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Jale Ozyurt

Publications and source records attributed to Jale Ozyurt.

2 recordsLinked to original sources

Cortical activation during memory-guided saccades.

Using functional magnetic resonance imaging, we compared responses during visually guided saccades with those evoked during memory-guided saccades, in which participants executed saccades to remembered locations. Eye movements were recorded in the magnetic resonance tomograph. Significantly stronger activation during memory-guided saccades was observed in the posterior portion of the right inferior frontal gyrus, in the left inferior frontal eye field, in the posterior parietal cortex, as well as in the right posterior superior temporal gyrus. The posterior part of the dorsal anterior cingulum and a small voxel cluster in the dorsolateral prefrontal area, anterior to the left inferior frontal eye field, were only active in the memory-guided condition.

Adult↗

Countermanding saccades: evidence against independent processing of go and stop signals.

In a stop signal paradigm, subjects were instructed to make a saccade to a visual target appearing left or right of the fixation point. In 25% of the trials, an auditory stop signal was presented after a variable delay that required the subject to inhibit the saccade. Observed saccadic response times in stop failure trials were longer than predicted by Logan and Cowan's (1984) race model. Saccadic response time and amplitude decreased with the time between stop signal presentation and saccade execution, suggesting an inhibitory effect between the stop signal and the go signal processes that is not compatible with an independent race assumption. Moreover, countermanding a saccade was more difficult when stop and go signals appeared at the same location.

Adult↗