According to some recent research, flipping the bird is a lot of work, as far as moving your digits goes. Neuroscientists Claudia Wilimzig, Patrick Ragert, and Hubert R. Dinse, from Cal Tech and the Max Planck institute in Germany, have shown that the middle finger has the slowest reaction time of all five manual digits. Apparently, this is due to the simple fact that the middle finger is the finger in the middle.
The somatosensory cortices, which are higher order regions of the brain involved with sensation and movement, are imbued with “topographical maps” of the regions they represent. Everything but your guts has corresponding neurons in the sensory cortices, and regions with a more detailed sense of touch (i.e. hands and face) have more real estate in the brain (as represented by this famous, creepy image). What’s more, bordering parts of the body correspond to bordering sections of brain – if one region of skin sends information to one group of neurons, an adjacent region of skin sends information to an adjacent group of neurons.
Read the rest at Motherboard.