Reduced Resting-State Functional Connectivity of the Somatosensory Cortex Predicts Psychopathological Symptoms in Women with Bulimia Nervosa

Abstract

Background: Alterations in the resting-state functional connectivity (rs-FC) of several brain networks have been demonstrated in eating disorders. However, very few studies are currently available on brain network dysfunctions in bulimia nervosa (BN). The somatosensory network is central in processing body-related stimuli and it may be altered in BN. The present study therefore aimed to investigate rs-FC in the somatosensory network in bulimic women.Methods: Sixteen medication-free women with BN (age = 23 ± 5 years) and 18 matched controls (age = 23 ± 3 years) underwent a functional magnetic resonance resting-state scan and assessment of eating disorder symptoms. Within-network and seed-based functional connectivity analyses were conducted to assess rs-FC within the somatosensory network and to other areas of the brain.Results: Bulimia nervosa patients showed a decreased rs-FC both within the somatosensory network (t = 9.0, df = 1, P = 0.005) and with posterior cingulate cortex and two visual areas (the right middle occipital gyrus and the right cuneus) (P = 0.05 corrected for multiple comparison). The rs-FC of the left paracentral lobule with the right middle occipital gyrus correlated with psychopathology measures like bulimia (r = −0.4; P = 0.02) and interoceptive awareness (r = −0.4; P = 0.01). Analyses were conducted using age, BMI (body mass index), and depressive symptoms as covariates.Conclusion: Our findings show a specific alteration of the rs-FC of the somatosensory cortex in BN patients, which correlates with eating disorder symptoms. The region in the right middle occipital gyrus is implicated in body processing and is known as extrastriate body area (EBA). The connectivity between the somatosensory cortex and the EBA might be related to dysfunctions in body image processing. The results should be considered preliminary due to the small sample size.

Altered intrinsic functional brain architecture in female patients with bulimia nervosa

“…45 The relevance of the sensorimotor and occipital regions to distorted body image has been emphasized in several previous studies. [9][10][11]14 For instance, reduced occipitotemporal responses during presentations of underweight or overweight human bodies were observed in patients with bulimia nervosa; 9 the lateral occipital activation was sensitive to stimuli of body size distortions in healthy people, whereas such a modulation was not observed in those with bulimia nervosa. 10 At rest, patients with bulimia nervosa showed abnormal iFC within the somatosensory network and between the paracentral lobule and 2 occipital regions.…”

“…These multidimensional pathological features collectively induce the body image distortion and binge eating and purging behaviours characteristic of bulimia nervosa. A few studies have highlighted an involvement of abnormal intrinsic functional connectivity (iFC) of the somatosensory network, 14 ACC and precuneus 15 in the disturbances of body image processing of bulimia nervosa.…”

“…17 These network properties are disrupted under pathological conditions, such as schizophrenia, 18 depression 19 and anorexia nervosa. 20 Although a few studies 14,15 have used resting-state fMRI to map the brain connectivity in patients with bulimia nervosa, they all adopted a seedbased analysis strategy examining connectivity between predefined regions -a potentially biased approach lacking a global brain perspective. Because bulimia nervosa involves disturbances of a broad range of neural processes from basic sensory and visual processing to higher-level cognition functions, 21 it is likely that this disorder affects information exchange across large-scale brain networks.…”

“…We hypothesized that patients with bulimia nervosa would show abnormal topological properties in functional brain networks and that the functional disturbances would be apparent in the cortical and subcortical regions involved in reward and emotional processing, sensorimotor and visual perception, and interoception, based on potential relevance of these neural functions to bulimia nervosa. [2][3][4][5][6][7][8][9][10][11][12][13][14][15] We also examined the behavioural/symptom correlates of these network properties.…”

Psychopathology of Eating Disorders According to Neurobiology of Attachment: An Instrument to Overcome Resistances to Treatment?

“…Thus, not only the relational attitudes described as attachment patterns are definite by the first interactions with the caregiver and will constitute the basis for the future relational interaction (included the therapeutic relationship), but the psychological functioning pertaining the Self and the related structures of the brain are modified in the subjects affected with eating disorders by their early interactions with their caregivers, and these alterations are strictly related to their eating psychopathology (Amianto et al, 2013a,b [14,15]; Cicereale et al, 2014 [16]; D'Agata et al, 2015 [17]; Lavagnino et al, 2014Lavagnino et al, , 2015 [18,19].…”