Abstract
Purpose: :
The aim of this study was to assess the activation of the cortical eye fields involved in vertical and horizontal saccades with a 3 teslas functional MRI.
Methods: :
Eight healthy right-handed subjects (6 men and 2 women) participated in the study. The tasks tested 2 different types of saccades: "visually guided" and voluntary. For each one, we compared cortical eye fields activation during vertical axis eye movements with those activated during horizontal axis movements. The acquisition of the data was carried out via the Neuro 3D software (Siemens, Germany). Statistic data treatment was carried out using FSL software (FMRIB Software Library) according to the General Linear Model (GLM). The analysis of the pictures was done with MRIcro software (v 1.4, Chris Rorden, the United Kingdom).
Results: :
Picture analysis was realized with the group analyses maps, and with the substraction maps. For each type of saccades, we could find the activation of most cortical areas involved in eye movements; the Frontal Eye Field (FEF), the Supplementary Eye Field (SEF) and the Posterior Parietal Cortex (PPC). An activation of the superior parietal cortex (7th Brodmann area) was observed for both types of vertical saccades. In addition, we found a specific activation of the right DorsoLateral PreFrontal Cortex (DLPFC) during voluntary vertical saccades.
Conclusions: :
Our study allowed to identify the various activated cortical eye fields according to the saccades direction. The superior parietal cortex and the DLPFC seem to be particularly involved during vertical saccades.
Keywords: eye movements • neuro-ophthalmology: cortical function/rehabilitation • imaging/image analysis: clinical