Differences Between Samba and Blackout

[SnuFPunK]

Hi
I would like to know,
What conditions need to apply for a samba to occur, and what is the difference between these conditions to those that need to apply for a blackout to occur.

More simply, what happens in the body that leads to samba, and what happens in the body that leads to a blackout, and if its the same physiological condition, when to expect a samba and when to expect a blackout ?

Thanks

 

[DeepThought]

Without getting too much into the mechanism (not that I know it thoroughly enough) and trying to use very lay terms, neurons have a constant energy demand (thus O2, though it might be indirectly) to keep a certain ion imbalance (=potential) compared to their environment. Normally when this potential is released the neurons will excite (=give order to) other neurons and then build that potential again.
When there's not enough O2 to keep that potential you will get an effect of repeated excitation. When this excitation cause motor movements or the lack of control over them you get a samba (Loss of Motor Control).

A BO happens when there's not enough energy to keep one conscious.

A blackout is usually diagnosed by not remembering a part at the end of the dive (last few meters, hitting the surface, surface breath, being rescued etc.)

A BO can be acompanied by a samba or not, it depends on a few things.
As for which to expect, a samba without a BO is considered less hypoxic than a BO, But I don't know if there's a pattern one can rely on (excpet experience).

Eric F wrote about GABA/Glutamate balance before though I think it may also depend on which part of the brain is disturbed from hypoxia first.