Results 1 - 10 of 126,366

Brain magnetic resonance imaging with contrast dependent on blood oxygenation.

by S Ogawa , T M Lee , A R Kay , D W Tank - Proc. Natl. Acad. Sci. USA , 1990
"... ABSTRACT Paramagnetic deoxyhemoglobin in venous blood is a naturally occurring contrast agent for magnetic resonance imaging (MRI). By accentuating the effects of this agent through the use of gradient-echo techniques in high fields, we demonstrate in vivo images of brain microvasculature with imag ..."
Abstract - Cited by 648 (1 self) - Add to MetaCart
ABSTRACT Paramagnetic deoxyhemoglobin in venous blood is a naturally occurring contrast agent for magnetic resonance imaging (MRI). By accentuating the effects of this agent through the use of gradient-echo techniques in high fields, we demonstrate in vivo images of brain microvasculature

The Computational Brain.

by P S Churchland , T J Sejnowski , Bruce Bridgeman , 1994
"... Keywords: reductionism, neural networks, distributed coding, Karl Pribram, computational neuroscience, receptive field 1.1 The broad goal of this book, expressed at the start, is ``to understand how neurons give rise to a mental life.'' A mental reductionism is assumed in this seductively ..."
Abstract - Cited by 450 (7 self) - Add to MetaCart
of single-cell recording methods. The problem is that millions of neurons participate in every behaviorally meaningful activity, but we normally record from only one neuron at a time, or at best a handful. The temptation is great to overestimate the one-millionth sample obtained from a single neuron

An integrative theory of prefrontal cortex function.

by Earl K Miller , Jonathan D Cohen - Annual Review of Neuroscience, , 2001
"... Abstract The prefrontal cortex has long been suspected to play an important role in cognitive control, in the ability to orchestrate thought and action in accordance with internal goals. Its neural basis, however, has remained a mystery. Here, we propose that cognitive control stems from the active ..."
Abstract - Cited by 1093 (20 self) - Add to MetaCart
the active maintenance of patterns of activity in the prefrontal cortex that represent goals and the means to achieve them. They provide bias signals to other brain structures whose net effect is to guide the flow of activity along neural pathways that establish the proper mappings between inputs, internal

Predictive reward signal of dopamine neurons

by Wolfram Schultz - Journal of Neurophysiology , 1998
"... Schultz, Wolfram. Predictive reward signal of dopamine neurons. is called rewards, which elicit and reinforce approach behav-J. Neurophysiol. 80: 1–27, 1998. The effects of lesions, receptor ior. The functions of rewards were developed further during blocking, electrical self-stimulation, and drugs ..."
Abstract - Cited by 747 (12 self) - Add to MetaCart
of rewards, and rons show phasic activations after primary liquid and food rewards and conditioned, reward-predicting visual and auditory stimuli. the availability of rewards determines some of the basic They show biphasic, activation-depression responses after stimuli parameters of the subject’s life

AFNI: software for analysis and visualization of functional magnetic resonance neuroimages

by Robert W Cox - Computers and Biomedical Research , 1996
"... email rwcoxmcwedu A package of computer programs for analysis and visualization of threedimensional human brain functional magnetic resonance imaging FMRI results is described The software can color overlay neural activation maps onto higher resolution anatomical scans Slices in each cardinal pl ..."
Abstract - Cited by 807 (3 self) - Add to MetaCart
email rwcoxmcwedu A package of computer programs for analysis and visualization of threedimensional human brain functional magnetic resonance imaging FMRI results is described The software can color overlay neural activation maps onto higher resolution anatomical scans Slices in each cardinal

Haploview: analysis and visualization of LD and haplotype maps

by J. C. Barrett, B. Fry, J. Maller, M. J. Daly - BIOINFORMATICS , 2005
"... Summary: Research over the last few years has revealed significant haplotype structure in the human genome. The characterization of these patterns, particularly in the con-text of medical genetic association studies, is becoming a routine research activity. Haploview is a software pack-age that prov ..."
Abstract - Cited by 1275 (6 self) - Add to MetaCart
Summary: Research over the last few years has revealed significant haplotype structure in the human genome. The characterization of these patterns, particularly in the con-text of medical genetic association studies, is becoming a routine research activity. Haploview is a software pack

Rho GTPases and the actin cytoskeleton

by Alan Hall - Science , 1998
"... The actin cytoskeleton mediates a variety of essential biological functions in all eukaryotic cells. In addition to providing a structural framework around which cell shape and polarity are defined, its dynamic properties provide the driving force for cells to move and to divide. Understanding the b ..."
Abstract - Cited by 615 (4 self) - Add to MetaCart
). In Swiss 3T3 fibroblasts, it was shown that Rho can be activated by the addition of extracellular ligands [for example, lysophos-phatidic acid] and that Rho activation leads to the assembly of contractile actin-myosin filaments (stress fibers) and of associated focal adhesion complexes (Fig. 1, C and D) (1

A Comparative Analysis of Methodologies for Database Schema Integration

by C. Batini, M. Lenzerini, S. B. Navathe - ACM COMPUTING SURVEYS , 1986
"... One of the fundamental principles of the database approach is that a database allows a nonredundant, unified representation of all data managed in an organization. This is achieved only when methodologies are available to support integration across organizational and application boundaries. Metho ..."
Abstract - Cited by 652 (10 self) - Add to MetaCart
. Methodologies for database design usually perform the design activity by separately producing several schemas, representing parts of the application, which are subsequently merged. Database schema integration is the activity of integrating the schemas of existing or proposed databases into a global, unified

Why We Twitter: Understanding Microblogging Usage and Communities

by Akshay Java, Tim Finin
"... Microblogging is a new form of communication in which users can describe their current status in short posts distributed by instant messages, mobile phones, email or the Web. Twitter, a popular microblogging tool has seen a lot of growth since it launched in October, 2006. In this paper, we present ..."
Abstract - Cited by 576 (2 self) - Add to MetaCart
our observations of the microblogging phenomena by studying the topological and geographical properties of Twitter’s social network. We find that people use microblogging to talk about their daily activities and to seek or share information. Finally, we analyze the user intentions associated at a

Is learning by exporting important? Micro-dynamic evidence from Colombia, Mexico and Morocco

by Sofronis K. Clerides, Saul Lach, James R. Tybout - Quarterly Journal of Economics , 1998
"... Do firms become more efficient after becoming exporters? Do exporters generate positive externalities for domestically oriented producers? In this paper we tackle these questions by analyzing the causal links between exporting and productivity using plant-level data. We look for evidence that firms ..."
Abstract - Cited by 604 (13 self) - Add to MetaCart
’ cost processes change after they break into foreign markets. We find that relatively efficient firms become exporters; however, in most industries, firms ’ costs are not affected by previous exporting activities. So the well-documented positive association between exporting and efficiency is explained
Results 1 - 10 of 126,366