The handsome chap above is called Homunculus Man. He’ll never appear on the front cover of any magazines, and he’ll probably not win any modelling contracts any time soon, but he is vital to you and me, and here’s why;
There is an area in your brain just above your ear that is similar in size and shape to your finger. This is called your ‘(somato)sensory cortex’.
Homunculus Man (HM) is a visual representation of your body within your sensory cortex. All skin – all body parts – have an area of the brain devoted to it, so that – for example – if you stub your toe, the area dedicated to the toe within your brain will ‘light up’. As you can see, Mr HM has abnormally large hands/fingers, genitals, lips and tongue (and head in general). This is because of the relative use day-to-day, meaning a bigger area dedicated within the sensory cortex. The more use, the bigger the area within the sensory cortex. Following? Good.
So why is this important to us? Well, the brain has a ‘plasticity’ meaning that the sensory cortex is, for want of a better word, changeable, or adaptable. If you are a violin player, chances are the part of your sensory cortex dedicated to the fingers of the left hand is larger than mine. Would David Beckham’s right foot ‘area’ be bigger than average? More than likely. It has even been show that London taxi drivers have a bigger hippocampus (part of the brain that is used in navigation) than healthy non-taxi drivers (1)! You’ll often hear talk of ‘muscle memory’, but you can see from this the importance of ‘functionality’ when training, not merely in the soft tissues (muscles) but also in the brain (there is an excellent book called ‘On Intelligence’ where the author, Jeff Hawkins, talks in more detail than i can go into here about the brain’s memory-prediction pattern). The more we lift/run/hit, the larger, more attuned that area of the cortex will become.
This goes someway (but by no means the whole way!) to explaining phantom pain post amputation, as the sensory cortex still – at least initially, and sometimes forever – has a visual/virtual representation of the missing limb. It also shows that the amount of pain you are suffering does not necessarily relate to the size of the tissue damage sustained.
The cortex can also suffer from ‘smudging’, where area’s dedicated to specific areas start to overlap. This is particlulary problematic in long term/chronic pain and something that is always worth remembering.
(1). “Explain Pain”, D.Butler, L.Moseley 2nd Edition
N.B. There are no ‘one size fits all’ style quick fixes in most injury scenarios, so these article shouldnt be seen as such. They are merely guides to a better understanding of how our bodies work.
For more information please visit www.dc-injuryclinic.co.uk