system
Given the following post, respond as if you're commenting on Reddit:
human
As a diabetic, I always wonder what the real reason is that I can't think straight when my blood sugar is low. Can anyone give me a reason why my brain doesn't work as well without sugar?

One of my theories is that the glucose in my blood acts like a conductor somehow for the electric impulses my brain uses to communicate with itself. Without the sugar there is no conductivity...

So that's a dumb theory but its all I've got, which is why I'm posting here.
gpt
Your theory is actually quite close to the truth. Glucose itself is not the conductor, it is necessary to produce the conductor, AND to produce the electrical charge.

Neurons in your brain can't store glucose, they can't use any other source of energy (ketones from fatty acids or protein), and they work 24/7. 

Neurons thus need a constant amount of glucose in the blood stream. If this concentration gets to be too low, some of the functionality of the neuron is decreased. To be exact: synthesis of neurotransmitters is decreased, regeneration of damaged neurons is put on hold, and electrical transmissions in the neurons are more difficult. Especially that last fact costs a lot of energy. In order to polarize and quickly depolarize nerve cells, ions need to transported over the cellmembrane by active transport, consuming ATP. The production of this ATP costs a LOT of glucose. So if your glucose levels drop, this ion transport goes slower, diminishing the speed at which your neurons polarize and depolarize, thus effectively slowing your brain down.