I was unfortunately unable to attend the afternoon “computational” session of the TCMC satellite, but I found the morning session very stimulating! Instead of going into detail on any of the talks, I think I’m going to summarize the findings they discussed, and I’ll go into more detail on another occasion (or upon request). I don’t know which of the authors was the speaker in some of the talks, but you can find the event’s schedule here.
There were six 20-minute talks, but I will just talk about two I found interesting. The first talk was a study of whether motor memories are context-dependent. Previous research has shown that memory of fear conditioning in rats can demonstrate a context dependence. The researchers of this study tried to examine whether the state of the brain during motor learning can affect the development of motor memory. They used transcranial direct current stimulation (tDCS) to affect the state of the brain. tDCS basically means that two electrodes are applied to the head and a current is run between them, which flows through the skull and into the brain. They used a very typical task for studies in my field call a “curl-field task”. Subjects are asked to push a robotic manipulandum forward, but the robot applies a velocity-dependent force perpendicular to the direction of movement. These researchers used tDCS to associate an up- or down-regulation of somatosensory cortex with curl fields in opposite directions. Then, in error-clamp trials (where only tDCS is applied and movement of the robot manipulandum is constrained to be error-free by only allowing movement of the manipulandum toward the target), the subjects performed the tasks associated with the different types of tDCS applied as if the appropriate curl fields were active!
During questions, there was one researcher who prefers to use transcranial magnetic stimulation (TMS) who pointed out that when you use tDCS, you don’t really know what brain areas you are affecting because the current flows over relatively large areas of the brain. While this may be true, I was extremely interested in this study because in our lab, we have attempted to use tDCS to treat dystonia in a number of studies that have had mixed to negative results. If dystonia is related to a failure in motor learning, perhaps it is indeed possible to use tDCS to help patients retrain themselves?