Aberrant resting-state functional connectivity and topological properties of the subcortical network in functional dyspepsia patients

Abnormal functional connectivity of the reward circuit associated with early satiety in patients with postprandial distress syndrome

Postprandial distress syndrome (PDS) is the most common functional dyspepsia (FD) subtype. Early satiety is one of the cardinal symptoms of the PDS subtype in FD patients. The heterogeneity of symptoms in FD patients hampered therapy for patients based on specific symptoms, necessitating a symptom-based understanding of the pathophysiology of FD. To investigate the correlation between reward circuit and symptom severity of PDS patients, seed (Nucleus accumbens, NAc, a key node in the reward circuit) based resting-state functional connectivity (FC) was applied in the neuroimaging data analysis. The results demonstrated that the patients with PDS manifested strengthened FC between NAc and the caudate, putamen, pallidum, amygdala, hippocampus, thalamus, anterior cingulate cortex (ACC), and insula. Moreover, the FC between NAc and ACC, insula, thalamus, and hippocampus exhibited significant positive associations with symptom severity. More importantly, the strengthened FC between NAc and the ACC, insula, amygdala, and hippocampus were found associated with the early satiety symptom of patients with PDS. This study indicated that the altered FC of reward circuit regions may play a role in the pathophysiology of patients with PDS, and some of the aberrant NAc-based FC within the reward circuit were more related to the early satiety of patients with PDS. These findings improve our symptom-based understanding of the central pathophysiology of FD, lay the groundwork for an objective diagnosis of FD, and shed light on the precise prescription for treating FD based on symptoms.

Disrupted topological organization of functional brain networks in traumatic axonal injury

Traumatic axonal injury (TAI) may result in the disruption of brain functional networks and is strongly associated with cognitive impairment. However, the neural mechanisms affecting the neurocognitive function after TAI remain to be elucidated. We collected the resting-state functional magnetic resonance imaging data from 28 patients with TAI and 28 matched healthy controls. An automated anatomical labeling atlas was used to construct a functional brain connectome. We utilized a graph theoretical approach to investigate the alterations in global and regional network topologies, and network-based statistics analysis was utilized to localize the connected networks more precisely. The current study revealed that patients with TAI and healthy controls both showed a typical small-world topology of the functional brain networks. However, patients with TAI exhibited a significantly lower local efficiency compared to healthy controls, whereas no significant difference emerged in other small-world properties (Cp, Lp, γ, λ, and σ) and global efficiency. Moreover, patients with TAI exhibited aberrant nodal centralities in some regions, including the frontal lobes, parietal lobes, caudate nucleus, and cerebellum bilaterally, and right olfactory cortex. The network-based statistics results showed alterations in the long-distance functional connections in the subnetwork in patients with TAI, involving these brain regions with significantly altered nodal centralities. These alterations suggest that brain networks of individuals with TAI present aberrant topological attributes that are associated with cognitive impairment, which could be potential biomarkers for predicting cognitive dysfunction and help understanding the neuropathological mechanisms in patients with TAI.