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 enhancingthe amplitude of event-related potentials (ERPs) when blood glucoselevels rise, primarily observed in sensory and early components usingthe glucose tolerance test. However, the impact of more physiologicallyrelevant, low doses of glucose on late cognitive ERPs, such as N400and late positive potential (LPP) peaking at 600 ms after stimulusonset, remains unclear. In this study, we aimed to examine the relationshipbetween behavioral motivation in the fasting state and physiologicalresponses to glucose elevation. Thirty-two healthy young adultsperformed a task differentiating between “Food” and “Non-Food” nounsduring both a fasting state (14–15 hours) and after ingesting a0.5 g/kg glucose solution. When comparing ERP responses to “Food”and “Non-Food” stimuli, we found significant differences in theamplitude of the LPP in the bilateral frontal, central, and parietalareas regardless of the glucose level. Additionally, glucose ingestionled to changes in the ERP amplitude at central (Cz, C4) electrodesfor both stimulus categories, while frontal (F3, Fz) electrodesexhibited changes in response to only “Non-Food” nouns. A reductionin the N400 amplitude for both “Food” and “Non-Food” stimuli post-glucoseintake suggests that the task may be perceived as easier after glucoseconsumption. Our findings highlight the brain's sensitivity to functionalchanges driven by peripheral blood glucose levels. In combinationwith behavioral data, including fewer errors and faster reactiontimes, our ERP results point to an increase in the selectivity for“Non-Food” stimuli in response to elevated glucose levels.