Individual abilities to perceive internal and external sensations are defined respectively as interoception and exteroception: the dysregulation of these functions can explain many psychotic symptoms. (Ardizzi et al. 2016)

We evaluated the differences in the interoceptive and exteroceptive perception between 39 patients with psychosis and 250 healthy controls using self-administered questionnaires. The association between interoception and exteroception in the two groups was also tested.

The tests we used are AASP (Adolescent / Adult Sensory Profile) and MAIA (Multidimensional Assessment of Interoceptive Awareness). Differences were measured with t-tests, associations with spearman’s correlation.

Significant differences emerged between the two samples in the AASP total score and in its Low registration (LR) and Sensory Avoiding (SA) sub-scales and in the MAIA total score and in all its sub-scales except “Not Worrying” (Fig.1). Different patterns of associations between AASP and MAIA were observed: psychotic patients showed negative correlations between MAIA and AASP in the LR and Sensation Seeking (SS) sub-scales and in the auditory (AU) and tactile (TO) sensory channels. Healthy controls, positive correlations emerged between MAIA and AASP in the Sensation Seeking (SK) sub-scale and in the “perception of movement” (MO) sub-score (Fig.2)(Fig.3).

Higher scores of psychotic patients in AASP and MAIA reveal both a disregulated sensory related behavior and a hightened awareness towards internal stimuli. The negative correlation between the two scales in psychotic subjects highlights the importance of the interaction between internal and external perception in determining the global subjective experience.

Despite the great number of resting state functional connectivity studies on Eating Disorders (ED), no biomarkers could be detected yet. Therefore, we here focus on a different measure of resting state activity that is neuronal variability. The objective of this study was to investigate neuronal variability in the resting state of women with ED and to correlate possible differences with clinical and psychopathological indices.

58 women respectively 25 with Anorexia Nervosa (AN), 16 with Bulimia Nervosa (BN) and 17 matched healthy controls (CN) were enrolled for the study. All participants were tested with a battery of psychometric tests and underwent a functional Magnetic Resonance Imaging (fMRI) resting state scanning. We investigated topographical patterns of variability measured by the Standard Deviation (SD) of the Blood-Oxygen-Level-Dependent (BOLD) signal (as a measure of neuronal variability) in the resting-state and their relationship to clinical and psychopathological indices.

Neuronal variability was increased in both anorectic and bulimic subjects specifically in the Ventral Attention Network (VAN) compared to healthy controls. No significant differences were found in the other networks. Significant correlations were found between neuronal variability of VAN and various clinical and psychopathological indices.

We here show increased neuronal variability of VAN in ED patients. As the VAN is relevant for switching between endogenous and exogenous stimuli, our results showing increased neuronal variability suggest unstable balance between body attention and attention to external world. These results offer new perspective on the neurobiological basis of ED. Clinical and therapeutic implication will be discussed.