The mental representation of the body in action can be explored using motor imagery (MI) tasks. MI tasks can be allocated along a continuum going from more implicit to more explicit tasks, where the discriminant is the degree of action monitoring required to solve the tasks (which is the awareness of using the mental representation of our own body to monitor our motor imagery). Tasks based on laterality judgments, such as the Hand Laterality Task (HLT) and the Foot Laterality Task (FLT), provide an example of more implicit tasks (i.e., less action monitoring is required). While, an example of a more explicit task is the Mental Motor Chronometry task (MMC) for hands and feet, where individuals are asked to perform or imagine performing movements with their limbs (i.e., more action monitoring is required). In our study, we directly compared hands and feet at all these tasks for the first time, as these body districts have different physical features as well as functions. Fifty-five participants were asked to complete an online version of the HLT and FLT (more implicit measure), and an online version of the MMC task for hands and feet (more explicit measure). The mental representation of hands and feet in action differed only when the degree of action monitoring decreased (HLT ≠ FLT); we observed the presence of biomechanical constraints only for hands. Differently, when the degree of action monitoring increased hands and feet did not show any difference (MMC hands = MMC feet). Our results show the presence of a difference in the mental representation of hands and feet in action that specifically depends on the degree of action monitoring.

Background: Positive changes in weight gain and eating pathology were reported after inpatient treatments for anorexia nervosa (AN). However, changes in the physical body do not always mirror changes in the imagined body. Here, the effect of a treatment focused on body image (BI) was described. Methods: This retrospective observational study had a quasi-experimental pre-post design without the control group. During the treatment, participants (N = 72) undertake a variety of activities focused on BI. The main outcome was tested through the Body Uneasiness Test. Results: At the end of the treatment, BI uneasiness decreased with a significant increase in weight gain. Conclusion: This study highlights the positive short-term effect of a multidisciplinary inpatient intensive rehabilitation treatment on BI in AN. We encourage to design of psychological treatments focusing on the cognitive and emotional bodily representation (i.e. the body in the mind) to increase physical well-being.

The hand laterality task (HLT) and the foot laterality task (FLT) are used to explore motor imagery, the ability to imagine an action without executing it. With our limbs, we interact with our body, with others, and with the environment. These contacts might cause negative feelings, such as disgust. Disgust is elicited by different drivers. For instance, body products and body envelope violations provoke disgust to avoid contaminations and to avoid damaging our bodies. However, not much is known about how disgust changes our motor imagery processes. In this study, we examined whether there is any difference in the ability to imagine hands and feet when these are emotionally charged with reminders of disgust. Thirty-six participants completed an online version of a classic (neutral) HLT and FLT and two emotionally charged (disgust) versions. Our findings show that when body parts are modified so that they elicit emotional processing, disgust is salient overall, rather than being salient specifically for actions. This is true for both our hands and our feet.

Perceptual illusions of having extra body parts offer an experimental method to investigate the limits of body perception. It is well established that the illusory perception of an artificial hand as one’s own is dependent on spatial congruency. That is, the seen hand needs to be in a posture congruent with the actual hand. In this study, we aimed to investigate how constrained the representation of a supernumerary body part is by systematically varying the perceived rotation of an illusory sixth finger. Surprisingly, participants felt a sixth finger on their hand consistently for all induced orientations of finger extension and abduction (0°, 90°, 135°, 180°). The illusion showed no apparent decrease with increased induced rotation of the extra finger. We also measured the perceived orientation of the sixth finger, and our results show that participants felt an extended and an abducted sixth finger increasingly more rotated as the induced rotation also increased, while feeling their actual little finger in a normal position. Our results indicate that one can feel a supernumerary finger in an incongruent spatial location from one’s actual fingers and hand, to an extent of 180° of extension (finger up) and 180° of abduction (finger to the side). We therefore propose that the representation of the supernumerary finger has a strong independence from the actual finger and hand-frame reference.

As fundamental primary processes in maintaining the body's health, sleep and eating habits influence reciprocally, and this relationship is also modulated by circadian rhythms. Consistently, the literature reports various levels of alterations in sleep parameters and circadian preferences among individuals exhibiting dysfunctional eating behaviors. The present review aims to provide an up-to-date overview of case-control studies conducted to date on this topic. A systematic literature search was conducted to detect case-control studies investigating both subjective and objective sleep parameters and circadian preferences in individuals with eating disorders. Thirty-three articles published between 1980 and 2025 were included. Patients with eating disorders show reduced sleep efficiency, prolonged sleep onset latency, and increased arousal levels. Specifically, individuals with anorexia nervosa experience more frequent and longer nighttime awakenings, as well as reductions in both slow-wave sleep and REM sleep. In contrast, findings related to bulimia nervosa and binge eating disorder are quite inconsistent, partly due to the limited number of studies available. Overall, individuals with eating disorders tend to exhibit a preference for evening chronotypes. This review supports the existence of an association between eating disorders and alterations in sleep and circadian rhythms. Nonetheless, current research does not provide a consistent picture of the nature, characteristics, or causality of these dysfunctions. Several factors - such as body mass index, the severity of eating disorder symptoms, and orexin levels - appear to be involved. Further investigation into these relatively understudied areas could inform the development of more effective rehabilitation strategies.