3. Explicit and Implicit Processes in Motor Learning
Pietro Mazzoni and John W. Krakauer
In this week's Journal, Mazzoni and Krakauer set up a conflict between implicit and explicit processes in visuomotor adaptation. Subjects rotated their hand to control a computer cursor that they tried to place within a target: one of eight radially arrayed circles. In a "rotation" condition, the cursor was rotated 45 counterclockwise, offsetting subject movements. In a "rotation plus strategy" condition, subjects were informed of the offset and given a strategy to cheat the system by aiming for the circle clockwise of the actual target. This cognitive strategy initially succeeded in canceling errors but ultimately failed as subjects implicitly adapted to the rotation at the expense of making correct responses. Interestingly, the rate of adaptation was the same with or without an explicit strategy. Thus, the motor system, with a mind of its own, overrides explicit strategies involving subject awareness. Sometimes it's better not to think too much, it seems.
4. Imbalanced Neural Activity in
Nicolas Mallet, Brangre Ballion, Catherine Le Moine, and Franois Gonon
The loss of dopaminergic inputs to the striatum in Parkinson's disease (PD) inevitably alters the balance of neural activity in striatal projections to substantia nigra pars reticulata (direct output) and the pallidum (indirect output). This has been attributed directly to a loss of dopamine receptor stimulation (e.g., striatonigral neurons express D1 receptors, whereas striatopallidal neurons express D2 receptors). This week, Mallet et
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Society for Neuroscience