/sci/ - Science & Math

I'm hoping some guys here can help me to better articulate/understand something about mental fatigue so if you know about the brain I'd appreciate the help.
You know the kind of brain drain you feel when you've been studying very hard all day, you get to the evening and then you hit the wall. You want to keep working but your brain is just too drained, you might even be wide awake on caffeine or medication but your thinking/processing capacity is greatly diminished.

What *is* that exactly and what is happening inside the brain? I know it's a number of factors, but what are they specifically. I ask as I want to look into recovery aspects of these, I know sleep trumps all of them as this is when vessels in the brain open up, waste products are flushed out, neurotransmitters are replenished, memories consolidated etc but where can I find that in more detail.

I've been looking around and see something about a buildup of glutamate in the prefrontal cortex,
>https://www.cell.com/current-biology/fulltext/S0960-9822(22)01111-3?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0960982222011113%3Fshowall%3Dtrue