Fasciculations (muscle twitches) are the result of some kind of irritability of the nerve fibers. Because fasciculations are benign, they have not been studied particularly deeply (but, not all involuntary muscle twitches are fasciculations--more on that later). So we do not really know even where in the nerve the irritation is picked up--it could be in the cell body, could be further out in the fibers, nobody really knows. It is also thought that the exact localization of the fasciculation is random, meaning that you will feel a twitch in your arm or leg or eyelid without having necessarily irritated a nerve anywhere near the place you experience the twitch.

Causes are also only loosely understood; there are certain behaviors that can trigg ...

http://www.youtube.com/watch?v=327-bwMQI-Y&feature=youtu.be

This tongue eating fish parasite is one of the creepiest and most disturbing creatures around.

This frog (Breviceps namaquensis) sounds like a bike horn.

This is supernova remnant W49B. It is located about 26,000 light-years from Earth, and as we see it it is approximately 1,000 years old. Compared to other supernova remnants of similar type and age, it is distorted in an usual way. Astronomers believe that it is distorted because it is in the infant stages of of forming a black hole -- the very first time this has been observed.

Sunda pangolins have become the most frequently seized mammal in the illegal wildlife trade in Asia, as smugglers sell the creatures to meet culinary and medicinal demand. These gentle insectivores are now on the endangered species list.

This is the pygmy marmoset (Cebuella pygmaea), the smallest known monkey in the world.

They are found in western Brazil, southeastern Colombia, eastern Ecuador, eastern Peru, and northern Bolivia and they typically live in the understory of the rain forest near rivers. Males weigh around 140 grams (4.9 oz), and females only 120 grams (4.2 oz).

A Taiwan-based company has built a transparent smartphone with a multi-touch display from a light piece of glass. Although it's still a prototype, the executives have mentioned the transparent smartphone could arrive in late 2013.