Beauchamp:TMSOverview: Difference between revisions

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== Computer control of TMS machines ==
== General Overview ==
Like with any other experiment you first need to design the experiment and determine what conditions you will be testing and how many repetitions and how many subjects, etc. Additionally for ALL TMS experiments you will need to have one or more "control" experiments. This is to rule out that the observed effect is due to non-specific effect of the TMS. It is best to have at least one "spatial" and one "temporal" control experiment. With the spatial control, you will move the coil to a different location on the brain. Some people move the coil away from the head or tilt it. I don't think that would be a good control. For a temporal control, you need to try different timings of TMS with respect to the stimulus. If the observed effect is a genuine neural effect, it has to be extremely dependent to the timing of TMS.


[[Media:BeauchampTMSSystemOverview.doc|Click here for the document describing Nafi's TMS system]]
Both machines (MagStim and Nafi's) use a National Instrument USB Data acquisition card (referred to here as NIDAQ). However the Presentation Library for these two machines are different. Here is the one for Magstim: [http://openwetware.org/images/6/61/USB_TMS_library.pcl] and here is the one for Nafi's: [http://openwetware.org/images/9/93/Nafi%27s_TMS_library.pcl]
The NIDAQ needs to be defined in Presentation (under Settings --> Port) as 3 output ports. For each port, "USB-6501" should be selected. For the first port choose "Data source: port0", for the second one choose "Data source: port1", and for the third one choose "Data source: port2". For Nafi's nothing else needs to be changed. For MagStim the "Inversion mask" of the seond port needs to be changed to 255 (because they have used inverse logic for their trigger circuit).
== Computer control of TMS machines2 ==
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== Computer control of TMS machines 3==
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== Presenting the stimuli and TMS ==
You will need to write a program to deliver the stimuli and TMS with precise control of timing of the stimuli. "Presentation" program (www.nuerobs.com) is a relatively good and easy software for this purpose. Computer control of TMS machine is explained here:


== Using Brainsight navigation ==
== Using Brainsight navigation ==

Revision as of 12:47, 21 April 2011

Brain picture
Beauchamp Lab




General Overview

Like with any other experiment you first need to design the experiment and determine what conditions you will be testing and how many repetitions and how many subjects, etc. Additionally for ALL TMS experiments you will need to have one or more "control" experiments. This is to rule out that the observed effect is due to non-specific effect of the TMS. It is best to have at least one "spatial" and one "temporal" control experiment. With the spatial control, you will move the coil to a different location on the brain. Some people move the coil away from the head or tilt it. I don't think that would be a good control. For a temporal control, you need to try different timings of TMS with respect to the stimulus. If the observed effect is a genuine neural effect, it has to be extremely dependent to the timing of TMS.


Presenting the stimuli and TMS

You will need to write a program to deliver the stimuli and TMS with precise control of timing of the stimuli. "Presentation" program (www.nuerobs.com) is a relatively good and easy software for this purpose. Computer control of TMS machine is explained here:

Using Brainsight navigation

1- Make sure the reflective markers holder is tightly fixed to the coil and calibrate the coil. (This doesn't need to be done every time if the markers have not moved)

2- Create a new project and load the anatomical images (NifTi file).

3- (Optional) Load functional images as well if available/needed. Note that some preprocessing is needed to make the functional images have the same resolution as the anatomical. See: http://openwetware.org/wiki/Beauchamp:TMS#Transferring_MRI_Data_To_The_Brainsight_System

4- Generate 3D brain (Full Brain Curvilinear) and skin reconstructions.

5- Mark anatomical landmarks. A minimum of three is needed. Four would be better: Nose Tip, Nasion, left and right ear notches.

6- Identify and mark targets based on the anatomy and/or functional map.

7-Do the experiment!

Extra: You can record the exact coordinates of each TMS pulse using the LabJack interface.