Individual Differences in Hippocampal Volume as a Function of BMI and Reward Sensitivity

Abstract

Sensitivity to reward is a personality trait that predisposes a person to several addictive behaviors, including the presence of different risky behaviors that facilitates uncontrolled eating. However, the multifactorial nature of obesity blurs a direct relationship between the two factors. Here, we studied the brain anatomic correlates of the interaction between reward sensitivity and body mass index (BMI) to investigate whether the coexistence of high BMI and high reward sensitivity structurally alters brain areas specifically involved in the regulation of eating behavior. To achieve this aim, we acquired T1-weighted images and measured reward sensitivity using the Sensitivity to Punishment and Sensitivity to Reward Questionnaire (SPSRQ) and BMI in a sample of 206 adults. Results showed that reward sensitivity and BMI were not significantly correlated. However, neuroimaging results confirmed a relationship between BMI and reduced volume in the medial and lateral orbitofrontal cortex, and between reward sensitivity and lower striatum volume. Importantly, the interaction between the two factors was significantly related to the right anterior hippocampus volume, showing that stronger reward sensitivity plus a higher BMI were associated with reduced hippocampal volume. The hippocampus is a brain structure involved in the higher-order regulation of feeding behavior. Thus, a dysfunctional hippocampus may contribute to maintaining a vicious cycle that predisposes people to obesity.

Neural Underpinnings of Obesity: The Role of Oxidative Stress and Inflammation in the Brain

“…Thus, it has become clear that the hippocampus actively participates in the decision-making of food consumption by altering the prediction of hedonic consequences of feeding [ 47 ]. Neuroimaging studies have shown that hippocampal volume is diminished with aberrant neural activity in obese individuals compared to lean healthy individuals [ 48 , 49 , 50 ], indicating a potential mechanistic link between hippocampal function and metabolic health. Consistent with these results, rodent studies indicate that diet-induced obesity (via HFD or high-sucrose diet) manifests impaired memory consolidation [ 51 , 52 , 53 ] that is associated with hippocampal BBB disruption [ 54 , 55 ], thereby potentially increasing the entry of systemic inflammatory mediators into the hippocampus.…”

The neural correlates of reinforcement sensitivity theory: A systematic review of the (f)MRI literature.

“…There was also some evidence of structural and resting state differences in the PFC in relation to BAS trait measures (Adrián-Ventura et al, 2019b;Hahn et al, 2012;Li et al, 2014). The involvement of the VS as a BAS structure was consistently supported by correlations with task-related activity (Costumero, Barro ´s-Loscertales, Bustamante, Ventura-Campos, Fuentes, & Ávila, 2013; Costumero, Barro ´s-Loscertales, Bustamante, Ventura-Campos, Fuentes, Rosell-Negre, et al, 2013;Costumero et al, 2016;Dong et al, 2018;Eryilmaz et al, 2017;Hahn et al, 2009Hahn et al, , 2011Mortensen et al, 2015;Radke et al, 2016;Simon et al, 2010;van Rijn et al, 2016) and structural and resting state differences (Adrián-Ventura et al, 2019b;Barro ´s-Loscertales et al, 2006a;Hahn et al, 2012;Parcet et al, 2020). BAS was also found to be related to connectivity between the right and left striatum and right frontal gyrus and right striatum (Dong et al, 2018).…”

“…Of the studies using the SRSPQ, two studies found a positive correlation between sensitivity to One study, using an all-male sample, found a negative correlation with GMV in the caudate, putamen, superior frontal cortex, and globus pallidus (Barro ´s-Loscertales et al, 2006b). Another study also found a negative correlation between SR and GMV in the left caudate (Parcet et al, 2020). The final study that investigated SR found a negative correlation with GMV in the ACC, the medial and left lateral PFC, left and superior temporal lobe and the left insula for both genders, and in the NAcc and left caudate for males only (Adrián-Ventura et al, 2019b).…”

Relationships between Personality Traits and Brain Gray Matter Are Different in Risky and Non-risky Drivers

“…Furthermore, the relationships between SR and SP and brain volume in risky driving contexts have not yet been studied, although some studies have explored the association between brain volume and personality traits such as SP and SR or impulsivity. Regarding SR, positive and negative correlations have been found with the volume of the striatum ([ 25 – 28 ]) and negative correlations with the volumes of the lateral and medial prefrontal and superior temporal cortices [ 25 , 27 , 29 ]. On the other hand, SP has been positively correlated with volumes of the amygdala and hippocampal formation and negatively with the insula and OFC volumes [ 25 , 30 – 35 ].…”