Action Potentials: How Does it Work?

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Discussion Overview

The discussion centers on the mechanisms of action potentials in neurons, including their initiation, propagation, and the effects of myelin on conduction speed. Participants explore both the physiological processes involved and the implications for conditions like Multiple Sclerosis, as well as philosophical questions related to free will and neuronal activity.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants inquire about how action potentials start, questioning the role of stimuli and the mechanisms of depolarization within the neuron.
  • There are discussions on how action potentials propagate along myelinated versus unmyelinated axons, with references to saltatory conduction and the role of ion channels at the nodes of Ranvier.
  • One participant suggests that the absolute refractory period of Na+ voltage-gated channels limits the firing frequency of action potentials, prompting questions about the fixed amplitude of action potentials.
  • Another participant expresses skepticism about the conventional explanation of saltatory conduction, stating it seems illogical based on their understanding of physics.
  • Philosophical considerations arise regarding the implications of action potentials being triggered by stimuli on the concept of free will, with some questioning whether neuronal activity can be entirely attributed to sensory responses.

Areas of Agreement / Disagreement

Participants express a range of views on the mechanisms of action potentials and the implications for free will, with no clear consensus reached on the explanations of saltatory conduction or the philosophical questions raised.

Contextual Notes

Some claims about the mechanisms of action potentials and their propagation may depend on specific definitions or assumptions that are not fully articulated in the discussion. Additionally, the relationship between neuronal activity and free will remains an open question without resolution.

  • #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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