Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
2,530
result(s) for
"Stam,"
Sort by:
Non-invasive measurements of ictal and interictal epileptiform activity using optically pumped magnetometers
Magneto- and electroencephalography (MEG/EEG) are important techniques for the diagnosis and pre-surgical evaluation of epilepsy. Yet, in current cryogen-based MEG systems the sensors are offset from the scalp, which limits the signal-to-noise ratio (SNR) and thereby the sensitivity to activity from deep structures such as the hippocampus. This effect is amplified in children, for whom adult-sized fixed-helmet systems are typically too big. Moreover, ictal recordings with fixed-helmet systems are problematic because of limited movement tolerance and/or logistical considerations. Optically Pumped Magnetometers (OPMs) can be placed directly on the scalp, thereby improving SNR and enabling recordings during seizures. We aimed to demonstrate the performance of OPMs in a clinical population. Seven patients with challenging cases of epilepsy underwent MEG recordings using a 12-channel OPM-system and a 306-channel cryogen-based whole-head system: three adults with known deep or weak (low SNR) sources of interictal epileptiform discharges (IEDs), along with three children with focal epilepsy and one adult with frequent seizures. The consistency of the recorded IEDs across the two systems was assessed. In one patient the OPMs detected IEDs that were not found with the SQUID-system, and in two patients no IEDs were found with either system. For the other patients the OPM data were remarkably consistent with the data from the cryogenic system, noting that these were recorded in different sessions, with comparable SNRs and IED-yields overall. Importantly, the wearability of OPMs enabled the recording of seizure activity in a patient with hyperkinetic movements during the seizure. The observed ictal onset and semiology were in agreement with previous video- and stereo-EEG recordings. The relatively affordable technology, in combination with reduced running and maintenance costs, means that OPM-based MEG could be used more widely than current MEG systems, and may become an affordable alternative to scalp EEG, with the potential benefits of increased spatial accuracy, reduced sensitivity to volume conduction/field spread, and increased sensitivity to deep sources. Wearable MEG thus provides an unprecedented opportunity for epilepsy, and given its patient-friendliness, we envisage that it will not only be used for presurgical evaluation of epilepsy patients, but also for diagnosis after a first seizure.
Journal Article
Modern network science of neurological disorders
Key Points
Healthy structural and functional brain networks are characterized by a cost-effective architecture, which has an optimal balance between local and global connectivity, and a hierarchical modular structure.
Normal brain-network organization arises during development under genetic control and is correlated with cognitive function.
Local brain lesions give rise to widespread changes to networks, whereas global brain disorders preferentially affect highly connected hub regions.
In many neurological disorders, the most consistent changes concern a breakdown of the hierarchical modular structure and, in particular, a loss of highly connected hub areas.
The pattern of network changes in neurological disorders may be explained by a hypothetical scenario of 'hub overload and failure'.
The application of network science to several common neurological disorders challenges the idea that these disorders are either 'local' or 'global'. In this Review, Kees Stam proposes a model of hub overload and failure as a possible final common pathway in diverse neurological disorders.
Modern network science has revealed fundamental aspects of normal brain-network organization, such as small-world and scale-free patterns, hierarchical modularity, hubs and rich clubs. The next challenge is to use this knowledge to gain a better understanding of brain disease. Recent developments in the application of network science to conditions such as Alzheimer's disease, multiple sclerosis, traumatic brain injury and epilepsy have challenged the classical concept of neurological disorders being either 'local' or 'global', and have pointed to the overload and failure of hubs as a possible final common pathway in neurological disorders.
Journal Article
Race in Translation
While the term culture wars often designates the heated arguments in the English-speaking world spiraling around race, the canon, and affirmative action, in fact these discussions have raged in diverse sites and languages. Race in Translation charts the transatlantic traffic of the debates within and between three zones - the U.S., France, and Brazil. Stam and Shohat trace the literal and figurative translation of these multidirectional intellectual debates, seen most recently in the emergence of postcolonial studies in France, and whiteness studies in Brazil. The authors also interrogate an ironic convergence whereby rightist politicians like Sarkozy and Cameron join hands with some leftist intellectuals like Benn Michaels, iek, and Bourdieu in condemning multiculturalism and identity politics. At once a report from various fronts in the culture wars, a mapping of the germane literatures, and an argument about methods of reading the cross-border movement of ideas, the book constitutes a major contribution to our understanding of the Diasporic and the Transnational.
eBook
The minimum spanning tree: An unbiased method for brain network analysis
The brain is increasingly studied with graph theoretical approaches, which can be used to characterize network topology. However, studies on brain networks have reported contradictory findings, and do not easily converge to a clear concept of the structural and functional network organization of the brain. It has recently been suggested that the minimum spanning tree (MST) may help to increase comparability between studies. The MST is an acyclic sub-network that connects all nodes and may solve several methodological limitations of previous work, such as sensitivity to alterations in connection strength (for weighted networks) or link density (for unweighted networks), which may occur concomitantly with alterations in network topology under empirical conditions. If analysis of MSTs avoids these methodological limitations, understanding the relationship between MST characteristics and conventional network measures is crucial for interpreting MST brain network studies. Here, we firstly demonstrated that the MST is insensitive to alterations in connection strength or link density. We then explored the behavior of MST and conventional network-characteristics for simulated regular and scale-free networks that were gradually rewired to random networks. Surprisingly, although most connections are discarded during construction of the MST, MST characteristics were equally sensitive to alterations in network topology as the conventional graph theoretical measures. The MST characteristics diameter and leaf fraction were very strongly related to changes in the characteristic path length when the network changed from a regular to a random configuration. Similarly, MST degree, diameter, and leaf fraction were very strongly related to the degree of scale-free networks that were rewired to random networks. Analysis of the MST is especially suitable for the comparison of brain networks, as it avoids methodological biases. Even though the MST does not utilize all the connections in the network, it still provides a, mathematically defined and unbiased, sub-network with characteristics that can provide similar information about network topology as conventional graph measures.
•Conventional network analyses are accompanied with methodological limitations.•The minimum spanning tree is an acyclic sub-network that connects all nodes in the original network.•The minimum spanning tree avoids several methodological biases.•Minimum spanning tree metrics can be interpreted along the lines of conventional network analyses.
Journal Article
CURRENT CONCEPTS: Thrombosis of the Cerebral Veins and Sinuses
Thrombosis of the cerebral veins and sinuses affects mainly young adults and children. This potentially disabling or fatal condition is usually not diagnosed until a week after the onset of symptoms. This review article describes the clinical presentations of the disorder such as those that occur after a head injury or lumbar puncture. Therapeutic options include anticoagulation, thrombolysis, and measures to control intracranial hypertension.
Journal Article
Micro-foundations for innovation policy
In economics, business, and government policy, innovation policy requires the creation of new approaches based on insight in what happens in innovation processes, on the micro level of people, firms and interaction between them. In innovation policy it should also be recognized that innovation entails a whole range of activities beyond R&D, such as entrepreneurship, design, commercialization, organization, collaboration and the diffusion of knowledge and innovations . This edited volume explores the roles of individuals and organizations involved in the creation and application of innovations. Covering topics as diverse as the macro-economic importance of innovation, theories of knowledge and learning, entrepreneurship, education and research, organizational innovation, networks and regional innovation systems, Micro-Foundations for Innovation Policy provides critical insights into the development of innovation policy.
eBook