Localization of brain function using magnetic resonance imaging
Trends in Neurosciences 17(7)268-277, 1994.
When magnetic resonance images (MRI's) of the brain are acquired in rapid succession they will show small differences in signal intensity in positions corresponding to focal areas of activation. These signal changes result from small differences in the magnetic resonance signal caused by variations in the oxygenation state of the venous vasculature. Using this non-invasive functional MRI (fMRI) method it is possible to localize functional brain activation in normal individuals with an accuracy of millimeters and a temporal resolution of seconds. Though numerous technical challenges remain, fMRI is increasingly becoming a key method in understanding the topographical organization of the human brain.
Spatial and temporal resolution of a variety fo techniques for the study of brain function (after Churchland and Sejnowski0 showing the place of fMRI as a minimally invasive method with resolution in time and space appropriate to the study of small (nearly cortical column size) areas of cortex in time scales of seconds.
Magnetic Resonance Imaging of activity in the primary visual cortex in response to stimulation with a blinking light.
This tomographic section is aligned parallel to the calcarine fissure. The movie shows a series of 75 images, taken three seconds apart. Overlaid in color are the regions showing significant signal increases during the stimulation, as measured by the t-statistic.