Search results for "Avoidance Learning"
showing 10 items of 102 documents
Differential effects of bupropion on acquisition and performance of an active avoidance task in male mice.
2015
Bupropion is an antidepressant drug that is known to aid smoking cessation, although little experimental evidence exists about its actions on active avoidance learning tasks. Our aim was to evaluate the effects of this drug on two-way active avoidance conditioning. In this study, NMRI mice received bupropion (10, 20 and 40mg/kg) or saline before a daily training session (learning phase, days 1-4) in the active avoidance task. Performance was evaluated on the fifth day (retention phase): in each bupropion-treated group half of the mice continued with the same dose of bupropion, and the other half received saline. Among the vehicle-treated mice, different sub-groups were challenged with diffe…
Using genetically-defined rodent strains for the identification of hippocampal traits relevant for two-way avoidance behavior: a non-invasive approach
1989
Genetically-defined rodent strains permit the identification of hippocampal traits which are of functional relevance for the performance of two-way avoidance behavior. This is exemplified here by analyzing the relationship between infrapyramidal mossy fibers (a tiny projection terminating upon the basal dendrites of hippocampal pyramidal neurons) and two-way avoidance learning in about 800 animals. The necessary steps include 1) identification of structural traits sensitive to selective breeding for extremes in two-way avoidance, 2) testing the robustness of the associations found by studying individual and genetical correlations between hippocampal traits and behavior, 3) establishing caus…
The Role of Perceived Control in the Psychophysiological Responses to Disgust of Subclinical OCD Women
2019
Obsessive‒compulsive disorder (OCD), and especially contamination obsessions and washing compulsions, has been related to disgust. However, when its cardiovascular correlates have been studied, contradictory results have been found, including heart rate accelerations and decelerations. The aim of this study is to analyze emotional, cognitive, and cardiovascular responses in nonclinical (control) and subclinical participants with obsessive‒compulsive contamination/washing symptoms when confronted with a disgusting stimulus. Twenty-seven participants (14 subclinical OCD) completed a behavioral avoidance task with a contamination-based stimulus while their heart rate and subjective variables w…
Predator experience on cryptic prey affects the survival of conspicuous aposematic prey.
2001
Initially, aposematism, which is an unprofitable trait, e.g. noxiousness conspicuously advertised to predators, appears to be a paradox since conspicuousness should increase predation by naive predators. However, reluctance of predators for eating novel prey (e.g. neophobia) might balance the initial predation caused by inexperienced predators. We tested the novelty effects on initial predation and avoidance learning in two separate conspicuousness levels of aposematic prey by using a 'novel world' method. Half of the wild great tits (Parus major) were trained to eat cryptic prey prior to the introduction of an aposematic prey, which potentially creates a bias against the aposematic morph. …
Co-mimics have a mutualistic relationship despite unequal defences
2007
Defensive mimicry, where species have evolved to resemble others in order to evade predators, is quite common in the animal kingdom. The two extremes of the mimicry spectrum are known as 'batesian' and 'mullerian'. Batesian mimics develop signals — visual cues for instance — that are similar to those of species being mimicked, but stop short of adopting the attribute that makes it unprofitable prey to predators. Mullerian mimics both resemble the model species and share the anti-predation attribute — by being dangerous or unpalatable. These different types of mimic were identified a century ago, but the dynamics of mimicry between unequally defended prey remain unresolved. In an experiment …
Can aposematic signals evolve by gradual change?
1999
Aposematic species, which signal conspicuously of their unprofitability to predators, have puzzled evolutionary biologists for over a century1,2. Although conspicuousness of unpalatable prey improves avoidance learning by predators3,4,5, it also involves an evolutionary paradox: with increasing detectability4,6,7,8 the deviant aposematic prey would suffer high predation initially from naive predators. Here we test a neglected idea7,8,9,10,11 that aposematic coloration may evolve by gradual change rather than by major mutations. Weak signals did not suffer high initial predation, but predators (great tits, Parus major) did not learn to separate them from cryptic palatable prey. Furthermore, …
A tale of 2 signals: signal mimicry between aposematic species enhances predator avoidance learning
2010
Mullerian mimicry, where 2 or more unrelated aposematic species resemble one another, is predicted to reduce the per capita mortality of co-mimics by allowing them to share the cost of educating nao ¨ve predators about their unpalatability. However, the specific assumptions and predictions of Muller's theory of shared resemblance have been previously unsupported; some authors have suggested that the benefits of signal similarity are undetectable or at best very small. We demonstrate clearly and un- ambiguously that mimicry between 2 defended forms can provide substantial protection from uneducated predators in the manner proposed originally by Muller. By utilizing prey signals that were des…
Multiple benefits of gregariousness cover detectability costs in aposematic aggregations
2001
Understanding the early evolution of aposematic (warning) coloration has been a challenge for scientists, as a new conspicuous morph in a population of cryptic insects would have a high predation risk and would probably die out before local predators learnt to avoid it1,2,3,4. Fisher5 presented the idea of aggregation benefit through the survival of related individuals; however, his theory has been strongly debated6,7,8 as the mechanisms that favour grouping have never been explored experimentally with the incorporation of detectability costs. Here we create a comprehensive ‘novel world’ experiment with the great tit (Parus major) as a predator to explore simultaneously the predation-relate…
Behavioural studies on rats injected with l-cycloserine and other compounds
1964
l-cycloserine, a cyclic derivative of O-substituted hydroxylamine, causes the suppression of the conditioned avoidance reaction in the rat. The subsequent injection of equimolar amounts of pyridoxine hydrochloride is responsible for a complete reversal of this suppression. The suppression of the conditioned response is not observed with the d-isomer of cycloserine. Isoniazid is a strong antagonist of l-cycoserine. Changes in the brain level of GABA under several conditions are described. These changes suggest though do not establish a relationship between the block of the conditioned response and the elevation of the aminoacid above its physiological concentration.
The role of self-compassion in the relationship between attachment, depression, and quality of life.
2019
Abstract Background Self-compassion may be shaped by early attachment experiences, and has been linked to mental health and well-being. This study examined the role of two distinct features of self-compassion, self-warmth and self-coldness, in the relationship between attachment insecurity and depression as well as quality of life in a general population sample in Germany. Methods Participants (N = 2,253; 53.4% female, Mage 50 years) completed the Self-Compassion Scale (SCS), Adult Attachment Scale (AAS), Beck Depression Inventory-Fast Screen (BDI-FS), and European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30). Mediation analysis was used to…