We can actively “sense” reality. But ‘How does the brain combine all senses into a single reality?’ That is a challenging question that is very much an area of active research.

Right now, billions of neurons in your brain are working together to generate a conscious experience — and not just any conscious experience, your experience of the world around you and of yourself within it. We’re all hallucinating all the time; when we agree about our hallucinations, we call it “reality.”

The reality maintained by the brain is fragmented and always just a bit out of sync despite the brain’s ongoing efforts to keep it unified. The reason for this is that sensory information is arriving at different brain areas, and while the brain is “putting the pieces together” to figure out what is going on out in the world, the world is changing. As a result, the brain’s understanding of the world is constantly out of date and even inconsistent with itself.

Question asked by Div

Sneezing while sleeping has never been studied extensively, but most sleep researchers and scientists agree that it is physically impossible to sneeze in our sleep.

Normally, humans should sneeze frequently during the night. Our mucus membranes swell when we lie on our back, stomach, or side and swollen mucus membranes are a common cause of sneezing. However, the body suppresses the instinct to sneeze through a process known as rapid-eye movement (REM) atonia, which happens when we are sleeping. The neurotransmitters that normally detect allergens and other irritants shut down during REM atonia, thus preventing the involuntary urge to sneeze.

It is possible though, with sufficient external stimulates, to trigger the need to sneeze. But you will wake up to do so.

Question asked by Mélanie

A man who died twice, for 2 minutes each time, and manged to pull through, said:

On dying:

“The first time was right before the [motorcycle] accident and the only thing in my mind was ‘oh god’.”

“The second time I had no idea. I was in pain and all of a sudden there was nothing, just no life. Then I was awake and in pain again.”

On the sensation of death:

“I had no idea, it was just black emptiness. No thoughts, no consciousness, nothing.”

“Both times I was just “not there”. It was just all black. I would describe it as when you take a nap. A short nap with no dream, you wake up and it feels like you’ve been sleeping a long time, when in reality it’s only been about 15 minutes.”

On being told he died:

“Well my first reaction was ‘Om, that’s so cool! Now I can tell my friends that I’ve been dead and come back to life etc’ but most of those thoughts were the morhpine talking.”

“Then reality sets in, and I realized that ‘wow, I could’ve been dead right now.’ That’s when I started to understand how serious my situation really was.”

“I definitely fear it less. I know now that death is nothing worse than sleeping. When you die, you just stop existing, nothing to worry about!”

In Summary:

“Death is death. Once your dead, that’s it, it’s over.”

…says the man who died twice.

Question asked by Lucas