The role of memory consolidation in motor learning: A positron emission tomography study

While it has been well documented that the process of motor learning is accompanied by a shift in cortical processing regions, there has been little investigation into the effects of memory consolidation. The present study builds on earlier work and aims to investigate changes in the functional anatomy of motor learning that occur when the process of motor memory consolidation is disrupted. Ten healthy, right-handed males took part in the new experimental protocol. A star shape was presented to the subject on a computer monitor positioned above the PET gantry. During each trial, the subject used a ‘Felix’ computer-pointing device to guide a small red dot around the star shape in an anticlockwise direction. Subjects were instructed to perform the trace as quickly and accurately as possible using their left hand. After the 10th trial, the Felix was reconfigured so that hand movements were ‘mirrored’ on the computer screen. In the original study, subjects performed the mirror task 15 times while in the second study a distracter task was inserted between each mirror trial in order to disrupt memory consolidation. PET images were recorded during the seventh trial and then every other trial, culminating in 10 images. The resulting images were analysed using the Minoshima analysis package and the two groups were compared to determine the effects of disrupting memory consolidation. The results showed that there was less transfer from frontal and parietal areas to the occipital and primary motor cortices in the second study. This suggests that interference with motor memory consolidation disrupts the shifts in cortical activation normally seen in motor learning.