The range of motor activation in the normal human cortex using bold fMRI

Understanding and documenting the nature of normal human brain functional motor activation using functional Magnetic Resonance Imaging (fMRI) is necessary, if valid statements are to be made about normal and disease functional states using fMRI activation maps. The present study examines activation maps in 'normal' adults. Six healthy adult volunteers performed three motor tasks isolating the tongue, non-dominant foot, and non-dominant thumb during a single magnetic resonance imaging (MRI)/fMRI scanning session. Group maps demonstrated discrete areas of activation that were task dependent. The degree of variability between the anatomical central location of global maximum intensity for each individual may mean extra care should be applied when using the global maximum to define the area of activation. These differences may represent anatomical variability among individuals, task complexity, paradigm design, data analysis techniques or a combination thereof, which form the basis of our ongoing research endeavors. Standard notions of strongly associated functions as related to anatomic foci may need to be revised.