Figure 1.

Possible mechanisms for the FEF to regulate pro- and anti-saccade generation. The target is displayed as a black dot. For pro-saccades, the FEF contralateral to saccade direction can send a motor command directly to the SC in the same hemisphere and/or through the CN > SNpr (the so called ‘direct pathway’) (A). For anti-saccades, more scenarios are possible: the FEF ipsilateral to saccade direction could actively inhibition ipsilateral SC (through the ‘indirect pathway’) (B), thus inhibiting a pro-saccade. The FEF contralateral to saccade direction could excite the SC in the same hemisphere directly (C) or through the CN > GPe > SNpr (‘direct’) pathway (D), enforcing an anti-saccade over a pro-saccade. Also, a combination of scenario (B–D) could underly anti-saccade generation.