Nếu các cửa sổ màu vàng (ở đây: rắn), sau đó người tham gia phải đáp ứng với các kích thích tương tự như trên thử nghiệm trước đây (tức là, phù hợp với quy tắc). Nếu các cửa sổ màu xanh (ở đây: chấm), sau đó người tham gia phải đáp ứng các mô hình đã không được lựa chọn. | 326 Task-Switching Figure 14-5 Sequence of trials in the paradigm used to assess the effects of striatal and frontal lesions on stimulus- and rule-based switching. On each trial two abstract visual patterns were presented within blue here stippled or yellow here solid stimulus windows with the color of the two windows identical for a given trial. Subjects were required to choose one of two stimuli by making right or left button presses corresponding to the location of the correct stimulus . The correct choice was determined by an abstract task-rule which was signaled to subjects by the color of the stimulus. If the windows were yellow here solid then the participant had to respond to the same stimulus as on the previous trial . matching rule . If the windows were blue here stippled then the participant had to respond to the pattern that had not been selected on the previous trial . non-matching rule . Thus some trials required that the participant switched responding between concrete stimuli . visual patterns and some trials required that the participant switched responding between abstract rules as indicated by the color of the boxes . More specifically there were four trial-types 1 non-switch trials the rule and the target-stimulus were the same as on the previous trial . yellow trials following yellow trials 2 stimulus-switch trials the rule remained the same and the target-stimulus switched that is blue trials following blue trials 3 rule-switch trials the rule switched from the previous trial and the targetstimulus remained the same that is yellow trials following blue trials 4 stimulus rule-switch trials the rule and the target-stimulus switched from the previous trial that is blue trials following yellow trials. with frontal lesions was not predicted and this null effect does not provide definitive evidence against a role for the PFC in abstract rule-based cognitive flexibility. Although the latter issue awaits further investigation we note that
