Dissociative symptoms refer to disturbances in the integration of thoughts, feelings, and experiences into consciousness and memory. They overlap with schizotypical features, notably paranoid thinking. In recent studies, I found evidence that labile sleep-wake cycles a) lead to dreamlike mentation invading the waking state, b) produce memory failures, and c) fuel dissociative symptoms. This pattern of findings may inspire new treatments for dissociative symptoms (e.g., interventions that focus on normalization of the sleep-wake cycle), which is important because dissociative symptoms are notoriously recalcitrant to pharmacological and psychotherapeutic interventions. In this proposal, I aim to study the mechanisms underlying the link between sleep problems, dissociative symptoms, and paranoid thinking. One candidate mechanism might be emotional memory processing during REM sleep. I propose to conduct three studies; 1) a cross-sectional study to look at the correlations between dissociation, paranoid thinking, sleep aberrations, and memory measures; 2) a sleep deprivation experiment to test whether sleep disruption per se induces dissociative symptoms, paranoid thinking, and deteriorated emotional processing, and 3) a Cognitive Behavioural Therapy (CBT) intervention study aimed at sleep normalization to explore whether sleep improvement reduces dissociative symptoms and paranoid thinking through the improvement of emotional memory processing.

Tinnitus, or the ringing of the ears, is defined as the perception of a continuous sound, in the absence of a corresponding acoustic stimulus in the external environment. It is estimated that in Europe over 70 million people experience tinnitus and that for 7 million it creates a chronic incapacitating condition, tenaciously haunting them up to the point where it interferes with every aspect of their daily living. Residing within and confined to the individuals subjective and perceptual experience, tinnitus is not measurable or quantifiable by objective physical recordings, and is furthermore not traceable to disease, injury, or pathology in the brain or elsewhere. Empirical evidence for either the effectiveness of curative tinnitus treatments or for audiological interventions, such as hearing-aids, and sound-generating devices to mask the sound, is lacking. Moreover, the audiometric characteristics of the tinnitus sound (loudness/pitch) hardly predict severity of the condition, or treatment outcomes. Contrary to scientific evidence, the clinical practice of masking/attenuating the tinnitus-sound is still the most widespread tinnitus-treatment approach. Presently I propose the counterintuitive conjecture that it is not the sound itself which is so devastating, but rather the fear-conditioned responses and the associated threat appraisals that maintain severe tinnitus disability. Indeed, empirical evidence is growing for the effectiveness of a cognitive behavioral approach and our recent findings support the importance of addressing tinnitus-related fear and fear-responses in the management of patients with disabling tinnitus. In this project I will experimentally test the idea that initial threat-appraisal and fearful responses predict increased tinnitus suffering. In addition, I will test the idea that exposure to the tinnitus sound is an effective way of decreasing fear of tinnitus and disability in the long term, whereas masking the sound is counterproductive. My research may provide an important impetus for the development of novel tinnitus-treatment approaches. Keywords: Tinnitus, threat-appraisal, fear-conditioning, exposure, masking

Fear of weight gain and restrictive eating are key symptoms of anorexia nervosa. It is unclear why patients continue to do so despite severe and sometimes life-threatening weight loss. We found that food avoidance can be learned. Learned food avoidance is persistent and reinforces a fear of eating in the healthy participants in our study. Moreover, avoidance became a signal: "If I avoid food, then that food must be dangerous for me". Fear and food avoidance thus reinforce each other. Such a vicious cycle could contribute to the increasingly extreme symptoms of anorexia nervosa.

Fear is a universal experience and fuels our response to cope with threat. Persistent fear, after the threat is no longer present, is a central symptom seen in a number of clinical disorders. Current treatment focuses exclusively on trying to reduce the fear response (fear extinction), rather than target the underlying mechanism: inhibitory learning. Using a newly developed paradigm, we will target inhibitory learning using intentional memory suppression during extinction. We will test whether intentional memory suppression can stop the retrieval of fear memories and, as a result be used to boost fear amnesia, the forgetting of the fear.

More and more people in our society are experiencing prolonged stress. Although it is known that stress affects memory, the impact on active forgetting remains a question. Our research showed that acute stress impaired active forgetting, depending on the strength of the memories. On the other hand, mindfulness improved the ability to control intentional memory. These findings contribute to our understanding of how the healthy brain actively manages memories, which factors can cause control to fail, and how we can enhance it. This has implications for the development of therapeutic interventions aimed at improving memory control.