Detour Test Research Articles

Scopolamine increases perseveration in mice subjected to the detour test

Increased perseveration is associated with aging and leads to an impaired ability to cope with problems. Aging is also associated with progressing dysfunction of the cholinergic system which is involved in the regulation of various cognitive processes. Therefore, we tested an effect of an anticholinergic drug on the level of perseveration in mice subjected to the detour test. The subjects tested on this task are expected to disengage from visually guided behavior and to move around a transparent barrier instead of traveling to the target directly along the line of sight. The failure to inhibit prepotent motivational drive leads to perseveration during the task. Our experiment showed that scopolamine increased perseveration in mice and this finding points to the involvement of muscarinic receptors in the control of perseveration. This study also shows that a mouse detour task is a suitable model for detecting the effect of anticholinergic drugs on perseveration in contrast to the previously applied tests.

Detour Behavior of Mice Trained with Transparent, Semitransparent and Opaque Barriers.

Detour tasks are commonly used to study problem solving skills and inhibitory control in canids and primates. However, there is no comparable detour test designed for rodents despite its significance for studying the development of executive skills. Furthermore, mice offer research opportunities that are not currently possible to achieve when primates are used. Therefore, the aim of the study was to translate the classic detour task to mice and to compare obtained data with key findings obtained previously in other mammals. The experiment was performed with V-shaped barriers and was based on the water escape paradigm. The study showed that an apparently simple task requiring mice to move around a small barrier constituted in fact a challenge that was strongly affected by the visibility of the target. The most difficult task involved a completely transparent barrier, which forced the mice to resolve a conflict between vision and tactile perception. The performance depended both on the inhibitory skills and on previous experiences. Additionally, all mice displayed a preference for one side of the barrier and most of them relied on the egocentric strategy. Obtained results show for the first time that the behavior of mice subjected to the detour task is comparable to the behavior of other mammals tested previously with free-standing barriers. This detailed characterization of the detour behavior of mice constitutes the first step toward the substitution of rodents for primates in laboratory experiments employing the detour task.

A general intelligence factor in dogs

Hundreds of studies have shown that, in people, cognitive abilities overlap yielding an underlying ‘g’ factor, which explains much of the variance. We assessed individual differences in cognitive abilities in 68 border collies to determine the structure of intelligence in dogs. We administered four configurations of a detour test and repeated trials of two choice tasks (point-following and quantity-discrimination). We used confirmatory factor analysis to test alternative models explaining test performance. The best-fitting model was a hierarchical model with three lower-order factors for the detour time, choice time, and choice score and a higher order factor; these accounted jointly for 68% of the variance in task scores. The higher order factor alone accounted for 17% of the variance. Dogs that quickly completed the detour tasks also tended to score highly on the choice tasks; this could be explained by a general intelligence factor. Learning about g in non human species is an essential component of developing a complete theory of g; this is feasible because testing cognitive abilities in other species does not depend on ecologically relevant tests. Discovering the place of g among fitness-bearing traits in other species will constitute a major advance in understanding the evolution of intelligence.

Zebrafish (Danio rerio) behaviour is largely unaffected by elevated pCO2.

Ocean acidification, the decrease in ocean pH caused by anthropogenic emission of carbon dioxide, can cause behavioural disturbances in marine teleost species. We investigated whether AB-strain zebrafish (Danio rerio) show similar behavioural disturbances in the presence of elevated CO2, because this model species could open up a toolbox to investigate the physiological and neurological mechanisms of CO2 exposure. We found no effect of elevated CO2 (~1600 μatm) on the behaviour of zebrafish in the open field test, indicating that zebrafish are largely insensitive to this elevated CO2 level. In the detour test of lateralization, however, zebrafish exposed to elevated CO2 swam more often to the right, whereas individuals exposed to control CO2 (~400 μatm) had no preference for left or right. This may indicate that some behaviours of some freshwater fishes can be altered by elevated CO2 levels. Given that elevated CO2 levels often occur in recirculating aquaculture and aquarium systems, we recommend that dissolved CO2 levels are measured and, if necessary, the aquarium water should be aerated, in order to exclude CO2 level as a confounding factor in experiments.

Predator-induced phenotypic plasticity of laterality

Lateralized brain function, or partitioning of tasks to separate hemispheres of the brain, directly impacts behaviour and fitness. Highly lateralized individuals tend to outperform nonlateralized individuals in many survival-related behaviours, such as the ability to learn, escape predators and multitask. Despite these benefits to lateralization, there is a great deal of observed variation in this trait within and between populations that is likely determined by the balance between costs and benefits of laterality in a given environment. Laterality appears to be heritable, but it can also vary with the environment experienced during development. We investigated the role of evolutionary history and developmental plasticity in determining the degree of laterality in the Trinidadian guppy, Poecilia reticulata, a freshwater fish that experiences variable predation pressure in its native range. We compared pairs of closely related populations that experience either high or low levels of predation in the wild, and manipulated the perceived predation risk in the rearing environment using a common garden split-brood design. We assayed laterality in mature male guppies using a detour test. Fish reared with exposure to chemical predator cues were more lateralized than their brothers reared without predator cues. This plastic response is in the direction we would predict if lateralization is favoured in environments with high predation risk. However, unlike findings in related species, we did not detect repeatable differences in degree of laterality associated with historical predation regime, suggesting that predation risk experienced over evolutionary history does not shape laterality patterns in guppies. Thus, although it is currently underemphasized in the literature, plasticity is likely an important contributor to variation in laterality.

Shifting from Right to Left: The Combined Effect of Elevated CO2 and Temperature on Behavioural Lateralization in a Coral Reef Fish

Recent studies have shown that elevated CO2 can affect the behaviour of larval and juvenile fishes. In particular, behavioural lateralization, an expression of brain functional asymmetries, is affected by elevated CO2 in both coral reef and temperate fishes. However, the potentially interacting effects of rising temperatures and CO2 on lateralization are unknown. Here, we tested the combined effect of near-future elevated-CO2 concentrations (930 µatm) and temperature variation on behavioural lateralization of a marine damselfish, Pomacentrus wardi. Individuals exposed to one of four treatments (two CO2 levels and two temperatures) were observed in a detour test where they made repeated decisions about turning left or right. Individuals exposed to current CO2 and ambient temperature levels showed a significant right-turning bias at the population level. This biased was reversed (i.e. to the left side) in fish exposed to the elevated-CO2 treatment. Increased temperature attenuated this effect, resulting in lower values of relative lateralization. Consequently, rising temperature and elevated CO2 may have different and interactive effects on behavioural lateralization and therefore future studies on the effect of climate change on brain functions need to consider both these critical variables in order to assess the potential consequences for the ecological interactions of marine fishes.

Asymmetry of the behavioral response in roach Rutilus rutilus (L.) (Teleostei: Cyprinidae) to a new object

The young roach Rutilus rutilus (L.) (Cyprinidae) displays lateralized behavior when facing a barrier through which a simulated bigger fish was visible. The asymmetry consists in a significant tendency to detour a barrier rightwards in the presence of a dummy fish. However, asymmetry is insignificant without the model. A comparison with the available literature shows that the roach has the same direction of this lateral bias as some other shoaling cyprinid fishes, which also preferentially turn to the right in the presence of a dummy fish. This seems to be a characteristic of cyprinids, as opposed to species of some other families displaying a leftward bias or a lack of asymmetry. The results of the study testify to the hypothesis that behavioral lateralization is associated with the taxonomic status of fishes. Currently, it is unclear whether the asymmetry found in roach in a detour test is due to the preferential use of the lateral fields of the right and left eyes as in some other fishes, or if it is a result of motor lateralization, which becomes evident in the presence of an unfamiliar and potentially dangerous object.

Relation between Morphological Antisymmetry and Behavioral Laterality in a Poeciliid Fish

Many animals show lateral bias in various behaviors. In fish, behavioral laterality has been studied from the perspective of its relation with brain lateralization. On the other hands, in some fishes, head dimorphism (righty or lefty) corresponds to behavioral laterality, such as foraging behavior. To examine the correlation between morphological asymmetry and behavioral laterality associated with brain lateralization, we conducted two behavioral tests (the detour test and fast-start test) using a poeciliid fish, Girardinus metallicus. In both behavioral tests, some individuals tended to move rightward, while others tended to move leftward, in a manner associated with head incline. In the detour-test, righty individuals primarily detoured leftward, whereas lefty individuals primarily detoured rightward. In the fast-start tests, the reverse tendency was seen; righty individuals tended to escape rightward, whereas lefty individuals tended to escape leftward. Such results indicate that brain lateralization may be also associated with morphological asymmetry.

When rank counts — dominant dogs learn better from a human demonstrator in a two-action test

AbstractDogs can learn effectively from a human demonstrator in detour tests as well as in different kinds of manipulative tasks. In this experiment we used a novel two-action device from which the target object (a ball) was obtained by tilting a tube either by pulling a rope attached to the end of the tube, or by directly pushing the end of the tube. Tube tilting was relatively easy for naïve companion dogs; therefore, the effect of the human demonstration aimed to alter or increase the dogs’ initial preference for tube pushing (according to the behaviour shown by naïve dogs in the absence of a human demonstrator). Our results have shown that subjects preferred the demonstrated action in the two-action test. After having witnessed the tube pushing demonstration, dogs performed significantly more tube pushing than the dogs in the rope pulling demonstration group. In contrast, dogs that observed the rope pulling demonstration, performed significantly more similar actions than the subjects of the other demonstration group. The ratio of rope pulling was significantly higher in the rope pulling demonstration group, than in the No Demo (control) group. The overall success of solving the task was also influenced by the social rank of the dog among its conspecific companions at home. Independently of the type of demonstration, dominant dogs solved the task significantly more often than the subordinate dogs did. There was no such difference in the No Demo group. This experiment has shown that a simple two-action device that does not require excessive pre-training, can be suitable for testing social learning in dogs. However, effects of social rank should be taken into account when social learning in dogs is being studied and tested, because dominant and subordinate dogs perform differently after observing a demonstrator.

Elevated carbon dioxide affects behavioural lateralization in a coral reef fish

Elevated carbon dioxide (CO(2)) has recently been shown to affect chemosensory and auditory behaviour, and activity levels of larval reef fishes, increasing their risk of predation. However, the mechanisms underlying these changes are unknown. Behavioural lateralization is an expression of brain functional asymmetries, and thus provides a unique test of the hypothesis that elevated CO(2) affects brain function in larval fishes. We tested the effect of near-future CO(2) concentrations (880 µatm) on behavioural lateralization in the reef fish, Neopomacentrus azysron. Individuals exposed to current-day or elevated CO(2) were observed in a detour test where they made repeated decisions about turning left or right. No preference for right or left turns was observed at the population level. However, individual control fish turned either left or right with greater frequency than expected by chance. Exposure to elevated-CO(2) disrupted individual lateralization, with values that were not different from a random expectation. These results provide compelling evidence that elevated CO(2) directly affects brain function in larval fishes. Given that lateralization enhances performance in a number of cognitive tasks and anti-predator behaviours, it is possible that a loss of lateralization could increase the vulnerability of larval fishes to predation in a future high-CO(2) ocean.

Behavioural asymmetry affects escape performance in a teleost fish

Escape performance is fundamental for survival in fish and most other animals. While previous work has shown that both intrinsic (e.g. size, shape) and extrinsic (e.g. temperature, hypoxia) factors can affect escape performance, the possibility that behavioural asymmetry may affect timing and locomotor performance in startled fish is largely unexplored. Numerous studies have found a relationship between brain lateralization and performance in several cognitive tasks. Here, we tested the hypothesis that behavioural lateralization may affect escape performance in a teleost, the shiner perch Cymatogaster aggregata. Escape responses were elicited by mechanical stimulation and recorded using high-speed video (250 Hz). A number of performance variables were analysed, including directionality, escape latency, turning rate and distance travelled within a fixed time. A lateralization index was obtained by testing the turning preference of each subject in a detour test. While lateralization had no effect on escape directionality, strongly lateralized fish showed higher escape reactivity, i.e. shorter latencies, which were associated with higher turning rates and longer distances travelled. Therefore, lateralization is likely to result in superior ability to escape from predator attacks, since previous work has shown that escape timing, turning rate and distance travelled are among the main determinants of escape success.

Lateralisation in a detour test in the common wall lizard (Podarcis muralis)

Detour tests provide a reliable indicator of the presence of visual lateralisation. Previous studies on fishes and birds suggest that preferences in choosing to detour an obstacle to reach a goal are due to asymmetries of eye use. We studied detour behaviour to reach a prey in males of Podarcis muralis in order to ascertain visual laterality for a predatory task. Lizards were found to be lateralised at both individual and population levels, although only a few lizards were found to express lateralisation at the level of the individual. The preferential direction of detouring is the left route around a transparent barrier, indicating a right eye/left hemisphere use to observe the prey and confirming the results of recent work. The eye used to fixate the prey was maintained longer in the same direction the lizards subsequently chose to approach it, confirming that the preference was basically due to visual asymmetry, not to motor asymmetry. To our knowledge this is the first study of detouring conducted on sauria, demonstrating how these lizards are right eye/left hemisphere lateralised for predatory tasks at individual and population level.

Visual lateralization and development of spatial and social spacing behaviour of chicks (Gallus gallus domesticus)

We investigated whether the development of spatial behaviour of the domestic chicken is influenced by light exposure of the embryo, as is known to be the case for some other lateralized visual functions. Ninety-six chicks were incubated in the dark or exposed to light during the final days of incubation. Half of the chicks in each group had the experience of moving behind opaque screens from 10 to 12 days of age. The other half were given transparent screens as a control. Chicks were tested in a detour test and a rotated floor test and their dispersal in groups was observed in larger pens. In the rotated floor test, chicks that had had experience with opaque screens used distal cues significantly more often than chicks that had experience with transparent screens (P=0.042), regardless of whether they had been exposed to light before hatching or incubated in the dark. There were no significant differences between treatments in the detour test or in the dispersal behaviour. Hence, visual lateralization has no influence on the development of the spatial behaviour that we tested, whereas the occlusion experience is quite specific and results in shifted attention to distal spatial cues.

The influence of early experience on, and inheritance of, cerebral lateralization

Cerebral lateralization refers to the lateralized partitioning of cognitive function in either hemisphere of the brain. Using a standard detour test, we investigated lateralized behaviour in wild-caught, female poeciliid fish, Brachyraphis (=Brachyrhaphis) episcopi, from high- and low-predation areas. Wild fish were bred and their offspring reared under controlled laboratory conditions. These laboratory-reared fish were screened in the same laterality assays as their parents. We observed differences between wild-caught females and their laboratory-reared female offspring in the pattern of lateralization (tendency to use one hemisphere over the other to process information). Conversely, the strength of lateralization (consistency of hemispherical bias) was largely conserved between generations, consistent with it being a heritable character. Both wild-caught females from high-predation sites and their laboratory-reared offspring showed stronger lateralized behaviour than their counterparts from low-predation sites. This difference in strength of lateralization is likely to provide fitness benefits to fish that occur in high-predation areas by enabling them to school and watch for predators simultaneously (dual processing). We hypothesized that the differences in the pattern of lateralization observed between species, and populations within species, are due to the manner in which they perceive and classify stimuli in the world around them. In particular, the perceived emotive content or context of a scene is likely to vary between individuals that have had different life experiences.

Artificial selection on laterality in the teleost fish Girardinus falcatus

We performed five generations of artificial selection on laterality of eye preference in Girardinus falcatus using a detour test. Two lines were selected for right turning when encountering a potential predator, two for left turning, one for no turning bias and one unselected line was used as control. We observed a prompt response to directional selection in all lines and the response was approximately symmetrical in left and right turning lines. However, the response to selection ceased after the first or the second generation and unexpectedly in all lines the average laterality score slowly decreased in subsequent generations. After selection was suspended for three generations, no significant variation in mean laterality was observed in most cases, indicating that natural selection was not actively opposing artificial selection during the experiment. After five generations, selected lines maintained substantial additive variance as evidenced by the possibility of rapidly reversing the direction of laterality bias in just one generation of counter-selection.

Perching behaviour in chickens and its relation to spatial ability

The early rearing environment plays an important role in the development of many behaviour patterns and it has been shown that an early use of perches by chicks improves their later three-dimensional spatial ability. But even if birds are reared in the same environment, there can be large individual differences in how well birds use the perches. Therefore, the aim of this study was to explore the link between the development of perching in chicks and their spatial ability. Ninety-day-old LSL chicks were housed in rearing pens ( n = 18). From day 1 they had access to perches (20 and 40 cm high). At 18 weeks of age the birds were moved to layer pens which were bigger and had more perches at different heights ( n = 5). The study included observations of perching behaviour of the birds in their home pens and two spatial tests. The first perching observations of the chicks were carried out in the rearing pens from 5 days until 6 weeks of age and the second during the first 5 days in the layer pens, when the birds were presumably adapting to these new pens. The two spatial tests were firstly, a detour test when the chicks were 4 days old and, secondly, a radial eight armed maze test when the birds were 15–16 weeks old. In addition to the spatial tests a TI (tonic immobility) test and a runway test were carried out to allow comparisons of the chicks’ spatial performance with their fearfulness and sociality. There was no evidence from this study that the two-dimensional spatial skill of a newly hatched chick influenced how it learnt to perch and so no support for there being an early link between a chicks spatial ability and perching behaviour. But spatial skill as a pullet did seem to influence perch use in a new and complex situation, suggesting that spatial skill in a two-dimensional test is related to performance in a three-dimensional spatial test situation.

Development of spatial memory in occlusion-experienced domestic chicks

At around day 11 of life, domestic chicks show a tendency to move out of sight of their mother before returning and regaining social and visual contact. We conducted a series of experiments to investigate the role of this voluntary ‘out-of-sight’ behaviour on the development of spatial memory in young chicks. We compared the behaviour of chicks that were reared in environments that provided opportunities to move out of sight of an imprinting stimulus (occlusion-experienced chicks) with the behaviour of chicks that were given minimal occlusion experience (controls). As in natural conditions, out-of-sight behaviour peaked on day 11. When chicks were released into larger pens at 14 days of age, occlusion-experienced chicks walked more than control chicks, but otherwise showed similar degrees of dispersal. Occlusion-experienced chicks tended to show better (although not significant, P=0.09) retrieval of a visually displaced imprinting stimulus than control chicks. Time spent out of sight in the rearing pens was negatively related to the number of orientation errors in a detour test. Occlusion-experienced chicks also tended to make fewer orientation errors in the first trial ( P=0.07) and in subsequent trials ( P=0.05). In contrast, experimentally manipulating the amount of time that chicks were out of sight of an imprinting stimulus (by confining the chicks) had no effect on their performance in displacement or detour tests. The results presented here suggest that active experience of occlusion around day 11 improved egocentric orientation towards an out-of-sight goal, supporting the hypothesis that enrichment-induced behavioural changes are dependent on the interaction with objects.

Interaction between individual experience and social learning in dogs

We investigated the interaction between individual experience and social learning in domestic dogs,Canis familiaris . We conducted two experiments using detour tests, where an object or food was placed behind a transparent, V-shaped wire-mesh fence, such that the dogs could get the reward by going around the fence. In some groups, two open doors were offered as an alternative, easier way to reach the reward. In experiment 1 we opened the doors only in trial 1, then closed them for trials 2 and 3. In experiment 2 other dogs were first taught to detour the fence with closed doors after they had observed a detouring human demonstrator, then we opened the doors for three subsequent trials. In experiment 1 all dogs reached the reward by going through the doors in trial 1, but their detouring performance was poor after the doors had been closed, if they had to solve the task on their own. However, dogs in the experimental group that were allowed to watch a detouring human demonstrator after the doors had been closed showed improved detouring ability compared with those that did not receive a demonstration of detouring. In experiment 2 the dogs tended to keep on detouring along the fence even if the doors had been opened, giving up a chance to get behind the fence by a shorter route. These results show that dogs can use information gained by observing a human demonstrator to overcome their own mistakenly preferred solution in a problem situation. In a reversed situation social learning can also contribute to a preference for a less adaptive behaviour. However, only repeated individual and social experience leads to a durable manifestation of maladaptive behaviour. Copyright 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour.

Effects of Neonatal Dietary Manganese Exposure on Brain Dopamine Levels and Neurocognitive Functions

Neonatal exposure to high levels of manganese (Mn) has been indirectly implicated as a causal agent in attention deficit hyperactivity disorder (ADHD), since Mn toxicity and ADHD both involve dysfunction in brain dopamine (DA) systems. This study was undertaken to examine this putative relationship in an animal model by determining if levels of neonatal dietary Mn exposure were related to brain DA levels and/or behavioral tests of executive function (EF) when the animals reached maturity. We used 32 newborn male Sprague–Dawley rats and randomly assigned them to one of the four dietary Mn supplementation conditions: 0, 50, 250 and 500 μg per day, administered daily in water from post-natal days 1–21. During days 50–64, the animals were given a burrowing detour test and a passive avoidance test. At day 65, the animals were killed and brains were assayed for DA. There was a statistically significant relationship ( P=0.003) between dietary Mn exposure and striatal DA. On the burrowing detour and passive avoidance, greater deficits were observed for animals subjected to higher Mn exposure, but these differences did not reach statistical significance. However, tests for heterogeneity of variance between groups were statistically significant for all measures, with positive relationship between Mn exposure and degree of within-group behavioral variability. Kendall’s non-parametric test of the relationship between the three behavioral measures and striatal DA levels was also statistically significant ( P=0.02). These results lend support to the hypothesis that neonatal Mn exposure is related to brain DA levels and neurocognitive deficit in the rodent.

Social learning in dogs: the effect of a human demonstrator on the performance of dogs in a detour task

We recorded the behaviour of dogs in detour tests, in which an object (a favourite toy) or food was placed behind a V-shaped fence. Dogs were able to master this task; however, they did it more easily when they started from within the fence with the object placed outside it. Repeated detours starting from within the fence did not help the dogs to obtain the object more quickly if in a subsequent trial they started outside the fence with the object placed inside it. While six trials were not enough for the dogs to show significant improvement on their own in detouring the fence from outside, demonstration of this action by humans significantly improved the dogs' performance within two–three trials. Owners and strangers were equally effective as demonstrators. Our experiments show that dogs are able to rely on information provided by human action when confronted with a new task. While they did not copy the exact path of the human demonstrator, they easily adopted the detour behaviour shown by humans to reach their goal.