Tidbit #25 - April 22, 2011

It's so weird when it happens, isn't it?
It's so weird when it happens, isn't it?

WHOA! Anyone else feel déjà vu there? I sure did, and it made me wonder: What makes déjà vu happen?

Question: What causes déjà vu?


Answer: By definition, déjà vu is "the feeling that you have experienced a situation before even though you know you haven't" (Re: science.howstuffworks.com).

Furthermore, there are different types of déjà vu that someone can have. Precognitive experiences are one type, in which someone feels like they know what's going to happen next, and that happens. There are many other types that we won't get into, seeing as this tidbit only focuses on what makes déjà vu occur.

So, I went ahead and searched up déjà vu on howstuffworks, and found a neat little article (or big article, rather). You can look at the article I viewed here.

"[Many scientists] have since determined that the medial temporal lobe is involved in our conscious memory. Within the medial temporal lobe are the parahippocampal gyrus, the rhinal cortex and the amygdala. John D.E. Gabrieli at Stanford University found in 1997 that the hippocampus enables us to consciously recall events. He also found that the parahippocampal gyrus enables us to determine what's familiar and what isn't (and without actually retrieving a specific memory to do it)." (Re: science.howstuffworks.com)

That wasn't a big wall of text, but it certainly had some big words! Let's break it down into my own summary:

Many parts of the brain are involved in déjà vu. Our conscious memory is where it generally happens, but a part of our brain called the hippocampus allows us to recall memories. Something called our parahippocampal gyrus (pretty much another name for the stuff around the hippocampus) also plays a role in déjà vu by encoding our initial memories so we can think we remember them later on.

I also found a neat article on Wikipedia (where else?) that really shone the light, if what you've already read didn't:

The similarity between a déjà-vu-eliciting stimulus and an existing, but different, memory trace may lead to the sensation. Thus, encountering something which evokes the implicit associations of an experience or sensation that cannot be remembered may lead to déjà vu.

Basically, that stated our condensed answer:

 Déjà vu happens when our brain associates an existing memory with a new one.

Tidbit #8 - April 3, 2011

Food can be one of the most pleasurable aspects of our day. And why? Because we all like the taste. There are entire reality shows (Top Chef, anyone?) based on food and its taste. But not everyone who tastes food knows how we taste it.


Question: How do we taste food?


Answer: If you know anything about the nervous system, then you should know that it's based on nerves. Your senses are caused by nerves, particularly specially made neurotransmitters. Your sense of taste is caused by (what else?) your tongue.

On the surface of your tongue are relatively 9000 different sensory receptors (called taste receptors) that pick up taste, also called taste buds. Different areas of the tongue correspond to different tastes, as shown in the diagram to the left. Speaking definitively, every taste bud on your tongue picks up the different chemicals in the food you eat and sends electrical signals through the neurons to the taste processing center of the brain, causing your food's taste.

By the way, all of those regions on the tongue diagram above which correspond to those tastes send more intense signals to the brain when the food you eat has chemicals that taste that way. (Basically, they taste stronger in those areas of the tongue)

Tidbit #4 - March 30, 2011

Question: What causes someone to forget something?


Answer: Think back to Tidbit #2 (how we make memories). Remember how I wrote that each memory is really a pattern of links between neurons?

My guess is that you forget something if you don't repeat that pattern of neuron links, which means you don't repeat the activity enough.

So, for example, let's say you've learned the formula: sin(2Θ)=2sin(Θ)cos(Θ). That's a lot to remember, right? It's because that's a special pattern of links between neurons in your brain. Every time you say that formula, or think about it, those linked neurons send impulses to each other, causing the formula to be remembered, therefore strengthening the memory.

But if you spend the week on your chemistry homework instead of your math homework, the neuron links will become weaker and weaker, making it harder for you to remember that formula.

If you have any tidbits you'd like to offer, comment on the post with your idea. Who knows? You might get it on the blog.

Did You Know That?? (Intro/Tidbits #1-2)

Ever wondered about all those little things worth pondering over? Maybe you've wondered why they use that weird symbol for the heart that we've learned means love. Or maybe you've wondered how our brain can make those memories that we're so fond of.
Whatever it is that you're thinking about, odds are I'll have it sooner or later. Check this place out as often as possible, because when I learn something new, it's going right on here.

By the way, the answers to the above questions are:

1. The origin of the heart symbol ( ♥ ) is debated, although some say that it is supposed to be a representative of the seed of the silphium plant, while others insist that it is supposed to depict a woman's genitalia or breasts. (Source: en.wikipedia.org)
   
2. Okay, this one's taken right from a book:
   Quoted: "Each memory is formed by a unique pattern of connections between the billions of neurons in various parts of the brain, especially the cerebral cortex. The event to be memorized-from reading a number to meeting a celebrity-occurs as a particular set of neurons sending impulses to each other during the initial experience. Activating this set of signals again, by remembering the experience, strengthens its pattern of links so they are more likely to occur together-a process known as potentiation. After several activations the links become semipermanent. Triggering a few of them, by a new thought or experience, activates the pattern's whole network and recalls the memory." (Source: The Complete Human Body, by Dr. Alice Roberts)
   Summarized: Every memory you form corresponds to a connection of electrical impulses between neurons. In a nutshell, the more you set that pattern off, the stronger the links between the neurons will be, the more vivid the memory will be.

By the way, if you want to read my other blog, you can drop by Teen Help Center and find out how to be a good teenager. If you want to find out how to be a good PARENT of a teenager, you can check out Teen Parent Café. Finally, if you want to know about random facts of history, visit my stepdad's blog, Deadwrite's Dailies.