Runway Tests Research Articles

Housing and personality effects on judgement and attention biases in dairy cows

Affective states can be inferred from responses to ambiguous and threatening stimuli, using Judgement Bias Tasks (JBTs) and Attention Bias Tasks (ABTs). We investigated the separate and interactive effects of personality and housing conditions on dairy cattle affective states. We assessed personality in 48 heifers using Open-Field, Novel-Object and Runway tests. Personality effects on responses to the JBT and to the ABT were examined when heifers were housed under reference conditions. Heifers were subsequently housed under positive or negative conditions, and housing effects on animal responses in both tasks were investigated while controlling for personality. A Principal Component Analysis revealed three personality traits labelled Activity, Fearfulness and Sociability. Under reference conditions, personality influenced heifers’ responses to the JBT and to the ABT, therefore questioning the tasks’ generalizability across individuals. Against expectations, housing did not influence responses to the JBT and heifers in the negative conditions looked at the threat later than heifers in the positive or reference conditions. More research is warranted to confirm the validity and the repeatability of the JBT and of the ABT as appropriate measures of affective states in dairy cows.

Groups and Individuals: Optical Flow Patterns of Broiler Chicken Flocks Are Correlated with the Behavior of Individual Birds.

Simple SummaryTechnology on farms potentially brings the benefits of improved animal welfare and productivity as well as reduction in disease, waste and environmental impact. However, it also raises public concern about the welfare of individual animals, particularly when applied to large groups such as broiler (meat) chickens. We here address this issue by showing that camera technology can both provide life-long continuous monitoring of the welfare of whole flocks and also give crucial information about the individuals making up the flock. The cameras detect variation between individuals and are sensitive to birds moving abnormally. By testing samples of birds individually, we show that on average slow-moving birds came from flocks that moved slowly overall and showed large variation between individuals whereas on average fast-moving birds came from more active flocks that moved more uniformly. Properly used, camera technology can thus monitor the welfare of flocks continuously throughout their lives and is correlated with the behavior of individual birds.Group level measures of welfare flocks have been criticized on the grounds that they give only average measures and overlook the welfare of individual animals. However, we here show that the group-level optical flow patterns made by broiler flocks can be used to deliver information not just about the flock averages but also about the proportion of individuals in different movement categories. Mean optical flow provides information about the average movement of the whole flock while the variance, skew and kurtosis quantify the variation between individuals. We correlated flock optical flow patterns with the behavior and welfare of a sample of 16 birds per flock in two runway tests and a water (latency-to-lie) test. In the runway tests, there was a positive correlation between the average time taken to complete the runway and the skew and kurtosis of optical flow on day 28 of flock life (on average slow individuals came from flocks with a high skew and kurtosis). In the water test, there was a positive correlation between the average length of time the birds remained standing and the mean and variance of flock optical flow (on average, the most mobile individuals came from flocks with the highest mean). Patterns at the flock level thus contain valuable information about the activity of different proportions of the individuals within a flock.

Biomechanical effects of continuous loop running in comparison to discontinuous runway running on locomotion and running shoe characterization

Running and running shoe biomechanics are usually measured in laboratory settings, capturing discontinuous running trials. Continuous running measured outdoors doesn’t allow comprehensive measurement equipment due to limited technology. This research compared biomechanical effects of continuous loop and discontinuous runway running on locomotion and running shoe characterisation. Twenty-two runners performed eight trials in three shoe conditions in a runway and a loop laboratory setting, while capturing ground reaction forces and lower limb kinematics. Running mode and shoe variable magnitudes and intra-participant variability, means were compared for main and interaction effects (p < 0.05) by a 2 × 3 within-participants repeated measures analysis of variance, and effect size estimation. Kinetic and kinematic variables indicated biomechanical effects induced by running mode. Continuous loop running significantly decreased ground contact time (241.31–234.47 ms), and braking force (0.37–0.35 bw). It showed a significantly flatter and inverted foot-strike at touchdown by reducing sagittal shoe ground angle (20.27–16.69°), and increasing ankle inversion angle (5.50–6.67°). Continuous loop running significantly increased intra-participant variability in ankle dorsiflexion (9.49–12.78) and maximal eversion angle (12.70–17.36). Kinetic and kinematics indicated biomechanical effects induced by running shoes, shoe classification was similar between modes. Running mode influences biomechanics, whilst shoe classification remains similar. Anterior-posterior braking force is overestimated in discontinuous runway running, combined with increased variability suggesting an inconsistent foot-strike. Variability at the ankle joint was seen to increase during continuous loop running, indicating a more rigid ankle complex during discontinuous runway running. Our findings suggest that continuous loop running should be used when precise absolute variable magnitudes are required while runway running tests appear sufficient for general comparative shoe evaluation.

The Onecut transcription factor HNF-6 contributes to proper reorganization of Purkinje cells during postnatal cerebellum development

The Onecut (OC) family of transcription factors comprises three members in mammals, namely HNF-6 (or OC-1), OC-2 and OC-3. During embryonic development, these transcriptional activators control cell differentiation in pancreas, in liver and in the nervous system. Adult Hnf6 mutant mice exhibit locomotion defects characterized by hindlimb muscle weakness, abnormal gait and defective balance and coordination. Indeed, HNF-6 is required in spinal motor neurons for proper formation of the hindlimb neuromuscular junctions, which likely explain muscle weakness observed in corresponding mutant animals. The goal of the present study was to determine the cause of the balance and coordination defects in Hnf6 mutant mice. Coordination and balance deficits were quantified by rotarod and runway tests. Hnf6 mutant animals showed an increase in the fall frequency from the beam and were unable to stay on the rotarod even at low speed, indicating a severe balance and coordination deficit. To identify the origin of this abnormality, we assessed whether the development of the main CNS structure involved in the control of balance and coordination, namely the cerebellum, was affected by the absence of HNF-6. Firstly, we observed that Hnf6 was expressed transiently during the first week after birth in the Purkinje cells of wild type newborn mice. Secondly, we showed that, in Hnf6-/- mice, the organization of Purkinje cells became abnormal during a second phase of their development. Indeed, Purkinje cells were produced normally but part of them failed to reorganize as a regular continuous monolayer at the interface between the molecular and the granular layer of the cerebellum. Thus, the Onecut factor HNF-6 contributes to the reorganization of Purkinje cells during a late phase of cerebellar development.

Selection for wheat digestibility affects emotionality and feeding behaviours in broiler chicks

In poultry farming, selection for high production, as for growth rate or feed efficiency, may be associated with risks for animal welfare. In this study, we tested whether divergent selection for a new trait linked to feed efficiency, i.e. digestibility, had correlated side effects on the behaviours of broiler chickens. Digestibility was assessed from apparent metabolisable energy values corrected to zero nitrogen balance (AMEn). We tested the behaviours of 80 broiler chickens from a divergent selection experiment for high (D+ line, 40 chicks) or low (D− line, 40 chicks) wheat digestibility. We used tonic immobility (TI), open-field and capture tests to evaluate the emotional reactivity of the birds. Social motivation was assessed with a runway test. Food consumption, food neophobia and exploration for food were also analysed. D+ birds had significantly longer duration of TI and latencies of the first step in the open-field and runway tests than D− birds. Our data thus suggest a higher emotional reactivity in D+ birds than in D− birds. On the other hand, D+ birds showed significantly lower latencies to approach novel food and were more willing to search for food in an open environment than D− birds. In the runway test, D− birds spent significantly more time away from the social stimulus than D+ birds. No significant difference was observed in the capture test results of the two lines. Feed consumption was significantly higher in D− birds than in D+ birds, but weight gain did not differ between the two lines during the first 3 weeks after hatching. Our results showed that selection indirectly affected different behavioural traits and different dimensions of fear behaviour. D+ birds expressed higher inhibition in novel environments (TI, open-field and runway tests) than D− birds. However, in the presence of food (novel food and exploration for food tests), the opposite behaviour was observed. Food rewards might have had a higher positive hedonic value in D+ birds than in D− birds and reduce D+ birds’ fear level. Behavioural differences as a result of divergent digestibility could potentially be due to ‘co-selection’ or genetic drift. Further investigations are needed to understand the underlying mechanisms and be able to select animals with genotypes associated with traits beneficial for both the environment and animal welfare.

Effects of a 16-hour light, 8-hour dark lighting schedule on behavioral traits and performance in male broiler chickens

SUMMARY The objective of this study was to examine the effects of a 16L:8D lighting schedule from d 2 of age through a 6-wk production trial on the performance and behavior of Cobb broiler males compared with a continuous 24-h light schedule (control). Behavioral tests included social reinstatement behavior measured in runway tests and fear response measured by tonic immobility. The 16L:8D group had BW and FCR similar to control birds at 6 wk. Based on behavior observations by scan sampling at 0900 to 1100 h and 1400 to 1600 h, the number of chicks eating, drinking, walking-standing, and pecking increased under the 16L:8D lighting schedule, whereas resting (sitting and sleeping) decreased (P ≤ 0.05). The 16L:8D group also exhibited comfort behaviors, such as preening and wing-shaking, more extensively than did control birds (P ≤ 0.05). Broilers in the 16L:8D group had a shorter duration of tonic immobility (P ≤ 0.05) at 11 and 35 d of age, which might represent less fearfulness. In runway tests at 13 and 30 d of age, the 16L:8D group exhibited shorter latencies to reach the zone of stimulus birds and spent more time near the stimulus birds (P ≤ 0.05). We therefore suggest that the birds in the 16L:8D group had a greater degree of sociality. Although we did not measure whole-day activity, we speculate that this greater sociality might have resulted from increased interactions among birds caused by increased activity during the observation periods. The16L:8D program tended to have more natural daytime behavioral patterns in broilers, to reduce fearfulness (and thus psychological stress), and to increase sociality. We conclude, based on the morning and afternoon measurements of this study, that birds in the 16L:8D group had a better welfare status than control birds without affecting 42-d broiler performance of the strain used.

Orexin mediates initiation of sexual behavior in sexually naive male rats, but is not critical for sexual performance

The hypothalamic neuropeptide orexin mediates arousal, sleep, and naturally rewarding behaviors, including food intake. Male sexual behavior is altered by orexin receptor-1 agonists or antagonists, suggesting a role for orexin-A in this naturally rewarding behavior. However, the specific role of endogenous orexin-A or B in different elements of male sexual behavior is currently unclear. Therefore, the current studies utilized markers for neural activation and orexin cell-specific lesions to test the hypothesis that orexin is critical for sexual motivation and performance in male rats. First, cFos expression in orexin neurons was demonstrated following presentation of a receptive or non-receptive female without further activation by different elements of mating. Next, the functional role of orexin was tested utilizing orexin-B conjugated saporin, resulting in orexin cell body lesions in the hypothalamus. Lesions were conducted in sexually naive males and subsequent sexual behavior was recorded during four mating trials. Lesion males showed shortened latencies to mount and intromit during the first, but not subsequent mating trials, suggesting lesions facilitated initiation of sexual behavior in sexually naive, but not experienced males. Likewise, lesions did not affect sexual motivation in experienced males, determined by runway tests. Finally, elevated plus maze tests demonstrated reduced anxiety-like behaviors in lesioned males, supporting a role for orexin in anxiety associated with initial exposure to the female in naive animals. Overall, these findings show that orexin is not critical for male sexual performance or motivation, but may play a role in arousal and anxiety related to sexual behavior in naive animals.

Effect of the density of conspecifics on runway social reinstatement behavior of male Japanese quail genetically selected for contrasting adrenocortical responsiveness to stress

Runway tests are considered indicative of underlying sociality in birds and their ability to make social discriminations and establish interactions among conspecifics. Herein, social reinstatement behavior in male juvenile Japanese quail selected for a reduced (LS, low stress) or exaggerated (HS, high stress) adrenocortical response to brief mechanical restraint was evaluated. Individual males were given the choice to reinstate with either 2 (low density, LD) or 8 (high density, HD) unfamiliar randombred conspecifics placed in goal boxes at opposite ends of a two-choice runway (TCRW). Then, the same males were individually retested in a single goal box runway wherein they were exposed to a goal box containing either a LD or a HD of males. In the TCRW, a higher (P < 0.01) number of HS males started their ambulation toward the goal box containing the HD as opposed to LD of conspecifics. The HS males also spent more (P < 0.01) time in close proximity (within a 10-cm close zone; CZ) to the HD (218 s) rather than LD (57 s) of conspecifics. In contrast, the LS males did not differ in their initial direction of travel and they spent similar average amounts of times in the CZ of their stimulus LD (141 s) and HD (124 s) conspecifics. Similar to the TCRW results, in the single goal box runway, HS males spent more (P < 0.01) time in the CZ of HD rather than LD conspecifics, whereas LS quail spent similar amounts of time in the CZ of LD and HD males. Considering that runways are novel (and therefore frightening) environments, our findings suggest that HS quail may find better shelter (i.e., more comfort) in close proximity to a larger rather than smaller group of conspecifics, whereas LS birds find groups of varying conspecific density equally attractive. The results suggest that LS quail possess favorable social adaptive qualities because they appear to be better suited to cope with situations where the density of conspecifics is variable.

Altered Neuron Excitability and Synaptic Plasticity in the Cerebellar Granular Layer of Juvenile Prion Protein Knock-Out Mice with Impaired Motor Control

Although the role of abnormal prion protein (PrP) conformation in generating infectious brain diseases (transmissible spongiform encephalopathy) has been recognized, the function of PrP in the normal brain remains mostly unknown. In this investigation, we considered the effect of PrP gene knock-out (PrP(0/0)) on cerebellar neural circuits and in particular on granule cells, which show intense PrP expression during development and selective affinity for PrP. At the third postnatal week, when PrP expression would normally attain mature levels, PrP(0/0) mice showed low performance in the accelerating rotarod and runway tests and the functioning of 40% of granule cells was abnormal. Spikes were slow, nonovershooting, and nonrepetitive in relation with a reduction in transient inward and outward membrane currents, and also the EPSPs and EPSCs had slow kinetics. Overall, these alterations closely resembled an immature phenotype. Moreover, in slow-spiking PrP(0/0) granule cells, theta-burst stimulation was unable to induce any long-term potentiation. This profound impairment in synaptic excitation and plasticity was associated with a protracted proliferation of granule cells and disappeared at P40-P50 along with the recovery of normal motor behavior (Büeler et al., 1992). These results suggest that PrP plays an important role in granule cell development eventually regulating cerebellar network formation and motor control.

Selection of social traits in juvenile Japanese quail affects adults’ behaviour

The inability of animals to cope with their social environment in husbandry systems could be a major source of problems for both animal welfare management and economy. In this context, previous studies selected lines of domestic Japanese quail diverging for their level of social reinstatement, hypothesizing that quail with high levels of social motivation would adapt better to crowded social situations than quail with low levels of social motivation. However, these selections were based only on social motivation evaluated in young birds. As behavioural traits can vary with age, this study analysed the persistence of selected social traits into adulthood. With this in mind, we used several behavioural tests to estimate social motivation of adult females from selected lines for high social reinstatement (HSR, n = 24) and for low social reinstatement (LSR, n = 24). The tests were: open-field tests, emergence tests, separation tests, runway tests and confrontation tests. As birds’ behaviour in these tests can be influenced by the emotive characteristics of the subjects, we measured the emotional reactivity of quail not only during these tests but also in specific emotive tests: tonic immobility tests. Our results showed that the social motivation characteristics of birds persist in adulthood. Adult HSR females still presented a higher social motivation than adult LRS females: their response to social isolation was stronger and their motivation to reach conspecifics and to stay close to them was higher. However, the behavioural expression of social motivation appeared to be modified during development. Whereas vocal behaviour reflected the social motivation of chicks, in isolated contexts, this characteristic was not observed in adult quail.

Social reinstatement responses of meat-type chickens to familiar and unfamiliar conspecifics after exposure to an acute stressor

Runway tests are considered indicative of underlying sociality in birds and their ability to make social discriminations. We evaluated whether experience of a prior stressor alters the subsequent affiliation responses of 9 or 10-day-old chicks simultaneously exposed to familiar (cagemates) and unfamiliar conspecifics placed in goal boxes at opposite ends of a runway. Birds were housed in groups of eight in home cages. Half of the birds in each home cage were used as either familiar or unfamiliar social stimuli in the goal boxes. The other half of the birds were randomly assigned either to a control (CON; n = 51) group that remained undisturbed until testing or to a stress-treatment (STR; n = 52) group that was exposed to a 5-min restraint stressor, returned to its home cage and then tested 1 h later. Birds were individually tested in the runway for 5 min and the behaviours video-recorded. During revision of tapes, the projected floor image of the runway was divided into squares and zones. The stressor decreased ( P < 0.01) the time spent in close proximity (close zone; CZ) to conspecifics regardless of the familiarity of the stimulus birds. Regardless of treatment, test chicks showed shorter latencies to enter ( P < 0.05) and spent longer time ( P < 0.02) in the familiar than in the unfamiliar CZ suggesting that young chicks can discriminate between familiar and unfamiliar conspecifics encountered in novel surroundings. While in close proximity to familiar conspecifics, STR birds showed a reduced ( P < 0.05) number of squares entered compared to CONs. This reduced locomotor activity was not accompanied by an increased activity in other zones of the runway. At the end of the trial, both CON and STR birds showed a reduced ( P < 0.05) locomotor activity in the unfamiliar CZ and an increased ( P < 0.05) activity in the central zone of the runway. Interestingly, no differences were detected between CON and STR birds in the total number of squares entered during the trial. These results suggest that prior stressor exposure did not affect the overall amount of locomotion but altered the spatial distribution of it. Collectively, our findings suggest that exposure to an acute stressor event subsequently affects chicks’ affiliation responses in runway tests. The way a bird will react depends on the identity (familiar or unfamiliar) of the conspecifics in its close environment.

Methods for assessing sociability of dairy cows

Sociability refers to the extent to which animals seek social companionship. Individual differences in social behaviour exist between animals. It is important to measure individual social motivation in order to develop suitable temperament scores that can be used in future breeding programmes or as part of welfare assessment schemes. Runway tests have been shown as reliable methods of measuring sociability in animals (Birds Mills &amp; Faure, 1991; Sheep Sibbald et al., 2005). The aim was to develop a suitable test that could be used to measure sociability of cows in a commercial situation. The following questions were addressed i) How repeatable is the runway test when carried out on dairy cattle, ii) Does a cow’s performance in a runway test correlate with social behaviour within a group house setting?

Evaluation and comparison of four methods of ranking horses based on reactivity

Four methods of ranking horses on reactivity were evaluated and compared: isolation from conspecifics, presentation of a static novel stimulus, traversing a novel stimulus in a runway (isolation, novel stimulus and runway tests, respectively) and assigning subjective emotionality scores. In all tests, horses’ heart rates were recorded and behaviour was videotaped. To be considered a valid test of reactivity, at least one heart rate and one behavioural measurement in the test had to change significantly between treatments (tranquilizer administation versus sham tranquilizer administration), and behavioural measures had to be displayed in at least 75% of the trials. Forty horses performed each of the three tests daily on three different days in a switchback design. Horses were assigned randomly to a daily test sequence, which was maintained throughout the study. In the runway test, no significant difference in heart rate values in tranquilized and non-tranquilized horses was found, and no behavioural attribute was displayed in more than 52% of the trials; therefore it was rejected as a valid test of reactivity. Both isolation and novel stimulus tests produced valid measurements. Mean heart rate was the most precise physiological measure for these tests, and walking and defecation frequency were the most precise behavioural measures for novel stimulus and isolation tests, respectively. Mean heart rates on the novel stimulus and isolation tests were correlated ( r s = 0.79, P < 0.01) indicating that these tests produced similar rankings based on physiological responses. However, behavioural measures ranked horses differently ( r s = 0.27, P < 0.10) on the tests. Rank correlations between mean heart rates and behavioural measures were higher in the novel stimulus ( r s = 0.66, P < 0.01) than the isolation test ( r s = 0.55, P < 0.01), indicating that the novel stimulus test ranked horses based on either physiological or behavioural responses more similarly than did the isolation test. Therefore, the novel stimulus test was considered the more accurate evaluation of reactivity. Subjective emotionality scores were correlated moderately with mean heart rates ( r s > 0.33, P < 0.01) from the novel stimulus and isolation tests and with walking scores ( r s = 0.47, P < 0.01) from the novel stimulus test. Assignment of subjective emotionality scores was not as accurate as the novel stimulus or isolation tests in ranking horses for reactivity. Using physiological data alone, combining physiological and behavioural measurements or using more than one behavioural measurement in reactivity tests may reflect the reactivity of the horse better than a single behavioural measurement.

Responses of Young Red Jungle Fowl (Gallus gallus) and White Leghorn Layers to Familiar and Unfamiliar Social Stimuli

Social preferences of familiar over unfamiliar social stimuli in chicks may be used to measure sociality, a characteristic important for the welfare of poultry in commercial production. We studied social preferences and reaction to strangers in young White Leghorns and red jungle fowl (Gallus gallus) in 3 tests. All chicks were raised and housed in 2 groups of 34 individuals per breed. At 24 to 29 d of age 38 chicks per breed were tested in 2 runway tests. In the first, chicks had a free choice between familiar and unfamiliar breed members, and in the second the choice was between unfamiliar chicks of their own breed and the other breed. On d 41 to 42, spacing and agonistic interactions of 28 pairs of chicks per breed (in half of the pairs, chicks were unfamiliar to each other) were observed in an open field for 10 min (pair test). In the first runway test, clear preference for familiar chicks and avoidance of unfamiliar social stimuli was found only in Leghorns, whereas both breeds showed a preference for their own breed members in the second runway test. Affiliation to the familiar breed, however, was more pronounced in Leghorns. In the pair test, Leghorns were significantly more involved in agonistic interactions than wild-type chicks. Avoidance of unfamiliar and preference for familiar conspecifics might suggest a weaker capacity of Leghorns to cope with novel social and environmental stimuli, which might have implications for the welfare of the birds in production environments when encountering unfamiliar individuals.

Sociality in Japanese quail ( Coturnix japonica) genetically selected for contrasting adrenocortical responsiveness

The growing realisation that selective breeding may offer rapid solutions to certain animal welfare problems and the associated production losses lends urgency to the search for suitable selection criteria. We have already shown that genetic selection of Japanese quail for a reduced (low stress, LS) rather than an exaggerated (high stress, HS) adrenocortical response to brief mechanical restraint was associated with marked reductions in underlying fearfulness, non-specific stress responsiveness and developmental instability. However, since genetic selection for one trait can also modify others, monitoring of other important characteristics is imperative before we can make any recommendations. Inappropriate levels of sociality (motivation to be near conspecifics) could cause pronounced social stress. The present study compared underlying sociality in LS and HS quail in two ways. In experiment 1, when undisturbed, same-line groups of six chicks were observed at 4 days of age we found that LS quail stayed closer together than HS ones. When naive, individually tested chicks were tested in a runway at 11–12 days of age in experiment 2, LS quail spent longer near a goal box containing cagemates than did the HS birds. Social proximity in the home cage and reinstatement responses in runway tests of social affiliation are positively related to underlying sociality. Therefore, these findings strongly suggest that underlying sociality is greater in quail of the LS than the HS line. Enhanced sociality could be regarded as an additional advantage of this type of selection programme, particularly if the phenomenon generalised to include commercially important species that are often housed at high stocking densities, like chickens or turkeys.

Effects of an acute stressor on fear and on the social reinstatement responses of domestic chicks to cagemates and strangers

Genetic selection for appropriate levels of sociality (motivation to be with conspecifics) could benefit poultry welfare and performance. Runway tests that require chicks to traverse a corridor in order to reach other chicks in a goal box are commonly used to measure this behavioural trait. However, we need to determine if the chicks’ responses in such tests are sensitive to certain experiential variables before we can recommend possible selection criteria for future breeding programmes. The present study focused on fear and on the identity of the stimulus birds. Broiler chicks either remained undisturbed or were exposed to an acute stressor (mechanical restraint) before their tonic immobility fear responses were measured 1 h later in Experiment 1. Exposure to the stressor significantly prolonged tonic immobility and, hence, presumably, underlying fear levels. In Experiment 2, the responses of stressed chicks and undisturbed controls were assessed when they were tested individually in a runway with a goal box containing either familiar or unfamiliar chicks of the same age. Our finding that stressed chicks emerged from the start box sooner and spent longer near the stimulus birds suggests that exposure to a frightening event increased social reinstatement motivation. Furthermore, social affiliation was more pronounced when the goal box contained familiar cagemates rather than strange chicks, regardless of prior treatment. This finding demonstrates that broiler chicks that were housed in groups of twelve can discriminate between familiar and unfamiliar conspecifics encountered in novel surroundings. Thus, sociality was positively associated with fearfulness and broilers clearly showed social discrimination in runway tests. These findings highlight the dangers of disregarding variables, such as fear and the capacity for social recognition in tests of social motivation. We strongly recommend that exposure to frightening events prior to test should be avoided and that the identity of the birds in the runway goal box should be standardized, i.e. either familiar or unfamiliar, and noted.

Behavioural differences in non-reproductive adult females in a long-term selection experiment for litter size in mice

In a previous study, it has been shown that adult, non-reproductive female mice from a line selected for high litter size at birth (S-line) have higher residual feed intake (RFI) than females of a non-selected control line (C-line). Several studies have indicated that a higher RFI is related to a higher activity level. Differences in activity may suggest underlying differences in coping strategies. To investigate whether coping strategies have been affected as a correlated effect of selection for high litter size, 48 non-reproductive mature C- and S-line females were twice subjected to an open field, seven times to a maze, once to a social confrontation and twice to a runway test. In the second open-field test, S-line females crossed more squares than C-line females and were less reserved to enter the centre of the open field. In the maze tests, S-line females showed more locomotion activity than C-line females. They encountered dead-ends more often and returned more often to the starting area in the first maze test. No differences were found in their reaction towards an extra-maze cue change. In the social confrontation test, S-line females showed more locomotion activity, were less immobile and investigated the floor and opponent less than C-line females. S-line females ran faster in both runway tests than C-line females. These results suggest that the novelty response of S-line females is more dominated by an active coping style than that of C-line females. However, more tests, such as additional behavioural tests, physiological tests and neurobiological tests are required to be more conclusive on whether selection for high litter size has resulted in mice that adopt the active coping strategy.

Cocaine self-administration increases the incentive motivational properties of the drug in rats.

A progressive increase in the frequency and intensity of drug use is one of the major behavioural phenomena characterizing the development of addiction. The nature of the drug-induced adaptations involved in this escalating drug intake remains unknown. Some theories propose that this escalation is due to a progressive decrease (tolerance) in the reinforcing or incentive effects of the drug. Alternative views posit that with chronic use the reinforcing or incentive effects of drugs increase, by a sensitization or a learning mechanism. In this report, we address the question of whether escalating cocaine intake is paralleled by an increase or a decrease in the reinforcing and incentive effects of the drug. Using the experimental model of intravenous drug self-administration with a within-session dose-response paradigm, we first studied the course of cocaine intake over 14 sessions in rats. After acquisition of cocaine self-administration, cocaine intake progressively increased at each dose tested. Then rats, previously allowed to self-administer cocaine during either six or 29 sessions, were compared in three different tests of the incentive and reinforcing effects of cocaine: cocaine-induced reinstatement of self-administration, cocaine-induced runway and cocaine-induced place conditioning. As compared with rats briefly exposed to cocaine self-administration (six sessions), rats with the longer experience (29 sessions) exhibited a higher intake of cocaine paralleled by a higher responsiveness in the cocaine-induced reinstatement and runway tests. Both groups of rats were similarly sensitive to the rewarding effects of the drug as evaluated by the threshold dose of cocaine inducing place conditioning. Our results demonstrate that escalating cocaine intake is paralleled by an increase in the motivational properties of the drug in the absence of apparent signs of tolerance to the reinforcing or incentive effects of cocaine.

Limited Study of Flight Simulation Evaluation of High-Speed Runway Exits

The provision of high-speed runway exits is one of several alternatives to increase airport runway capacity through reductions in runway occupancy time. The Runway Exit Design Interactive Model developed at Virginia Tech proposes new geometric design standards for high-speed turnoffs and an algorithm to locate optimal runway exits. The results from a limited flight simulation study that was conducted to assess the operational suitability of high-speed runway exits developed at Virginia Tech are presented. The flight simulation experiments were conducted at the Mike Monroney Aeronautical Center in Oklahoma City in a Boeing 727-200, 6-degree-of-freedom, full-motion-base aircraft simulator. The study used six FAA pilots rated in the Boeing 727-200 aircraft to obtain information about the operational suitability of the proposed high-speed exits. Pilot responses were extracted from questionnaires that were administered during the flight-simulation experiments. Aircraft state variable time histories extracted from the flight simulator computer were analyzed to verify the dynamic behavior of the aircraft as high-speed runway exits were negotiated. Two statistical experiments were carried out to evaluate the acceptance of the high-speed exit designs: ( a) a two-factor analysis of variance test to verify differences in runway exit speeds and ( b) nonparametric tests of pilots questionnaire responses. The results suggest that a new generation of high-speed runway exit geometries could be used to increase runway exit speeds without compromising safety or inducing extra workload on pilots.

Sex differences in social reinstatement motivation of the domestic chick (Gallus gallus) revealed by runway tests with social and nonsocial reinforcement.

Sex differences in social reinstatement motivation of the domestic chick (Gallus gallus) revealed by runway tests with social and nonsocial reinforcement.