Heart Like a Wheel: A relatively simple model of electrical activity in the heart may help explain sudden coronary deaths

A new interpretation of thalamocortical circuitry

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2002.1164 ◽

2002 ◽

Vol 357 (1428) ◽

pp. 1767-1779 ◽

Cited By ~ 11

Author(s):

Paul Adams ◽

Kingsley Cox

Keyword(s):

Simple Model ◽

Electrical Activity ◽

Neural Activity ◽

New Interpretation ◽

Almost All

Almost all the information that is needed to specify thalamocortical and neocortical wiring derives from patterned electrical activity induced by the environment. Wiring accuracy must be limited by the anatomical specificity of the cascade of events triggered by neural activity and culminating in synaptogenesis. We present a simple model of learning in the presence of plasticity errors. One way to achieve learning specificity is to build better synapses. We discuss an alternative, circuit–based, approach that only allows plasticity at connections that support highly selective correlations. This circuit resembles some of the more puzzling aspects of thalamocorticothalamic circuitry.

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Heart Like a Wheel: A relatively simple model of electrical activity in the heart may help explain sudden coronary deaths

Science ◽

10.1126/science.248.4954.424-b ◽

1990 ◽

Vol 248 (4954) ◽

pp. 424-424

Author(s):

R. Pool

Keyword(s):

Simple Model ◽

Electrical Activity

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Measurement of spontaneous neuronal membrane activity by time lapse confocal microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100141238 ◽

1995 ◽

Vol 53 ◽

pp. 972-973

Author(s):

R H. Selinfreund ◽

A. H. Cornell-Bell

Keyword(s):

Membrane Potential ◽

Confocal Microscopy ◽

Patch Clamp ◽

Electrical Activity ◽

Time Lapse ◽

Neuronal Firing ◽

Neuronal Membrane ◽

Pituitary Cells ◽

Patch Clamp Recording ◽

Spontaneous Electrical Activity

Cellular electrophysiological properties are normally monitored by standard patch clamp techniques . The combination of membrane potential dyes with time-lapse laser confocal microscopy provides a more direct, least destructive rapid method for monitoring changes in neuronal electrical activity. Using membrane potential dyes we found that spontaneous action potential firing can be detected using time-lapse confocal microscopy. Initially, patch clamp recording techniques were used to verify spontaneous electrical activity in GH4\C1 pituitary cells. It was found that serum depleted cells had reduced spontaneous electrical activity. Brief exposure to the serum derived growth factor, IGF-1, reconstituted electrical activity. We have examined the possibility of developing a rapid fluorescent assay to measure neuronal activity using membrane potential dyes. This neuronal regeneration assay has been adapted to run on a confocal microscope. Quantitative fluorescence is then used to measure a compounds ability to regenerate neuronal firing.The membrane potential dye di-8-ANEPPS was selected for these experiments. Di-8- ANEPPS is internalized slowly, has a high signal to noise ratio (40:1), has a linear fluorescent response to change in voltage.

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Fate of sperm membrane in fertilized ova

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100146047 ◽

1993 ◽

Vol 51 ◽

pp. 40-41

Author(s):

Frank J. Longo

Keyword(s):

Electron Microscopy ◽

Electrical Activity ◽

Sea Urchins ◽

Morphological Changes ◽

Integrated System ◽

Electrophysiological Recording ◽

Experimental Conditions ◽

The Status ◽

Sperm Membrane ◽

Temporal And Spatial

Measurement of the egg's electrical activity, the fertilization potential or the activation current (in voltage clamped eggs), provides a means of detecting the earliest perceivable response of the egg to the fertilizing sperm. By using the electrical physiological record as a “real time” indicator of the instant of electrical continuity between the gametes, eggs can be inseminated with sperm at lower, more physiological densities, thereby assuring that only one sperm interacts with the egg. Integrating techniques of intracellular electrophysiological recording, video-imaging, and electron microscopy, we are able to identify the fertilizing sperm precisely and correlate the status of gamete organelles with the first indication (fertilization potential/activation current) of the egg's response to the attached sperm. Hence, this integrated system provides improved temporal and spatial resolution of morphological changes at the site of gamete interaction, under a variety of experimental conditions. Using these integrated techniques, we have investigated when sperm-egg plasma membrane fusion occurs in sea urchins with respect to the onset of the egg's change in electrical activity.

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Fit Vs Faint: Assessing Work Causation in “Idiopathic Fall” Cases

Guides Newsletter ◽

10.1001/amaguidesnewsletters.2014.sepoct01 ◽

2014 ◽

Vol 19 (5) ◽

pp. 3-12

Author(s):

Lorne Direnfeld ◽

David B. Torrey ◽

Jim Black ◽

LuAnn Haley ◽

Christopher R. Brigham

Keyword(s):

Blood Flow ◽

Electrical Activity ◽

Loss Of Consciousness ◽

Brain Electrical Activity ◽

Medical Terminology ◽

Scientific Analysis ◽

Medical Causation ◽

The Individual ◽

The Brain ◽

Current Science

Abstract When an individual falls due to a nonwork-related episode of dizziness, hits their head and sustains injury, do workers’ compensation laws consider such injuries to be compensable? Bearing in mind that each state makes its own laws, the answer depends on what caused the loss of consciousness, and the second asks specifically what happened in the fall that caused the injury? The first question speaks to medical causation, which applies scientific analysis to determine the cause of the problem. The second question addresses legal causation: Under what factual circumstances are injuries of this type potentially covered under the law? Much nuance attends this analysis. The authors discuss idiopathic falls, which in this context means “unique to the individual” as opposed to “of unknown cause,” which is the familiar medical terminology. The article presents three detailed case studies that describe falls that had their genesis in episodes of loss of consciousness, followed by analyses by lawyer or judge authors who address the issue of compensability, including three scenarios from Arizona, California, and Pennsylvania. A medical (scientific) analysis must be thorough and must determine the facts regarding the fall and what occurred: Was the fall due to a fit (eg, a seizure with loss of consciousness attributable to anormal brain electrical activity) or a faint (eg, loss of consciousness attributable to a decrease in blood flow to the brain? The evaluator should be able to fully explain the basis for the conclusions, including references to current science.

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