7 research outputs found
Restenosis and Therapy
The vascular disease involves imbalanced function of the blood vessels. Risk factors playing a role in development of impaired vessel functions will be briefly discussed. In ischemia/reperfusion (I/R), ischemic hypoxia is one of the cardinal risk factors of restenosis. Various insults are shown to initiate the phenotype switch of VSMCs. The pathological process, leading to activated inflammatory process, complement activation, and release of growth factors, initiate the proliferation of VSMCs in the media and cause luminal narrowing and impaired vascular function. The review summarizes the alteration process and demonstrates some of the clinical genetic background showing the role of complement and the genotypes of mannose-binding lectin (MBL2). Those could be useful markers of carotid restenosis after stent implantation. Gene therapy and therapeutic angiogenesis is proposed for therapy in restenosis. We suggest a drug candidate (iroxanadine), which ensures a noninvasive treatment by reverse regulation of the highly proliferating VSMCs and the disturbed function of ECs
Corticocortical evoked potentials reveal projectors and integrators in human brain networks.
The cerebral cortex is composed of subregions whose
functional specialization is largely determined by their
incoming and outgoing connections with each other. In the
present study, we asked which cortical regions can exert the
greatest influence over other regions and the cortical
network as a whole. Previous research on this question has
relied on coarse anatomy (mapping large fiber pathways) or
functional connectivity (mapping inter-regional statistical
dependencies in ongoing activity). Here we combined direct
electrical stimulation with recordings from the cortical
surface to provide a novel insight into directed, inter-
regional influence within the cerebral cortex of awake
humans. These networks of directed interaction were
reproducible across strength thresholds and across subjects.
Directed network properties included (1) a decrease in the
reciprocity of connections with distance; (2) major projector
nodes (sources of influence) were found in peri-Rolandic
cortex and posterior, basal and polar regions of the temporal
lobe; and (3) major receiver nodes (receivers of influence)
were found in anterolateral frontal, superior parietal, and
superior temporal regions. Connectivity maps derived from
electrical stimulation and from resting electrocorticography
(ECoG) correlations showed similar spatial distributions for
the same source node. However, higher-level network topology
analysis revealed differences between electrical stimulation
and ECoG that were partially related to the reciprocity of
connections. Together, these findings inform our
understanding of large-scale corticocortical influence as
well as the interpretation of functional connectivity
networks
Mapping human brain networks with cortico-ortical evoked potentials
The cerebral cortex forms a sheet of neurons organized into a network of interconnected modules that is highly expanded in humans and presumably enables our most refined sensory and cognitive abilities. The links of this network form a fundamental aspect of its organization, and a great deal of research is focusing on understanding how information flows within and between different regions. However, an often-overlooked element of this connectivity regards a causal, hierarchical structure of regions, whereby certain nodes of the cortical network may exert greater influence over the others. While this is difficult to ascertain non-invasively, patients undergoing invasive electrode monitoring for epilepsy provide a unique window into this aspect of cortical organization. In this review, we highlight the potential for corticocortical evoked potential (CCEP) mapping to directly measure neuronal propagation across large-scale brain networks with spatio-temporal resolution that is superior to traditional neuroimaging methods.We first introduce effective connectivity and discuss the mechanisms underlying CCEP generation. Next, we highlight how CCEP mapping has begun to provide insight into the neural basis of non-invasive imaging signals. Finally, we present a novel approach to perturbing and measuring brain network function during cognitive processing. The direct measurement of CCEPs in response to electrical stimulation represents a potentially powerful clinical and basic science tool for probing the large-scale networks of the human cerebral cortex. © 2014 The Author(s) Published by the Royal Society. All rights reserved