Differences In General Activity Research Articles

Soluble amyloid-β dimers are resistant to amyloid-β prion conversion in vivo suggesting antiprion properties.

According to the instructions for authors, short communications should be published without abstract.

Weak evidence for personality and behavioural syndrome in Teleogryllus commodus crickets

ABSTRACT Individuals of the same species and even within the same populations often vary in their behavioural responses to environmental cues. Individual variation in behaviour can be consistent across time (personality) and may also be correlated across contexts (behavioural syndromes). Here, we assessed whether Australian black field crickets (Teleogryllus commodus) display consistent inter-individual variation in four different contexts: general activity, exploration in a novel environment, boldness after a predation-risk event, and aggression towards a conspecific (fighting). We then assessed whether these four behaviours are linked, forming a behavioural syndrome. We found weak evidence for consistent individual differences in general activity, latency to touch novel objects (i.e. proxy of boldness), and the outcome of a fight. However, none of the repeatable behaviours were correlated across contexts, indicating that there is no behavioural syndrome linking these three particular behaviours. These results suggest that these behavioural traits might be regulated by different biological processes.

Cognitive, emotional and social phenotyping of mice in an observer-independent setting.

Based on the intellicage paradigm, we have developed a novel cognitive, emotional and social phenotyping battery that permits comprehensive standardized behavioral characterization of mice in an experimenter-independent social setting. Evaluation of this battery in a large number of male and female C57BL/6 wildtype mice, tested in >20 independent cohorts, revealed high reproducibility of the behavioral readouts and may serve as future reference tool. We noticed robust sex-specific differences in general activity, cognitive and emotional behavior, but not regarding preference for social pheromones. Specifically, female mice revealed higher activity, decreased sucrose preference, impaired reversal and place-time-reward learning. Furthermore, female mice reacted more sensitively than males to reward-withdrawal showing a negative emotional contrast/Crespi-effect. In a series of validation experiments, we tested mice with different pathologies, including neuroligin-3 deficient mice (male Nlgn3y/- and female Nlgn3+/-) for autistic behavior, oligodendrocyte-specific erythropoietin receptor knockout (oEpoR-/-) mice for cognitive impairment, as well as mouse models of renal failure (unilateral ureteral obstruction and 5/6 nephrectomy) and of type 2 diabetes (ApoE-/-) - for delineating potentially confounding effects of motivational factors (thirst, glucose-craving) on learning and memory assessments. As prominent features, we saw in Nlgn3 mutants reduced preference for social pheromones, whereas oEpoR-/- mice showed learning deficits in place or reversal learning tasks. Renal failure led to increased water intake, and diabetic metabolism to enhanced glucose preference, limiting interpretation of hereon based learning and memory performance in these mice. The phenotyping battery presented here may be well-suited as high-throughput multifaceted diagnostic instrument for translational neuropsychiatry and behavioral genetics.

Evidence for litter differences in play behaviour in pre-weaned pigs

The aim of this study was to analyse spontaneous play behaviour in litters of domestic pigs (Sus scrofa) for sources of variation at individual and litter levels and to relate variation in play to measures of pre and postnatal development. Seven litters of commercially bred piglets (n=70) were born (farrowed) within a penning system (PigSAFE) that provided opportunities for the performance of spontaneous play behaviours. Individual behaviour was scored based on an established play ethogram for 2 days per week over the 3 week study period. We found strong evidence of litter differences in play behaviour (F(6,63)=27.30, p<0.001). Of the variance in total play, 50% was attributable to differences between litters with a lesser proportion (11%) to between piglets within litters. We found similar evidence of litter differences when we analysed the separate play categories (e.g. for locomotor play: F(6,63)=27.50, p<0.001). For social and locomotor play the variance was partitioned in a broadly similar way to total play; however for object play the variance was distributed with a more even balance across and within litters. In terms of explanatory factors we found little evidence that at the litter level differences in play were associated with differences in general activity. Of the prenatal factors measured, we found that birth weight was positively associated with total play and the play categories (e.g. with total play: F(1,64)=12.8, p<0.001). We also found that postnatal piglet growth up to weaning (as a percentage of birth weight) had a significant positive association with total play and the play categories (e.g. with object play: F(1,66)=20.55, p<0.001). As found in other studies, on average males engaged in more social play (e.g. non-injurious play fighting: F(1,63)=39.8, p<0.001). Males also initiated more play bouts on average than females (F(1,62)=4.41, p=0.040). We conclude that the study of differences between litters and individuals provides a robust approach to understanding factors potentially influencing play behaviour in the pig. This work also provides support for the use of play as a welfare indicator in pre-weaned piglets as the litter differences in play we observed were associated positively with physical development.

Sevoflurane exposure during the neonatal period induces long-term memory impairment but not autism-like behaviors.

To examine whether neonatal exposure to sevoflurane induces autism-like behaviors in mice. There are continuing reports regarding the potential negative effects of anesthesia on the developing brain. Recently, several studies suggest that neurotoxicity caused by anesthesia may lead to neurodevelopmental impairments. However, unlike reports focusing on learning and memory, there are only a few animal studies focusing on neurodevelopmental disorders after general anesthesia. Therefore, we have focused on autism, a representative neurodevelopmental disorder. Neonatal mice (P6-7) were exposed to a titrated dose of sevoflurane for 6 h. Apoptosis was evaluated by assessing the expression level of cleaved (activated) caspase-3. Autism-like behaviors, general activity, anxiety level, and long-term memory were evaluated with multiple behavioral assays. Western blotting confirmed that neonatal exposure to sevoflurane increased the expression level of activated caspase-3, indicative of apoptosis. Mice exposed to sevoflurane also showed impaired long-term memory in fear tests. However, sevoflurane-exposed mice did not exhibit autism-like features in all of the following assays: social interaction (three-chamber test, caged social interaction), social communication (ultrasonic vocalization test), or repetitive behavior (self-grooming test, digging). There were also no differences in general activity (open field test, home cage activity) and anxiety (open field test, light-dark box) after sevoflurane exposure. Our results confirm previous studies that neonatal sevoflurane exposure causes neurodegeneration and long-term memory impairment in mice. However, sevoflurane did not induce autism-like features. Our study suggests that mice are more vulnerable to long-term memory deficits than autism-like behaviors after exposure to sevoflurane.

Boldness and Reproductive Fitness Correlates in the Eastern Mosquitofish,Gambusia holbrooki

AbstractAnimals are known to exhibit ‘personality’; that is, individual differences in behaviour that are consistent across time and/or situations. One axis of personality of particular importance for behavioural ecology is boldness, which can be defined as the tendency of an individual to take risks. The relationship between individual personality and fitness correlates, particularly those involved in reproduction, remains largely unexplored. In the current study, we used female Eastern mosquitofish (Gambusia holbrooki) to ascertain whether certain reproductive traits (e.g. stage of pregnancy, fecundity) are correlated with individual personality in two wild populations in New South Wales, Australia. To quantitatively assess this relationship, we tested individual fish for their level of boldness, as measured by their latency to exit a refuge and tendency to shoal in a novel environment. We also quantified individual differences in general activity and tendency to swim near the water surface and substratum. For both populations taken together, bolder individuals tended to be smaller, relatively less fecund (when taking body size into account), and spent more time near the water surface than near the substratum compared with timid individuals. Individual boldness was not correlated with either general activity or stage of pregnancy. To our knowledge, our study characterizes for the first time a relationship between an individual personality trait (boldness) and a reproductive fitness correlate (fecundity) in fishes.

Evaluation of two genetic animal models in behavioral tests of anxiety and depression

Anxiety- and depression-related disorders often appear associated and may be affected by common genetic factors. The inbred rat strains Lewis (LEW) and spontaneously hypertensive rats (SHR) and the outbred rat lines Floripa H and L, which were selectively bred for high and low locomotion in the central area of the open field (OF) test, respectively, have been proposed as experimental tools to study anxiety. The main goal of the present study was to characterize the behavior of these animals in two models of anxiety, elevated plus-maze (EPM) and OF, in two models of depression, forced swim test (FST) and tail suspension test (TST) and in their home-cages. Emotionality-related differences between LEW and SHR rats and between Floripa H and L rats were found in the EPM, OF and FST. Those lines showing low anxiety-like profiles in the EPM and OF (SHR and Floripa H) also showed low immobility in the FST. The TST failed to unveil any line differences. Factor analysis involving all tests revealed three independent factors with one of them associating anxiety-related measures from the OF and EPM to immobility in the FST. When observed in their home-cages, LEW and SHR rats showed no differences in general activity, but when acutely treated with imipramine (15 mg/kg), only LEW rats were sensitive to its antidepressant effects. These results suggest the existence of a genetic link between two tests used in the screening of anxiolytic drugs and one test of antidepressant activity. Moreover, the LEW and SHR rat strains were shown to be an interesting model to study the comorbidity between anxiety- and depression-related disorders.

Consistent individual differences in early exploratory behaviour of male great tits

Abstract. Individual differences in early exploratory behaviour were investigated in hand-reared juvenile male great tits, Parus major, during the first 18 weeks of their life. The juveniles differed consistently in their reaction to a novel object in a familiar environment, either when tested with different objects or when tested again after 9 weeks. Birds that approached a novel object more quickly were also quicker to visit all artificial trees present in a novel environment than birds that approached a novel object more slowly. These behavioural differences extended to the strength of foraging habits, built up during a training period in which food was always offered at the same place. After a change in the location of food, the quicker birds would keep going to the place where the food used to be. The slower birds tended to change their behaviour and stop going to the former place. The results show that juvenile male great tits differ consistently in various aspects of their exploratory behaviour at least during the first 18 weeks of life. The variation in behaviour was not likely to arise from differences in general activity or physical condition, but seems to refer to differences in the way in which information concerning the environment is collected and dealt with.

Behavioral differences between male and female wistar rats on DRL schedules: Effect of stimuli promoting collateral activities

Female rats are more active than males in open-field procedures. They also make fewer unreinforced responses than males on schedules which maintain low rates of responding (differential reinforcement of low rate responding, DRL). The addition of objects to promote collateral activities facilitates the acquisition of efficient DRL behavior. It was hypothesized that differences in activity levels might underlie the observed sex differences in DRL learning. If females are more likely than males to engage in activities other than lever pressing, the addition of objects to the experimental environment should not as much influence the behavior of females than that of males. Male and female rats were exposed to a DRL 15 sec or a DRL 30 sec schedule, either with or without objects to promote collateral activities. General activity was tested twice in an open-field procedure. Females showed higher activity levels than males in the open-field. They also acquired a DRL task more efficiently than males. The addition of objects facilitated the acquisition of efficient DRL performance in males, but not in females. The results of the present experiments, therefore, suggest that differences in general activity between male and female rats may underlie sex differences in some experimental paradigms.

Differential alterations in brain sensitivity to amphetamine and pentylenetetrazol in socially deprived mice

1. 1. Mice deprived of social interactions for different periods of time (56, 69, 79, 89 or 97 days) were studied. 2. 2. Social isolation increased both general activity observed in an open-field and amphetamine-induced hyperactivity; CNS responsiveness to pentylenetetrazol-induced convulsions, however, decreased. 3. 3. The differences in general activity were detected after 69 and 79 days of social deprivation; the hyperactivity induced by amphetamine was greater after 79 days of isolation and the pentylenetetrazol CD 50's were higher after 56, 69 and 79 days of solitude. 4. 4. These data, obtained with mice, show first that isolation time is an important variable to display drug effects and secondly that long-term deprivation of social stimuli does not increase CNS susceptibility to all stimulant drugs. 5. 5. A combination of a higher release of catecholamines onto previously supersensitive receptors was considered to be involved with the differences observed.

Sex differences in running-wheel behaviour in the rat: The inductive and activational effects of gonadal hormones

I compared the effect of oestradiol benzoate (OB) administration on running-wheel activity in gonadectomized male, female and neonatally androgenized female rats. In the first experiment, conducted on 300–400-day-old animals, OB stimulated running-wheel activity of female rats to a significantly greater extent than that of males or neonatally androgenized females. In the second experiment, conducted on 91-day-old rats, females exhibited maximal activity at lower doses of OB than males. Previous experiments have shown that open-field activity, a putative measure of susceptibility to fear, is subject to group differences in OB responsiveness (i.e. between male, female, androgenized female) which parallel those seen in the present study; thus, gender differences in open-field activity may reflect group differences in general activity rather than male/female differences in emotionality or susceptibility to fear.

Antibodies to synaptosomal membranes of rat hippocampus and caudate nucleus: Immunological and behavioral characteristics

Synaptosomal plasma membranes (SPMs) from the caudate nucleus (Cd) and hippocampus (HPC) were used as immunogens against which antisera were raised in rabbits (anti-HPC and anti-Cd serum, respectively). All immunologic reactivity of anti-Cd serum could be neutralized by absorption of the serum with either HPC-SPMs or Cd-SPMs. Similarly, all reactivity of the anti-HPC serum was neutralized by absorption with HPC-SPMs. On the other hand, a substantial part of the reactivity of anti-HPC serum remained after absorption with Cd-SPMs. These results indicate that the HPC-SPM preparation contains antigenic determinants which are absent from Cd-SPM preparation. When the immunoglobulin type G (IgG) fractions isolated from anti-HPC serum and anti-Cd serum were injected daily for 14 days into neonatal rats, they caused behavioral deficits which were observed in adulthood. No differences in general activity or in open-field behavior were found between those animals and controls. However, rats which had been injected for 14 days with anti-HPC IgG showed impairments in reversal learning in a T maze, in the retention of a passive avoidance task and in the acquisition of active avoidance. Rats injected with anti-Cd IgG showed much smaller impairments.