Objective: Using resting-state (RS) fMRI, we investigated the functional integrity of the default-mode network (DMN) in cognitively unimpaired patients with Parkinson disease (PD). Methods: RS fMRI at 3 T was collected in 16 cognitively unimpaired patients with PD and 16 age- and gender-matched healthy controls. Single-subject and group-level independent component analysis was used to investigate differences in functional connectivity within the DMN in patients with PD and healthy controls. Statistical analysis was performed using BrainVoyager QX. In addition, we used voxel-based morphometry to test whether between-group differences in RS functional connectivity were related to structural abnormalities. Results: Patients with PD compared with controls showed a decreased functional connectivity of the right medial temporal lobe and bilateral inferior parietal cortex within the DMN. Although patients with PD were cognitively unimpaired, the decreased DMN connectivity significantly correlated with cognitive parameters but not with disease duration, motor impairment, or levodopa therapy. The analysis of regional volume differences did not reveal any differences in local gray matter between patients and controls. Conclusions: Our findings revealed a functional disruption of the DMN in cognitively unimpaired patients with PD, in the absence of significant structural differences between patients and controls. We hypothesize that a dysfunction of the DMN connectivity may have a role in the development of cognitive decline in PD.

Background: The default-mode network (DMN) has been increasingly recognized as relevant to cognitive status.

Resting-state functional magnetic resonance imaging (RS-fMRI) has demonstrated disrupted default mode network (DMN) connectivity in a number of pain conditions, including migraine. However, the significance of altered resting-state brain functional connectivity in migraine is still unknown. The present study is aimed to explore DMN functional connectivity in patients with migraine without aura (MwoA) and investigate its clinical significance.

Background: Converging neuropsychological evidence suggests that in migraine executive functions (EF) may be affected during interictal periods. Objective: To evaluate the functional connectivity of the fronto-parietal networks (FPN) known to be associated with EF, in migraine without aura (MwoA) patients, in the interictal period, in comparison to healthy controls (HC). Methods: Using resting-state functional MRI (RS-fMRI), we compared functional connectivity within the FPN in 14 patients with MwoA versus 14 sex- and age-matched HC, and assessed the correlation between functional connectivity within FPN, clinical features of MwoA patients, and EF. We used voxel-based morphometry to assess whether between-group differences in functional connectivity were dependent on structural differences. Results: Neuropsychological data revealed no significant executive dysfunction in MwoA patients. RS-fMRI showed that MwoA patients, compared to HC, had significant functional connectivity reduction within the right FPN and specifically in the middle frontal gyrus (MFG) and the dorsal anterior cingulate cortex. In addition, we found that MFG reduced connectivity was negatively correlated with the pain intensity of migraine attacks. There were no structural differences between the two groups. Conclusions: Our data suggest that, even in the absence of clinically evident EF deficits, MwoA is associated with reduced FPN functional connectivity. This study provides further insights into the complex scenario of migraine mechanisms.

Objective: To evaluate the resting-state visual network functional connectivity in patients with migraine with aura and migraine without aura during the interictal period. Population and methods: Using resting-state functional magnetic resonance imaging, the resting-state visual network integrity was investigated in 20 patients with migraine with aura, 20 age- and sex-matched patients with migraine without aura and 20 healthy controls. Voxel-based morphometry and diffusion tensor imaging were used to assess whether between-groups differences in functional connectivity were dependent on structural or microstructural changes. Results: Resting-state functional magnetic resonance imaging data showed that patients with migraine with aura, compared to both patients with migraine without aura and healthy controls, had a significant increased functional connectivity in the right lingual gyrus within the resting-state visual network ( p < 0.05, cluster-level corrected). This abnormal resting-state visual network functional connectivity was observed in the absence of structural or microstructural abnormalities and was not related to migraine severity. Conclusions: Our imaging data revealed that patients with migraine with aura exhibit an altered resting-state visual network connectivity. These results support the hypothesis of an extrastriate cortex involvement, centred in the lingual gyrus, a brain region related to mechanisms underlying the initiation and propagation of the migraine aura. This resting-state functional magnetic resonance imaging finding may represent a functional biomarker that could differentiate patients experiencing the aura phenomenon from patients with migraine without aura, even between migraine attacks.