Home About us Contact
|
Home About us Contact | ||
|
|
||
Same Stimuli (same + stimulus)
Selected AbstractsCortical sources of the early components of the visual evoked potentialHUMAN BRAIN MAPPING, Issue 2 2002Francesco Di Russo Abstract This study aimed to characterize the neural generators of the early components of the visual evoked potential (VEP) to isoluminant checkerboard stimuli. Multichannel scalp recordings, retinotopic mapping and dipole modeling techniques were used to estimate the locations of the cortical sources giving rise to the early C1, P1, and N1 components. Dipole locations were matched to anatomical brain regions visualized in structural magnetic resonance imaging (MRI) and to functional MRI (fMRI) activations elicited by the same stimuli. These converging methods confirmed previous reports that the C1 component (onset latency 55 msec; peak latency 90,92 msec) was generated in the primary visual area (striate cortex; area 17). The early phase of the P1 component (onset latency 72,80 msec; peak latency 98,110 msec) was localized to sources in dorsal extrastriate cortex of the middle occipital gyrus, while the late phase of the P1 component (onset latency 110,120 msec; peak latency 136,146 msec) was localized to ventral extrastriate cortex of the fusiform gyrus. Among the N1 subcomponents, the posterior N150 could be accounted for by the same dipolar source as the early P1, while the anterior N155 was localized to a deep source in the parietal lobe. These findings clarify the anatomical origin of these VEP components, which have been studied extensively in relation to visual-perceptual processes. Hum. Brain Mapping 15:95,111, 2001. © 2001 Wiley-Liss, Inc. [source] Integrative nuclear FGFR1 signaling (INFS) as a part of a universal "feed-forward-and-gate" signaling module that controls cell growth and differentiationJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 4 2003Michal K. Stachowiak Abstract A novel signaling mechanism is described through which extracellular signals and intracellular signaling pathways regulate proliferation, growth, differentiation, and other functions of cells in the nervous system. Upon cell stimulation, fibroblast growth factor receptor-1 (FGFR1), a typically plasma membrane-associated protein, is released from ER membranes into the cytosol and translocates to the cell nucleus by an importin-,-mediated transport pathway along with its ligand, FGF-2. The nuclear accumulation of FGFR1 is activated by changes in cell contacts and by stimulation of cells with growth factors, neurotransmitters and hormones as well as by a variety of different second messengers and thus was named integrative nuclear FGFR1 signaling (INFS). In the nucleus, FGFR1 localizes specifically within nuclear matrix-attached speckle-domains, which are known to be sites for RNA Pol II-mediated transcription and co-transcriptional pre-mRNA processing. In these domains, nuclear FGFR1 colocalizes with RNA transcription sites, splicing factors, modified histones, phosphorylated RNA Pol II, and signaling kinases. Within the nucleus, FGFR1 serves as a general transcriptional regulator, as indicated by its association with the majority of active nuclear centers of RNA synthesis and processing, by the ability of nuclear FGFR1 to activate structurally distinct genes located on different chromosomes and by its stimulation of multi-gene programs for cell growth and differentiation. We propose that FGFR1 is part of a universal "feed-forward-and-gate" signaling module in which classical signaling cascades initiated by specific membrane receptors transmit signals to sequence specific transcription factors (ssTFs), while INFS elicited by the same stimuli feeds the signal forward to the common coactivator, CREB-binding protein (CBP). Activation of CBP by INFS, along with the activation of ssTFs by classical signaling cascades brings about coordinated responses from structurally different genes located at different genomic loci. © 2003 Wiley-Liss, Inc. [source] Contrasting effects of HSP72 expression on apoptosis in human umbilical vein endothelial cells and an angiogenic cell line, ECV304BRITISH JOURNAL OF HAEMATOLOGY, Issue 4 2000M. Lucas The effect of overexpression of heat shock protein (HSP)72 on apoptosis induced by different stimuli in human umbilical vein endothelial cells (HUVECs) and the angiogenic cell line, ECV304, was studied. Transient overexpression of HSP72 was achieved using an adenoviral vector (Advhsp72) and apoptosis was induced by heat shock, tumour necrosis factor (TNF)-, with cycloheximide (CHX), lipopolysaccharide (LPS) with TNF-, and verocytotoxin (VT). Apoptosis induced by heat shock was reduced by HSP72 expression. However, HSP72 expression in HUVECs increased apoptosis induced by TNF-,/CHX, LPS and VT measured by flow cytometric analysis of propidium iodide (PI)-stained permeabilized cells. In contrast, apoptosis in ECV304 induced by the same stimuli was reduced by HSP72 expression. No difference was seen in cells transduced with a control adenoviral vector expressing ,-galactosidase. These data imply that induction of HSP72 in cells modulates responses to apoptotic stimuli, but that the nature of the response varies with the cell type. However, it is clear that in situations where apoptosis may be part of a pathological process, HSP72 induction, for example by reperfusion injury, may exacerbate the process. [source] Space and Time in the Child's Mind: Evidence for a Cross-Dimensional AsymmetryCOGNITIVE SCIENCE - A MULTIDISCIPLINARY JOURNAL, Issue 3 2010Daniel Casasanto Abstract What is the relationship between space and time in the human mind? Studies in adults show an asymmetric relationship between mental representations of these basic dimensions of experience: Representations of time depend on space more than representations of space depend on time. Here we investigated the relationship between space and time in the developing mind. Native Greek-speaking children watched movies of two animals traveling along parallel paths for different distances or durations and judged the spatial and temporal aspects of these events (e.g., Which animal went for a longer distance, or a longer time?). Results showed a reliable cross-dimensional asymmetry. For the same stimuli, spatial information influenced temporal judgments more than temporal information influenced spatial judgments. This pattern was robust to variations in the age of the participants and the type of linguistic framing used to elicit responses. This finding demonstrates a continuity between space-time representations in children and adults, and informs theories of analog magnitude representation. [source] Lateral parabrachial afferent areas and serotonin mechanisms activated by volume expansionJOURNAL OF NEUROSCIENCE RESEARCH, Issue 16 2008Lisandra Oliveira Margatho Abstract Recent evidence has shown that the serotonergic mechanism of the lateral parabrachial nucleus (LPBN) participates in the regulation of renal and hormonal responses to isotonic blood volume expansion (BVE). We investigated the BVE-induced Fos activation along forebrain and hindbrain nuclei and particularly within the serotonergic clusters of the raphé system that directly project to the LPBN. We also examined whether there are changes in the concentration of serotonin (5HT) within the raphé nucleus in response to the same stimulus. With this purpose, we analyzed the cells doubly labeled for Fos and Fluorogold (FG) following BVE (NaCl 0.15 M, 2 ml/100 g b.w., 1 min) 7 days after FG injection into the LPBN. Compared with the control group, blood volume-expanded rats showed a significant greater number of Fos-FG double-labeled cells along the nucleus of the solitary tract, locus coeruleus, hypothalamic paraventricular nucleus, central extended amygdala complex, and dorsal raphé nucleus (DRN) cells. Our study also showed an increase in the number of serotonergic DRN neurons activated in response to isotonic BVE. We also observed decreased levels of 5HT and its metabolite 5-hydroxyindoleacetic acid (measured by high-pressure liquid chromatography) within the raphé nucleus 15 min after BVE. Given our previous evidence on the role of the serotonergic system in the LPBN after BVE, the present morphofunctional findings suggest the existence of a key pathway (DRN-LPBN) that may control BVE response through the modulation of 5HT release. © 2008 Wiley-Liss, Inc. [source] | ||||||||||