Abstract:
:Recently, we have demonstrated that the fine-digit topography (millimeter sized) previously identified in the primary somatosensory cortex (SI), using electrophysiology and intrinsic signal optical imaging, can also be mapped with submillimeter resolution using blood-oxygenation-level-dependent (BOLD) functional magnetic resonance imaging at high field. In the present study, we have examined the dependence of BOLD signal response on stimulus intensity in two subregions of SI, Areas 3b and 1. In a region(s)-of-interest (ROI) analysis of Area 3b, BOLD signal amplitude increased linearly with increasing amplitude of an 8-Hz vibrotactile stimulus, and BOLD signal was sustained throughout the stimulation period. In contrast, in Area 1, a significant BOLD signal response was only observed with more intense stimuli, and ROI analysis of the dependence of BOLD response showed no significant dependence on stimulus intensity. In addition, activation was not sustained throughout the period of stimulation. Differing responses of Areas 3b and 1 suggest potentially divergent roles for subregions of SI cortices in vibrotactile intensity encoding. Moreover, this study underscores the importance of imaging at small spatial scales. In this case, such high-resolution imaging allows differentiation between area-specific roles in intensity encoding and identifies anatomic targets for detailed electrophysiological studies of somatosensory neuronal populations with different coding properties. These experiments illustrate the value of nonhuman primates for characterizing the dependence of the BOLD signal response on stimulus parameters and on underlying neural response properties.
journal_name
Magn Reson Imagingjournal_title
Magnetic resonance imagingauthors
Zhang N,Gore JC,Chen LM,Avison MJdoi
10.1016/j.mri.2007.05.002subject
Has Abstractpub_date
2007-07-01 00:00:00pages
784-94issue
6eissn
0730-725Xissn
1873-5894pii
S0730-725X(07)00277-9journal_volume
25pub_type
杂志文章abstract::In this work an interleaved multiple-gradient-echo chemical shift imaging (IMGE-CSI) technique was designed, implemented and evaluated at 1.5 and 4T for high-resolution lipid quantification and R(2)* measurement in-vivo. The method is analogous to echo planar CSI but utilizes conventional gradient echoes, exploiting t...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/s0730-725x(00)00165-x
更新日期:2000-09-01 00:00:00
abstract:PURPOSE:This study aimed to establish the topographical and zonal T2 patterns of multi-resolution MRI in medial tibial cartilage in a canine model of osteoarthritis (OA), initiated by the anterior cruciate ligament (ACL) transection surgery, and studied after 8-weeks and 12-weeks post-surgery. METHODS:Articular cartil...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2021.01.002
更新日期:2021-01-22 00:00:00
abstract::The subthalamic nucleus (STN) is one of the most common stimulation targets for treating Parkinson's disease using deep brain stimulation (DBS). This procedure requires precise placement of the stimulating electrode. Common practice of DBS implantation utilizes microelectrode recording to locate the sites with the cor...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2012.02.006
更新日期:2012-06-01 00:00:00
abstract::Complete dissection is the current reference method to quantify muscle and fat tissue on pig carcasses. Magnetic resonance imaging (MRI) is an appropriate nondestructive alternative method that can provide reliable and quantitative information on pig carcass composition without losing the spatial information. We have ...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2005.05.001
更新日期:2005-07-01 00:00:00
abstract::Poly(L-glutamic acid) (PGA)-cystamine-[gadolinium (Gd)-DO3A] was prepared in high yield with a high Gd-DO3A conjugation efficiency. Approximately 55% of the carboxylic groups in PGA were loaded with Gd-DO3A via cystamine as the spacer. Cystamine can be readily cleaved by endogenous thiols to release the Gd(III) chelat...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2006.03.009
更新日期:2006-09-01 00:00:00
abstract::The extent of reaction of 153Gd-radiolabeled Gd(L) chelates with 25 mM CO23- (25 mF), PO34-, Zn2+ and Cu2+ at pH 7 was determined for L = EDTA, DTPA, DOTA, HP-DO3A, and DO3A. Gd(EDTA)- and Gd(DTPA)2- reacted (greater than 20% in 10 min) with Cu2+ and Zn2+ in the presence of PO34-. These double replacement reactions yi...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(91)90429-p
更新日期:1991-01-01 00:00:00
abstract::Disseminated osseous tuberculosis is a rare disease. This is a report of two cases of disseminated osseous tuberculosis imaged with MRI at 1.5-T, CT, plain radiography and bone scintigraphy. CT and plain radiography demonstrated either highly destructive or cystic lesions with sclerotic margins. Bone scintigraphy and ...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(87)90384-5
更新日期:1987-01-01 00:00:00
abstract::Trabecular bone structure and bone density contribute to the strength of bone and are important in the study of osteoporosis. Wavelets are a powerful tool in characterizing and quantifying texture in an image. The purpose of this study was to validate wavelets as a tool in computing trabecular bone thickness directly ...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2006.09.020
更新日期:2007-04-01 00:00:00
abstract::Peripheral magnetic resonance angiography (MRA) is growing in use. However, methods of performing peripheral MRA vary widely and continue to be optimized, especially for improvement in illustration of infrapopliteal arteries. The main purpose of this project was to identify imaging factors that can improve arterial vi...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/s0730-725x(02)00531-3
更新日期:2002-09-01 00:00:00
abstract::Quantitative cerebral blood flow (CBF) values can be determined from residue function estimates obtained from magnetic resonance dynamic susceptibility contrast (DSC) perfusion studies using a variety of deconvolution approaches. However, there are significant differences between the CBF estimates obtained, difference...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2004.12.001
更新日期:2005-04-01 00:00:00
abstract::In magnetic resonance elastography (MRE), shear waves at a certain frequency are encoded through bipolar gradients that switch polarity at a controlled encoding frequency and are offset in time to capture wave propagation using a controlled sampling frequency. In brain MRE, there is a possibility that the mechanical a...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2011.09.017
更新日期:2012-02-01 00:00:00
abstract::Macroscopic protonation constants were measured for a series of DTPA mono- and bis-amide ligands using potentiometric titrations. Proton NMR pH titrations yielded protonation populations of the various nitrogen and oxygen basic sites of the ligands for the different protonation stages. Amide formation decreased the ba...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(94)00117-l
更新日期:1995-01-01 00:00:00
abstract::Etched particle tracks produced after heavy ion irradiation of polymer foils are used as model systems to test the performance of NMR in a newly developed ultrahigh magnetic field gradient system. The stimulated NMR echo decay of molecules diffusing in the channels, formulated in terms of the self part of the intermed...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(94)91527-x
更新日期:1994-01-01 00:00:00
abstract::Within the magnetic resonance imaging (MRI) community the trend is going to higher and higher magnetic fields, ranging from 1.5 T to 7 T, corresponding to Larmor frequencies of 63.8-298 MHz. Since for high-field MRI the magnetization increases with the applied magnetic field, the signal-to-noise-ratio increases as wel...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2012.06.014
更新日期:2013-02-01 00:00:00
abstract::The general aims of functional brain magnetic resonance imaging (fMRI) studies are to ascertain which areas of the brain are activated during a specific task, the extent of this activation, whether different groups of subjects demonstrate different patterns of activation, and how these groups behave in different tasks...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/s0730-725x(97)00278-6
更新日期:1998-04-01 00:00:00
abstract::The medical specialty radiology has experienced a number of extremely important and influential technical developments in the past that have affected how medical imaging is deployed. Artificial intelligence (AI) is potentially another such development that will introduce fundamental changes into the practice of radiol...
journal_title:Magnetic resonance imaging
pub_type: 社论
doi:10.1016/j.mri.2019.12.006
更新日期:2020-05-01 00:00:00
abstract::In this paper, a new reaction-diffusion model with viscous stress tensor is proposed for modeling the diffusion and invasion of brain glioma cells, which is based on the model in Yuan J.J., Liu L., Hu Q.M. Mathematical modeling of brain glioma growth using modified reaction-diffusion equation on brain MR images. Compu...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2015.10.012
更新日期:2016-02-01 00:00:00
abstract::In pharmacological magnetic resonance imaging (phMRI) with anesthetized animals, there is usually only a single time window to observe the dynamic signal change to an acute drug administration since subsequent drug injections are likely to result in altered response properties (e.g., tolerance). Unlike the block-desig...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2008.02.020
更新日期:2008-11-01 00:00:00
abstract::Gels consist of crosslinked polymer network swollen in solvent. The network of flexible long-chain molecules traps the liquid medium they are immersed in. Some gels undergo abrupt volume change, a phase transition process, by swelling-shrinking in response to external stimuli changes in solvent composition, temperatur...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/s0730-725x(02)00639-2
更新日期:2003-02-01 00:00:00
abstract:OBJECTIVES:To compare the accuracy of contrast-enhanced ultrasound (CEUS) and Dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) for the assessment of changes in tissue vascularization as result of sorafenib treatment in a rat model of hepatocellular carcinoma (HCC). METHODS:Male Buffalo rats with orthot...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2018.11.012
更新日期:2019-04-01 00:00:00
abstract::One of the main problems with rapid magnetic resonance imaging (MRI) techniques is the artifacts that result from off-resonance effects. The proposed off-resonance frequency filtered MRI (OFF-MRI) method focuses on the elimination of off-resonance components from the image of the observed object. To maintain imaging s...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2009.12.027
更新日期:2010-05-01 00:00:00
abstract::The phase difference method of phase contrast MR angiography provides a means of measuring the average velocity in each voxel of an MR scan. When static tissue is present in a voxel containing flow, the measured velocity is not the average velocity of the flow alone, but is lower due to the partial volume effect of th...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(94)91245-r
更新日期:1994-01-01 00:00:00
abstract:PURPOSE:To assess the value of semi-automated segmentation applied to diffusion MRI for predicting the therapeutic response of liver metastasis. METHODS:Conventional diffusion weighted magnetic resonance imaging (MRI) was performed using b-values of 0, 150, 300 and 450s/mm(2) at baseline and days 4, 11 and 39 followin...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2015.08.006
更新日期:2015-12-01 00:00:00
abstract::Primary epiploic appendagitis (PEA) occurs secondary to inflammation of an epiploic appendage, and is considered to be a rare cause of acute abdomen. In this case report, we describe the magnetic resonance imaging (MRI) findings of PEA correlated with computed tomographic (CT) findings. MRI findings included an oval s...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/s0730-725x(02)00478-2
更新日期:2002-01-01 00:00:00
abstract::The successful use of magnetic resonance imaging (MRI) of a moldic fossil dicynodont from the Permian aeolian Hopeman Sandstone Formation of Elgin, Scotland, UK, provides paleontologists with a nondestructive technique for examining fossils preserved in this fashion. For large moldic fossils, medical scanners such as ...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2003.09.006
更新日期:2004-02-01 00:00:00
abstract:AIM:Matrix metalloproteases (MMPs) expression and their inhibitors (TIMPs) play an important role in tumor physiopathology, so we investigated the relationship between the magnetic resonance (MR) and MMPs/TIMPs expression by breast carcinomas. MATERIALS AND METHODS:MRI parameters of 64 breast carcinomas were investiga...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2016.04.005
更新日期:2016-10-01 00:00:00
abstract::The CNS involvement is frequently found in human immunodeficiency virus (HIV) infection. The purpose of our study was to determine whether proton magnetic resonance spectroscopy (MRS) could detect early brain involvement in neurologically asymptomatic HIV-infected patients with normal MR imagings and to find the corre...
journal_title:Magnetic resonance imaging
pub_type: 临床试验,杂志文章
doi:10.1016/s0730-725x(00)00173-9
更新日期:2000-09-01 00:00:00
abstract::More than a dozen Nuclear Magnetic Resonance (NMR) imaging methods have been described using different radio-frequency pulse sequences, magnetic field gradient variations, and data processing. In order to have a theoretical understanding in the most general case, we have conceived a computer program for the simulation...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(84)90065-1
更新日期:1984-01-01 00:00:00
abstract::The effects of varying the inversion or excitation RF pulse flip angles on image contrast and imaging time have been investigated in IR imaging theoretically, with phantoms and with normal volunteers. Signal intensity in an IR pulse sequence as a function of excitation, inversion and refocusing pulse flip angles was c...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/0730-725x(92)90481-e
更新日期:1992-01-01 00:00:00
abstract::The aim of the study was to evaluate the relationship between the presence of right ventricular abnormalities detected by cardiac magnetic resonance (CMR) and QRS dispersion, the strongest independent predictor of sudden death in ARVC. A consecutive series of 40 patients from a single institution were recruited with a...
journal_title:Magnetic resonance imaging
pub_type: 杂志文章
doi:10.1016/j.mri.2012.06.005
更新日期:2012-12-01 00:00:00