, nous avons mis évidence qu'un traitement autre qu'un antidépresseur (pentoxifylline) pouvait réduire le comportement dépressif dans la dépression post-infarctus du myocarde lorsqu'il est administré quelques minutes avant la période ischémique. Il apparait donc important d’intervenir rapidement chez les patients à la suite d'un IM et ce dès les premiers jours et avant même l’apparition des premiers signes d’insomnie et de dépression. Une combinaison de traitements pharmacologique et comportemental serait une voie intéressante à considérer dans la prise en charge de ces patients.

Towards powerful experimental and statistical approaches to study intraindividual variability in labile traits

There is a long-standing interest in behavioural ecology, exploring the causes and correlates of consistent individual differences in mean behavioural traits ('personality') and the response to the environment ('plasticity'). Recently, it has been observed that individuals also consistently differ in their residual intraindividual variability (rIIV). This variation will probably have broad biological and methodological implications to the study of trait variation in labile traits, such as behaviour and physiology, though we currently need studies to quantify variation in rIIV, using more standardized and powerful methodology. Focusing on activity rates in guppies (Poecilia reticulata), we provide a model example, from sampling design to data analysis, in how to quantify rIIV in labile traits. Building on the doubly hierarchical generalized linear model recently used to quantify individual differences in rIIV, we extend the model to evaluate the covariance between individual mean values and their rIIV. After accounting for time-related change in behaviour, our guppies substantially differed in rIIV, and it was the active individuals that tended to be more consistent (lower rIIV). We provide annotated data analysis code to implement these complex models, and discuss how to further generalize the model to evaluate covariances with other aspects of phenotypic variation.

Are motivational deficits part of the behavioural phenotype of Down syndrome?

Motivational deficits are generally accepted to be part of the behavioural phenotype associated with Down syndrome (DS). A motivational profile comprising low or inconsistent levels of task persistence, avoidance of challenging activities and over-dependence on adult direction has been described. However, comparisons are usually made between children with DS and those who are developing typically, without the inclusion of samples with intellectual disability (ID) from aetiologies other than DS. Such comparisons are needed to determine the extent to which motivational deficits are specific to DS, as opposed to being a feature of ID generally. Methods: The current study collected data about the personality-motivation profiles of children in three groups matched for mental age. They consisted of 80 typically developing (TD)3–7 year old children, 62 children with DS aged 7–15 years, and 54 children with moderate ID aged 7–15 years. Parents completed the 37-item EZ-Personality Questionnaire (EZPQ; Zigler et al., 2002), a measure of personality-motivational functioning. Results: There were significant differences between TD children and those with ID on all EZPQ scales. In most respects children with DS did not differ significantly from others with moderate ID, although they were rated as having greater expectancy of success and fewer negative reactions. Conclusion: The finding that children with DS are less motivated than TD children of the same mental age is consistent with previous studies in which parents have rated motivation. It seems, however, that motivation difficulties are associated with ID more generally, rather than being specific to those with DS. The study raises questions about phenotypic versus experiential effects on motivation for children with ID.

Mastery motivation in children with intellectual disability : Is there evidence for a Down syndrome behavioural phenotype?

The main purpose of the current study was to provide empirical evidence to support or refute assumptions of phenotypic deficits in motivation for children with Down syndrome. Children with moderate intellectual disability associated with etiologies other than Down syndrome were recruited in an extension of a previous study that involved children with Down syndrome and typically developing children. The participants were 29 children with moderate intellectual disability and 33 children with Down syndrome who were matched on mental age to 33 typically developing children, aged 3 to 8 years. Mastery motivation was assessed on task measures of curiosity, preference for challenge, and persistence, as well as parental reports. There were no significant group differences on the mastery motivation tasks. Parental ratings of mastery motivation differed, with typically developing children generally being rated more highly than each of the disability groups. The view that motivational deficits are part of the Down syndrome behavioural phenotype was not supported.

A long-term follow-up of cognitive, emotional, and behavioural sequelae to Reye syndrome

Eighteen adolescents who had survived Reye syndrome (RS) in early childhood were assessed on cognitive, emotional, and behavioural variables in a second follow-up study tracking this group. Siblings were used as controls. The entire group with RS had survived with no obvious neurological damage at the first follow-up study. Indeed, current findings suggested that long-term cognitive, emotional, and behavioural functioning was comparable to siblings in approximately half of the group with RS. However, two factors were associated with a less favourable outcome. Cognitive, emotional, and behavioural functioning were significantly poorer in the subgroup of survivors whose illness had occurred in the first year of life. In addition, loss of consciousness, although the association with poor outcome was not as noticeable, was also associated with relative deficits on some scales of cognitive ability. Many of these deficits had not been obvious at the first follow-up and the importance of neurodevelopmental factors are considered. Finally, the implications of these findings for research and interventions in RS and other such encephalopathies are discussed.

Temper outbursts in Prader-Willi syndrome: causes, behavioural and emotional sequence and responses by carers

Background: Temper outbursts are common in Prader-Willi syndrome but rarely described in detail. This study investigated the phenomenology of temper outbursts in terms of antecedents, sequence of behaviours and emotions and intervention strategies used.

Method: A semi-structured interview about temper outbursts was conducted with the main carers of seven children (9.5 to 16.7 years) and seven adults (24.7 to 47.10 years) with Prader-Willi syndrome (10 male, 4 female). Reliability and validity of the interview results was established.

Results: Various setting events increased and reduced the likelihood of temper outbursts. The most common antecedent was a change to routine or expectation. There were marked similarities in the sequence of behaviours and emotions during temper outbursts, with anger rising quickly followed by expressions of remorse and distress at the end of an outburst.

Discussion: The sequence of behaviours and emotions within outbursts was similar to that described in temper tantrums in typical development. Cognitive and emotional processes are likely to be important in the understanding of temper outbursts with implications for early intervention.

The Relationship between Components of the Behavioural Phenotype in Prader-Willi Syndrome

Background

Repetitive questions and temper outbursts form part of the behavioural phenotype of Prader-Willi syndrome (PWS). We investigated the phenomenology of temper outbursts in PWS and their relationship with other PWS behavioural characteristics.

Method

Four individuals with PWS were observed (5-10 h), during a number of experimental and natural environment challenges, some of which were expected to trigger temper outbursts. Individual behaviours including crying, ignoring, arguing, questioning, stereotypy, frowning and posture changes were recorded and subjected to lag sequential analysis.

Results

All participants were significantly more likely to show repetitive questioning before more challenging behaviours such as crying, arguing or ignoring requests. Precursor behaviours such as frowning and stereotypical behaviour were identified in three participants.

Conclusions

Temper outbursts in PWS may be associated with other PWS behavioural phenotypic characteristics such as repetitive questions and 'stubbornness'. A progression of behaviours may lead up to the most challenging temper outburst behaviours. This may have important implications for effective coping strategies.

Cognitive-behavioural phenotype in a group of girls from 1.2 to 12 years old with the Incontinentia Pigmenti syndrome:recommendations for clinical management

Incontinentia Pigmenti (IP, OMIM#308300) is a rare X-linked genomic disorder (about 1,400 cases) that affects the neuroectodermal tissue and Central Nervous System (CNS). The objective of this study was to describe the cognitive-behavioural profile in children in order to plan a clinical intervention to improve their quality of life. A total of 14 girls (age range: from 1 year and 2 months to 12 years and 10 months) with IP and the IKBKG/NEMO gene deletion were submitted to a cognitive assessment including intelligence scales, language and visuo-spatial competence tests, learning ability tests, and a behavioural assessment. Five girls had severe to mild intellectual deficiencies and the remaining nine had a normal neurodevelopment. Four girls were of school age and two of these showed no intellectual disability, but had specific disabilities in calculation and arithmetic reasoning. This is the first description of the cognitive-behavioural profile in relation to developmental age. We stress the importance of an early assessment of learning abilities in individuals with IP without intellectual deficiencies to prevent the onset of any such deficit.

Understanding the literacy difficulties of students with Asperger's syndrome in middle years' classrooms

Among the students in Australian classrooms who are experiencing learning difficulties are increasing numbers of children who have been diagnosed with Asperger's syndrome. Although the general cognitive and language abilities of these students are comparable with most of their peers, they experience significant difficulties with social communication, social interactions and social-emotional/behavioural functioning. Despite indications that there are features inherent in Asperger's syndrome that are likely to have a negative effect on the development of advanced literacy skills, studies to date have primarily focused on social-emotional/behavioural challenges. Without effective literacy skills, however, students' access to educational and career opportunities may be curtailed. This article reviews features of Asperger's syndrome that appear to have a negative impact upon the development of advanced literacy skills and suggests ways in which inclusive classroom teachers could support the development of their learners.

Cortical processing of speech and non-speech sounds in autism and Asperger syndrome

Autism and Asperger syndrome (AS) are neurodevelopmental disorders characterised by deficient social and communication skills, as well as restricted, repetitive patterns of behaviour. The language development in individuals with autism is significantly delayed and deficient, whereas in individuals with AS, the structural aspects of language develop quite normally. Both groups, however, have semantic-pragmatic language deficits. The present thesis investigated auditory processing in individuals with autism and AS. In particular, the discrimination of and orienting to speech and non-speech sounds was studied, as well as the abstraction of invariant sound features from speech-sound input. Altogether five studies were conducted with auditory event-related brain potentials (ERP); two studies also included a behavioural sound-identification task. In three studies, the subjects were children with autism, in one study children with AS, and in one study adults with AS. In children with autism, even the early stages of sound encoding were deficient. In addition, these children had altered sound-discrimination processes characterised by enhanced spectral but deficient temporal discrimination. The enhanced pitch discrimination may partly explain the auditory hypersensitivity common in autism, and it may compromise the filtering of relevant auditory information from irrelevant information. Indeed, it was found that when sound discrimination required abstracting invariant features from varying input, children with autism maintained their superiority in pitch processing, but lost it in vowel processing. Finally, involuntary orienting to sound changes was deficient in children with autism in particular with respect to speech sounds. This finding is in agreement with previous studies on autism suggesting deficits in orienting to socially relevant stimuli. In contrast to children with autism, the early stages of sound encoding were fairly unimpaired in children with AS. However, sound discrimination and orienting were rather similarly altered in these children as in those with autism, suggesting correspondences in the auditory phenotype in these two disorders which belong to the same continuum. Unlike children with AS, adults with AS showed enhanced processing of duration changes, suggesting developmental changes in auditory processing in this disorder.

Linguistic and perceptual processing of communicative cues in Asperger Syndrome

Asperger Syndrome (AS) belongs to autism spectrum disorders where both verbal and non-verbal communication difficulties are at the core of the impairment. Social communication requires a complex use of affective, linguistic-cognitive and perceptual processes. In the four studies included in the current thesis, some of the linguistic and perceptual factors that are important for face-to-face communication were studied using behavioural methods. In all four studies the results obtained from individuals with AS were compared with typically developed age, gender and IQ matched controls. First, the language skills of school-aged children were characterized in detail with standardized tests that measured different aspects of receptive and expressive language (Study I). The children with AS were found to be worse than the controls in following complex verbal instructions. Next, the visual perception of facial expressions of emotion with varying degrees of visual detail was examined (Study II). Adults with AS were found to have impaired recognition of facial expressions on the basis of very low spatial frequencies which are important for processing global information. Following that, multisensory perception was investigated by looking at audiovisual speech perception (Studies III and IV). Adults with AS were found to perceive audiovisual speech qualitatively differently from typically developed adults, although both groups were equally accurate in recognizing auditory and visual speech presented alone. Finally, the effect of attention on audiovisual speech perception was studied by registering eye gaze behaviour (Study III) and by studying the voluntary control of visual attention (Study IV). The groups did not differ in eye gaze behaviour or in the voluntary control of visual attention. The results of the study series demonstrate that many factors underpinning face-to-face social communication are atypical in AS. In contrast with previous assumptions about intact language abilities, the current results show that children with AS have difficulties in understanding complex verbal instructions. Furthermore, the study makes clear that deviations in the perception of global features in faces expressing emotions as well as in the multisensory perception of speech are likely to harm face-to-face social communication.

Behavioural and psychological syndromes in Alzheimer's disease

The origins of behavioural and psychological symptoms of dementia are still poorly understood. By focusing on piecemeal behaviours as opposed to more robust syndrome change valid biological correlates may be overlooked. Our understanding of BPSD via the identification of neuropsychiatric syndromes.