The location probability effects of saccade reaction times are modulated in the frontal eye fields but not in the supplementary eye field.
The visual system constantly utilizes regularities that are embedded in the environment and by doing so reduces the computational burden of processing visual information. Recent findings have demonstrated that probabilistic information can override attentional effects, such as the cost of making an eye movement away from a visual target (antisaccade cost). The neural substrates of such probability effects have been associated with activity in the superior colliculus (SC). Given the immense reciprocal connections to SC, it is plausible that this modulation originates from higher oculomotor regions, such as the frontal eye field (FEF) and the supplementary eye field (SEF). To test this possibility, the present study employed theta burst transcranial magnetic stimulation (TMS) to selectively interfere with FEF and SEF activity. We found that TMS disrupted the effect of location probability when TMS was applied over FEF. This was not observed in the SEF TMS condition. Together, these 2 experiments suggest that the FEF plays a critical role not only in initiating saccades but also in modulating the effects of location probability on saccade production.
Institute of Cognitive Neuroscience, National Central University, No. 300 Jhongda Road, Jhongli City, Taoyuan County, Taiwan.
Chia-Lun
CL
Liu
Philip
P
Tseng
Hui-Yen
HY
Chiau
Wei-Kuang
WK
Liang
Daisy L
DL
Hung
Ovid J L
OJ
Tzeng
Neil G
NG
Muggleton
Chi-Hung
CH
Juan
D000704:Analysis of Variance; D001931:Brain Mapping; D005260:Female; D006801:Humans; D008297:Male; D010775:Photic Stimulation; D017397:Prefrontal Cortex / Q000502:physiology*; D011336:Probability; D011930:Reaction Time / Q000502:physiology*; D012438:Saccades; D050781:Transcranial Magnetic Stimulation; D014794:Visual Fields / Q000502:physiology*; D055815:Young Adult