scholarly journals Layer-specific diffusion weighted imaging in human primary visual cortex in vitro

Cortex ◽  
2013 ◽  
Vol 49 (9) ◽  
pp. 2569-2582 ◽  
Author(s):  
Michiel Kleinnijenhuis ◽  
Valerio Zerbi ◽  
Benno Küsters ◽  
Cornelis H. Slump ◽  
Markus Barth ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Diffusion Weighted Imaging ◽  
Diffusion Weighted

scholarly journals Functional diffusion-weighted magnetic resonance spectroscopy of the human primary visual cortex at 7 T

2012 ◽  
Vol 69 (2) ◽  
pp. 303-309 ◽  
Author(s):  
Francesca Branzoli ◽  
Aranee Techawiboonwong ◽  
Hermien Kan ◽  
Andrew Webb ◽  
Itamar Ronen
Keyword(s):  
Visual Cortex ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Primary Visual Cortex ◽  
Resonance Spectroscopy ◽  
Diffusion Weighted

scholarly journals Acetylcholine Dynamically Controls Spatial Integration in Marmoset Primary Visual Cortex

2005 ◽  
Vol 93 (4) ◽  
pp. 2062-2072 ◽  
Author(s):  
M. J. Roberts ◽  
W. Zinke ◽  
K. Guo ◽  
R. Robertson ◽  
J. S. McDonald ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Dynamic Change ◽  
Gaussian Model ◽  
Spatial Integration ◽  
Feed Forward ◽  
Cortical Connections ◽  
Classical Receptive Field ◽  
Underlying Mechanisms

Recent in vitro studies have shown that acetylcholine (ACh) selectively reduces the efficacy of lateral cortical connections via a muscarinic mechanism, while boosting the efficacy of thalamocortical/feed-forward connections via a nicotinic mechanism. This suggests that high levels of ACh should reduce center-surround interactions of neurons in primary visual cortex, making cells more reliant on feed-forward information. In line with this hypothesis, we show that local iontophoretic application of ACh in primate primary visual cortex reduced the extent of spatial integration, assessed by recording a neurons' length tuning. When ACh was externally applied, neurons' preferred length shifted toward shorter bars, showing reduced impact of the extra-classical receptive field. We fitted a difference and a ratio of Gaussian model to these data to determine the underlying mechanisms of this dynamic change of spatial integration. These models assume overlapping summation and suppression areas with different widths and gains to be responsible for spatial integration and size tuning. ACh significantly reduced the extent of the summation area, but had no significant effect on the extent of the suppression area. In line with previous studies, we also show that applying ACh enhanced the response in the majority of cells, especially in the later (sustained) part of the response. These findings are similar to effects of attention on neuronal activity. The natural release of ACh is strongly linked with states of arousal and attention. Our results may therefore be relevant to the neurobiological mechanism of attention.

scholarly journals Decreased APE-1 by Nitroxoline Enhances Therapeutic Effect in a Temozolomide-resistant Glioblastoma: Correlation with Diffusion Weighted Imaging

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Hye Rim Cho ◽  
Nisha Kumari ◽  
Nishant Thakur ◽  
Hien Thi Vu ◽  
Hyeonjin Kim ◽  
...  
Keyword(s):  
Diffusion Weighted Imaging ◽  
Tumor Volume ◽  
Morphological Changes ◽  
Control Group ◽  
Therapeutic Effects ◽  
Adc Value ◽  
Diffusion Weighted ◽  
Resistant Cells

Abstract Glioblastoma multiforme (GBM) is one of the most aggressive human tumors with poor survival rates. The current standard treatment includes chemotherapy with temozolomide (TMZ), but acquisition of resistance is a persistent clinical problem limiting the successful treatment of GBM. The purpose of our study was to investigate therapeutic effects of nitroxoline (NTX) against TMZ-resistant GBM in vitro and in vivo in TMZ-resistant GBM-bearing mouse model, which was correlated with diffusion-weighted imaging (DWI). For in vitro study, we used TMZ-resistant GBM cell lines and evaluated therapeutic effects of NTX by clonogenic and migration assays. Quantitative RT-PCR was used to investigate the expression level of TMZ-resistant genes after NTX treatment. For in vivo study, we performed 9.4 T MR imaging to obtain T2WI for tumor volume measurement and DWI for assessment of apparent diffusion coefficient (ADC) changes by NTX in TMZ-resistant GBM mice (n = 8). Moreover, we performed regression analysis for the relationship between ADC and histological findings, which reflects the changes in cellularity and apurinic/apyrimidinic endonuclease-1 (APE-1) expression. We observed the recovery of TMZ-induced morphological changes, a reduced number of colonies and a decreased rate of migration capacity in TMZ-resistant cells after NTX treatment. The expression of APE-1 was significantly decreased in TMZ-resistant cells after NTX treatment compared with those without treatment. In an in vivo study, NTX reduced tumor growth in TMZ-resistant GBM mice (P = 0.0122). Moreover, ADC was increased in the NTX-treated TMZ-resistant GBM mice compared to the control group (P = 0.0079), which was prior to a tumor volume decrease. The cellularity and APE-1 expression by histology were negatively correlated with the ADC value, which in turn resulted in longer survival in NTX group. The decreased expression of APE-1 by NTX leads to therapeutic effects and is inversely correlated with ADC in TMZ-resistant GBM. Therefore, NTX is suggested as potential therapeutic candidate against TMZ-resistant GBM.

MRT des Prostatakarzinoms: Diffusion Weighted Imaging im Vergleich mit der Histologie

2009 ◽  
Vol 181 (S 01) ◽  
Author(s):  
J Yamamura ◽  
G Salomon ◽  
J Graessner ◽  
A Hohenstein ◽  
M Graefen ◽  
...  
Keyword(s):  
Diffusion Weighted Imaging ◽  
Diffusion Weighted

Diffusion-Weighted Imaging Features of Urachal Abscess

2008 ◽  
Author(s):  
Ozgur Kilickesmez ◽  
Arda Kayhan ◽  
Bengi Gürses ◽  
Neslihan Tasdelen ◽  
Baki Ekci ◽  
...  
Keyword(s):  
Diffusion Weighted Imaging ◽  
Imaging Features ◽  
Diffusion Weighted ◽  
Urachal Abscess
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