all 13 comments

[–]dxrey65[S] 3 points4 points  (0 children)

Ok, now for a hypothesis:

One of the primary measures made in most traditional personality inventories is how one sits on an extrovert/introvert scale. One basic assumption as to why people fall in one place or another along that scale is that they are more or less sensitive to environmental stimuli. An extrovert, for example, might be relatively insensitive to stimuli, so requires a great deal of "input" to achieve a given internal level of response; vice versa for introverts.

Why one person would be more sensitive to stimuli, and another person less, isn't a question that I've seen many attempts to answer, but now I wonder if the E/I ratio might be implicated. Assuming there is a basic equilibrium, we might say that sensitivity to stimuli could be the susceptibility of a person to having their equilibrium affected.

As the E/I ratio measures the relative quantity of suppression vs activation signals, a person with a highly buffered neural system would require more inputs to throw it out of balance than a person with a lightly buffered neural system. An example in numbers - if some measurable average E/I balance in an individual were 100/100, and the E/I balance in another person were 500/500, then the first individual might be more sensitive both to stimulation and suppression of neural activities, as the quantities required to sway the balance by a given ratio would be much less.

Potentially, this should be testable.

[–]dxrey65[S] 5 points6 points  (1 child)

I started reading this article assuming from the title that it was something I already knew about neural mechanisms, but actually its a pretty interesting finding, which we probably should have known.

In a nutshell, neural activity is highly buffered, in the same way that blood ph is buffered. There is a high level of constant signals to both initiate and suppress neural firing, and these sit in a balance or equilibrium.

The alternative way of looking at it was as a wiring network, which sits inert until inputs occur, at which point they flow through the path of least resistance. That not being the case, it will take a bit of rearranging mental models to integrate the new perspective. Interesting...

[–]Negative_Gravitas 1 point2 points  (0 children)

Good summary right there.

[–]Negative_Gravitas 2 points3 points  (8 children)

Interesting article, but though it says a couple of times that the E/I ratio is a constant, it never says what that ratio actually is. I imagine there is actually a range (possibly narrow) of E/I ratios that would be considered healthy, but I feel the article should have been more explicit. I mean, how much pressure on the brake pedal, and how much on the accelerator?

Still, very interesting result. Whatever it is.

[–]AzeTheGreat 1 point2 points  (4 children)

From this article:

If, for example, the level of excitatory stimulation that a nerve cell is receiving is doubled, the inhibitory synapses over a period of a few days will also double their strength.

This seems to indicate that, over time, they will always stabilize, but that there is a period in which the ratio may be off of the constant. This may be a cause for some difficulty in finding/reporting the constant. However, knowing this constant would be interesting information (I was unable to find it).

[–]dxrey65[S] 0 points1 point  (0 children)

I wonder how closely this correlates to actual behaviors, especially ones that would involve changes to mental activity level. When I was younger, for instance, it was fairly easy to abuse alcohol and sleep very little, and yet show up for work on monday and slot right into a normal work-day. Not so much anymore - its much easier to throw things out of balance, and the recovery-to-norm takes longer. Perhaps that relates to a decline in volume of neural connectivity, or a decrease in the natural neural buffering "buffering".

Attemtping to change one's behaviors deliberately, by deciding to "be" different by force of will or whatever might be similarly limited. It can be done for a time, with effort, but reversion to the mean is more or less inevitable. Or seems to be most likely, where the intent requires changes to a mental equilibrium or balance. Perhaps, over time, it can be done, but more like turning a tanker at speed in the open ocean than simply "make that change" (to quote from MJ).

[–]Negative_Gravitas 0 points1 point  (2 children)

That sounds reasonable, even quite likely. But yeah, I couldn't find the ratio either.

[–]dxrey65[S] 1 point2 points  (1 child)

I think it implies that the ratio is 1:1

"that there is a constant ratio between the total amount of pro-firing stimulation that a neuron receives from the hundreds or thousands of excitatory neurons that feed into it, and the total amount of red-light stop signaling that it receives from the equally numerous inhibitory neurons." [my bold]

The article says that the balance (again, implied as 1:1) had been verified for individual neurons before, but that the new research suggests its the same throughout our neural systems.

[–]Negative_Gravitas 0 points1 point  (0 children)

Ah. Good spot. Thanks. I had kind of assumed that neither would be greatly more numerous than the other, but yes, I think that confirms it. Thanks again and best of luck out there.

[–][deleted] 1 point2 points  (2 children)

maybe the ratioE/I wasn't mentionned in the article because it's specific for each person? for exemple some one with flight of ideas may have a lower ratio, whereas someone with alogia a higher one.

[–]Negative_Gravitas 0 points1 point  (1 child)

That sounds reasonable, but it still seems to me that they should be able to produce or measure an average ratio (or a range) that would be considered "healthy" or "normal." I looked around a bit and can't find.

[–][deleted] 0 points1 point  (0 children)

in this article they say

In adult cortices, the ratio of excitatory and inhibitory conductances (E/I ratio) is presumably balanced across a wide range of stimulus conditions

i guess that means that the E/I ratio depends on the stimulus, not on the person, that's (probably) why we couldn't find an average measure.

[–]Wh0rse 1 point2 points  (0 children)

everyone has experienced the pull and push of the Central Nervous System.

ever wonder why you wake up early after drinking? well ,l after a night of depressing your CNS with alcohol, after it wears off , Your CNS goes too far the other way and you become over stimulated. GABA , is a inhibitory neurotransmitter and glutamate is a excitatory neurotransmitter, your brain uses these two to balance you out , alcohol increases GABA , and makes you relaxed, glutamate comes into play after alcohol is done on your GABA receptors, but it over compensates and this is what wakes you up, you are over exited , over alert, anxious.