Neural Mechanisms of Forward Conditional Reasoning：A Functional MRI Study / 中国医学影像学杂志

ABSTRACT

Purpose Two kinds of forward conditional reasoning including modus ponens (MP) and denial of the antecedent (DA) are the most common deductive reasoning in daily life. The present study aimed to explore the difference between the two neural machanisms. Materials and Methods Three kinds of tasks including MP, DA, and baseline were administrated to 14 undergraduates [7 males and 7 females, mean age (23.4±1.3) years] by using functional magnetic resonance imaging (fMRI) technique. fMRI data was analyzed. Results The reaction times were significantly slower for MP and DA than that of BS (P<0.001), while the effect was not significant for accuracy. In contrast to baseline, both MP and DA tasks activated the left inferior frontal cortex (BA 9), inferior parietal lobule (BA 40), and postcentral gyrus. Bilateral caudate significant activation was found in MP task when compared with DA, whereas the frontal, parietal, occipital lobe and anterior cingulate cortex were acivated more in the DA than in MP task. Conclusion Both forward conditional reasoning of MP and DA commonly activate the left frontoparietal cortex, while significant dissociations can be seen in the regions of caudate and bilateral frontal, parietal and occipital. These results firstly demonstrates the different neural mechanism underlying the two forward conditional reasoning, which might help to further uncover the brain mechanism of conditional reasoning.