Corticobulbar Activity and Motivational Arousal in Healthy Participants

Background. Corticobulbar (CB) projections linking tongue/submental effectors to motor cortex are implicated in reward processing and motivational arousal (Alipour et al., 2002; Kringelbach et al., 2003; Kringelbach, 2005; O’Doherty, 2004; Volkow et al., 2011; 2017). Submental muscle (SbM) surface EMG may thus provide a convenient physiological window on motivational states during foods selection (Sato et al., 2021; Ferraioli and Vicario 2024). Objective. To test, in healthy participants, whether SbM activity recorded during an immersive virtual‑reality (VR) supermarket varies as a function of food motivational category (Daily, Hedonic, Dislike) and whether SbM contributes to the prediction of self‑reported preference, along with personality traits, like impulsivity in monetary choice, measured by Monetary Choice Questionnaire (MCQ; Kaplan et al., 2016). Methods. Fourteen adults completed a VR shopping task selecting 10 products per three different conditions. SbM was recorded continuously and summarized within pre‑selection (−550/−200 ms) and post‑selection (T0/+550 ms) windows, as specified in our published protocol (Ferraioli et al., 2025). Linear mixed‑effects models (LME) examined effects of Condition and Phase on SbM. A separate LME predicted Preference from SbM, Condition, and impulsivity (MCQ). Results. SbM was higher in Hedonic vs Daily (β=0.342, p=.022), with no main effect of Phase (p=.774) and no Condition×Phase interactions. Preference was positively associated with SbM (β=0.441, p=.043) and strongly reduced in Dislike (β=−5.760, p<.001); MCQ had no effect. Conclusions. Our preliminary analyses on an ecologically valid VR environment, showed SbM differentiates motivational categories and independently predicts reported preference, supporting SbM as a candidate biomarker of motivational arousal and complementing the broader CB‑excitability program (Ferraioli et al., 2025). Keywords: corticobulbar tract; submental EMG (SbM); virtual reality; food preference; motivational arousal; linear mixed‑effects models.