Abstract:
Functional magnetic resonance imaging (fMRI) offers the possibility of acquiring functional data of different brain areas in a non invasive manner. In this work a method was established, which allows to examine the visual system of children and patients with reduced cooperation. A pediatric stimulation scheme was developed using a small cartoon located in the center of a 4 quadrant, 4 Hz flickering 'dartboard' stimulating field as a fixation assistance. This stimulation scheme was tested and modified on healthy adults, and subsequently applied to six children and young adults at the age of 11 to 22 years with occipital malformations and lesions before possible epilepsy-surgical interventions. Activations were always found at their retinotopically expected localization within the primary visual cortex. Two patients with visual field defects showed corresponding deficits of fMRI activation. No evidence for reorganization within the primary visual cortex, as controversially discussed in the literature, was observed.