Fig 1.
Sample sequences for each of the six trial types.
Rows illustrate the following trial types: A, Hand-cognitive; B, Hand-spatial; C, Ghost-cognitive; D, Ghost-spatial; E, Text-cognitive; F, Text-spatial. Note that the demonstration phase differs between trial types while the response (execution) phases are very similar.
Fig 2.
The full 3 x 2 factorial design.
Arrows show each of the simple effects examined in the results.
Fig 3.
Reaction times (A) and error rates (B) when participants performed the task during fMRI. Error bars show standard errors.
Fig 4.
Simple effects of viewing demonstrations of the cognitive task compared to the spatial task for each of the three demonstration types: Hand (A), Ghost (B), and Text (C). (D) Conjunction of the three contrasts shown above. The coordinates of the area activated in all three conditions are −35 −36 −20. Coordinates for all clusters are given in Table 1. Abbreviations: CaS, calcarine sulcus; FUS, fusiform gyrus; IFG, inferior frontal gyrus; OCC, occipital gyrus; ORB, orbital gyrus. Region names in parentheses indicate that clusters are not visible in this view.
Table 1.
Brain region, MNI coordinates, size (no. of voxels, k), and significance of clusters.
Fig 5.
Simple effects of viewing demonstrations of the spatial task compared to the cognitive task for each of the three demonstration types: Hand (A), Ghost (B), and Text (C). (D) Conjunction of the three contrasts shown above. The coordinates of the area activated in all three conditions are −35 −36 50. Coordinates for all clusters are given in Table 2. Abbreviations: CUN, cuneus; IFG/MFG, inferior frontal gyrus/middle frontal gyrus; IPS, intraparietal sulcus; LG, lingual gyrus; OCC, occipital gyrus; PCUN, precuneus; POG, postcentral gyrus; SPG, superior parietal gyrus. Clusters of activation in the precuneus (Ghost) and right caudate nucleus, left putamen, and right cerebellum (Text) are not visible in this depiction.
Table 2.
Brain region, MNI coordinates, size (no. of voxels, k), and significance of clusters.
Fig 6.
Specialisation for observing hand actions in the cognitive task (A and B) and the spatial task (C and D). IFG, inferior frontal gyrus, IPS, intraparietal sulcus; MFG, middle frontal gyrus; OCC, occipital gyrus; SFG, superior frontal gyrus; SPG; superior parietal gyrus; TG, temporal gyrus. Clusters of activation in the thalamus (A) and precuneus (C) are not visible in this depiction.
Table 3.
Brain region, MNI coordinates, size (no. of voxels, k), and significance of clusters showing activation in the Hand or Text condition.
Fig 7.
Detail of effects in intraparietal sulcus.
HC, Hand-cognitive; GC, Ghost-cognitive; TC, Text-cognitive; HS, Hand-spatial; GS, Ghost-spatial; TS, Text-spatial. (A) An anterior region of left IPS shows a significant pattern HS > HC and HC > TC, that is, this region responds preferentially to a Hand demonstration of the spatial task. (B) Middle intraparietal sulcus responds selectively to Hand demonstrations over Text demonstrations in both the cogntive task and the spatial task. Parameter estimates (betas) for the six conditions in the overlapping areas are shown in the bar graphs (right).
Fig 8.
Some results from the interaction contrast [Hand-cognitive–Hand-spatial] > [Text-cognitive–Text-spatial].
Two clusters are illustrated here, which include left precentral and inferior frontal gyri and right middle and inferior frontal gyri. (A) Visualisation of the significantly activated clusters in this contrast. (B) Parameter estimates (betas) for the two clusters. Orange bars indicate conditions weighted positively in this interaction, purple bars indicate conditions weighted negatively, and blue bars indicate conditions that were not evaluated in this contrast. Coordinates for all clusters activated in this condition are given in Table 4. Abbreviations: IFG, inferior frontal gyrus; MFG, middle frontal gyrus; PCG, precentral gyrus.
Table 4.
Brain region, MNI coordinates, size (no. of voxels, k), and significance of clusters activated in the interaction contrasts.