12/27/2023 0 Comments Flick em up vs terrorLikewise, low freezing after extinction is taken to indicate successful suppression of the conditioned response, a new memory ( Quirk and Mueller, 2008). Accordingly, low freezing is generally interpreted as reflecting a weak association and thus poor learning. In these assays, the strength of a tone-shock association is traditionally measured by the fraction of time during the conditioned stimulus (CS) that subjects exhibit freezing, defined as the cessation of all movement not required for respiration ( Fanselow, 1980). In the laboratory, auditory or “cued” fear conditioning and extinction in rodents are the predominant tools for studying the neural mechanisms of learning and memory for aversive stimuli ( Blanchard and Blanchard, 1969 LeDoux, 2000 Maren, 2001). The next steps will be to understand the biological basis of the darting response in female rats. Gruene et al.’s findings suggest that there are differences in the ways that males and females respond in fear of a threatening stimulus, and highlight the importance of analyzing a variety of fear responses in experiments. During a subsequent extinction test, females that darted also displayed quicker reductions in both types of fear responses, which suggests that darting might be an active coping response that promotes long term reductions in fear. Animals that displayed darting were also less likely to freeze in response to the sound cue, which suggests that darting may represent an alternative fear strategy that is more common in females. The experiments found that females were four times more likely than males to display fear in the form of rapid movements (referred to as “darting”). However, if the sound is then played repeatedly without a footshock, the rats learn to become less fearful of the sound in another learning process called “extinction”. When rats learn that the sound predicts the shock, the sound alone causes them to produce a fear response. The experiments used a technique called cued fear conditioning, which pairs a sound with a mild electrical shock to a foot. analyzed different types of fear responses in large groups of male and female rats. However, since the vast majority of these experiments have used male animals, it is not clear if freezing is a sufficient measure of fear in females. Freezing is the most common measure of fear that has been used in research studies. Moreover, rats that darted during initial fear conditioning exhibited lower freezing during the second day of extinction testing, suggesting that females employ distinct and adaptive fear response strategies that improve long-term outcomes.Īnimals can respond to fear in a variety of ways, such as by standing still (freezing), or rapidly escaping from an apparent threat. This finding motivates a reinterpretation of rodent fear conditioning studies, particularly in females, and it suggests that conditioned fear behavior is more diverse than previously appreciated. In females, darting exhibits the characteristics of a learned fear behavior, appearing during the CS period as conditioning proceeds and disappearing from the CS period during extinction. Here we identify a novel, active fear response (‘darting’) that occurs primarily in female rats. Consequently, alternative expressions of associative learning are rarely considered. However, sole reliance on this measure includes the de facto assumption that any locomotor activity reflects an absence of fear. Traditional rodent models of Pavlovian fear conditioning assess the strength of learning by quantifying freezing responses.
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