Research master thesis | Psychology (research) (MSc)
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Novelty can be defined as a motivationally and attentionally salient learning signal. Past research has found benefits of novelty to include increased plasticity and enhanced memory encoding....Show moreNovelty can be defined as a motivationally and attentionally salient learning signal. Past research has found benefits of novelty to include increased plasticity and enhanced memory encoding. Briefly exposing subjects to a novel stimulus or environment in place of an expected threat has also been shown to enhance the extinction process following fear conditioning in both rodents and humans. This is important, as the treatment for trauma-based disorders such as post-traumatic stress disorder (PTSD) has only been demonstrated effective for up to 66% of those affected and a dysfunction in the fear extinction process appears central in the development and continuation of such disorders. The current study explored whether replacing a fear-inducing stimulus with a novel visual stimulus resulted in more effective fear extinction, as quantified using both subjective and objective parameters, namely subjective arousal, and pupil dilation. In addition, a condition with olfactory novelty was included to explore the effects of contextual novelty on preventing the reinstatement of the conditioned fear 24 hours following fear conditioning. The study successfully established fear conditioning using threatening visual stimuli in a classical conditioning paradigm. However, there was no support for novelty-enhanced fear extinction, nor for the benefit of olfactory novelty on the retention of fear extinction 24 hours post-extinction. Rather, an increase in pupil dilation in the context of a novel olfactory environment was found especially in conditions where a fear-inducing unconditioned stimulus had been paired with a novel replacement stimulus, possibly suggesting a contextual novelty-induced fear reinstatement effect.Show less
Anxiety disorders are highly prevalent mental disorders. Treatment of these disorders, such as exposure-based treatment, is commonly derived from the principle of fear conditioning and fear...Show moreAnxiety disorders are highly prevalent mental disorders. Treatment of these disorders, such as exposure-based treatment, is commonly derived from the principle of fear conditioning and fear extinction. In the current study the element of novelty was introduced into the process of extinction to explore how to promote fear extinction, as with standard extinction fear frequently returns over time. Extinction by means of novelty was studied in 32 human subjects using a within-subjects design. First, the participants underwent fear conditioning, in which conditioned stimuli (sounds) were paired with fearful images. This phase was directly followed by an extinction phase with a novelty-facilitated, familiar and standard extinction condition. After a time gap of a minimum of 12 to a maximum of 36 hours responses to the conditioned stimuli were tested again. Pupil size measurements and subjective arousal ratings during this post-extinction phase did not indicate an effect for novelty-facilitated extinction on the extent of fear, this may be the result of potential weak conditioning in the current study. The results of this study express the need for more research to understand the effect of novelty on fear extinction. This could contribute to future implementation of novelty in treatment of anxiety disorders.Show less
