Figure 4.

Relation of human orbitofrontal risk signals to individual risk attitude. (a, b) Risk signal in lateral OFC covarying with increasing risk aversion across participants (e.g. a ‘safety’ or ‘fear’ signal). (b) Correlation of contrast estimates of individual participants with their individual risk aversion (p<0.001, r=0.74; unpaired t-test in seven risk seekers and six risk averters). (c, d) Risk signal in medial OFC covarying with risk seeking (=inverse relation to risk aversion; e.g. a ‘risk seeking’ or ‘gambling’ signal). (d) Risk correlation analogous (r=0.85, p<0.0001) to (b). Abscissae in (b, d) show risk aversion as expressed by preference scores (−4 most risk seeking, +4 most risk aversion). To obtain these graphs, we correlated risk-related BOLD responses to individual risk attitude in two steps. First, we determined in each participant the contrast estimates reflecting the goodness of fit between brain activation and risk (variance as inverted U function of probability). Then, we regressed the contrast estimates of all participants to their individual behavioural risk preference scores and identified brain areas showing positive (a) or negative correlations (c). We plotted the regressions of risk aversion against the contrast estimates in (b, d). Reprinted with permission from Tobler et al. (2007). Copyright © The American Physiological Society.