Distinct neurocognitive mechanisms underlying learning and representations of symbols of life and death.

Life and death are 2 fundamental concepts regarding existence of organisms. People often signify these concepts using symbols to facilitate communications, but how the brain learns and represents these symbols remains unclear. In the present study, we quantified behavioral and brain responses during learning associations between words ("life" or "death") with shapes as concrete referents. Behavioral responses to word-shape pairs showed an affirmative response bias to life-shape pairs but a denial response bias to death-shape pairs. Multimodal brain imaging results revealed that the right frontal and dorsal cingulate cortices monitored these response biases, respectively. Moreover, relative to unlearned shapes, life-related shapes induced increased alpha (9-14 Hz) oscillations in the right parietal cortex and precuneus, whereas death-related shapes enhanced beta (15-30 Hz) oscillations in the left parietal cortex, superior temporal sulcus, and precuneus. Our findings unraveled distinct neurocognitive mechanisms underlying learning and representations of concrete referents of life and death concepts.