Monday, 5 September 2011

Think Of A Number Between 1 and 20... (post 1 of 2)

Now if you have thought of a number between 1 and 20, then the chances are you would have said it to yourself in your head. This inner voice is also used when reading these words on your screen, I myself am using it while typing. When we think of words in our inner voice we generate an internal dialogue, a conversation with ourselves – The question I would like to consider is this: what if we could hack into someone else's internal dialogue and understand it? 

Besides the ethical questions this undoubtedly raises, there are profound scientific applications for the ability to read a person’s internal dialogue. Take for instance a person suffering from locked-in syndrome, whereby they are awake and aware but completely unable to communicate in any way more complex than the blinking of the eyes. If we could read the mind of patients suffering from this terrible syndrome we would be able to provide them a much higher quality of life. The key reason that it is believed we may indeed one day be able to hack into the internal dialogue is based on the fact that the brain produces a characteristic electrical signal when we think of any word. All we need to do is work out which words correspond to which electrical signals. No small task…

So the key to mind reading lies in the electrical signals produced by the brain. The first time these electrical signals were recorded was in 1924 by Hans Berger (the chap on the right), who invented the electroencephalograph (EEG) by placing electrodes on the head of a subject and measured the electrical output of all the brain's neurones. The ability to read these electrical signals progressed over the next 70 years and by the mid-1990s it was possible to have them processed by a computer make a cursor move on a screen. This “brain computer interface” (BCI) allowed the cursor to move on a screen by training the computer to recognise two distinct electrical signals and respond to these in the appropriate way. For instance, one signal would correspond to left and another to right. These electrical signals were produced by thinking of specific movements (i.e. using electrical signals generated in the motor cortex) for instance, thinking of hitting a tennis ball produced a signal that the computer interpreted as left, while kicking a football would produce a different signal, interpreted as right.

Early EEG recording by Berger

While moving a cursor on a screen is no doubt a fantastic achievement, having to communicate solely by moving a cursor around a screen would be pretty difficult and slow. Just imagine moving a mouse around an image of a keyboard on a screen, let alone having to focus on precise movements in your head, which a computer has to interpret. If we really want to read minds, we need to be able to focus in on the brain areas governing speech and decipher the electrical signals produced there in real time. If we can do that, we may then be able to produce a speech synthesiser to convert these electrical signals into sounds – in essence, giving the patients a voice.

The question is, which areas of the brain do we need to look at and what work being done to study these areas?

Stay tuned to find out...

No comments:

Post a Comment