Modulation of cortical resting state functional connectivity during a visuospatial attention task in Parkinson's disease

Abstract

Visual dysfunction is a recognized early symptom of Parkinson's disease (PD) that partly scales motor symptoms, yet its background is heterogeneous. With additional deficits in visuospatial attention, the two systems are hard to disentangle and it is not known whether impaired functional connectivity in the visual cortex is translative in nature or disrupted attentional modulation also contributes. In this study, we investigate functional connectivity modulation during a visuospatial attention task in patients with PD. In total, 15 PD and 16 age-matched healthy controls performed a visuospatial attention task while undergoing fMRI, in addition to a resting-state fMRI scan. Tensorial independent component analysis was used to investigate task-related network activity patterns. Independently, an atlas-based connectivity modulation analysis was performed using the task potency method. Spearman's rank correlation was calculated between task-related network expression, connectivity modulation, and clinical characteristics. Task-related networks including mostly visual, parietal, and prefrontal cortices were expressed to a significantly lesser degree in patients with PD (p < 0.027). Resting-state functional connectivity did not differ between the healthy and diseased cohorts. Connectivity between the precuneus and ventromedial prefrontal cortex was modulated to a higher degree in patients with PD (p < 0.004), while connections between the posterior parietal cortex and primary visual cortex, and also the superior frontal gyrus and opercular cortex were modulated to a lesser degree (p < 0.001 and p < 0.011). Task-related network expression and superior frontal gyrus–opercular cortex connectivity modulation were significantly associated with UPDRSIII motor scores and the Hoehn–Yahr stages (R = −0.72, p < 0.006 and R = −0.90, p < 0.001; R = −0.68, p < 0.01 and R = −0.71, p < 0.007). Task-related networks function differently in patients with PD in association with motor symptoms, whereas impaired modulation of visual and default-mode network connectivity was not correlated with motor function.

Parkinson’s disease patients show delayed hemodynamic changes in primary motor cortex in fine motor tasks and decreased resting-state interhemispheric functional connectivity: a functional near-infrared spectroscopy study

“… 18 RSFC has been used to compare differences in functional connectivity (FC) between patients with PD and age-matched controls using fMRI. 19 Comparing RSFC between these two groups can provide insights into the pathophysiology of PD and help identify potential biomarkers for early diagnosis and treatment. 19 …”

“… 19 Comparing RSFC between these two groups can provide insights into the pathophysiology of PD and help identify potential biomarkers for early diagnosis and treatment. 19 …”

“…18 RSFC has been used to compare differences in functional connectivity (FC) between patients with PD and age-matched controls using fMRI. 19 Comparing RSFC between these two groups can provide insights into the pathophysiology of PD and help identify potential biomarkers for early diagnosis and treatment. 19 In the present study, fNIRS was used to examine the hemodynamic response to fine motor skills in the motor cortex of PD patients and control participants.…”

“…19 Comparing RSFC between these two groups can provide insights into the pathophysiology of PD and help identify potential biomarkers for early diagnosis and treatment. 19 In the present study, fNIRS was used to examine the hemodynamic response to fine motor skills in the motor cortex of PD patients and control participants. First, correlations between the hemodynamic response function (HRF) parameters and clinical markers were analyzed.…”

Brain network analysis in Parkinson’s disease patients based on graph theory

“…Therefore, researchers in clinical practice are more likely to increase the statistical power of their study by employing more people, thereby enabling them to study the functional differences in Parkinson's disease without affecting error in the detection of specific tasks. This is important because in task-fMRI studies the activity or inactivity in motor or non-motor tasks due to abnormal brain function is not recognizable [12,13].…”