The Location Probability Effects of Saccade Reaction Times Are Modulated in the Frontal Eye Fields but Not in the Supplementary Eye Field

Abstract

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.

Trial type probability modulates the cost of antisaccades

“…In contrast, the less probable saccade type not only misses out on such facilitation but also has to inhibit and override those preestablished neural responses that favor the likely saccade type and reselect a new end point. Again, converging evidence has pointed to FEF for this kind of probabilistic responses (Liu et al 2011;Sato and Schall 2003). However, the FEF neurons prefer a specific retinotopic end point for saccades, yet our paradigm does not rely on spatial probabilities.…”

The involvement of posterior parietal cortex and frontal eye fields in spatially primed visual search

“…Nevertheless, it is now apparent that motor preparation is only part of rFEF's role (28) . Evidence supporting a visual selection role for rFEF stems for a recent study by Liu and colleagues (29) , who used theta-burst TMS to show that disruption of rFEF affected saccades to a greater extent when the probability of target location was high in a singletontype display. They conclude that along with the accepted role of FEF in saccade initiation, rFEF plays a critical role in modulating the effects of location probability on saccade production.…”

The Benefit of Object Interactions Arises in the Lateral Occipital Cortex Independent of Attentional Modulation from the Intraparietal Sulcus: A Transcranial Magnetic Stimulation Study

“…A theta burst stimulation protocol was the same as that used in the study by Vallesi et al (2007) with the following parameters: three pulses given at 50 Hz every 200 ms (at 0 ms, 20 ms, and 40 ms followed by 160 ms of rest) for 20 s. This resulted in a total of 300 pulses per session, with the effect of TMS expected to last ϳ20 -30 min (Huang et al, 2005;Nyffeler et al, 2006). A single threshold of 40% of the maximal stimulator output (2 tesla) was used based on past studies showing reliable TMS effects across a wide range of tasks (Liu et al, 2010;Chao et al, 2011) and because motor cortex excitability does not provide a good guide to TMS thresholds in other cortical regions (Stewart et al, 2001). The coil handle was placed at each ROI pointed upward and parallel to the midsagittal plane.…”