So a question you might ask yourself is… does the brain regard every part of the body the same? That is, does the brain give an equal amount of cortex (brain matter) to each part of your body for movement and touch? The answer is a big no.
There is a division of your brain called the central sulcus (fancy term for a ‘rift valley’ in the brain). On one side of the valley, there is a strip of cortex called the primary motor cortex which initiates movement and action. On the other side of the valley, there is the primary somatosensory cortex which receives and exchanges information about ‘touch’.
On each side of the valley, the brain allocates a different amount of ‘strip’ to different bodily areas in a hierarchical system – this is the cortical ‘homunculus‘, meaning a pictorial representation (below) of the body within your brain based on how much ‘space’ each part of your body is given. In the primary motor cortex, body areas that are required to have very precise and intricate movements (such as the hands) have more cortical ‘strip’ than areas that are less important for movements. So, if the body actually looked like it is represented in the brain, you may be slightly alarmed to find out you look a little bit like this:
