Highlights A single night of TMR benefits procedural memories up to 10 days later. Spindle density and SO-spindle coupling strength increase immediately upon cue onset. Time spent in N2 but not N3 predicts cueing benefit.

Memory reactivation during Non-Rapid Eye Movement (NREM) sleep is important for memory consolidation but it remains unclear exactly how such activity promotes the development of a stable memory representation. We used Targeted Memory Reactivation (TMR) in combination with longitudinal structural and functional MRI to track the evolution of a motor memory trace over 20 days. We show that repeated reactivation of motor memory during sleep leads to increased precuneus activation 24 h post-TMR. Interestingly, a decrease in precuneus activity over the next 10 days predicts longer-term cueing benefit. We also find both functional and structural changes in sensorimotor cortex in association with effects of TMR 20 days post-encoding. These findings demonstrate that TMR can engage precuneus in the short-term while also impacting on task-related structure and function over longer timescales.

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Memory traces develop gradually and link to neural plasticity. Memory reactivation during sleep is crucial for consolidation, but its precise impact on plasticity and contribution to long-term memory storage remains unclear. We used multimodal diffusion-weighted imaging to track the location and timescale of microstructural changes following Targeted Memory Reactivation (TMR) of a motor task. This showed continuous microstructure plasticity in precuneus across 10 days post-TMR, paralleling the gradual development of behavioural benefit. Both early (0 - 24 h post-TMR) and late (24 h - 10 days post-TMR) microstructural changes in striatum and sensorimotor cortex were associated with the emergence of behavioural effects of TMR at day 20. Furthermore, the baseline microstructural architecture of sensorimotor cortex predicted TMR susceptibility. These findings demonstrate that repeated reactivation of memory traces during sleep engenders microstructural plasticity which continues days after the stimulation night and is associated with the emergence of memory benefits at the behavioural level.

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Background: A feeling of vulnerability is believed to be the foundation upon which paranoia is built. Factors that may increase vulnerability include negative affective states, low self-esteem and high social rejection sensitivity. Body image, which is one aspect of overall self-esteem, has recently been shown to be associated with paranoia, and this relationship is likewise thought to be based on increased feeling of vulnerability. However, little is known about factors underlying this association.Methods: In this online study conducted on a non-clinical sample, self-report data assessing paranoia-like thoughts, body image, self-esteem, negative emotions, rejection sensitivity as well as various attitudes and beliefs related to body appearance were collected. Results: The results revealed a significant serial mediation effect of negative emotions, self-esteem and rejection sensitivity in the relationship between body image and paranoia-like thoughts. Parallel mediation analysis showed an effect of social criticism as the only one of four studied groups of beliefs related to body appearance in the relationship between paranoia-like thoughts and body image. Paranoia-like thoughts were increased in people who were not satisfied with their body, both as a result of feeling too thin and overweight.Conclusions: Body image is an important factor related to paranoia-like thoughts, through its association with increased vulnerability and negative general self-view. The importance of negative emotions, low self-esteem and high rejection sensitivity, as well as the role of critical comments and lack of perceived acceptance was emphasized as a potential (socially-focused) mechanisms paving the way from negative body image to paranoia-like thoughts.

The way they look at me makes me feel worse about my body. How can paranoia-like thoughts lead to a more negative body image? Psychological Medicine 1-3.

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