Selectivity for “Non-Food” versus “Food” Nouns Is Increased in Healthy Adults in Response to Elevated Peripheral Blood Glucose Levels as Indicated by Event-Related Potentials (ERPs)

The glucose facilitation effect is well-documented in enhancing the amplitude of event-related potentials (ERPs) when blood glucose levels rise, primarily observed in sensory and early components using the glucose tolerance test. However, the impact of more physiologically relevant, low doses of glucose on late cognitive ERPs, such as N400 and late positive potential (LPP) peaking at 600 ms after stimulus onset, remains unclear. In this study, we aimed to examine the relationship between behavioral motivation in the fasting state and physiological responses to glucose elevation. Thirty-two healthy young adults performed a task differentiating between “Food” and “Non-Food” nouns during both a fasting state (14–15 hours) and after ingesting a 0.5 g/kg glucose solution. When comparing ERP responses to “Food” and “Non-Food” stimuli, we found significant differences in the amplitude of the LPP in the bilateral frontal, central, and parietal areas regardless of the glucose level. Additionally, glucose ingestion led to changes in the ERP amplitude at central (Cz, C4) electrodes for both stimulus categories, while frontal (F3, Fz) electrodes exhibited changes in response to only “Non-Food” nouns. A reduction in the N400 amplitude for both “Food” and “Non-Food” stimuli post-glucose intake suggests that the task may be perceived as easier after glucose consumption. Our findings highlight the brain's sensitivity to functional changes driven by peripheral blood glucose levels. In combination with behavioral data, including fewer errors and faster reaction times, our ERP results point to an increase in the selectivity for “Non-Food” stimuli in response to elevated glucose levels.