A study of neural plasticity in stroke survivors
A study of stroke survivors with right arm weakness (Carey et al 2002) asked subjects to practice moving their right index finger to follow a target on a screen and then perform the same movement in a MRI scanner. After the training, there was clear evidence of neural plasticity, as there were areas of the brain that were being activated that had been completely silent before the training. Further, many of these new areas of activation were near the site of the stroke, so it appeared that new pathways had started activating around the area of damage. This was accompanied by improved co-ordination of the movements of the right index finger.
So, how many reps did this take? The stroke survivors did 1200 one-minute trials, which, calculated out, is approximately 6000 to 7000 finger movements. Timewise, this worked out to around 60 minute sessions every day for 20 days.