Cortical Resting-state Functional Connectivity Research Articles

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

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.

Effects of cannabis use on striatal and cortical resting-state functional connectivity: Data from adolescents and adults

Effects of cannabis use on striatal and cortical resting-state functional connectivity: Data from adolescents and adults

Abnormal dynamics of cortical resting state functional connectivity in chronic headache patients

The goals of this study are to characterize the temporal dynamics of inter-regional connectivity of the brain in chronic headache (CH) patients versus their age/gender matched controls (CONCH, n=28 pairs), and to determine whether dynamic measures reveal additional features to static functional connectivity and correlate with psychometric scores. Cortical thickness and inter-regional resting state fMRI connectivity were quantified and compared between CH and CONCH groups. Six cortical regions of interest (ROI) pairs that exhibited correlated cortical thickness and static functional connectivity abnormalities were selected for temporal dynamic analysis. Two methods were used: temporal sliding-window (SW) and wavelet transformation coherence (WTC). SW analyses using three temporal windows of 30, 60, 120s revealed that all six ROI pairs of CH exhibited higher percentage of strong connectivity (high r values), and smaller fast Fourier transform (FFT) amplitudes at a very low frequency range (i.e., 0.002–0.01Hz), compared to those of CONCH. These features were particularly prevalent in the 120s window analysis. Less variable dynamic fluctuation (i.e., smaller standard deviation of r values) was identified in two out of six ROI pairs in CH. WTC analysis revealed that time-averaged coherence was generally greater in CH than CONCH between wavelet decomposition scales 20 to 55 (0.018–0.05Hz), and was statistically significant in three out of six ROI pairs. Together, the most robust and significant differences in temporal dynamics between CH and CONCH were detected in two ROI pairs: left medial-orbitofrontal–left posterior-cingulate and left medial-orbitofrontal–left inferior-temporal. The high degrees of sleep disturbance (high PSQI score), depression (high HRSD score) and fatigue (low SF-36 score) were associated with high degree of inter-regional temporal coherence in CH. In summary, these dynamic functional connectivity (dFC) measures uncovered a temporal “lock-down” condition in a subset of ROI pairs, showing static functional connectivity changes in CH patients. This study provides important evidence for the presence of associated psychological wellbeing and abnormal temporal dynamics in between specific cortical regions in CH patients.

Su1974 Classification of Cyclic Vomiting Syndrome Patients in Inter-Episodic Phase From Healthy Controls Using Cortical Resting State Functional Connectivity

Background/Aims: Anecdotal clinical evidence supports the use of carbonated liquids in reducing the likelihood of aspiration in dysphagic patients (Bulow et al,Acta Radiol 2003; Sdravou et al, Dysphagia 2011). Repetitive transcranial magnetic stimulation (rTMS) delivered at 1-Hz can induce transient focal suppression of pharyngeal motor cortex (Mistry S., et al. J Physiol, 2007). Here we investigated whether swallowing of carbonated water can reverse the inhibitory effects of a virtual lesion to pharyngeal motor cortex, compared to still water and saliva swallowing. Methods: In 9 healthy subjects (5 male, mean age 33.7 ± 14.34(SD)) pharyngeal electromyographic responses were recorded using an intraluminal catheter after the application of Transcranial Magnetic Stimulation (TMS) over pharyngeal motor cortex, as a measure of cortico-bulbar excitability. On 3 randomised visits, subjects were cued by a visual feedback software to perform a total of 40 swallows over 10 minutes (swallows every 15 s) of either carbonated water or still water vs. 10 minutes of saliva swallowing ad libitum (control), before and after an unilateral 1-Hz virtual lesion of the pharyngeal motor cortex. Cortical excitability (presented as mean ± SEM) was then reassessed bilaterally for 60 minutes post-interventions and analysed with two-way ANOVA (SPSS 14). Results: Compared to saliva swallowing (control), swallowing of carbonated water appeared to increase cortical excitability bilaterally (lesioned pharyngeal motor cortex: 68 ± 38% at 30 minutes post intervention, and to the unlesioned: 60 ± 24%, at 15 minutes post), not seen with still water swallowing. However, using a 2-way ANOVA, only the effects over the ipsilateral (lesioned) pharyngeal motor projection were statistical significant for carbonation (F1,8=6.2, p=0.037, Figure 1). Conclusion: Carbonation reverses the effects of a unilateral virtual lesion with significant increases in cortical excitability limited to the lesioned hemisphere. These data support the notion that chemesthetic solutions of carbonation may provide the required peripheral sensory information that can influence greater neuronal activity compared to still water swallowing. These data provides the platform for considering the use of carbonation as facilitating stimuli in dysphagic patients who aspirate thin liquids.