Medical Action Potentials: How Does it Work?

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An action potential in a nerve begins when a stimulus causes the opening of ion channels, allowing positive ions to flow into the neuron, leading to depolarization. In myelinated nerves, action potentials propagate quickly through saltatory conduction, where the impulse jumps between nodes of Ranvier, bypassing the myelinated sections. In multiple sclerosis, the breakdown of myelin disrupts this process, slowing down or blocking the transmission of action potentials. The absolute refractory period prevents immediate successive action potentials, ensuring a fixed amplitude and frequency of firing. Overall, the integrity of myelin is crucial for efficient nerve signal transmission.
  • #31
Hey guys,

I suspect (alright believe) neurons are sufficient but not necessary to build conscious phenomena, but we should not expect the same qualitative behavior in synthetic cognitive constructs as we observe in biological ones: we build airplanes to duplicate the flight of birds and computers to duplicate the computational brain but planes and computers are qualitatively different from their natural counterparts. I expect the same with awareness: more than one substrate may be capable of realizing its expression.

The consequence of this belief leads me to suspect then that maybe the phenomenon of mind is separate from biology in the same way that flight is separate from birds: No, the strips of paper written with all the equations of mathematical physics scattered across the kitchen floor won't get up and dance but if they behaved in the same non-linear fashion as the dancer, perhaps they would. Dancing from this perspective thus becomes a consequence of dynamics. So too I believe with mind.

And I disapprove of Chalmers claim, "from dynamics, one only gets more dynamics". Dynamics alright but in some cases, qualitatively different dynamics providing the genesis of emergence.:smile:

Edit:

Alright, here's an example of qualitatively different behavior from dynamics: the cubic differential equation.

\frac{dy}{dt}=a+by-y^3

It exhibits the cusp catastrophe which contains a bifurcation point (curve): changing the parameters a and b alters the solution naturally. If the change is sufficient to traverse the bifurcation point, solutions become qualitatively different from solutions on the other side of the bifurcation point.
 
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  • #32
SaltyDog said:
The consequence of this belief leads me to suspect then that maybe the phenomenon of mind is separate from biology in the same way that flight is separate from birds

My god, a Cartesian! :eek: :bugeye: :bugeye:
(In the way where Decartes, afraid of Religious power, said that soul was immaterial and outside of the body).

Read Spinoza, Damasio, Changeux, Ledoux, Ramachandran, Flor...
 
  • #33
somasimple said:
My god, a Cartesian! :eek: :bugeye: :bugeye:
(In the way where Decartes, afraid of Religious power, said that soul was immaterial and outside of the body).

Not quite since I don't believe in a soul or God and consider religion just another survival strategy for a limited intellect.:smile:
 
  • #34
But at these tenebrous ages of neurophysiology, soul and mind were a same thing. :wink:
 
  • #35
somasimple said:
But at these tenebrous ages of neurophysiology, soul and mind were a same thing. :wink:

Hey Somasimple,

Perhaps I spoke in haste up there: I've been reading about Cartesian Dualism. It seems that I must consider myself such albeit a modern sort: the earlier Dualist, Descartes included, were not referring to "emergent" properties (like I am) when they suggested the mind and body are made up of different "substances".

Hum, "Modern Dualism: The Emergence of Mind". I like the sound of that. :smile:
 
  • #36
hey SaltyDog,

A body without a brain is a cadaver with no mind.:zzz:
A brain without a body is a piece of dead meat with no mind.:approve:

Body is the vehicule that brain uses to apprehend the world. :wink:
There is no mind without the two since brain and body form an human being.
 

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