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175 results on '"Rosen, B.R."'

3. Top-down facilitation of visual recognition

Author

Bar, M., Kassam, K.S., Ghuman, A.S., Boshyan, J., Schmidt, A.M., Dale, A.M., Hamalainen, M.S., Marinkovic, K., Schacter, D.L., Rosen, B.R., and Halgren, E.

Subjects
Magnetic resonance imaging -- Analysis, Spatial analysis (Statistics) -- Analysis, Visual cortex -- Research, Science and technology
Abstract

Cortical analysis related to visual object recognition is traditionally thought to propagate serially along a bottom-up hierarchy of ventral areas. Recent proposals gradually promote the role of top-down processing in recognition, but how such facilitation is triggered remains a puzzle, We tested a specific model, proposing that low spatial frequencies facilitate visual object recognition by initiating top-down processes projected from orbitofrontal to visual cortex. The present study combined magnetoencephalography, which has superior temporal resolution, functional magnetic resonance imaging, and a behavioral task that yields successful recognition with stimulus repetitions. Object recognition elicited differential activity that developed in the left orbitofrontal cortex 50 ms earlier than it did in recognition-related areas in the temporal cortex. This early orbitofrontal activity was directly modulated by the presence of low spatial frequencies in the image. Taken together, the dynamics we revealed provide strong support for the proposal of how top-down facilitation of object recognition is initiated, and our observations are used to derive predictions for future research. feedback | object recognition | orbitofrontal cortex | visual cortex | low spatial frequency

Published
2006

4. fMRI studies of associative encoding in young and elderly controls and mild Alzheimer's disease. (Paper)

Author

Sperling, R.A., Bates, J.F., Chua, E.F., Cocchiarella, A.J., Rentz, D.M., Rosen, B.R., Schacter, D.L., and Albert, M.S.

Subjects
Brain -- Diseases -- Medical examination -- Physiological aspects -- Usage, Magnetic resonance imaging -- Usage -- Physiological aspects, Alzheimer's disease -- Physiological aspects -- Usage, Health, Psychology and mental health, Diseases, Physiological aspects, Usage, Medical examination
Abstract

Objective: To examine alterations in patterns of brain activation seen in normal aging and in mild Alzheimer's disease by functional magnetic resonance imaging (fMRI) during an associative encoding task. Methods: [...]

Published
2003

5. The value of multichannel MEG and EEG in the presurgical evaluation of 70 epilepsy patients

Author

Knake, S., Halgren, E., Shiraishi, H., Hara, K., Hamer, H.M., Grant, P.E., Carr, V.A., Foxe, D., Camposano, S., Busa, E., Witzel, T., Hämäläinen, M.S., Ahlfors, S.P., Bromfield, E.B., Black, P.M., Bourgeois, B.F., Cole, A.J., Cosgrove, G.R., Dworetzky, B.A., Madsen, J.R., Larsson, P.G., Schomer, D.L., Thiele, E.A., Dale, A.M., Rosen, B.R., and Stufflebeam, S.M.

Published
2006
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7. Facilitation of postischemic reperfusion with alpha-PBN: assessment using NMR and Doppler flow techniques

Author

Schulz, J.B., Panahian, N., Chen, Y.I., Beal, M.F., Moskowitz, M.A., Rosen, B.R., and Jenkins, B.G.

Subjects
Ischemia -- Physiological aspects, Reperfusion injury -- Physiological aspects, Magnetic resonance imaging -- Research, Free radicals (Chemistry) -- Physiological aspects, Biological sciences
Abstract

Laser-Doppler flow and flow-sensitive magnetic resonance imaging (MRI) were utilized to determine the effects of N-tert-butyl-alpha-phenylnitrone (PBN) on postischemic reperfusion in halothane-anesthetized rats. MRI analysis of postischemic reperfusion in the presence of PBN indicated the role of the free radical trapping agent in attenuating the lesion volume during ischemia in halothane-anesthetized rats. Furthermore, PBN exhibited cytoprotective effects on the vascular endothelium during focal ischemia/reperfusion.

Published
1997

8. The Cretaceous-Tertiary biotic transition

Author

Macleod, N., Rawson, P.F., Forey, P.L., Banner, F.T., Boudagher-Fadel, M.K., Bown, P.R., Burnett, J.A., Chambers, P., Culver, S., Evans, S.E., Jeffery, C., Kaminski, M.A., Lord, A.R., Milner, A.C., Milner, A.R., Morris, N., Owen, E., Rosen, B.R., Smith, A.B., Taylor, P.D., Urquhart, E., and Young, J.R.

Subjects
Biotic communities -- Research, Mass extinction theory -- Research, Phylogeny -- Research, Geology, Stratigraphic -- Cretaceous, Earth sciences
Abstract

Mass extinctions are recognized through the study of fossil groups across event horizons, and from analyses of long-term trends in taxonomic richness and diversity. Both approaches have inherent flaws, and data that once seemed reliable can be readily superseded by the discovery of new fossils and/or the application of new analytical techniques. Herein the current state of the Cretaceous-Tertiary (K-T) biostratigraphical record is reviewed for most major fossil clades, including: calcareous nannoplankton, dinoflagellates, diatoms, radiolaria, foraminifera, ostracodes, scleractinian corals, bryozoans, brachiopods, molluscs, echinoderms, fish, amphibians, reptiles and terrestrial plants (macrofossils and palynomorphs). These reviews take account of possible biasing factors in the fossil record in order to extract the most comprehensive picture of the K-T biotic crisis available. Results suggest that many faunal and floral groups (ostracodes, bryozoa, ammonite cephalopods, bivalves, archosaurs) were in decline throughout the latest Maastrichtian while others (diatoms, radiolaria, benthic foraminifera, brachiopods, gastropods, fish, amphibians, lepidosaurs, terrestrial plants) passed through the K-T event horizon with only minor taxonomic richness and/or diversity changes. A few microfossil groups (calcareous nannoplankton, dinoflagellates, planktonic foraminifera) did experience a turnover of varying magnitudes in the latest Maastrichtian-earliest Danian. However, many of these turnovers, along with changes in ecological dominance patterns among benthic foraminifera, began in the latest Maastrichtian. Improved taxonomic estimates of the overall pattern and magnitude of the K-T extinction event must await the development of more reliable systematic and phylogenetic data for all Upper Cretaceous clades. Keywords: K-T boundary, mass extinctions, taxonomy, phylogeny.

Published
1997

9. Object-related activity revealed by functional magnetic resonance imaging in human occipital cortex

Author

Malach, R., Reppas, J.B., Benson, R.R., Kwong, K.K., Jiang, H., Kennedy, W.A., Ledden, P.J., Brady, T.J., Rosen, B.R., and Tootell, R.B.H.

Subjects
Craniology -- Research, Neurobiology -- Research, Magnetic resonance -- Usage, Brain research -- Analysis, Science and technology
Abstract

A study of object-related activation shows that it is positioned at the occipital lobe's lateral posterior area, just touching the motion-sensitive area MT/V5s posterior aspect, in a region termed the lateral occipital complex (LO). Despite the preferential activation to objects, LO did not seem to be involved in the final recognition process stages but as an intermediate link.

Published
1995

10. Borders of multiple visual areas in humans revealed by functional magnetic resonance imaging

Author

Sereno, M.I., Dale, A.M., Reppas, J.B., Kwong, K.K., Belliveau, J.W., Brady, T.J., Rosen, B.R., and Tootell, R.B.H.

Subjects
Cerebral cortex -- Research -- Physiological aspects, Brain -- Localization of functions, Vision -- Physiological aspects -- Research, Brain mapping -- Research -- Physiological aspects, Visual evoked response -- Research -- Physiological aspects, Science and technology, Physiological aspects, Research
Abstract

The borders of human visual areas V1, V2, VP, V3, and V4 were precisely and noninvasively determined. Functional magnetic resonance images were recorded during phase-encoded retinal stimulation. This volume data set was then sampled with a cortical surface reconstruction, making it possible to calculate the local visual field sign (mirror image versus non-mirror image representation). This method automatically and objectively outlines area borders because adjacent areas often have the opposite field sign. Cortical magnification factor curves for striate and extrastriate cortical areas were determined, which showed that human visual areas have a greater emphasis on the center-of-gaze than their counterparts in monkeys. Retinotopically organized visual areas in humans extend anteriorly to overlap several areas previously shown to be activated by written words., Over half of the neocortex in nonhuman primates is occupied by visual areas. At least 25 visual areas beyond the primary visual cortex (V1) have been identified with a combination [...]

Published
1995

11. Functional mapping of the human visual cortex by magnetic resonance imaging

Author

Belliveau, J.W., Kennedy, D.N., McKinstry, R.C., Buchbinder, B.R., Weisskoff, R.M., Cohen, M.S., Vevea, J.M., Brady, T.J., and Rosen, B.R.

Subjects
Magnetic resonance imaging -- Usage -- Methods, Visual cortex -- Methods -- Usage, Brain mapping -- Methods -- Usage, Science and technology, Usage, Methods
Abstract

Knowledge of regional cerebral hemodynamics has widespread application for both physiological research and clinical assessment because of the well-established interrelation between physiological function, energy metabolism, and localized blood supply. A magnetic resonance technique was developed for quantitative imaging of cerebral hemodynamics, allowing for measurement of regional cerebral blood volume during resting and activated cognitive states. This technique was used to generate the first functional magnetic resonance maps of human task activation, by using a visual stimulus paradigm. During photic stimulation, localized increases in blood volume (32 ± 10 percent, n = 7 subjects) were detected in the primary visual cortex. Center-of-mass coordinates and linear extents of brain activation within the plane of the calcarine fissure are reported., PHYSIOLOGICAL, ANATOMICAL, AND cognitive psychophysical studies indicate that the brain possesses anatomically distinct processing regions [1,2]. During cognitive task performance, local alterations in neuronal activity induce local changes in metabolism [...]

Published
1991

12. fMRI Brain Mapping: Clinical Applications of Functional Magnetic Resonance Imaging**I thank all our colleagues at the MGH-NMR Center, particularly Drs. Aronen, Benson, Breiter, Chesler, Cohen, Jiang, Kennedy, Kosslyn, Tootell, Weisskoff, and Brady. This work was supported by grants from General Electric, Human Frontier Science Program Organization, McDonnell-Pew Program in Cognitive Neuroscience, and the National Institutes of Health.

Author

Belliveau, J.W., primary, Baker, J.R., additional, Buchbinder, B.R., additional, Stern, C.E., additional, Kwong, K.K., additional, Cosgrove, G.R., additional, Alpert, N.M., additional, and Rosen, B.R., additional

Published
1995
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18. Imaging Subcortical Auditory Activity in Humans

Author

Guimaraes, A.R., Melcher, J.R., Talavage, T.M., Baker, J.R., Ledden, P., Rosen, B.R., Kiang, N.Y.S., Fullerton, B.C., and Weisskoff, R.M.

Subjects
Auditory Cortex, Male, Brain Mapping, Auditory Pathways, Echo-Planar Imaging, Heart Rate, Reference Values, Humans, Female, Article, Inferior Colliculi, Brain Stem
Abstract

There is a lack of physiological data pertaining to how listening humans process auditory information. Functional magnetic resonance imaging (fMRI) has provided some data for the auditory cortex in awake humans, but there is still a paucity of comparable data for subcortical auditory areas where the early stages of processing take place, as amply demonstrated by single-unit studies in animals. It is unclear why fMRI has been unsuccessful in imaging auditory brain-stem activity, but one problem may be cardiac-related, pulsatile brain-stem motion. To examine this, a method eliminating such motion (using cardiac gating) was applied to map sound-related activity in the auditory cortices and inferior colliculi in the brain stem. Activation in both the colliculi and cortex became more discernible when gating was used. In contrast with the cortex, the improvement in the colliculi resulted from a reduction in signal variability, rather than from an increase in percent signal change. This reduction is consistent with the hypothesis that motion or pulsatile flow is a major factor in brain-stem imaging. The way now seems clear to studying activity throughout the human auditory pathway in listening humans.

Published
1998

20. Pushing the limits of in vivo diffusion MRI for the Human Connectome Project

Author

Setsompop, K., primary, Kimmlingen, R., additional, Eberlein, E., additional, Witzel, T., additional, Cohen-Adad, J., additional, McNab, J.A., additional, Keil, B., additional, Tisdall, M.D., additional, Hoecht, P., additional, Dietz, P., additional, Cauley, S.F., additional, Tountcheva, V., additional, Matschl, V., additional, Lenz, V.H., additional, Heberlein, K., additional, Potthast, A., additional, Thein, H., additional, Van Horn, J., additional, Toga, A., additional, Schmitt, F., additional, Lehne, D., additional, Rosen, B.R., additional, Wedeen, V., additional, and Wald, L.L., additional

Published
2013
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22. Cenozoic palaeogeography and the rise of modern biodiversity patterns

Author

Crame, J.A., Rosen, B.R., Crame, J.A., and Rosen, B.R.

Abstract

The steepest latitudinal and longitudinal gradients in taxonomic diversity at the present day are those associated with tropical high diversity foci. Although there has been a tendency in the past to regard these features as either evolutionary 'cradles' or 'museums' of considerable antiquity, this may not be the case. Within the marine realm, a uniform, pan-tropical fauna was progressively disrupted by a series of plate tectonic events, the most important of which were the Early Miocene (c. 20 Ma) collisions of Africa/Arabia with Europe and Australia/New Guinea with Indonesia, and the Middle Miocene-latest Pliocene rise of the Central American Isthmus. This had the net effect of establishing two main tropical high diversity foci: the Indo-West Pacific and the Atlantic-Caribbean-East Pacific. Similar foci were also established at the same time in the terrestrial realm. Together with the physical isolation of Antarctica, these same tectonic events contributed significantly to global cooling throughout the Cenozoic Era. This in turn led to the imposition of a series of thermally defined provinces, and thus a considerable degree of biotic differentiation on a regional scale. However, something else seems to have been involved in the creation of very steep tropical diversity peaks. This could in part be a coincidental radiation of a series of unrelated taxa, or some sort of evolutionary feedback mechanism,between interacting clades. Alternatively, Late Cenozoic rates of origination may have been enhanced by an external forcing mechanism such as changes in Orbital Range Dynamics.

Published
2002

29. The integrated neurofunctional MRI exam in ALS

Author

Makris, N., primary, Jenkins, B.G., additional, Vonsattel, J.P., additional, Sorensen, A.G., additional, Papadimitriou, G.M., additional, Chen, Y.I., additional, Wu, O., additional, Cudkowicz, M.E., additional, Rosas, H.D., additional, Rosen, B.R., additional, Caviness, V.S., additional, and Kennedy, D.N., additional

Published
2000
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31. Echoplanar chemical shift imaging

Author

Guimaraes, A.R., primary, Baker, J.R., additional, Jenkins, B.G., additional, Lee, P.L., additional, Weisskoff, R.M., additional, Rosen, B.R., additional, and Gonz�lez, R.G., additional

Published
1999
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47. Imaging subcortical auditory activity in humans

Author

Guimaraes, A.R., primary, Melcher, J.R., additional, Talavage, T.M., additional, Baker, J.R., additional, Ledden, P., additional, Rosen, B.R., additional, Kiang, N.Y.S., additional, Fullerton, B.C., additional, and Weisskoff, R.M., additional

Published
1998
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49. Spatiotemporal imaging of motion selective areas in human visual cortex

Author

Ahlfors, S.P., primary, Aronen, H.J., additional, Belliveau, J.W., additional, Dale, A., additional, Houtilainen, M., additional, Ilmoniemi, R.J., additional, Kennedy, W.A., additional, Korvenoia, A., additional, Liu, A.K., additional, Rosen, B.R., additional, Sereno, M.I., additional, Simpson, G.V., additional, Standertskjold-Nordenstam, C.-G., additional, Tootell, R.B.H., additional, and Virtanen, J., additional

Published
1997
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