Response to Novelty Correlates with Learning Rate in a Go/No-Go Task in Göttingen Minipigs

Novelty-seeking and harm-avoidance personality traits influence Go/No-go (GNG) learning in humans. Animal studies have also indicated a link between response to novelty and spatial discrimination learning. In the present study, we test the hypothesis that learning rate in a GNG task correlates with the behavioral response of Göttingen minipigs to novelty. In a group of 12 minipigs of mixed genders, response to novelty was measured by numbers of contacts with a novel object, and the total duration of exploration of the novel object. These parameters were correlated to individual learning rate in a GNG task. The number of sessions to reach criterion in the GNG task correlated significantly with the number of contacts to a novel object (r = 0.70, p = 0.03), but not with the duration of object exploration (r = 0.29, p = 0.41). Thus, pigs with a low behavioral response to novelty learned the GNG task faster than did pigs with a strong behavioral response to novelty, indicated by the tendency to approach novel objects. We hypothesize that the critical factor in this relation is difference in emotional reactivity rather than difference in motivation for exploration. In conclusion, in addition to ‘cognitive’ ability, ‘temperamental’ factors are likely to influence learning in individual pigs

Effects of dopamine D4 receptor antagonist on spontaneous alternation in rats

<p>Abstract</p> <p>Background</p> <p>The present study was a component of a series of studies scrutinising the neuroreceptor substrate of behavioural flexibility in a rat model. Spontaneous alternation paradigms model the natural tendency of rodents to spontaneously and flexibly shift between alternative spatial responses. In the study it was tested for the first time if the neurochemical substrate mediating spontaneous alternation behaviour includes the dopamine D₄receptor.</p> <p>Methods</p> <p>The acute effects of the highly selective dopamine D₄receptor antagonist L-745,870 on rats' performance in a spontaneous alternation paradigm in a T-maze were examined. The paradigm was a food-rewarded continuous trial procedure performed for 20 trials.</p> <p>Results</p> <p>The spontaneous alternation rate was not affected by the doses of the drug administered (0.02 mg/kg; 0.2 mg/kg; 2 mg/kg), but the position bias of the group receiving the highest L-745,870 dose (2 mg/kg) was significantly increased compared to the group that received the lowest dose (0.02 mg/kg). No significant effects on position bias were found compared to saline. The drug did not increase response perseveration.</p> <p>Conclusion</p> <p>The results show that the neural substrate mediating the spatial distribution of responses in the spontaneous alternation paradigm includes the D₄receptor. However, the statistically significant effect of L-745,870 on position bias was found comparing a high drug dose with a low drug dose, and not comparing the drug doses with saline. For the tested doses of L-745,870 the effect on position bias was not large enough to affect the alternation rate.</p

Induction of Strategies and Habits in Rats Through two Behavioural T-maze Paradigms

Two different behavioural paradigms in T-maze were developed with the aim to induce patterns of behavioural  persistence in rats. These new procedures were based not on traditional asymmetric reinforcement  methodology, but on a modified Krechevsky paradigm using olfactory stimuli, where we found rats  spontaneously developed patterns of behavioural persistence – or behavioural “strategies” - with less than  1% probability of these occurring by chance. Rats predominantly developed spatial position (win-stay)  strategies, but also spatial alternation (win-shift) strategies, olfactory strategies, and, to a minor degree,  olfactory alternation strategies. Spatial alternation behaviour was significantly more frequent during early  (first 40 trials) than during late testing. Position bias (spatial win-stay behaviour) increased gradually with  the number of trials and was significantly increased in late (over 120 trials) compared to early testing. In  the second paradigm, habits were induced in rats using a forced-choice procedure. After 100 forced-choice  trials of running to the same side in a T- or Y-maze, the rats showed a significant propensity for this side  when allowed to choose freely, compared to the situation in which only one forced-choice trial had been  performed. Ten forced trials were not sufficient to induce this habit. Both paradigms may be useful for modelling  aspects of human habit formation and for behavioural neuroscience experiments.

Spontaneous Object Recognition in the Göttingen Minipig

Göttingen minipigs were tested in an object recognition procedure based on spontaneous exploration. Eight pigs were exposed to two similar objects in a sample trial and after a one-hour delay exposed to two objects, one familiar and one novel, in a test trial. The pigs explored the novel object significantly more than the familiar object in the test trial (p<0.05), thereby showing recognition of the familiar object. Furthermore, habituation of exploration of the familiar object between the sample trial and the test trial was found (p<0.05). The procedure can be useful for testing of spontaneous trial-unique memory in pigs