Stimulus content effect on the visual cortex with functional MRI

Employing fMRI techniques, brain activity in the visual cortex was identified related to three different visual stimuli: a vertical bar, a semi-random and a random pattern. Two main changes were observed: the intensity of the radio frequency (RF) signal employed for image reconstruction increases and the area of activity spreads with the presentation of the semi-random pattern in comparison with the presentations of the other two stimuli. These findings would suggest the type of visual information content processing occurring at the level of the calcarine fissure.