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Showing posts with label hippocampus. Show all posts
Showing posts with label hippocampus. Show all posts

November 10, 2015

Pregnancy Brain: A Neuroscientific Guide for the Expectant Mom (Part 1 of 2)

Shutterstock
My friend recently asked me, “Why have I become so forgetful since I became pregnant?” I told her I didn’t know, but that I’d look into it and write an article for her.

She then followed with, “I was going to ask you to explain something else to me, but I totally forgot what it was.”

Does “pregnancy brain” actually exist? There’s no doubt that many changes are happening to a woman’s body during pregnancy, but how do these changes affect (or originate in) the brain? To answer my friend’s question - and in an effort to address whatever else she was forgetting at the time - here is Part 1 of my expectant mom’s guide to the crazy neuroscience of pregnancy.

November 9, 2015

Implanting and Erasing Memories: Life-Changing, or Taking Science Too Far?

Most people who have experienced emotional trauma — such as war veterans, sexual assault survivors, or those whose lives have been threatened — are able to heal emotionally within weeks and months of the distressing event.

Breakthrough: Decoding the Brain (National Geographic Channel)
But for some individuals, the anxiety associated with the event never quite goes away with the passage of time. Recurring and intrusive flashbacks, nightmares, feelings of numbness or hopelessness, and avoidance of places, people, and activities that remind you of the traumatic event are common symptoms. At some point in their lives, around 7.8% of Americans will experience post-traumatic stress disorder, or PTSD.

Cognitive behavioral therapy, exposure therapy, and antidepressant medication are the current treatments for PTSD, but they're not successful in everybody.

But what if doctors and researchers could attack PTSD at the source: actually implanting or erasing specific memories in a person's brain?

It may sound like science fiction — not unlike Lord Voldemort luring Harry Potter to the Ministry of Magic by creating false images in Harry's mind, or the entire premise of the movie Inception — but science is actually getting close. In mice, neuroscientists have found ways to not only identify the location of certain memories, but to actually manipulate those memories.

But can we do this in humans — in patients with PTSD? And perhaps the bigger question: should we?

October 1, 2015

#BrainBits 5: "What the Heck is Déjà Vu? Why Do I Get It and Some People Never Do?"

This is the latest post in my #BrainBits series, where I'll answer your burning neuroscience questions in 60 seconds or less. If you have a question you'd like me to answer, you can e-mail me, tweet me, or submit your questions anonymously here.

Erika Wittlieb (Pixabay)
What is déjà vu?  Many of us know the feeling. You'll be going about your day, minding your own business, folding some laundry...nothing out of the ordinary. Suddenly a sensation of familiarity washes over you, and you're completely aware that it's happening. I've been here before. Except you haven't. Or have I? You might try to think back and pinpoint when you'd experienced this moment before. But just as quickly as the feeling hits you, it's gone again.

Did you predict the future? Were you seeing something from a past life? What the heck is déjà vu, anyway?

Perhaps unsurprisingly, déjà vu (French for "already seen") is, scientifically, pretty poorly understood. There are a few theories, however:

University of Bristol
  • Déjà vu may be the result of some sort of "mismatch" in how we're simultaneously sensing and perceiving the world around us. Perhaps we smell something familiar, for example, and our mind is instantly transported to the first time we smelled it. (It's a vague theory, though, and doesn't explain why most déjà vu episodes don't reflect true past events.)
  • Déjà vu may be a fleeting malfunctioning between the long- and short-term circuits in the brain. The information our brain takes in about its surroundings may "shortcut" its way straight to long-term memory, bypassing typical storage transfer mechanisms. When we have a moment of déjà vu, it feels as though we're experiencing something from our distant past. 
  • A region of the brain called the rhinal cortex, involved in detecting familiarity, may be inexplicably activated without actually activating memory (hippocampal) circuits. That may explain why déjà vu episodes feel so non-specific when we try to figure out where and when we had previously experienced a particular moment. In fact, some patients with epilepsy reliably experience déjà vu at the beginning of a seizure. For these individuals, experimental stimulation of the rhinal cortex — and not so much the hippocampus itself — induces déjà vu.

Déjà vu is estimated to occur in 60-70% of people, and most commonly in those between the ages of 15 and 25 years. (Why? No idea.) Interestingly, I had previously written about déjà vu years ago out of my own curiosity on the matter, having experienced it fairly frequently. I'm now 26, though, and can't remember the last time I had an episode.

Are any of these theories correct? We may never know. After all, an episode of déjà vu is completely unexpected and, for most of us, extremely rare. Empirical research on the topic is next to impossible.

The most parsimonious explanation, then, is likely the following:


What about you?
Do you experience déjà vu?
Let us know
In this anonymous poll!

Stay tuned for the next #BrainBits: "What are hiccups?"

November 5, 2011

Hippocampus (or should I say, elephant-campus)

I am always in awe of "unlikely animal friends," and there are plenty of these videos on YouTube from which to enjoy. This CBS Evening News Assignment America particularly interested me:


Steve Hartman has reported two follow-ups since this 2009 feature about an unlikely friendship between Tarra the elephant and Bella the dog. The latest, which I caught when aired two nights ago, was heartbreaking, but extraordinarily fascinating. Sadly, Bella was killed by what appeared to be a coyote attack on October 26. When the location of the attack was pinpointed, the blood on Tarra's trunk made it evident that the elephant had carried her friend a mile back to the house. Tarra is now showing all the signs of depression—her fellow elephant friends at the Elephant Sanctuary in Hohenwald, TN have been reaching out to her, spending more time with her and offering her their food. Nothing short of amazing, right?