Human brain mapping
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Human brain mapping · May 2015
Disrupted resting-state functional connectivity and its changing trend in migraine suffers.
Chronic pain has been linked with learning and memory processes and functional changes in brain plasticity in its development and maintenance via neuroimaging studies. However, the principle of reorganization of the migraine brain network as the brain progresses into chronic pain remain poorly understood. Here, using resting-state functional magnetic resonance imaging (rs-fMRI) and graph theory approaches, we aimed to investigate the dynamic dysfunctional connectivity in 108 patients with migraine without aura (MWoA) and 30 gender-matched healthy controls (HC). ⋯ Moreover, these brain regions exhibited a tendency to link to each other were organized into a strongly interconnected community. These interconnected brain regions were mainly located in the sensory-discriminative brain areas. Our results exhibited a working model of the central mechanisms of migraine where the brain functional connectivity was altered from the local central nervous system to a densely interconnected center, which may extend our understanding of the role of learning mechanisms which are likely involved in maintenance of chronic pain.
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Human brain mapping · May 2015
Measuring vascular reactivity with breath-holds after stroke: a method to aid interpretation of group-level BOLD signal changes in longitudinal fMRI studies.
Blood oxygenation level-dependent (BOLD) contrast functional magnetic resonance imaging (fMRI) is a widely used technique to map brain function, and to monitor its recovery after stroke. Since stroke has a vascular etiology, the neurovascular coupling between cerebral blood flow and neural activity may be altered, resulting in uncertainties when interpreting longitudinal BOLD signal changes. The purpose of this study was to demonstrate the feasibility of using a recently validated breath-hold task in patients with stroke, both to assess group level changes in cerebrovascular reactivity (CVR) and to determine if alterations in regional CVR over time will adversely affect interpretation of task-related BOLD signal changes. ⋯ CVR was reduced in the peri-infarct tissue but remained unchanged over time. Therefore, although a lack of activation in this region compared with the controls may be confounded by a reduced CVR, longitudinal group-level BOLD changes may be more confidently attributed to neural activity changes in this cohort. By including this breath-hold-based CVR assessment protocol in future studies of stroke recovery, researchers can be more assured that longitudinal changes in BOLD signal reflect true alterations in neural activity.
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Human brain mapping · May 2015
Meta AnalysisPain anticipation: an activation likelihood estimation meta-analysis of brain imaging studies.
The anticipation of pain has been investigated in a variety of brain imaging studies. Importantly, today there is no clear overall picture of the areas that are involved in different studies and the exact role of these regions in pain expectation remains especially unexploited. To address this issue, we used activation likelihood estimation meta-analysis to analyze pain anticipation in several neuroimaging studies. ⋯ The results of the meta-analytic connectivity analysis provide an overall view of the brain responses triggered by the anticipation of a noxious stimulus. Such a highly distributed perceptual set of self-regulation may prime brain regions to process information where emotion, action and perception as well as their related subcategories play a central role. Not only do these findings provide important information on the neural events when anticipating pain, but also they may give a perspective into nocebo responses, whereby negative expectations may lead to pain worsening.
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Human brain mapping · May 2015
Morphometric MRI alterations and postoperative seizure control in refractory temporal lobe epilepsy.
Refractory mesial temporal lobe epilepsy (mTLE) is a debilitating condition potentially amenable to resective surgery. However, between 40 and 50% patients continue to experience postoperative seizures. The development of imaging prognostic markers of postoperative seizure outcome is a crucial objective for epilepsy research. ⋯ Data uncorrected for multiple comparisons also revealed focal atrophy of the ipsilateral hippocampus posterior to the margins of resection in patients with persistent seizures. This data indicates that persistent postoperative seizures after temporal lobe surgery are related to localized preoperative shape alterations of the thalamus bilaterally and the hippocampus contralateral to intended resection. Imaging techniques that have the potential to unlock prognostic markers of postoperative outcome in individual patients should focus assessment on a bihemispheric thalamohippocampal network in prospective patients with refractory mTLE being considered for temporal lobe surgery.
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Human brain mapping · May 2015
Meta AnalysisDetermination of the posterior boundary of Wernicke's area based on multimodal connectivity profiles.
Wernicke's area is one of the most important language regions and has been widely studied in both basic research and clinical neurology. However, its exact anatomy has been controversial. In this study, we proposed to address the anatomy of Wernicke's area by investigating different connectivity profiles. ⋯ Anatomical connectivity, RSFC and MACM analyses consistently identified that the two anterior subregions in the posterior STG primarily participated in the language network, whereas the most posterior subregion in the temporoparietal junction area primarily participated in the default mode network. Moreover, the behavioral domain analyses, meta-analyses of semantics, execution speech and phonology and intraoperative electrical stimulation mapping also confirmed that only the two anterior subregions were involved in language processing, whereas the most posterior subregion primarily participated in social cognition. Our findings revealed a convergent posterior anatomical border for Wernicke's area and indicated that the brain's functional subregions can be identified on the basis of its specific structural and functional connectivity patterns.