Excitable Systems Aron Wolinetz Who am I Ph

Excitable Systems Aron Wolinetz

Who am I? • Ph. D student at the CUNY Graduate Center • Masters from Lehman College (almost) • B. S. in Real Estate from Baruch College • Husband • Father • Not much else

Lets have some fun!

What should we play? • LETS PLAY AIR-TO-GROUND ACTIONS!!! • WOULDN’T YOU PREFER A NICE GAME OF CHESS? • LETS PLAY AIR-TO-GROUND ACTIONS!!! • What do we need? – Paper airplanes – Rules – Ruthlessness

Simple Paper Airplane

Air-to-Ground Actions Rules • • First create a squadron Then wait for an attack Finally launch an attack of your own Build a new squadron Wait for an attack Launch an attack Etc etc

Additional Rules • A squadron consists of five planes • You must build your entire squadron, before you may attack. • You may only attack, right after being attacked • When you attack, you may attack anyone you choose • No points for hitting ME

LETS ROCK ! ! !

What we might have seen? • Nothing? Mayhem? Chaos? • People crying? Collateral damage? • Waves of attacks followed by lulls? • Lets call the lulls between waves… Refractory time

Refractory time • Every EXCITABLE SYSTEM needs it • Before the Refractory time has elapsed, a new wave cannot begin or propagate. • Ever try flushing the toilet before the tank fills up? Did it work?

Excitable Systems • Lets do the Wave! • Successive groups of spectators briefly stand, yell, and raise their arms. Immediately upon stretching to full height, the spectator returns to the usual seated position. (Wikipedia)

What are excitable systems? Excitable media can be defined as a system formed by segments or elemental cells, each of which has the following properties: • A well defined steady state (or rest state) • A threshold for excitation • An excitation that only a function of the system and independent of the stimulus. • A refractory period following excitation • A diffusive coupling with near neighbors (in space ) They can be: Physical, biological, mechanical, electrical, mathematical, chemical, … and they can lead to chaos.

What else is an excitable system? Example: Forest fires Good example to understand refractory period and collision between waves. (not solitons) Problem: very long wave length, even longer refractory period

One more example? • Dominos falling • Refractory Period? • Set them back up

Cool… but why are we learning this? • This is exactly the way the heart works • Electrical signal starts at (SA node). • Propagates around the heart • Refractory period • Repeat as necessary

To the cellular level •

Add some stimulus!!! •

Phew… That was exhausting •

Neural is similar to Cardiac

ETC… till your dying breath

Thank You