Day 13: Techniques and Risks and Coils, Oh My!

http://www.teamworksdesign.com/our-work/magstim/

This image can be seen in "Photo Gallery: The Lab"

Magstim, as it states in the image, is "the leading provider of advanced neurostimulation products." The TMS machine we use in the lab was actually created by Magstim. How did I not think of going to their website before! I found Magstim's wonderfully informational website and will be using it as another source for my present and future TMS discussions on this blog.

So to cover what I have discovered over the past week, I will create a 3-day series, talking about the different techniques, risks, and coils of TMS--one subject for each day. Let's begin.

Part 1: Techniques

http://www.magstim.com/techniques/

To the left is a compiled list of different ways TMS is used in research. To not cause confusion, I'll discuss only the techniques relevant to my project, indicated by the red stars. 

Brain Mapping-MRI: fMRI measures neural activity by looking at changes in blood flow activity. fMRI provides great visuals, but it is unable to indicate "whether activation within a particular cortical region is directly related to perception or behavior" (Magstim). By adding TMS, we can make those correlations between region and perception or behavior. Moreover, fMRI can be used to find areas affected by TMS through either direct stimulation or stimulation from an interconnected area.

Motor Evoked Potentials: The first to stimulate the brain through a noninvasive procedure were Merton and Morton. Why stimulate the brain? To observe what happens. With TMS, a small area of the brain can be stimulated to see what that area does. 

Inhibition and Excitation: Excitability thresholds increase among stroke victims, making it harder for muscles to be excited. TMS can enhance the excitability threshold when stimulation comes prior to voluntary movement.

References:

1. Magstim
2. Merton, P.A.; Morton, H.B. Stimulation of the cerebral cortex in the intact human subject. Nature. [Online] 1980. http://www.nature.com/nature/journal/v285/n5762/abs/285227a0.html (accessed March 6, 2013).
3. Wikipedia - Functional Magnetic Resonance Imaging