No abstract

The purpose of this study is to investigate whether the topological organization of whole-brain functional network is disrupted in patients with Parkinson's disease (PD). We employed resting-state functional MRI (R-fMRI) and graph theory to investigate the topological organization of the functional connectome in 47 early-stage drug-naïve PD patients and 47 healthy control subjects. Correlations between network properties and clinical variables were tested. Both the PD and control groups showed small-world architecture in brain functional networks. However, the PD patients had lower clustering coefficient and local efficiency relative to control subjects, indicating disrupted topologic organization and a shift toward randomization in their functional brain network. At node and connection level, reduced node centralities and connectivity strength were found mainly in temporal-occipital regions and also in sensorimotor regions of PD patients. In PD patients, altered global network properties correlated with cognitive function, while motor impairment was correlated with local connection changes. This study demonstrates a disruption of whole-brain topological organization of the functional brain networks in early-stage drug-naïve PD patients and this disruption might contribute to preclinical changes in cognitive process in these patients.

Duricki et al. show that intramuscular delivery of human neurotrophin-3 induces corticospinal plasticity and locomotor recovery in adult and elderly rats 24 hours post-stroke. This time-frame would be clinically feasible for most stroke victims, and the safety and tolerability of neurotrophin-3 in humans have been established for other disorders.

Our study demonstrates that PD-Dep patients are characterised by increased regional spontaneous neural activity in the orbitofrontal area and decreased functional integration within the prefrontal-limbic network. These findings may be helpful for facilitating further understanding of the potential mechanisms underlying depression in PD.

By detecting spontaneous low-frequency fluctuations (LFF) of blood oxygen level–dependent (BOLD) signals, resting-state functional magnetic resonance imaging (rfMRI) measurements are believed to reflect spontaneous cerebral neural activity. Previous fMRI studies were focused on the examination of motor-related areas and little is known about the functional changes in the extra-motor areas in amyotrophic lateral sclerosis (ALS) patients. The aim of this study is to investigate functional cerebral abnormalities in ALS patients on a whole brain scale. Twenty ALS patients and twenty age- and sex-matched healthy volunteers were enrolled. Voxel-based analysis was used to characterize the alteration of amplitude of low frequency fluctuation (ALFF). Compared with the controls, the ALS patients showed significantly decreased ALFF in the visual cortex, fusiform gyri and right postcentral gyrus; and significantly increased ALFF in the left medial frontal gyrus, and in right inferior frontal areas after grey matter (GM) correction. Taking GM volume as covariates, the ALFF results were approximately consistent with those without GM correction. In addition, ALFF value in left medial frontal gyrus was negatively correlated with the rate of disease progression and duration. Decreased functional activity observed in the present study indicates the underlying deficits of the sensory processing system in ALS. Increased functional activity points to a compensatory mechanism. Our findings suggest that ALS is a multisystem disease other than merely motor dysfunction and provide evidence that alterations of ALFF in the frontal areas may be a special marker of ALS.