V1/MT fMRI demo
Functional magnetic resonance imaging (fMRI) is a novel, non-invasive method for measuring activity in the human brain, and for investigating the relationship between brain activity and behavior. The technique is similar to conventional MRI, which is used to acquire structural images of the brain, but fMRI can generate images of brain activity in addition to brain anatomy. It works again by measuring the flow of blood in the brain. The brain controls the flow of oxygenated blood to brain regsions where there is more neuronal activity. Oxy- and dexy-hemoglobin have different magnetic properties, and this can be picked up by the MR scanner.
The following is a demonstration of how different visual brain areas can be identified using fMRI.
Top right: Flickering checkerboard stimulus alternating with
a blank uniform gray field.
Bottom right: Axial (horizontal) slice through the of the brain
with functional activity superimposed in color. Flickering checkerboards
"light up", evoking strong activity, in the primary visual cortex (V1)
at the very back of the brain.
Top left: Moving versus stationary dots stimuli.
Bottom left: Moving dots again "light up" V1, but also evoke
strong activity in area MT+, a lateral area of the occipital lobe that
is known to be involved in visual motion perception.
Further information about this research.