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What's up with deja vu? Your inquiring minds want to know

Last week, we outsourced part of our job to our Facebook fans, letting you guys ask the odd health questions this time. This week, we investigated the answers to some of our favorite wonderfully weird queries -- on deja vu, seemingly random memories, hiccups and sneezes. Here's what we found. 

The answer: First of all -- it's not just you. "In recent community studies, approximately 70 percent of the individuals reported some déjà vu experiences," explains Dr. Orly Avitzur, a New York state neurologist. On average, it happens about once a year in healthy individuals -- but it appears to be more frequent when we're tired or stressed. But it can also be pathological, often seen in patients with epilepsy. 

"The temporal lobe, particularly the region of the hippocampus, has been linked to this phenomenon," Avitzur says. "Neurons there store new experiences in a 'mental map' and some scientists have theorized that when very similar events overlap, déjà vu occurs."

Hmm. We feel like we've heard that explanation before.

The answer: We gave this one to Avitzur to tackle, too. "Detailed memories for episodes from our past can be triggered when we’re suddenly exposed to a stimulus that was present during the original event," she explains. "When you’re working at your desk and you experience a memory of a place or person from your past, you may not be consciously aware that an auditory stimulus (like music), or visual stimulus from your computer screen sparked the memory."

But these associations your brain is making might be so subtle that they appear "random" to you. Here's what's happening inside your brain: "Results from functional MRI studies and neuropsychological testing suggest that the prefrontal cortex area of the brain is responsible for episodic retrieval of memories," Avitzur says.

You know, that reminds me of something ... 

The answer: We asked Dr. Peter Abramson, an ear, nose and throat doctor from Atlanta to explain why some of us seem to be more hiccups-prone than others. "Hiccups, essentially, can be caused by a number of different things -- it could be anything from a (gastro-intestinal) issue from having an over-distended stomach to having irritation of the nerves that control the diaphragm," he explains.

People who often get the hiccups may have unusually sensitive nerves that control the diaphragm, Abramson says. Another theory: If you eat too much, and your stomach is often distended, that can trigger the hiccups. A brain tumor is another scary, but unlikely, potential cause of frequent hiccups. 

The answer: We picked Abramson's brain again for this one. Some sneezes are initiated by sensory nerves in the nose, and pressing on the upper lip may help distract those nerves, he explains. "What it may do is decrese the brain’s ability to sense that there’s an irritant in the nose and decrease their chance of having another (sneeze)," Abramson says. 

Got any more weird wonderings about the human body? Ask away -- either here, on our Facebook page, or ask us on Twitter (@bodyodd) with the hashtag #inquiringminds. (And, hey -- keep it SFW, please.) We'll be back next Friday with more answers to your questions.

Follow Melissa Dahl on Twitter: @melissadahl