Ethological validation and the assessment of anxiety-like behaviours: methodological comparison of classical analyses and structural approaches

The research on emotional reactivity usually implies the use of standardised behavioural tests that provide a quick idea of the effect of a treatment on the reactivity of subjects to potentially dangerous situations. Many validity criteria have been considered to evaluate these tests. This validity concept supports the idea that animals' behaviour in these tests model human anxiety. Generally, those criteria repeatedly labelled as "ethological validation" refer to the analogy between animals and human in the meaning of the test situation. Although the content of the ethological validation concept is heterogeneous, it is steadily related to a fixed interpretation of the behavioural items produced in a given experimental setting. The basic assumption of such reasoning is that the behavioural items would always be expressed in the same behavioural context whatever the subject, its gender, strain or species, thoroughly asserting a predefined subjective state. Using multivariate and textual analysis, we found evidence that the "ethological validation" recourse to an a priori interpretation for a given behavioural variable may be deceptive. We defend the idea that the meaning of a behavioural variable should be restricted to the general context where it arose. Theoretical propositions and methodological options are discussed.     

Patterns of emotional and motivational interrelationships of irradiated male cats

After gamma irradiation within a wide range of doses (from 5 to 100 Gy) it was found that behavioural response of an emotional type (an evoked "pleasure" test) was more labile than the reaction based on a pronounced congenital hunter motivation (a "predator-victim" test). Exposure (50 Gy) of abdomen, when CNS was unaffected while a pronounced vegetative syndrome of the primary reaction developed within the first two hours, resulted in a more significant decrease in either behavioural pattern than it was observed after irradiation of the head.     

Behavioral specialization of cortical and hypothalamic neurons in the rabbit

Behavioural specialization was analyzed of hypothalamic and limbic neurones, with their activity recorded in rabbits during food-acquisition behaviour. The neurones with activity changed during staying of the animal in a definite place of the cage or during behavioural acts, characteristic of a specific behaviour in the cage, are considered as specialized in relation to the most "new" systems, acquired by the rabbit directly during learning of the given behaviour. Neurones with the activity changed with rabbit's turns, i.e. connected with behavioural acts, which the rabbit has not specially learnt, are considered specialized in relation to more "old" inborn systems. Neurones, in which no constant connection with any part of the studied behaviour was observed, are related to the most "ancient" systems. Comparison of the number of hypothalamic and limbic neurones of different groups showed that in the cortex there were some more neurones specialized in relation to behavioural acts, which were formed directly during learning of the rabbit in the experimental cage.     

Evolutionary dynamics of habitat use

I examine the evolution of alternate genotypes that use two habitats that differ in vegetative cover, focusing on the interplay between ecological dynamics of the community and changes in selective advantage. Facultative habitat choice can stabilize a predator population that would cycle if isolated in the more open habitat. This has important implications for the evolution of habitat use strategies. Local stability arising from facultative habitat use allows any number of behavioural genotypes to co-exist: selective use of the open habitat, selective use of the dense habitat, opportunistic use of both habitats in proportion to availability, and facultative switching between habitats to maximize energy gain. Co-existence occurs because the fitness landscape is flat at the ecological equilibrium imposed by the facultative genotype. In contrast, ecological instability favours the evolution of genotypes with behavioural flexibility to avoid being in the wrong place at the wrong time or selective exploitation of one of the habitats. Uncertain information about habitat quality erodes the adaptive advantage of otherwise optimal behaviours, favouring a bet-hedging behavioural strategy synonymous with partial habitat preferences. These results suggest that ecological dynamics could have a strong influence on behavioural heterogeneity within forager populations and that a mixed ESS for habitat use should predominate.     

PRegnancy Outcomes after a Maternity Intervention for Stressful EmotionS (PROMISES): study protocol for a randomised controlled trial

Background

There is ample evidence from observational prospective studies that maternal depression or anxiety during pregnancy is a risk factor for adverse psychosocial outcomes in the offspring. However, to date no previous study has demonstrated that treatment of depressive or anxious symptoms in pregnancy actually could prevent psychosocial problems in children. Preventing psychosocial problems in children will eventually bring down the huge public health burden of mental disease. The main objective of this study is to assess the effects of cognitive behavioural therapy in pregnant women with symptoms of anxiety or depression on the child's development as well as behavioural and emotional problems. In addition, we aim to study its effects on the child's development, maternal mental health, and neonatal outcomes, as well as the cost-effectiveness of cognitive behavioural therapy relative to usual care.

Methods/design

We will include 300 women with at least moderate levels of anxiety or depression at the end of the first trimester of pregnancy. By including 300 women we will be able to demonstrate effect sizes of 0.35 or over on the total problems scale of the child behavioural checklist 1.5-5 with alpha 5% and power (1-beta) 80%.Women in the intervention arm are offered 10-14 individual cognitive behavioural therapy sessions, 6-10 sessions during pregnancy and 4-8 sessions after delivery (once a week). Women in the control group receive care as usual.Primary outcome is behavioural/emotional problems at 1.5 years of age as assessed by the total problems scale of the child behaviour checklist 1.5 - 5 years.Secondary outcomes will be mental, psychomotor and behavioural development of the child at age 18 months according to the Bayley scales, maternal anxiety and depression during pregnancy and postpartum, and neonatal outcomes such as birth weight, gestational age and Apgar score, health care consumption and general health status (economic evaluation).

Trial Registration

Netherlands Trial Register (NTR): NTR2242

     

On the neuronal basis of figure-ground discrimination by relative motion in the visual system of the fly

A fly can discriminate an object (figure) from its background on the basis of motion information alone. This information processing task has been analysed, so far, mainly in behavioural studies but also in electrophysiological experiments (Reichardt et al., 1983). The present study represents a further attempt to bridge the gap between the behavioural and the neuronal level. It is based on behavioural and electrophysiological experiments as well as on computer simulations. The characteristic properties of figureground discrimination behaviour impose specific constraints on the spatial integration properties of the output cells of the underlying neuronal network, the heterolateral interactions in their input circuitry, as well as on the range of variability of their response. These constraints are derived partly from previous behavioural studies (Reichardt et al., 1983), partly, however, from behavioural response characteristics which have not been addressed explicitly so far. They are interpreted in terms of one of the alternative model circuits shown by Reichardt et al. (1983) to be sufficient to account for figure-ground discrimination. It will be demonstrated, however, that this can be done equally well by means of a further alternative model circuit. These constraints are used in the electrophysiological analysis for establishing visual interneurones as output elements of the neuronal network underlying figure-ground discrimination.In the behavioural experiments on figure-ground discrimination as well as on the optomotor course control the yaw torque generated by the tethered flying fly under visual stimulation was used as a measure for the strength and time course of the reaction. Therefore, it has initially been proposed that the three Horizontal Cells, which are regarded as the output elements of the neuronal network underlying the optomotor reaction (e.g. Hausen, 1981), might also control yaw torque generation in figure-ground discrimination (Reichardt et al., 1983). New behavioural data show, however, that the Horizontal Cells do not meet all the constraints imposed on the presumed output cells of the figure-ground discrimination network: (1) The Horizontal Cells are not sensitive enough to motion of small objects. (2) The heterolateral interactions within their input circuitry are not in accordance with the behavioural data (see also Reichardt et al., 1983). (3) The variability found in the time course of certain components of the yaw torque response to relative motion of figure and ground cannot be explained by their response characteristics. Hence, the Horizontal Cells cannot account for figure-ground discrimination on their own and additional output cells of the optic lobes with different functional properties are required to accomplish this task.     

Changes in the level of oxygen tension in different brain structures of rats in positive and negative emotional states

Changes of oxygen tension (pO2) level in various brain structures were studied in rats in positive and negative emotional states. It is established that pO2 level changes depend on the character of behavioural reactions: "active" type of behaviour (emotionally positive orienting-investigatory, actively defensive) is accompanied by pO2 level increase, and "passive" type of behaviour ("freezing" reaction)--by a decrease of pO2 level. Changes of oxidative brain metabolism observed at "active" and "passive" types of behaviour indicate, respectively, adaptive and nonadaptive character of these behavioural reactions.     

Energy metabolism and animal personality

In this paper we show how animal personality could explain some of the large inter-individual variation in resting metabolic rate (MR) and explore methodological and functional linkages between personality and energetics. Personality will introduce variability in resting MR measures because individuals consistently differ in their stress response, exploration or activity levels, all of which influence MR measurements made with respirometry and the doubly-labelled water technique. Physiologists try to exclude these behavioural influences from resting MR measurements, but animal personality research indicates that these attempts are unlikely to be successful. For example, because reactive animals "freeze" when submitted to a stress, their MR could be classified as "resting" because of immobility when in fact they are highly stressed with an elevated MR. More importantly, recent research demonstrating that behavioural responses to novel and highly artificial stimuli are correlated with both behaviour and fitness under more natural circumstances calls into question the wisdom of excluding these behavioural influences on MR measurements. The reason that intra-specific variation in resting MR are so weakly correlated with daily energy expenditure (DEE) and fitness, may be that the latter two measures fully incorporate personality while the former partially excludes its influence. Because activity, exploration, boldness and aggressiveness are energetically costly, personality and metabolism should be correlated and physiological constraints may underlie behavioural syndromes. We show how physiological ecologists can better examine behavioural linkages between personality and metabolism, as required to better understand the physiological correlates of personality and the evolutionary consequences of metabolic variability.     

Appetitive conditioning technique reveals behavioural limits to passage performance in fishes

Numerous environmental features have the potential to act as barriers to fishes in the field. Passage of these barriers depends on two main properties: willingness (behavioural) and physiological capacity. The physiological swimming capacity of fishes has been well studied. However, because most barrier research has focused on the population level effects of man – made barriers, little attention has been given to the behavioural aspects of fish passage. We used appetitive conditioning to create a simple laboratory based protocol to estimate behavioural limits to fish passage. We tested our protocol using barrier height (or passage space) as a model. Our protocol successfully identified behavioural limits in two species, juvenile rainbow trout, Oncorhynchus mykiss, and fathead minnows, Pimephales promelas. Our most interesting observation was that even a partial, submerged barrier had the potential to block fish movements. Our results suggest a potential use for conditioning techniques in assessing factors that constitute behaviour barriers to fishes. This information may help us to better predict fish movements in the field and may help us to design barriers that are more efficient at passing fishes.     

Bearbeitergesteuerte Analyse von Verhaltenszeitreihen am Digitalrechner

1. Both the organization of behaviour and communicative interactions can be established by analyzing behavioural time series. By means of an analysis of this kind, conclusions about the control of behaviour and the principles of interindividual communication can be reached. An analysis may be based on simultaneous and successive behavioural events. In these multi-channel time series the temporal arrangement of patterns (“Strukturierung”), the organization and the conditions determining the occurrence of behavioural events can be specified.
2. Data-analysis by digital computer permits rapid processing of a large quantity of material in regard to several respects. “Sets of data” can be stored, thus enabling the user to correct, alter, combine and finally analyze them with respect to various questions. For this purpose, a program system for the digital processing of behavioural time series (title “PROVED”) was developed.
3. The course of behavioural events is composed of temporal patterns which are ordered in a definite hierarchy (Fig. 1). Several quantitative and qualitative characteristics (“Muster-Merkmale”) can be attributed to each pattern (Figs. 2,4). With the PROVED-System, the temporal arrangement of behavioural patterns is reestablished by the computer according to the control orders of the user. These orders must take into consideration the physiological relevance that is to be confirmed by an analysis of time serics (Fig. 3). The orders controlling the temporal arragement as well as the asignment of pattern characteristics to sets of data are available for further evaluation.
4. The PROVED-System includes several procedures involving input, output, storage, administration, correction, assignment of characteristics, temporal arrangement and analysis of data. The examiner can select and combine these procedures at will using statements of a particular control language.
5. During the first step of data analysis, a fixed number of parameters for each pattern is determined, the number of parameters varying with the complexity of the problem. Any measured value which is related to the pattern under investigation can be regarded as a parameter. During the second step, multidimensional frequency distributions of crossclassified parameters are established which can be examined by means of statistical tests (third step) (Figs. 5,6).
6. Determination of the parameters by the examiner decisively influences the further course of the analysis. The control statements for one parameter consist of two parts: 1. quality of the parameter (type of pattern, temporal distance, etc.), 2. position of the parameter in the behavioural time series (pattern under investigation, immediately subsequent pattern, next pattern with the same characteristics, etc.). The latter is determined by a series of shifts of indices controlled by the user (Fig. 7,8).
7. The PROVED-System can be applied to the analysis of various behavioural time series (succession of sounds, recordings of movements, observations of behavioural acts, etc.). Depending upon the aim of the analysis (temporal arrangement, organization, control of behaviour or communication), spontaneous behavioural events, input-output experiments (stimulus-reaction) and social interaction can be evaluated.

     

Chance and adaptation in the evolution of island bumblebee behaviour

We used a population biological approach to assist our understanding of the evolution of behaviour, with island bumblebees as our model system. The widespread European species Bombus terrestris occurs on all major Mediterranean, and some Atlantic islands. Bees from different populations differ in a variety of behavioural traits, including floral colour preferences, flower detection, and learning behaviour. We attempted to correlate these behavioural differences with each populations environment, but could not find straightforward adaptive explanations. We also performed reciprocal transplant studies to compare nectar foraging performance of bees from three different populations, but found that non-native bees consistently outcompeted native bees. Thus, we consider genetic drift, exaptation, and pleiotropy as possible alternative explanations to a strictly adaptive explanation for between population behavioural differences in bumblebees.     

Behavioural thermoregulatory tactics in lacustrine brook charr, Salvelinus fontinalis

The need to vary body temperature to optimize physiological processes can lead to thermoregulatory behaviours, particularly in ectotherms. Despite some evidence of within-population phenotypic variation in thermal behaviour, the occurrence of alternative tactics of this behaviour is rarely explicitly considered when studying natural populations. The main objective of this study was to determine whether different thermal tactics exist among individuals of the same population. We studied the behavioural thermoregulation of 33 adult brook charr in a stratified lake using thermo-sensitive radio transmitters that measured hourly individual temperature over one month. The observed behavioural thermoregulatory patterns were consistent between years and suggest the existence of four tactics: two "warm" tactics with both crepuscular and finer periodicities, with or without a diel periodicity, and two "cool" tactics, with or without a diel periodicity. Telemetry data support the above findings by showing that the different tactics are associated with different patterns of diel horizontal movements. Taken together, our results show a clear spatio-temporal segregation of individuals displaying different tactics, suggesting a reduction of niche overlap. To our knowledge, this is the first study showing the presence of behavioural thermoregulatory tactics in a vertebrate.     

Reducing ambiguity in describing plant–insect interactions: "preference", "acceptability" and "electivity"

Ecologists and evolutionary biologists have a common interest in plant–insect interactions. Ecologists develop terminology describing patterns of association between plants and insects, while evolutionary biologists use the same words to denote potentially heritable traits of individuals. Use of the same terms to describe both traits of the interaction and traits of the organisms hinders communication. An example is "preference", often used by ecologists to denote properties of the plant–insect interaction and by behavioural or evolutionary biologists to denote insect traits. The existing term "electivity" could be incorporated into the lexicon of plant–insect interactions to supplant the ecological use of "preference". The term "preference" would then denote a behavioural trait of the insect. The mirror-image trait of the plant would be "acceptability". This could be a step towards a common terminology that would be usable by both ecologists and evolutionists.     

Chronic Mild Stress (CMS) in Mice: Of Anhedonia, ‘Anomalous Anxiolysis’ and Activity

Background

In a substantial proportion of depressed patients, stressful life events play a role in triggering the evolution of the illness. Exposure to stress has effects on different levels in laboratory animals as well and for the rat it has been shown that chronic mild stress (CMS) can cause antidepressant-reversible depressive-like effects. The adoption of the model to the mouse seems to be problematic, depending on the strain used and behavioural endpoint defined. Our aim was to evaluate the applicability of CMS to mice in order to induce behavioural alterations suggested to reflect depression-like symptoms.

Methodology/Principal Findings

A weekly CMS protocol was applied to male mice of different mouse strains (D2Ola, BL/6J and BL/6N) and its impact on stress-sensitive behavioural measures (anhedonia-, anxiety- and depression-related parameters) and body weight was assessed. Overnight illumination as commonly used stressor in CMS protocols was particularly investigated in terms of its effect on general activity and subsequently derived saccharin intake. CMS application yielded strain-dependent behavioural and physiological responses including ‘paradox’ anxiolytic-like effects. Overnight illumination was found to be sufficient to mimic anhedonic-like behaviour in BL/6J mice when being applied as sole stressor.

Conclusions/Significance

The CMS procedure induced some behavioural changes that are compatible with the common expectations, i.e. ‘anhedonic’ behaviour, but in parallel behavioural alterations were observed which would be described as ‘anomalous’ (e.g. decreased anxiety). The results suggest that a shift in the pattern of circadian activity has a particular high impact on the anhedonic profile. Changes in activity in response to novelty seem to drive the ‘anomalous’ behavioural alterations as well.     

Personality and behavioural syndrome in <Emphasis Type="Italic">Necromys lasiurus</Emphasis> (Rodentia: Cricetidae): notes on dispersal and invasion processes

Recent studies showed that behavioural individual features are related to species invasion and occupation abilities. In particular, the recent literature on animal personality has pointed to a correlation between behavioural profiles and the success in different phases of the invasion. In the present study, we investigated personality traits in the Neotropical species Necromys lasiurus. This wild rodent is expanding its original distribution to disturbed areas in the Atlantic Forest biome in response to anthropogenic impacts, acting as an invasive species (broad sense). In order to evaluate personality, we performed three behavioural assays as follows: open field, aversive open field and holeboard field. We extracted three personality domains—activity, exploration, and neophilia—using principal component analysis. There was significant positive correlation between these personality domains characterising a behavioural syndrome. We discussed the implications of this behavioural profile to dispersal and potential invasion abilities in this species.     

Latent foci of excitation and the unpredictability of behavioral reactions

As a model for studying of "subconsciousness" mechanisms, latent foci of excitation may serve formed in animals under different influences on the brain: direct current, endogenous shifts and also under trace excitation after suprathreshold activity. It is experimentally shown that latent foci of excitation can intensify at activation of other CNS areas; as a result externally unmotivated "unpredictable" behavioural reaction arises. Between two latent foci of excitation associative connection can be established. The latent foci of excitation in the human CNS are also able to be activated under the influence of sensory stimuli, and behavioural reaction arising as a result of summation has no reflection in consciousness. Conclusion is made: it is rightful to consider the dominant foci of excitation formed at the level of subconsciousness as one of possible mechanisms of "unpredictability" of behaviour.     

Behavioural phenotypes over the lifetime of a holometabolous insect

Introduction: Behavioural traits can differ considerably between individuals, and such differences were found to be consistent over the lifetime of an organism in several species. Whether behavioural traits of holometabolous insects, which undergo a metamorphosis, are consistent across ontogeny is virtually unexplored. We investigated several behavioural parameters at five different time points in the lifetime of the holometabolous mustard leaf beetle Phaedon cochleariae (Coleoptera: Chrysomelidae), two times in the larval (second and third larval stage) and three times in the adult stage. We investigated 1) the stability of the behavioural phenotype (population level), 2) whether individuals rank consistently across behavioural traits and over their lifetime (individual level), and 3) in how far behavioural traits are correlated with the developmental time of the individuals.Results: We identified two behavioural dimensions in every life stage of P. cochleariae, activity and boldness (population level). Larvae and young adults ranked consistently across the investigated behavioural traits, whereas consistency over time was only found in adults but not between larvae and adults (individual level). Compared to adult beetles, larvae were less active. Moreover, younger larvae were bolder than all subsequent life stages. Over the adult lifetime of the beetles, males were less active than females. Furthermore, the activity of second instar larvae was significantly negatively correlated with the development time.Conclusions: Our study highlights that, although there is no individual consistency over the larval and the adult life stage, the behavioural clustering shows similar patterns at all tested life stages of a holometabolous insect. Nevertheless, age- and sex-specific differences in behavioural traits occur which may be explained by different challenges an individual faces at each life stage. These differences are presumably related to the tremendous changes in life-history traits from larvae to adults and/or to a niche shift after metamorphosis as well as to different needs of both sexes, respectively. A faster development of more active compared to less active second instar larvae is in line with the pace-of-life syndrome. Overall, this study demonstrates a pronounced individuality in behavioural phenotypes and presumably adaptive changes related to life stage and sex.     

Effect of etimizol on behavioral responses, brain serotonin concentration and plasma corticosteroid levels

The influence of ethymisol on behavioural reactions was studied on 100 albino rats in the "open field" and "passive avoidance" tests. It was shown that a 5 mg/kg dose of this neurotropic drug with synaptic effect, changes behavioural reactions, lowers the general emotional stress and emotional memory of the electro-cutaneous stimulation. Simultaneously the level of corticosteroids in the blood plasma significantly rises, while the serotonin content in the hypothalamus decreases. A direct correlation between the changes in the emotional stress and the content of corticosteroids in blood plasma is noted. The effects of ethymisol partially persists after adrenalectomy. Ethymisol in optimal doses may be used for regulation and lowering of emotional stress.