Contrasting frontal cortical responses to food versus money rewards across BMI groups

ABSTRACTPrevious research has linked obesity with an altered perception of rewards. This study aimed to contrast frontal cortical activities across body mass index (BMI) groups, in responding to differential rewards (monetary versus food). A total of 60 male participants (27.43 ± 6.07 years of age; 21 normal weight [BMI: 18.5–24.9 kg·m−2]; 20 overweight [BMI: 25.0–29.9 kg·m−2]; and 19 individuals with obesity [BMI ≥ 30 kg·m−2]) were tested for their response bias towards food and money rewards using the Probabilistic Reward Task (PRT), while their frontal cortical responses were recorded using electroencephalography (EEG). The feedback-related negativity (FRN), a reliable measure of reward valuation and learning, was calculated for food (FRN(Food)) and money (FRN(Money)). Results indicate a left-lateralised frontal cortical activity associated with the food reward condition, in the group of overweight and obesity. In contrast, a right-lateralisation was observed in the money reward condition only in the group with obesity. More specifically, FRN(Food) was shown to significantly differ between left and right frontal cortical areas among individuals with obesity (p = 0.035) and overweight (p = 0.012), but not in normal-weight individuals (p = 0.153). Additionally, results revealed that FRN(Food) and FRN(Money) were significantly different for individuals with obesity (p = 0.019), but such a significant difference was not evident in the overweight and normal-weight individuals (p ≥ 0.05). These findings offer intriguing new insights into neuropsychological differentiation across BMI groups, adding to the understanding of obesity-related behaviour.KEYWORDS: ObesityrewardfoodmoneyEEGfrontal lobefeedback-related negativityprobabilistic reward task ‌ AcknowledgementsWe declare that the present study has been assessed and approved by the University of Otago Ethics Committee for Human Participation (Reference number: H18/111) on the 9th of December 2020.Disclosure statementNo potential conflict of interest was reported by the author(s).Data availability statementThe datasets generated and analysed in the present study are available from the corresponding author upon reasonable request.Additional informationFundingThis study is supported by the New Zealand Royal Society Te Apa ̄rangi via Marsden Fund - Fast Start Grants [grant number UOO_1720]. PI: Dr M Peng (University of Otago).Notes on contributorsRachel GinieisRachel Ginieis is a dynamic young researcher with eating behaviour and neuroendocrinology as areas of expertise. She has gained experience in translational research investigating the influence of nutrient intake and sensory perception on one's brain plasticity and/or physiological and behavioural responses. Recently, she has been focussing on the effect of eating and sleeping misalignment on one's cognitive functions.Fu YanDr. Fu Yan works in the department of Psychology (University of Otago) using the techniques of EEG and fMRI to investigate neuroplasticity in the context of learning and memory tasks.Elizabeth A. FranzProfessor Elizabeth Franz's current research explores psychological and neural processes associated with the action system, using the techniques of MRI, DTI, fMRI, and EEG, combined with laboratory protocols. She is specifically interested in the way the brain organises complex behaviours so that goal-directed actions can occur. In her range of research experience, she has worked with over 20 different neurological disorders of the motor and/or cognitive systems.Mei PengDr Mei Peng is a senior lecturer in Sensory Science in the Department of Food Science. With a background in Experimental Psychology, Mei's research focuses on people's food choices and intake behaviour in the modern food environment. She is particularly intrigued by the complex interplay between brain and food. Her laboratory uses psychological, behavioural, and neuroscience methods to understand how sensory, cognitive, and behavioural factors can shape one's diet and their impacts on people's general wellbeing. Currently, Mei is leading an Otepoti-based longitudinal study, funded by the Royal Society of New Zealand, to understand how people's eating behaviour changes during major metabolic reprogramming, such as pregnancy.