The final thing I wanted to test was electric shocks. Is it safe to shock your brain? For some years scientists have been using tDCS (transcranial direct current stimulation, a small electrical charge to the skull) to try to improve a whole range of things, from learning to reaction times.
Dr Charlotte Stagg of Oxford University, has been using it to help people recover strength in their hands after a stroke. Charlotte has found that, compared with a sham treatment, tDCS seems to speed up recovery, probably because of the effect that tiny electric currents have on neuronal connections inside the brain.
To see what effect it would have on me, Dr Stagg carefully positioned some electrodes on my skull and turned on the machine.
There was a slight itchiness and it did feel as if my brain had been given a jolt, but had it actually made any difference?
The short answer is yes. In a test which involved pressing a button when I saw a light go on, my reaction times improved from an average of 650 milliseconds before the machine was turned on, to 550 milliseconds with it on. These findings are in line with results from other subjects.