Objective: To investigate the influence of injury of prefrontal cortex on the risk-taking decision-making and to test the hypothesis that the orbitofrontal area is involved in the special network of risk-taking decision-making.
Methods: 47 patients with lesions in the prefrontal lobe, 21 in the orbitofrontal area (OBF) and 19 in the dorsolateral prefrontal cortex (DLF), and 40 healthy controls (HC group) were administered with a risk-taking task.
Results: The risky response rate after punishment of the HC group was 0.54 +/- 0.23, significantly fewer than before punishment (t = -3.82, P < 0.01), and the risky response rate after punishment of the DLF injury group was 0.68 +/- 0.16, significantly fewer than before punishment too (t = -2.32, P < 0.05). The risky response rate after reward of the patients with lesions in OBF areas was 0.79 +/- 0.19, significantly higher than that of the HC group (0.68 +/- 0.16, P < 0.05), and the risky response rate after punishment of the patients with lesions in OBF areas was 0.82 +/- 0.18, significantly higher than that of the HC group (0.54 +/- 0.23, P < 0.05). The risky response rates after reward and after punishment of the DLP group were 0.72 +/- 0.22 and 0.63 +/- 0.25 respectively, both not significantly different from those of the HC group (both P > 0.05).
Conclusion: The patients with lesions in the orbitofrontal area, not in the dorsolateral prefrontal cortex, have a specific deficit in risk-taking decision-making, i.e. an inhibition effect of punishment, reduced sensitivity to punishment but increased sensitivity to reward. The orbitofrontal areas play an important role in risk-taking decision-making processes.