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Feedback from an avatar facilitates risk-taking by modulating the amygdala response to feedback uncertainty
Fig 5
Amygdala response to feedback uncertainty explains differential risk-taking in avatar and human conditions.
(a) Whole-brain subtraction analysis comparing avatar and human observer conditions revealed lower amygdala activity in the avatar condition. Peak activity was identified in the CM (MNI coordinates: [20 −4 −12] and PFWE = 8.5 × 10−6, T-value = 8.21, Z-value = 6.46). For display purposes, a threshold of punc. < 10−4 and k > 100 was applied (y = −4). (b) To find brain regions associated with differential valuation of feedback uncertainty (
), we weighted differential activity correlated with feedback uncertainty (avatar–human) by the differential behavioral coefficient for feedback uncertainty (i.e. 
). A significant correlation was observed in the CM, with an FWE-corrected p-value of 0.039 at the peak (small-volume corrected using the Anatomy toolbox CM ROI). For display purposes, a threshold of punc. < 0.001 and k > 10 was applied (y = −6). (c) Activity correlated with differential feedback uncertainty at the center of an independent anatomical ROI of the CM is plotted against the differential feedback uncertainty coefficient (
). The negative slope indicates that participants who exhibited greater risk-taking behavior in the avatar condition had a lower feedback uncertainty-correlated response in the CM during interactions with avatars. (d) Participants were divided into two groups: risk-takers against avatars (RTA; left panel) with higher values of 
in the avatar condition 
and risk-takers against humans (RTH; right panel) with lower values of 
in the avatar condition 
. CM responses to feedback uncertainty were compared with zero separately for the avatar and human conditions within each group. In RTA (left), the CM response was significantly negative in the avatar condition (p = 4.7 ×10−2, t = −1.73), while in RTH (right), the CM response was negative in the human condition (p = 5.6 × 10−4, t = −3.79). Asterisks indicate statistical significance. Numerical data are provided in S2 Data (b, d).
doi: https://doi.org/10.1371/journal.pbio.3003122.g005