When neurons do not mirror the agent's intentions: sex differences in neural coding of goal-directed actions

Abstract

In the current research we used a neurolinguistic paradigm (N400), in which brain activation to semantically congruent and incongruent actions (with respect to the context) was compared in men and women. Twenty-three right-handed students viewed 260 pictures portraying people engaged in simple actions. Perception of plausible and understandable actions (e.g., smiling couple clinking glasses of champagne) was contrasted with that of implausible and unintelligible actions (e.g., businesswoman balancing on one foot in desert). ERP data showed early processing of the action's purpose in the female brain, with a larger parietal N200 to understandable behavior. Source reconstruction (swLORETA) located the neural generators of this effect in the inferior/parietal, left inferior/frontal, left and right premotor areas, right cingulate cortex, right superior/temporal and extra-striate cortex belonging to the so-called "human mirror-neuron system (MNS)". Anterior N400 discriminative response (implausible-plausible) was greater in women than men. The data suggest that congruent/incongruent actions are processed differently from the two sexes, with a prevalence of limbic and cingulate activation in women, and orbito/frontal one in men, along with a right STG activation of comparable amplitude in men and women.