Search results for "Neural"
showing 10 items of 2783 documents
The human brain subventricular zone: stem cells in this niche and its organization.
2007
The human brain harbors stem cells in the subventricular zone (SVZ). The authors have collected postmortem and intraoperative tissue from adult human patients and found that it contains a unique ribbon of astrocytes that proliferate in vivo and can function as neural stem cells in vitro. Furthermore, they have conducted an anatomic, cytoarchitectural, and ultrastructural study in complete postmortem brains to define the precise organization of the lateral walls of the human lateral ventricles. With immunohistochemistry, the authors mapped a proliferative glial fibrillary acidic protein (GFAP)--positive ribbon of astrocytic cells in the human SVZ. In this article, the authors report on four …
Study on the transient characteristic in the human visual system using masking experiments
1979
In this paper the visual masking effect is interpreted on the basic of the transient characteristic in two dimensional neuronal networks. The study investigates the suitability of the effect for use as a measurement method. It is shown that the stimulus distribution in space can be scanned at different points in time and that various dynamic characteristic values of the system can be measured.
Retrograde monosynaptic tracing reveals the temporal evolution of inputs onto new neurons in the adult dentate gyrus and olfactory bulb
2013
Identifying the connectome of adult-generated neurons is essential for understanding how the preexisting circuitry is refined by neurogenesis. Changes in the pattern of connectivity are likely to control the differentiation process of newly generated neurons and exert an important influence on their unique capacity to contribute to information processing. Using a monosynaptic rabies virus-based tracing technique, we studied the evolving presynaptic connectivity of adult-generated neurons in the dentate gyrus (DG) of the hippocampus and olfactory bulb (OB) during the first weeks of their life. In both neurogenic zones, adult-generated neurons first receive local connections from multiple typ…
Neuronal network characteristics in the cat superior colliculus
1977
The system theoretical description of the superficial layers of neurons in the cat's superior colliculus is based on homogeneous linear space-time filters. The most important neurophysiological findings on the superior colliculus are simulated on the digital computer by generating suitable coupling functions and matching the space and time parameters. It is shown that the neurophysiological measurements can be interpreted by varying a few system parameters. The curves of velocity dependent responses, direction specificity and the effects of the colliculus specific surround are examined in particular. Computer simulation shows that such a surround can evaluate small moving stimuli differentl…
Multitasking associative networks.
2012
We introduce a bipartite, diluted and frustrated, network as a sparse restricted Boltzman machine and we show its thermodynamical equivalence to an associative working memory able to retrieve multiple patterns in parallel without falling into spurious states typical of classical neural networks. We focus on systems processing in parallel a finite (up to logarithmic growth in the volume) amount of patterns, mirroring the low-level storage of standard Amit-Gutfreund-Sompolinsky theory. Results obtained trough statistical mechanics, signal-to-noise technique and Monte Carlo simulations are overall in perfect agreement and carry interesting biological insights. Indeed, these associative network…
Architecture and cell types of the adult subventricular zone: in search of the stem cells.
1998
Neural stem cells are maintained in the subventricular zone (SVZ) of the adult mammalian brain. Here, we review the cellular organization of this germinal layer and propose lineage relationships of the three main cell types found in this area. The majority of cells in the adult SVZ are migrating neuroblasts (type A cells) that continue to proliferate. These cells form an extensive network of tangentially oriented pathways throughout the lateral wall of the lateral ventricle. Type A cells move long distances through this network at high speeds by means of chain migration. Cells in the SVZ network enter the rostral migratory stream (RMS) and migrate anteriorly into the olfactory bulb, where t…
Neurogenesis in adult subventricular zone
2002
Much excitement has been generated by the identification of adult brain regions harboring neural stem cells and their continual generation of new neurons throughout life. This is an important departure from traditional views of the germinal potential of the postnatal brain. However, a more profound
Serotonin-dopamine interaction: electrophysiological evidence.
2008
In this review, the most relevant data regarding serotonin (5-hydroxytryptamine, 5-HT)/dopamine (DA) interaction in the brain, as studied by both in vivo and in vitro electrophysiological methods, are reported and discussed. The bulk of neuroanatomical data available clearly indicate that DA-containing neurons in the brain receive a prominent innervation from 5-HT originating in the raphe nuclei of the brainstem. Furthermore, this modulation seems to be reciprocal; DA neurons innervate the raphe nuclei and exert a tonic excitatory effect on them. Compelling electrophysiological data show that 5-HT can exert complex effects on the electrical activity of midbrain DA neurons mediated by the va…
A combined ex/in vivo assay to detect effects of exogenously added factors in neural stem cells.
2007
We describe a protocol developed/modified by our group for the ex vivo and in vivo assessment of the response to a soluble factor of murine neural stem cells from the adult sub-ventricular zone (SVZ). The procedure includes several experimental options that can be used either independently or in combination. Potential factor effects on self-renewal, survival and proliferation are assayed by means of neurosphere cultures, with the factor administered directly in vitro to the culture plates (Step 1) or infused in vivo immediately before tissue dissociation (Step 3). We also use bromodeoxiuridine (BrdU) retention to label slowly dividing cells in vivo and subsequently perform two different typ…
Imported Stem Cells Strike against Stroke.
2015
Cells with neural stem cell (NSC)-like properties can be isolated from the cortex of adult brains following injury, but their origins and function are unclear. Now in Cell Stem Cell, Faiz et al. (2015) show that subventricular-zone-derived NSCs home to injured cortical area following stroke, where they generate reactive astrocytes.