Article Figures & Data
Figures
- Figure 1.
Two examples of the touch-screen layout for trials of each condition: a, inside; b, intermediate; c, far; d, white distractor; and e, color distractor. In all cases, the monkeys made responses to either the left or the right response boxes, which were indicated by flashing red squares. Two copies of the same visual stimulus were shown on the screen on every trial. The visual stimuli instructed responses to either the box on the left or the right. The correct response is to the right in each of the example problems shown at the top of the figure, whereas the correct response is to the left for each example problem shown at the bottom. Instructing visual stimuli were present on every trial. On inside trials (a), the instructing visual stimuli were placed inside the response box, but they were moved farther away in the intermediate (b) and far (c) trials. On other trials, white distractors (d) or color distractors (e) were also shown on the screen between the instructing stimuli and the response boxes.
- Figure 2.
Stippling indicates the intended lesion on a lateral and orbital view of the brain (a) and in coronal cross sections (b) redrawn from the atlas of Paxinos et al. (2000). Three coronal sections taken at 5 mm intervals starting ∼2.5 mm rostral to the bow of the arcuate sulcus illustrate that the lesion was much as intended in animals PFV1 (c) and PFV2 (d). Scalebar: c, d, ∼10 mm distance.
- Figure 3.
Three coronal sections taken through the lesions inanimals PFV3 (a), PFV4 (b), and PFV5 (c). The sections were taken at approximately the same levels as in Figure 2. Scale bar: a, b, c, ∼10 mm distance.
- Figure 4.
Experiment 1. Before surgery, RT significantly increased with increasing distance between the visual stimuli and the response boxes (a), but the introduction of distractors did not lead to any additional increase in RT (b).
- Figure 5.
Experiment 1. The effect of the PFv+o lesion on action selection and stimulus selection is illustrated by a comparison of the errors made by the lesion group (bottom) and the control group (top) before and after surgery or an equivalent time period (left and right, respectively) in the inside, intermediate, and far conditions. The gray bars are used to indicate performance by animals with lesions. The PFv+o lesion impaired performance across conditions, but the decrement in performance was significantly worse in the far condition. The open circles and triangles indicate the scores for animals PFV1 and PFV2. The filled circles, triangles, and squares indicate scores for animals PFV3, PFV4, and PFV5.
- Figure 6.
Experiment 1. The effect of distractors is illustrated by a comparison of the errors made by the lesion group (bottom) and the control group (top) before and after surgery or an equivalent time period (left and right, respectively) in the far, white distractor, and color distractor conditions. The gray bars are used to indicate performance by animals with lesions. The PFv+o lesion impaired performance uniformly across all three conditions. Animals with PFv+o lesions did not get significantly worse when distractors were interposed between the instructing stimuli and the response boxes; performance was already approximately at chance in the far condition even before any distractors were added. The open circles and triangles indicate the scores for animals PFV1 and PFV2. The filled circles, triangles, and squares indicate scores for animals PFV3, PFV4, and PFV5.
- Figure 7.
Experiment 2b. After learning four new inside problem pairs to a criterion of 85% correct, animals were tested on additional trials in the inside condition format in two cases. In two other cases, however, the animals were transferred to a version of the same problem pair in which the stimuli and response boxes were separated in the manner of the far condition. A positive score indicates a continued improvement beyond the 85% criterion, and a negative score indicates a worsening of performance below the 85% criterion. Gray bars indicate the PFv+o lesion group. PFv+o animals were significantly worse when they transferred to performing the same problem pair but in the far condition format. The open circles and triangles indicate the scores for animals PFV1 and PFV2. The filled circles, triangles, and squares indicate scores for animals PFV3, PFV4, and PFV5.
- Figure 8.
In experiment 2a (left), PFv+o animals (gray bars) made significantly more errors learning new inside condition problems. The deficit confirms that PFv+o lesions impair action selection even in the absence of interleaved trials of the more difficult intermediate, far, and distractor conditions. Data from experiment 3 are shown on the right. Animals with PFv+o lesions made significantly more errors when learning a new far problem pair than when learning new inside problem pairs (left). The increased size of the PFv+o deficit suggests that PFv+o is not just concerned with using a conditional rule to select actions, but it is also involved in the selection of the behavioral relevant stimulus. The open circles and triangles indicate the scores for animals PFV1 and PFV2. The filled circles, triangles, and squares indicate scores for animals PFV3, PFV4, and PFV5.
- Figure 9.
Experiment 4. PFv+o lesions had a significantly greater impact on learning in the far condition than in the inside condition. The numbers of errors made learning in the two conditions are compared before and after surgery. Postoperative performance is shown on the right and indicated by gray bars. The filled circles, triangles, and squares indicate scores for animals PFV3, PFV4, and PFV5.
