Functional Magnetic Resonance images can be acquired and reconstructed in any of three geometric planes. By choosing the plane that reveals the area of cortex which contains the important population of cells, we can make the scan very specific. The image below shows a coronal oblique slice (tilted rearward from the main axis of a person's body) showing the left motor cortex, and supplementary cortex to be active, while simultaneously showing that visual cortex is inactive. The individual was asked to touch each of the fingers of the right hand to the right thumb, successively, and then to repeat this sequence. Moving the fingers in opposition to the thumb (sequential finger opposition) produced increased blood flow to the left motor and sensory cortex and these are shown as higher intensity signals (reds and yellows) below.
position of slice
View of Sensory/Motor and Visual Cortex of a volunteer while she moved her fingers and thumb in a sequential alternating pattern, touching her thumb to her pointer finger, then to her middle finger, and so on. This image shows that motor components are involved, and that sensory components are involved too.
Careful procedures insure that any motion during the scan series is kept to a minimum. Swallowing, for example, can move the base of the brain by more than several millimeters, adding uncertainty to the data sets. Individuals frequently nod their head when answering "yes" or "no" and these unwarranted movements present additional challenges to the reliability of the data analysis.