In 1963, by invitation, particle physicist George Reynolds (Princeton University) brought an image intensifier to Woods Hole Marine Biological Laboratory. Together, he and a group of biologists began experimenting wit...
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In 1963, by invitation, particle physicist George Reynolds (Princeton University) brought an image intensifier to Woods Hole Marine Biological Laboratory. Together, he and a group of biologists began experimenting with the device as a way to create images of cells in low-light level situations, especially in the study of bioluminescence. In this paper I am interested in how the scientists, a physicist and biologists in collaboration, assessed, interpreted and presented the pictures that they created with the aid of image intensification. In particular, I consider the problem of 'noise' in the image. The paper ends with an example of how Reynolds and a biologist at Woods Hole contended with the presence of noise in images used for publication. Here is an example of how data is modified, that is, enhanced, to serve as scientific evidence. By presenting an early and simple case of the altered image I reveal one way scientists addressed the potentiality of presenting inappropriately modified data a concern that has garnered much attention in the current age of digital imaging technologies.
Spin-echo fMRI offers a potentially better intrinsic functional spatial resolution than its gradient echo counterpart, as well as the elimination of signal dropouts in the image. This comes at the price of a significa...
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Spin-echo fMRI offers a potentially better intrinsic functional spatial resolution than its gradient echo counterpart, as well as the elimination of signal dropouts in the image. This comes at the price of a significant loss in sensitivity. In this article the main methods for measuring spin-echo fMRI are presented: HASTE, SSFP, RASER and most importantly spin-echo EPI. Their relative merits and limitations are discussed. The BOLD contrast mechanisms responsible for spin echo fMRI are summarised, and the spatial origin of the signal within the neocortex discussed. The major publications concerning the use of spin echo fMRI are examined. At present the most promising application for this methodology would appear to be in the examination of cortical layers and columns. The balance of experimental and theoretical evidence accumulated to date leads the author to propose that: (i) There is little point in conducting spin-echo fMRI at main magnetic field strengths of 3 T and below;(ii) There are fundamental limitations to acquiring spin-echo BOLD data at 7 T and above;(iii) Whole brain coverage with SE-BOLD at very high static magnetic field strengths could prove valuable: and (iv) SE-BOLD is probably better suited to study cortical columns than cortical layers. Recently gradient-echo approaches for high spatial resolution fMRI have been demonstrated that employ special techniques to avoid the effects of larger post capillary vessels. The coming years will show whether spin-echo techniques can remain the method of choice for high spatial resolution studies, and whether they can extend their range of application at 7 T and above. (C) 2012 Elsevier Inc. All rights reserved.
Two decades of technology development has continually improved the image quality, spatial-temporal resolution, and sensitivity of the fMRI acquisition. In this article, I assess our current acquisition needs, briefly ...
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Two decades of technology development has continually improved the image quality, spatial-temporal resolution, and sensitivity of the fMRI acquisition. In this article, I assess our current acquisition needs, briefly examine the technological breakthroughs that have benefited fMRI in the past, and look at some promising technologies that are currently under development to try to envision what the fMRI acquisition protocol of the future might look like. (C) 2012 Elsevier Inc. All rights reserved.
I provide a selective review of the literature on the multiple testing problem in fMRI. By drawing connections with the older modalities, PET in particular, and how software implementations have tracked (or lagged beh...
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I provide a selective review of the literature on the multiple testing problem in fMRI. By drawing connections with the older modalities, PET in particular, and how software implementations have tracked (or lagged behind) theoretical developments, my narrative aims to give the methodological researcher a historical perspective on this important aspect of fMRI data analysis. (C) 2012 Elsevier Inc. All rights reserved.
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