In the memory block, each trial began with a central fixation cross (<0.01 cd/m2, 0.4 × 0.4° of visual angle, 800–1200 ms, randomly jittered with a rectangular distribution), followed by a high-quality picture of an object with texture and color (200 ms). After a delay period (3000 ms) during which no information was presented, a probe stimulus appeared (200 ms), which was either identical to the previously presented target or a slightly modified version of the target (50% of all trials, randomly interleaved). The modifications of target stimuli consisted of changes based on adding, removing, distorting, or rotating individual object features. Subjects were instructed to store the target in memory over the delay period and report whether or not the probe stimulus was the same or different from the target by pressing a gamepad button as quickly and accurately as possible using the thumb of their right hand. Subjects received performance accuracy feedback at the end of every trial (200 ms).
