Resting state functional connectivity of networks associated with reward and habit in anorexia nervosa

Abstract

Neurobiological disturbances associated with reward and/or habit learning are theorized to maintain symptoms of anorexia nervosa (AN). Although research has investigated responses in brain regions associated with reward and habit to disorder-specific cues (e.g., food) and presumed rewards (e.g., money), little is known about the functional organization of the circuits underlying these constructs independent of stimulus. This study aimed to provide initial data on the synchrony of networks associated with reward and habit in AN by comparing resting-state functional connectivity (RSFC) patterns between AN and healthy control (HC) participants in these circuits and delineating how these patterns relate to symptoms. Using theoretically selected seeds in the nucleus accumbens (NAcc), ventral caudate, and dorsal caudate, reflecting a continuum from reward- to habit- oriented regions, RSFC patterns were compared between AN restricting subtype (n = 19) and HC (n = 19) participants (cluster threshold: p < .01). Exploratory correlations between RSFC z-scores and Eating Disorder Examination (EDE) scores, BMI, and illness duration were conducted. The AN group demonstrated lower RSFC between the NAcc and superior frontal gyrus, between the ventral caudate and frontal and posterior regions, and between the dorsal caudate and frontal, temporal, and posterior regions. In the AN group, lower NAcc- superior frontal gyrus RSFC correlated with greater EDE Global scores (r = −.58, CI: −.83, −.13). These resting-state synchrony disruptions of the ventral and dorsal frontostriatal circuits, considered in context of the broader literature, support the utility of further investigating possible reward and habit disturbances supporting symptoms in AN.

Resting‐state connectivity within and across neural circuits in anorexia nervosa

“…Subtypes effects have not been systematically assessed in prior research. Some studies have not reported subtype analyses (Biezonski et al, ; Favaro et al, ; Phillipou et al, ) and other studies only included AN‐R (Haynos et al, ). One study had unbalanced numbers in each subtype group which limited between‐group comparisons (Boehm et al, ).…”

“…The direction of effect differs across studies. Our patient sample was unmedicated and included individuals with both AN subtypes, whereas the study by Haynos et al () permitted psychotropic medications and studied individuals with AN‐R only. As frontal activation has been shown to change with psychotropics (Posner et al, ), medication status may influence frontostriatal circuit connectivity results.…”

“…It is used to investigate the functional architecture of the brain at rest (Lee, Smyser, & Shimony, ). In AN, a number of rs‐fcMRI studies have demonstrated evidence of disturbed functional connectivity in brain regions associated with cortico‐striato‐thalamo‐cortical (CSTC) circuitry which have also been implicated in OCD (Biezonski, Cha, Steinglass, & Posner, ; Cha et al, ; Ehrlich et al, ; Haynos et al, ). Using network‐based statistics (NBS), Ehrlich et al identified reduced functional connectivity in a thalamo‐insular subnetwork among underweight adolescents and young adults with AN relative to healthy control participants (HC) (Ehrlich et al, ).…”

“…Another study measuring thalamo‐frontal functional connectivity in acutely ill individuals with AN relative to HC found evidence of altered connectivity between the thalamus and both the dorsal and anterior prefrontal cortices which were associated with impairments in tasks measuring cognitive control and working memory, respectively (Biezonski et al, ). Haynos et al () used a seed‐based approach to investigate ventral and dorsal frontostriatal circuits and found evidence of reduced functional connectivity in both circuits among underweight individuals with restricting type AN relative to HC. Cha et al () found increased left‐sided nucleus accumbens (NAcc)–medial orbitofrontal cortex (mOFC) connectivity among underweight AN relative to HC.…”

Multimodal neuroimaging in anorexia nervosa

“…As abovementioned, parietal cortex is severely involved. Functional neuroimaging studies reported its alteration (Kojima et al, 2005;Van Kuyck et al, 2009) specifying that parietal activity at rest is treatment sensitive, since it increases after treatment (Delvenne et al, 1995;Kojima et al, 2005 (Haynos et al, 2019).…”