At about 4pm on Friday the 20th of August, if you were anywhere in the vicinity of central London, you may have noticed an audible collective gasp; a long and satisfied expulsion of anxious tension. This was the moment that my masters drew to a close, as each and every student on the course handed over their thesis, the fruits of nine months hard slog, before promptly retiring to either the pub, or to bed. In my case, the latter was my chosen option, having spent the entire previous evening, night, morning and afternoon tweaking, redrafting, and desperately trying to get the darn thing printed in time. I did, with five minutes to spare.
In the end, I think I turned in a really good piece of work. I hope so. It has certainly had a lot of praise from the two individuals who will be marking my work, which can only be a good sign. As an extra bonus, it looks likely to be published in a peer-reviewed academic journal, which will be a huge boost to my fledgling career.
Essentially, our project set out to examine what happens when a specific sound becomes behaviourally important. Numerous studies on animals have shown that when a target frequency is paired with an electric shock (to make it behaviourally significant) the area of the brain which ‘looks out’ for that sound gets bigger. What isn’t understood is how this affects the ability to perceive that tone.
We paired a target frequency with a shock, like the animal studies, and participants had to discriminate between the target frequency and other frequencies, some very close and some much further from the target. If, as the animal studies suggest, this leads to an expansion of the target representation on the cortex, will the participants get better at telling the target frequency from tones that are very very close to the target?
The answer, is yes. When subjects were being conditioned with the shock, they became much better at telling apart tones that were very close in frequency. This effect happened rapidly, and did not occur when participants were not being conditioned.
The neuroimaging results also indicated that there was greater brain activity in response to the frequency that was paired with the shock, compared to all other tones. This would fit with the expanded representation demonstrated in the animal studies.
So what? What does all this mean? Well, firstly, we have demonstrated that the human brain begins to adapt and change to our environment within minutes, something that would have been inconceivable a few years ago. Secondly, studies like ours help us to understand the basics of more complex mechanisms, which future studies will elucidate further. How does early musical training produce a child genius? How are our sensory memories stored, and what does this tell us about memory as a whole? What are the limits of the brains ability to change itself, and how can we use this information to treat brain damage or stroke? All these bigger questions will need a basic foundation to expand upon, and studies like ours, which may in isolation appear trivial, can provide the basis for these foundations.
