À propos de ce cours
Most people know that electrically active cells in nerves, in the heart and in the brain generate electrical currents, and that somehow these result in measurements we all have heard about, such as the electrocardiogram. But how? That is, what is it that happens within the electrically active tissue that leads to the creation of currents and voltages in their surroundings that reflect the excitation sequences timing, and condition of the underlying tissue. This course explores that topic. Rather than being a primer on how to interpret waveforms of any kind in terms of normality or disease, the goal here is to provide insight into how the mechanism of origin actually works, and to do so with simple examples that are readily pictured with simple sketches and one’s imagination, and then moving forward into comparison with experiments and finding outcomes quantitatively.
Globe

Cours en ligne à 100 %

Commencez dès maintenant et apprenez aux horaires qui vous conviennent.
Intermediate Level

Niveau intermédiaire

Clock

Approx. 6 hours to complete

Recommandé : 7 weeks of study, 1-3 hours/week
Comment Dots

English

Sous-titres : English
Globe

Cours en ligne à 100 %

Commencez dès maintenant et apprenez aux horaires qui vous conviennent.
Intermediate Level

Niveau intermédiaire

Clock

Approx. 6 hours to complete

Recommandé : 7 weeks of study, 1-3 hours/week
Comment Dots

English

Sous-titres : English

Syllabus - What you will learn from this course

1

Section
Clock
1 hour to complete

Week 1

A brief history of extracellular measurements, and an example of such a recording. The goal is to understand the amplitudes and time variation of such measurements, as well as learn about some interesting and useful historical events....
Reading
3 videos (Total 20 min), 3 readings, 1 quiz
Video3 videos
The First Extracellular Measurements5m
Observing Wave Forms Between Human Hands7m
Reading3 readings
Course Overview10m
Assessments, Grading and Certificates10m
Week 1 Slides10m
Quiz1 practice exercises
120m

2

Section
Clock
2 hours to complete

Week 2

A presentation of the cylindrical fiber model of a nerve. The goal is to see how this geometrically simple model of a nerve actually is sufficient to explain complex bioelectric events within and around electrically active tissue. One learns that currents are driven forward by voltages across cell membranes,. Current loops are created, with some parts of the current loop inside and other parts outside the active cells. Electrical potentials are created by the current loops, and are positive when these are approaching, negative when they are receding. In so doing they form the basis of all extracellular wave forms....
Reading
9 videos (Total 44 min), 3 readings, 1 quiz
Video9 videos
Left or right side stimulation5m
Simultaneous stimulation model2m
Definitions and questions6m
Origin in the membrane6m
Big loops as well as small4m
Approaching wave forms5m
Departing wave forms3m
Observations4m
Reading3 readings
Cylinderical Fiber Model Slides9m
Current Loops Slides10m
Current Loops and the Extracellular Waveforms Slides10m
Quiz1 practice exercises
224m

3

Section
Clock
1 hour to complete

Week 3

Notable and useful aspects of extracellular wave forms are their changes in shape. What causes such changes? Two illuminating examples are studied, one that does not, and then another that does....
Reading
7 videos (Total 33 min), 3 readings, 1 quiz
Video7 videos
Vm and current inside3m
Vm patterns3m
Current loops3m
Experimental setup, cardiac Purkinje6m
Stimulation at the left or right3m
Stimulation at both ends, collision5m
Reading3 readings
When do Wave Shapes Change? Slides10m
Simultaneous Left and Right Stimulation Slides10m
Experimental Data Slides10m
Quiz1 practice exercises
324m

4

Section
Clock
1 hour to complete

Week 4

Weeks 1 to 3 present some intriguing concepts and explain them with drawings and sketches. Do the wave forms so drawn have any connection with real tissue? Indeed they do. The goal of this week is to examine some specific experimental wave forms that were measured in cardiac Punkinje fibers, and to compare them those anticipated in earlier weeks.Week 4 is the end of the standard course. The remaining weeks are for honors study....
Reading
4 videos (Total 17 min), 1 reading, 1 quiz
Video4 videos
Two-fiber model, asynchronous2m
Experimental findings6m
Multiphasic summary3m
Reading1 readings
Multiphasic Recordings Slides10m
Quiz1 practice exercises
424m

5

Section
Clock
3 hours to complete

Week 5

The concepts of week 3 give insight, but there is power in equations and numbers. The goal of week 5 is to show how the models of week 3 can be represented quantitatively, so that one can go beyond asking “What?” and ask “How much?” With equations available, the lectures and questions for this week focus on finding specific numerical results for several examples....
Reading
18 videos (Total 75 min), 6 readings, 1 quiz
Video18 videos
A Thought experiment6m
Resistance of a fiber gap4m
Conductivity and conductance3m
The circuit5m
The extracellular resistance2m
The axial current numerically3m
The source and sink5m
Potential at e14m
Voltage from e1 to e24m
Source strength3m
Source distances8m
Finding the voltage1m
Summary2m
Mathematics2m
Python program4m
Wave form comparison3m
Summary3m
Reading6 readings
Resistivity and Resistance Slides10m
Axial Current Slides10m
Extracellular Voltage Formula Slides10m
Extracellular Voltage Numbers Slides10m
Python program and sample output10m
Extracellular V as a Function of Time Slides10m
Quiz1 practice exercises
520m

6

Section
Clock
2 hours to complete

Week 6

This week’s goal is to introduce the concept and the mathematical definition of dipole sources. Such sources pair a current source and current sink, separated in a specific orientation by a small distance. A dipole model allows easy evaluation of many electrode configurations, such as the widely used “bipolar” configuration, often used experimentally to determine the timing of excitation. More extensive models also allow consideration of action potential repolarization (return to resting potentials) as well as excitation....
Reading
14 videos (Total 47 min), 3 readings, 1 quiz
Video14 videos
Dipole representation6m
Iso-potential lines4m
Summary0m
Bipolar lead configuration2m
Bipolar wave form2m
Bipolar math5m
Why use bipolar?1m
Summary2m
Repolarization profile5m
Two axial currents7m
Three membrane sources3m
Extracellular potentials3m
Summary0m
Reading3 readings
Dipole Representation Slides10m
Bipolar Electrodes Slides10m
A Fiber Model with Repolarization Slides10m
Quiz1 practice exercises
624m

7

Section
Clock
1 hour to complete

Week 7

As a conclusion to the course, two diverse subjects are considered. One, the multipole expansion, is used when one has no model of the true origin of observed potentials but still needs to create an “equivalent” model to represent the data. The other, cardiac excitation, is characterized by large, broad excitation waves. One sees that an equation for the extracellular potentials has the same components as the expression for a simple cylindrical fiber, translated into a geometrically suitable form....
Reading
13 videos (Total 43 min), 2 readings, 1 quiz
Video13 videos
Gulrajani, Multipole calculations3m
Geselowitz, quality of reproduction4m
vanOosterom, dipole sources for the heart4m
Summary1m
Body Isopotentials from cardiac sources4m
Heart sources with unipolar and bipolar measurements3m
Excitation waves in the ventricles1m
Plonsey’s equation1m
Solid angles2m
Body potentials from cardiac excitation5m
Major factors summarized3m
Summary2m
Reading2 readings
Multipole Expansion Slides10m
Cardiac Potentials Slides10m
Quiz1 practice exercises
724m
4.5

Top Reviews

By AJApr 15th 2018

Great follow up course to the previous within the installment regarding bioelectricity. Taught me quite a lot and am looking forward to further releases to the series if they are in the works.

By PWMar 8th 2017

Having been out school for over 30 years this was a very challenging but rewarding course for myself. I'm glad i took it

Instructor

Avatar

Dr. Roger Barr

Anderson-Rupp Professor of Biomedical Engineering and Associate Professor of Pediatrics

About Duke University

Duke University has about 13,000 undergraduate and graduate students and a world-class faculty helping to expand the frontiers of knowledge. The university has a strong commitment to applying knowledge in service to society, both near its North Carolina campus and around the world....

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