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Another site to view an action potential…

http://highered.mcgraw-hill.com/olc/dl/120107/bio_d.swf

I really find myelination fascinating, especially in regards to the different types of medical conditions and associated behavioral changes demyelination can have on the body, severely slowing down action potentials or completely halting them. . In respect to the topic of action potential and myelin, after reading over a couple of chapters in Principals of Neural Science (Kandel, Schwartz, and Jessell-this book has been very useful for me and I highly recommend it!) in regards to conduction of an action potential, my understanding is that depolarization is one of the primary mechanisms controlling conduction, which is affected by:

·         Capacitance-higher rates slow down conduction of signals

·         Axial resistance -“axons with the largest diameter have the lowest threshold for extracurricular current. The larger the diameter of the axon, the lower the axial resistance to the flow of longitudinal current because of the greater number of ions per unit length of the axon” (146).

Another important factor is ion channels involved with resting potential break down the signaling capacity of the neurons, which can delay the action potential and reduce the distance a signal can move.

Ok, I have no idea…I was jotting down notes as I was reading and don’t know if I got it, but have a lot of stuff swirling around in my BRAIN…

Philosophical notes…what type of consciousness are we talking about?? Are we as human beings really that more conscious than birds or bears, for instance? A bird makes a nest, knowing it is the season to lay its eggs, looks for the materials to makes it nest, than after laying her eggs, keeps them warm until they hatch. If humans or other animals come into contact with the eggs or babies, she will not go back to them. Are these conscious decisions, flight or fight responses, etc? Are we more conscious when there are genocides in Darfur, Rwanda, DRC, and in our own back yard going on every day and we turn our heads? Just a thought…

Kandel, Eric R., James H. Schwartz, and Thomas M. Jessell.  Principles of Neural Science.  McGraw Hill,  2000.