1. Cross-correlation technique to identify activated pixels in a three-condition fMRI task
- Author
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Singh, M., Al-Dayeh, L., Jeong, J., Kim, T., and Colletti, P.
- Subjects
Magnetic resonance imaging -- Research ,Pixels -- Identification and classification ,Business ,Electronics ,Electronics and electrical industries - Abstract
Most fMRI studies are conducted with a stimulus 'on' and a stimulus 'off' or control state to delineate pixels activated during a two-condition presentation. We have developed a multiple reference function based novel cross-correlation technique that is not restricted to two conditions but could be applied to delineate pixels activated in multi-condition tasks. A logic-based analysis to form functional images, where each pixel is uniquely assigned to an image based on which reference function produced the highest correlation-coefficient for that pixel, has also been developed. Both steady-state and event-related fMRI studies have been conducted. Using steady-state motor stimulation as an example with right and left hand movements representing conditions 1 and 2, and no movement representing condition 3, results of images generated through a three-condition processing technique are in good agreement with those generated through two separate two-condition experiments. Similarly, the results of right and left finger flexions in a multicondition event-related study show that the logic based correlation coefficient approach provides unique information about the activation characteristics of individual pixels.
- Published
- 1999