Tagged: TMS

F—— Magnets, How Do They Work?

February 1st, 2011 in News 1 comment

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It has been said “The most exciting phrase to hear in science, the one that heralds new discoveries, is not ‘Eureka!’ but ‘That’s funny…’” (Isaac Asimov), and a recent observation by a Harvard Medical School lab studying the brain chemistry of Bipolar Disorder has researchers uttering that precise phrase…as well as the one alluded to in the title of this post.

The initial study prompting such observations recruited patients suffering specifically from Bipolar Disorder, also known as Manic-Depression, for 20-minute brain scans in an MRI.  MRI scans subject patients to a harmless magnetic field and pulses of radio waves to create detailed structural images of various body parts, in this case, the brain.  While the procedure is painless and relatively short, it can be unpleasant for reasons wholly unrelated to the magnets and radio signals; patients frequently report unrelated bodily discomfort or claustrophobia.  For this reason it was all the more surprising, according to one researcher, that patients participating in the study started to report mood elevations (that for some lasted days or even a week) following the scan.  One patient even subtly suggested that the researchers had slipped her something without her permission.


Patient undergoing TMS treatment for depression

The use of magnets to improve the effects of depression is not uncharted territory in neuroscience and it might even sound familiar to some.  Transcranial magnetic stimulation, or TMS, is another technique that has recently been adapted to depression therapy, yet it is more akin to electroconvulsive, or “electroshock”, therapy (ECT) than MRI.

TMS uses a magnetic field to induce a relatively small electric current, without causing seizure or loss of consciousness, to stimulate the left prefrontal cortex, the area thought to be under-active in depression.  Whereas ECT treatments are utilized only in the most extreme depression cases because of the risk of seizure and necessity of sedation, TMS carries much fewer risks and can be used for more mild depression. While the exact mechanisms are still not known, particularly the roll of seizure for the antidepressant effects, both ECT and TMS have been cleared by the FDA.

But the magnet employed in MRI does not excite specific brain regions (if it did the entire imaging method of functional magnetic resonance imaging, fMRI, would be ineffective) and it is certainly not strong enough to induce seizures.  After observing the curious side-effects of their initial study, the aforementioned researchers set up a small preliminary study with both bipolar and normal controls who confirmed respectively that the effects were not placebo, and that even those without depression can experience the mood-boosting effects of MRI.

So could a new depression treatment soon be joining the ranks of such accidental scientific breakthroughs as penicillin and Post-It notes?  At this point it really is unclear.  The actual mechanism of the mood-boosting effects of MRI on depressed patients is not yet understood, nor have the effects been generalized to unipolar depression.  However, the safety of exposure to MRI has been confirmed by the FDA and a lack of total understanding regarding what causes the “miraculous” effects of that other magnet-based depression treatment, TMS, as well as a host of other medical treatments (including lithium for Bipolar Disorder) certainly has not prevented their use.

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Piano Teachers Must Be Neuroscientists

July 21st, 2010 in Uncategorized 0 comments

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Involvement of the prefrontal cortex (in yellow) seems to make variable practice effective.

The familiar mantra “practice makes perfect” may be taken too literally. The definition of effective practice as the constant repetition of a particular exercise - a golf swing, a tennis serve, a dance step - is faulty, as it turns out.

Time has reported on a study published in Nature Neuroscience by neuroscientists at the University of Southern California and UCLA. The study compares the results of repetitive, “constant practice” with the results of “variable practice."  In one experiment, scientists instructed a group of subjects to copy a movement with their forearm as displayed by a line on a computer screen. One group representing constant practice repeated a movement holding their arm at 60-degrees 120 times. The variable practice group was asked to do the same 60-degree movement only 60 times, but they were also asked to do three other movements 20 times each. The two groups did equally well in practice. However, when they were retested 24 hours later, the variable practice group outperformed the rote repetition group on the 60-degree task.

So, variable practice works - but why? Some of the subjects from each group were treated with transcranial magnetic stimulation (TMS). A portion of each group had TMS in the prefrontal cortex, and another portion received TMS in the primary motor cortex. The prefrontal cortex is the part of the brain that allows for executive functions like reasoning and planning while the primary motor cortex deals with simple, physical task learning. Fittingly, when the prefrontal cortices of variable-practice group members were “messed with” by TMS, the performance of the participants declined. Performance levels also decreased when constant-practice subjects underwent TMS in their primary motor cortices. It seems that “tedium is bad for the brain,” and it needs variety to actively learn by using higher structures like the prefrontal cortex to better retain what has been practiced.

It would be interesting to find out whether or not this concept applies to different types of learning, like studying for exams or playing an instrument. Even when training a dog, it is suggested to work amid distractions and to increase the time between clicking the “clicker” to let the dog know it has performed a task correctly and rewarding it with a treat. A higher level of focus seems to occur when there are more variables in the practice routine. My piano teacher must have been on to something when she gave me so much homework!

Study: Why Athletes Should Mix Sports-Training Routines - Time

Article: Practice Structure and Motor Memory -Nature Neuroscience

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