fMRI of optokinetic eye movements with and without a contribution of smooth pursuit.
OBJECTIVE
Optokinetic eye movements are elicited when tracking a moving pattern. It can be argued that a moving pattern of stripes invokes both the optokinetic and the smooth pursuit eye movement system, which may confound the observed brain activation patterns using functional magnetic resonance imaging (fMRI). A moving pattern of limited-lifetime-dot stimulation does not target the smooth pursuit eye movement system.


METHODS
fMRI was used to compare the cortical activity elicited by an optokinetic eye movement response evoked by a moving pattern of stripes and a moving pattern of limited lifetime dots.


RESULTS
The eye movement behavior showed that both types of stimuli evoked an adequate and similar optokinetic eye movement response, but stimulation with stripes evoked more activation in the frontal and parietal eye fields, MT/V5, and in the cerebellar area VI than stimulation with limited-lifetime dots.


CONCLUSIONS
These brain areas are implicated in smooth pursuit eye movements. Our results suggest that indeed both the optokinetic and the smooth pursuit eye movement system are involved in tracking a moving pattern of stripes.
Schraa-Tam
Caroline K L
CK
Department of Radiology, Erasmus MC, Rotterdam, The Netherlands.
van der Lugt
Aad
A
Smits
Marion
M
Frens
Maarten A
MA
van Broekhoven
P C A
PC
van der Geest
Josef N
JN
D000328:Adult; D000704:Analysis of Variance; D001931:Brain Mapping / Q000379:methods*; D005133:Eye Movements / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D017120:Nystagmus, Optokinetic / Q000502:physiology; D010775:Photic Stimulation; D011698:Pursuit, Smooth / Q000502:physiology