Stretchy Finger and Why You Can't Tickle Yourself

Nottingham University’s research team stumbled on these findings completely by chance during the University’s Community Open Day in April last year.

As part of the event they invited members of the public to experience some of the body distortion illusions they use as part of their everyday research using Nottingham’s unique MIRAGE technology that takes a real-time video capture image of a hand and uses computer manipulations combined with physically pulling or pushing on the hand to fool the brain into believing the hand is stretching or shrinking.

 

http://www.nottingham.ac.uk/news/pressreleases/2011/april/stretchyfinger.aspx

In this case, while you are ‘seeing the finger being stretched’ the brain is being tricked into thinking that the finger is lengthening, releasing tension and arthritic pain due to tightly held joint surfaces. We are not told whether the finger becomes more mobile as a result.

However, just the thought of an action will generate a physical response.

We traditionally think of the brain as a hierarchical system receiving information through an assembly line type system but in fact, it is more a feed-forward/feedback type of loop system.

Your brain, enclosed in a completely dark box, needs information from sensory nerves to modify your brain’s internal representation of you. As a movement command is given, the brain forward projects this representation to predict the outcome of the movement. As the movement takes place, the unconscious regions of the brain compares sensory information to the predicted, projected outcome.

What we think we are doing isn’t always what we are actually doing. Sometimes, from injury and pain or poor postural habits, this internal representation becomes inaccurate.

We get so used to doing things our way, we can no longer tell what we're up to. Our picture of ourselves doesn't match reality

 

Alexander Technique gives your brain a conscious, reliable and accurate internal representation we call Primary Control. This internal representation is projected forward ahead of movement taking place. All physical responses to the movement command are directed through the filter of this internal model. So, Primary Control is the first or primary function of the brain before a movement command is given and it is also primary in importance. As the brain compares the resulting sensory feedback from the movement to the predicted outcome, we are able to consciously notice and adjust if something different occurs. In this way, the brain’s internal dialogue is not about the ‘rightness’ of all actions but ‘wrong’ actions are highlighted against the predicted outcome.

Whether our predictions are accurate or not, this feed-forward prediction of outcome is why you can’t tickle yourself—you can’t creep up on yourself while you’re not looking.

Exercise Facts and Fallacies

Alexander Technique is not an exercise but is a detailed study of the fundamental principles of human co-ordination and movement that underlies all activity. A unique form of neuro-muscular rebalancing, it is concerned with how you direct your Primary Control. Primary Control is a fundamental concept of The Alexander Technique that describes a certain relationship between the head, neck and back and how this relationship affects poised, co-ordinated action. Alexander teachers call this ‘use’, i.e. how you use your head, neck, back relationship so that you maintain a central co-ordination of the trunk as a core structure. The technique ensures that, in using your limbs, breathing, voice, etc. the central co-ordination of the head, neck and back is not disturbed.

drawings taken from 'The Alexander Principle', Wilfred Barlow

Why exercise is not always the solution

Core stability exercises were devised in response to the perceived problem of poor support. The exercises encourage concentration on individual muscle activation during activity to stabilise ‘the core’ in order to support an area known to have weakness. The problem with this action is that it is contrary to the function of the nervous system. If our innate balance mechanisms are allowed to perform their function unimpeded, there is no need to consciously engage muscle or strengthen the middle of the structure independently. In the absence of interference, the reflexes responding to gravity will help to ensure optimum balance and movement. 

However, exercise cannot ensure ‘good use’ of the body. We have probably "exercised" ourselves into bad posture by just doing a normal daily routine for years and years. Now we are proposing to exercise our way back out of it. If we have learned misuse or poor postural habits, when we exercise, we will exercise with misuse unless we deal with our misuse and learn to eliminate it. It is also worth noting that we cannot exercise these deep stabilising, supporting muscles to produce strength; these muscles are reflexive and not subject to our direct control.

A few more exercise fallacies

Sadly, doing sit-ups will not flatten your tummy. There is a layer of fat between the muscle and the skin and if this layer of fat is excessive, the only way to flatten your stomach is to lose fat – harsh but true.

The muscle that we call the ‘six-pack’ that shows its definition so strongly is Rectus Abdominis. It runs from the pubic bone to the lower end of the breastbone (sternum).

Sit-ups will over-tighten 

Rectus Abdominis and when it is over-tightened it pulls down the rib cage, rounds the shoulders and pulls the neck forward.

Drawing of 'muscle man' reproduced by kind permission of Christopher Stevens

And while we are on the subject of facts and fallacies...how about relaxation?
It is tempting to think that the solution to many of our problems is to ‘just relax’ but what do we mean by relaxation? We would like to think that by relaxing we are letting go of excessive tension in our muscles. Most people when they relax, however, over-slacken their muscles and the result is collapse. What is actually needed is appropriate tension in the muscles: collapse is not relaxed.

See Professor Lederman's research 'Myth of Core Stability'