Abstract
Purpose::
To identify the anatomical correlates of saccadic and pursuit voluntary predictive eye movements based on fMRI at 3T.
Methods::
fMRI was undertaken utilizing a 3.0T GE system scanning the whole head and the BOLD technique. Data analysis was carried out using FEAT (FMRI Expert Analysis Tool) Version 5.4 (FMRIB’s Software Library, www.fmrib.ox.ac.uk/fsl). Saccadic and pursuit eye movements were elicited using a white dot (0.5 cm in diameter and average visual dot size of 0.66º ) moving horizontally (19º from center in each direction) at 0.5Hz with binocular viewing. Subjects included 7 normal adults ranging in age from 18-54 years with normal visual acuity (20/20 or better) and normal stereoacuity (40 sec of arc or better).
Results::
Average activation across the seven subjects with p<0.05 showed more activation sites with saccadic eye movements (X² = 12.37, p<.001). The culmen in the cerebellum was activated with both saccades and pursuit; however not in the same location. Activation was found in the tuber and uvula of the cerebellum only with saccades. Brodmann areas 4,6,7,9,18,19,21,32,37,38, and 46 were activated with saccades while Brodmann areas 7,8,36,37 were activated in pursuit.
Conclusions::
When whole brain imaging is employed with 3T fMRI, a significantly greater number of activated areas are found with saccadic as opposed to pursuit eye movements, with a number of overlapping sites responsible for both types of eye movements.
Keywords: eye movements: saccades and pursuits • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • visual cortex