NeuroImage. Clinical
-
NeuroImage. Clinical · Jan 2018
Short timescale abnormalities in the states of spontaneous synchrony in the functional neural networks in Alzheimer's disease.
Alzheimer's disease (AD) is a prevalent neurodegenerative condition that can lead to severe cognitive and functional deterioration. Functional magnetic resonance imaging (fMRI) revealed abnormalities in AD in intrinsic synchronization between spatially separate regions in the so-called default mode network (DMN) of the brain. To understand the relationship between this disruption in large-scale synchrony and the cognitive impairment in AD, it is critical to determine whether and how the deficit in the low frequency hemodynamic fluctuations recorded by fMRI translates to much faster timescales of memory and other cognitive processes. ⋯ These findings highlight relevance of studying short-scale temporal evolution of spontaneous activity in functional neural networks to understanding the AD pathophysiology. Capacity of flexible intrinsic synchronization in the DMN may be crucial for memory and other higher cognitive functions. Our analysis yielded metrics that quantify distinct features of the neural synchrony disorder in AD and may offer sensitive indicators of the neural network health for future investigations.
-
NeuroImage. Clinical · Jan 2018
Isolated focal dystonia phenotypes are associated with distinct patterns of altered microstructure.
Isolated adult-onset focal dystonia is considered a network disorder with disturbances to the motor basal ganglia and cerebellar circuits playing a pathophysiological role, but why specific body regions become affected remains unknown. We aimed to use diffusion tensor imaging to determine if the two most common phenotypes of focal dystonia are associated with distinguishing microstructural changes affecting the motor network. ⋯ Different focal dystonia phenotypes are associated with distinct patterns of altered microstructure within constituent regions of basal ganglia and cerebellar circuits.
-
NeuroImage. Clinical · Jan 2018
The two-year progression of structural and functional cerebral MRI in amyotrophic lateral sclerosis.
MRI has emerged as one of several urgently needed candidate disease progression biomarkers for the neurodegenerative disorder amyotrophic lateral sclerosis (ALS), not least due to its unique ability to non-invasively assess structural and functional cerebral pathology. We sought to identify the extent of detectable change in cerebral MRI metrics over a more prolonged period. Analysis of multi-modal MRI data was performed in a cohort of sixteen patients (13 ALS and 3 with primary lateral sclerosis) in whom it was possible to acquire six-monthly images over two years. ⋯ FC increases between the left primary motor cortex and left fronto-parietal network were seen for both statistical approaches. A longer period of follow-up, though necessarily involving more slowly-progressive cases, demonstrated widespread changes in both grey and white matter structural MRI measures. The mixed picture of regional decreases and increases in FC is compatible with compensatory change, in what should be viewed as a brain-based disease characterised by larger-scale disintegration of motor and frontal projection cerebral networks.
-
NeuroImage. Clinical · Jan 2018
Cortical markers of cognitive syndromes in amyotrophic lateral sclerosis.
Amyotrophic lateral sclerosis (ALS) can be associated with a spectrum of cognitive and behavioural symptoms, but the related patterns of focal cortical atrophy in non-demented ALS patients remain largely unknown. We enrolled 48 non-demented ALS patients and 26 healthy controls for a comprehensive neuropsychological assessment and a magnetic resonance exam. Behavioural and cognitive impairment was defined on the basis of a data-driven multi-domain approach in 21 ALS patients. ⋯ Cortical thinning in a fronto-parietal network, suggesting a disease-specific pattern of neurodegeneration, was present in all patients, independent of cognitive and behavioural status. Between-group and correlational analyses revealed that inferior frontal, temporal, cingular and insular thinning are markers for cognitive and behavioural deficits, with language impairment mainly related to left temporal pole and insular involvement. These specific correlates support the concept of a spectrum of deficits, with an overlap between the ALS cognitive phenotypes and the syndromes of frontotemporal dementia.
-
NeuroImage. Clinical · Jan 2018
Integrated imaging of [11C]-PBR28 PET, MR diffusion and magnetic resonance spectroscopy 1H-MRS in amyotrophic lateral sclerosis.
To determine the relationship between brain tissue metabolites measured by in vivo magnetic resonance spectroscopy (1H-MRS), and glial activation assessed with [11C]-PBR28 uptake in people with amyotrophic lateral sclerosis (ALS). ⋯ Integrated PET-MR and 1H-MRS imaging demonstrates associations between markers for neuronal integrity and neuroinflammation and may provide valuable insights into disease mechanisms in ALS.