Magnetic Source Imaging

Hämäläinen, Matti S.; Nenonen, Jukka

doi:10.1002/047134608x.w4707

Cited by 7 publications

(1 citation statement)

References 79 publications

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“…Magnetocardiographic (MCG) mapping has provided promising results in locating various intracardiac sources, such as the sites of origin of life-threatening arrhythmias (Hämäläinen and Nenonen 1999). Reported clinical MCG localization accuracies range from 5 mm to 30 mm (Fenici and Melillo 1993, Fenici et al 1999, Moshage et al 1996, Oeff and Burghoff 1994.…”

Section: Introductionmentioning

confidence: 99%

Bioelectromagnetic localization of a pacing catheter in the heart

Pesola¹,

Nenonen

Fenici

et al. 1999

Phys. Med. Biol.

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The accuracy of localizing source currents within the human heart by non-invasive magneto- and electrocardiographic methods was investigated in 10 patients. A non-magnetic stimulation catheter inside the heart served as a reference current source. Biplane fluoroscopic imaging with lead ball markers was used to record the catheter position. Simultaneous multichannel magnetocardiographic (MCG) and body surface potential mapping (BSPM) recordings were performed during catheter pacing. Equivalent current dipole localizations were computed from MCG and BSPM data, employing standard and patient-specific boundary element torso models. Using individual models with the lungs included, the average MCG localization error was 7+/-3 mm, whereas the average BSPM localization error was 25+/-4 mm. In the simplified case of a single homogeneous standard torso model, an average error of 9+/-3 mm was obtained from MCG recordings. The MCG localization accuracies obtained in this study imply that the capability of multichannel MCG to locate dipolar sources is sufficient for clinical purposes, even without constructing individual torso models from x-ray or from magnetic resonance images.

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Section: Introductionmentioning

confidence: 99%

Bioelectromagnetic localization of a pacing catheter in the heart

Pesola¹,

Nenonen

Fenici

et al. 1999

Phys. Med. Biol.

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A sensorimotor account of vision and visual consciousness

Ο’Regan¹,

2001

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In this commentary we review evidence concerning the true sensitivity of viewers to visual changes in scene images. We argue that the data strongly suggest that "change blindness" experiments, while revealing of a variety of important constraints on encoding and retrieval processes in visual memory, do not demonstrate the lack of scene representations assumed by O&N. Instead, the data suggest that detailed scene representations can be generated and survive relatively intact across views (e.g., across saccades) and over extended periods of time. Of course, as we have known at least since the seminal work of Sperling (1960) and Averbach and Coriell (1961), these representations are not "iconic" in nature. CommentaryIn the target article, O'Regan and Nöe (O&N) reject the assumption prevalent in computational vision and visual cognition that the visual system generates an accurate, detailed, and stable scene representation. Instead, O&N propose that the experience of visual coherence is an illusion brought about by the fact that visual information can be sampled from the world when needed via sensory motor interaction, i.e., via shifts of attention and fixation. In this view, there is no need for an internal scene representation because the world can serve as its own external memory, and it is the ability of the system to sample this outside memory at will in the service of ongoing perceptual and cognitive processing that produces perceptual experience.O&N suggest that an important prediction of their theory is that viewers should be insensitive to what appear to be relatively large and obvious changes when detecting the change depends on visual memory rather than on the perception of image transients; that is, the theory predicts "change blindness". Aside from the issue of whether the theory motivated the experiments or vice versa (in fact, change blindness as a phenomenon has been known at least since the mid-1970s, and the most recent demonstrations of these phenomena in images of real-world scenes were produced by McConkie and

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