To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Functional magnetic resonance imaging (fMRI) of multiple neural networks during the brain's ‘resting state’ could facilitate biomarker development in patients with Huntington's disease (HD) and may provide new insights into the relationship between neural dysfunction and clinical symptoms. To date, however, very few studies have examined the functional integrity of multiple resting state networks (RSNs) in manifest HD, and even less is known about whether concomitant brain atrophy affects neural activity in patients.
Using MRI, we investigated brain structure and RSN function in patients with early HD (n = 20) and healthy controls (n = 20). For resting-state fMRI data a group-independent component analysis identified spatiotemporally distinct patterns of motor and prefrontal RSNs of interest. We used voxel-based morphometry to assess regional brain atrophy, and ‘biological parametric mapping’ analyses to investigate the impact of atrophy on neural activity.
Compared with controls, patients showed connectivity changes within distinct neural systems including lateral prefrontal, supplementary motor, thalamic, cingulate, temporal and parietal regions. In patients, supplementary motor area and cingulate cortex connectivity indices were associated with measures of motor function, whereas lateral prefrontal connectivity was associated with cognition.
This study provides evidence for aberrant connectivity of RSNs associated with motor function and cognition in early manifest HD when controlling for brain atrophy. This suggests clinically relevant changes of RSN activity in the presence of HD-associated cortical and subcortical structural abnormalities.
Major depressive disorder (MDD) is characterized by alterations in brain function that are identifiable also during the brain's ‘resting state’. One functional network that is disrupted in this disorder is the default mode network (DMN), a set of large-scale connected brain regions that oscillate with low-frequency fluctuations and are more active during rest relative to a goal-directed task. Recent studies support the idea that the DMN is not a unitary system, but rather is composed of smaller and distinct functional subsystems that interact with each other. The functional relevance of these subsystems in depression, however, is unclear.
Here, we investigated the functional connectivity of distinct DMN subsystems and their interplay in depression using resting-state functional magnetic resonance imaging.
We show that patients with MDD exhibit increased within-network connectivity in posterior, ventral and core DMN subsystems along with reduced interplay from the anterior to the ventral DMN subsystems.
These data suggest that MDD is characterized by alterations of subsystems within the DMN as well as of their interactions. Our findings highlight a critical role of DMN circuitry in the pathophysiology of MDD, thus suggesting these subsystems as potential therapeutic targets.
In patients with major depressive disorder (MDD), functional neuroimaging studies have reported an increased activation of the dorsolateral prefrontal cortex (DLPFC) during executive performance and working memory (WM) processing, and also an increased activation of the anterior cingulate cortex (ACC) during baseline conditions. However, the functional coupling of these cortical networks during WM processing is less clear.
In this study, we used a verbal WM paradigm, event-related functional magnetic resonance imaging (fMRI) and multivariate statistical techniques to explore patterns of functional coupling of temporally dissociable dorsolateral prefrontal and cingulate networks. By means of independent component analyses (ICAs), two components of interest were identified that showed either a positive or a negative temporal correlation with the delay period of the cognitive activation task in both healthy controls and MDD patients.
In a prefronto-parietal network, a decreased functional connectivity pattern was identified in depressed patients comprising inferior parietal, superior prefrontal and frontopolar regions. Within this cortical network, MDD patients additionally revealed a pattern of increased functional connectivity in the left DLPFC and the cerebellum compared to healthy controls. In a second, temporally anti-correlated network, healthy controls exhibited higher connectivity in the ACC, the ventrolateral and the superior prefrontal cortex compared to MDD patients.
These results complement and expand previous functional neuroimaging findings by demonstrating a dysconnectivity of dissociable prefrontal and cingulate regions in MDD patients. A disturbance of these dynamic networks is characterized by a simultaneously increased connectivity of the DLPFC during task-induced activation and increased connectivity of the ACC during task-induced deactivation.
Email your librarian or administrator to recommend adding this to your organisation's collection.