This is the entire course in one slide (neuromodulation, brain machine interface, medical technology.....):

The City College of New York of CUNY

Department of Biomedical Engineering

BME I3000 Introduction to Neural Engineering and Applied Bioelectricity

Prof. Marom Bikson (homepage) Course Director

Course Overview Overview of topics covered and grading policy for 2011

Questions for Neural Engineering Including general 'discussion topics' of broad medical and health importance that the course will touch upon. Also include suggestions for final project topics

Neural Engineering on Wikipedia (link) - as part of this course every student might write a contribution here or on a specific topic

Neural Engineering research at the CCNY Neural Engineering Lab. NeuralEngr

Lets start with a motivating TED talk all about Neural Engineering and medical device development by pioneer Robert Fischell

In this course we will understand how each of these technologies works- as well as consider how they can be improved. well as two none technical profiles from the New Yorker

Steve Jobs This New Yorker profile describes Jobs as a "Tweaker" rather than an "Inventor". Lets keep this in mind as we discuss Neural Engineering technology, fundamentals, and device.

Peter Thiel The New Yorker describes Thiel as maybe the "most successful technology investor in the world". But Thiel is dissapointed with the impact of technology saying "We wanted flying cars, instead we got 150 characters [twitter]". How much has Neural Engineering changes the world and can it produce the next "flying cars" of medicine?

Part 1: How the brain works.

If you don't know how it works you can't fix it. Good news is that electrical engineering is the ideal basis for quantifying brain function.

In this course we will just cover some basic on "brain excitability" that will allow us to design brain interface and stimulation devices in part 2.

Brain Function Book/Chapter Reading:

Neuroscience Book A "staple" of graduate Neuroscience - touches on most central topics in brain , geared largely for non-engineers


Modeling the brain (with electrical circuits)

Models and our ability to understand how the brain works go hand-in-hand. Later on, they also allow us to design brain interface and brain stimulation technology

Though over 50 years old, Hodgin-Huxley types neuron models dominate how we model the brain including for brain stimulation (see numerical models below). So we need to understand this stuff - to help there are plenty of free simple simulators ready to play with:

Link to HH Simulator Download site password: CCNY

And a fully online HH simulator Limited functionality but easy to use

These simulators allow you to electrically stimulate the HH neuron with an INTRA-CELLULAR current pulse - this is great to understand the role of pulse shape etc...but keep in mind all clinical brain stimulation stuff is EXTRA-CELLULAR stimulation- discussed in the next part of the course."

To be complete we need to mention that there are other ways to model neurons and the following talk does a nice job of summarizing them:

A nice set of lecture slides by Larry Yaeger on computer modeling of Spiking Neurons (from simple to HH) link

Paper by Davide at CCNY This is getting ahead of where we are at this point in the course -Rather technical reading, but to show: This is one of a few examples of a simpler (non-HH) model being used successfully to model brain stimulation


Trade Articles on Brain Function and Disease

Brain Facts An review or "lay-people" on how the brain works and breaks



Is this an Neural Engineering Problem??:

A Mystery: Why Can't We Walk Straight? from NPR on Vimeo.

Part 2: Zapping the brain

Brain Stimulation Overview Some general slides and images related to brain electrotherapy and functional electrical stimulation

We will conduct a full bio-electric forensic analysis of this tragic case:

OK: Before we dive into the technical aspects of brain stimulation device design - these general articles provide a overview of the potential to improve lives. See also the video at the top.

Trade Articles on Funtional Electrical Stimulaiton / Electrical Therapy

IEEE Spectrum 2006 A popular article entitled "Psychiatry's Shocking New Tools" In addition to a really 'catchy' title - touches broadly on some topics in brain stimulation

Scientific American 2005 "Stimulating the Brain" A pretty intro so brain stimulation including TMS

Washington Post - VNS 2006 A article on the controversial approval of Vagus Nerve Stimulation for Depression.

A commerical video by Advanced Bionics about how the Chochlear Impant Works (as much art as science, but fun to watch):


Lets get technical!


Brain Stimulation - Book/Chapter Reading:

History of Brain Stimulators An interesting historical review by a founder in the field

Power History "The Damnable Alternating Current" A historical article about the adoption of AC (vs DC) power in in the states and its relation to human shock

Bin He Neural Engineering Reading Part 1 A general intro to neural prostheses and brain main interfaces. Part 1: Includes book preface, table of contents, and chapter of BMI

Bin He Neural Engineering Reading Part 2 Chapter on neuromuscular stimulation

Essential Neuromodulation Broad and accessible. Very application oriented book, with a nice chapter on clinical "electronics"

Federal RF Overview "Questions and Answers about Biological Effects and Potential Hazards of Radiofrequency Electromagnetic Fields" By the FCC. A introduction to types of RF energy, historical review of safety standards, not much good insight into mechanisms.


Models of Brain and Brain Stimulation - Journal Article Reading:

In CCNY Neural Engineering we develop the concept that all neural engineering analysis of existing and improved brain stimulation technology has only two steps.

1) Figure out where in the brain the current goes during stimulation ("forward model") and then 2) Figure out what the current does to those brain regions (neuromodulation")

I propose this simple concept applies to every brain stimulation application including all the examples indicated below (either can be be approached analytically or numerically)

"2 step" approach analysis from 2011 class 3 slides per paper summarized.

We need to compute (predict) what electrical stimulation does to the brain. As with any problem, if it is simple enough(in this case both the stimulation source and cell) then this can be done analytically - people worked on this but didn't get much farther than spheres and simple rods.

For more complicated stimulation sources and tissue properties (DBS leads, whole head current flow) numerical solutions are used. Examples follow but keep in mind in all cases the "2-step" CCNY process.

Sphere polarization models - analytical solutions to modeling brain stimulation

Polarization of spherical cells generally just related to the extracellular ELECTRIC FIELD (negative first spatial derivative of voltage).

Spheroid Polarization Analytical Descripion of Transmembrane Voltage Induced by UNIFORM electric fields on SPHEROIDAL cells (read for concept, not derivation).

Now lets think simple axons (tubes) both infinite and terminating

The ACTIVATING FUNCTION is a "holy grail" in electical stimulation. The second derivative of the extracellular voltage = actions on the membrane. We also need to understand the cable equation.
PAPERs coming soon.....

Numerical approached to modeling brain stimulation: Compartment based models with HH type kinetics

This all all about the "activating funcion" applied to each and evert compartment, the compartments are then connected by the cable equation. Set up in NEURON and hit solve:

Bikson et al. CA1 Neuron Model - Epileptic Conditions An article illustrating a recent scientific journal article implementing HH type channel kinetics (math).

McIntyre et al. 1999 Excitation of Neurons with non-uniform fields An article illustrating a recent scientific article implementing monopolar excitation theory and HH type kinetics

McIntyre et al. 2004 DBS model Model of neuronal excitation during Deep Brain Stimulation


And now for something completely different: The MIRROR PAPERS says "never mind electric field, never mind activating function, it is JUST the extracellular voltage (sorta)"

This is an amazing idea because it "challenges" the core reliance on electric field or activating function, while presenting a super simple method.

The Mirror Estimate Paper The “Mirror” Estimate: An Intuitive Predictor of Membrane Polarization during Extracellular Stimulation. Sébastien Joucla, Blaise Yvert

Portion of 2011 Mirror Lecture - I further show how in a uniform electric field the MIRROR ESTIMATE becomes even more intuitive.

Don't try this at home (or in the subway)

Advanced Journal Article Reading

These papers get into new concepts and details, maybe beyond the scope of this course. See also the Neural Engineering publications. here

Bikson et al. 2004 Modulation of hippococampal activity with 'sub-thershold' fields


Electrocution Forensics

The same principles we apply to brain stimulation technology, apply to electrocution and electrical accidents including the "CCNY 2-step" process.

Though some lighter material is included on this page, remember electrical accidents can be devastating to people.

This is funny but consider which is actually realistic:

Ways to die from electric shock

This I don't understand but all the "bioelectricity" elements are there:

Random Additional Reading

The Electrically Excitable Cortex Historical Note. For a long time the cortex was considred not electrically excitable. Go figure....