MINNEAPOLIS (WCCO) — We often have a hard time recalling random days and details in our lives. But when tragic events like the 35-W bridge collapse happens, we can remember where we were and who we were with. So, why does that happen?

“I certainly recall where I was when John F. Kennedy was shot,” said Dr. Eduardo Colon, a psychiatrist with Hennepin County Medical Center. “Whenever a tragic event occurs there is a strong arousal of emotions. There are a lot of emotions that come out.”

If something irregular happens during our regular routine that causes major stress, a part of the brain called the “hippocampus” encodes the event in your memory.

“The amygdala, which responds to emotional stimuli, gets aroused and the hippocampus records that. And you will remember it vividly and emotionally,” said Colon.

The brain is like a computer that saves and stores major life events. Over time, smaller details can fade away but the overall memory stays with you.

The same thing holds true with happy occasions. Birthdays, graduations, weddings, anniversaries and other life events that make us smile. Sometimes, just a song on the radio brings them back.

“Music goes a long way towards memory recall. There are some events, positive and negative, that just stay with you. Almost like a scene. And you will recall them for a long time,” said Colon.

Colon said that when we are involved in an accident it may feel like things are happening in slow motion.

That’s because our bodies release hormones and adrenaline that put our brain on high alert- and cause it to process information faster than normal.