Fig. 2. From agents to actions to interactions. (A) Statistical map of enhanced
activation for the Agents contrast. Shown is an inflated F99 cortical model of
the right hemisphere, with dark gray regions representing sulci and light gray
regions representing gyri (P < 0.01, FDR-corrected for multiple comparisons).
The fMRI signal is enhanced in regions of the STS and frontal cortex that
overlap with face and body patches independently identified (fig. S3A).
(B) Agent-object interactions assessed with the contrast (actions > agents)
show enhanced activation of the body but not face patches. Bar plots are
normalized signal changes for the contrast. Error bars represent SD (*P < 0.05,
**P < 0.01, ***P < 0.001; all other comparisons are not significant; Holm-
Bonferroni–corrected for multiple comparison). (C) Same as (B). Agent-agent
interactions assessed with the contrast (social interactions > actions)
show both body and face patches enhanced activation. (D) Same as (B). Object-
object interactions assessed with the contrast (physical interactions > social
interactions) show that only object patches are more activated by physical than
social interactions. (E) Statistical map of enhanced activation for the action
contrast [same conventions as in (A)]. Significant activation is found in
the parietal and premotor cortices in addition to the STS, in regions that overlap
with classical MNS areas independently identified (fig. S3B). (F) Brain
activity for social interactions compared with agents and landscapes and
scramble controls shows a similar overlap. (G) Brain activity for physical
interactions compared with objects moving independently and landscapes and
scramble controls shows a similar overlap. (H) Overlaid activations for action,
social interaction, and physical interaction contrasts showing MNS recruitment
by different types of interactions. (I) Statistical map of enhanced activation
for the social interaction contrast [same conventions as in (A)] showing an
extended network of regions significantly active for watching social interactions.
Significant activation is found in the medial and dorsomedial prefrontal
cortices (mPFC and dmPFC), in the ventrolateral prefrontal cortex (VLPFC),
in the temporal pole (TP), and in parietal areas (7a), in addition to activation
in the STS and in the parietal and premotor cortices. (J) Same map presented on
anterior (“A”), dorsal (“D”), medial (“M”), ventral (“V”), and posterior (“P”)
views of the flattened F99 cortical model of the right hemisphere, with
black regions signifying not-represented noncortical parts of the brain.
(K to N) Corresponding activations in subcortical areas (Amg BL/BM, BM, and
Ce; Cd, caudate) displayed on coronal slices of the MNI-Paxinos template brain
in radiological convention (left in figure is the right side of the brain). Coordinates
are relative to interaural line. Cortical results are masked for display purposes.