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Size: 767
Comment:
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Size: 869
Comment:
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| Deletions are marked like this. | Additions are marked like this. |
| Line 8: | Line 8: |
| coils attached to their head, with 2 on the forehead and 2 behind the ears. In addition | coils attached to their head: 2 on the forehead and 2 behind the ears. In addition |
| Line 12: | Line 12: |
| The location of the coils needs to be measured with a 3D digitiser. We also | The location of the coils needs to be recorded with a 3D digitiser. We also |
| Line 14: | Line 14: |
| headshape and enable easier matching to an MRI structural scan. | headshape and enable easier matching to an MRI structural scan. The digitiser has a pen-like sensor that will record the location of its tip when the button is pressed. |
Subject Preparation
Subjects need to be free of magnetic materials, like coins, watches and other metal items. Underwired bras can be a problem, and even dyes in clothing or hairdye can cause interference.
To track head movements volunteers need to have 4 small HPI (Head Position Indicator) coils attached to their head: 2 on the forehead and 2 behind the ears. In addition we normally attach 5 electrodes to the face as well to measure eye movements and blinks.
The location of the coils needs to be recorded with a 3D digitiser. We also measure 3 landmarks and a number of additional points on the head to indicate headshape and enable easier matching to an MRI structural scan. The digitiser has a pen-like sensor that will record the location of its tip when the button is pressed.
