Biology subjects

Aarts, E.

Publications and source records attributed to Aarts, E..

18 recordsLinked to original sources

bioRxiv2026

Exploring the role of multivariate associations between brain networks and gut microbiota in (food) value-based decision-making

Food reward valuation and decision making are key psychological processes regulating eating behaviour. Stress and negative affect can shape these processes, increasing vulnerability to overeating high caloric, ultra-processed foods and thereby elevating obesity risk. Yet not all individuals under stress exhibit such behavioural shifts, highlighting the need to understand which modulating factors explain this inter individual variability. Emerging evidence suggests that anxiety-/stress-induced changes in gut microbiota might alter reward sensitivity via the gut-brain axis. An integrative framework linking microbiota, neural, and affective processes is thus essential for explaining individual differences in emotional eating, yet such a framework is still lacking. To this end, supervised linked independent component analysis (Super- BigFLICA) was used to explore multivariate gut-brain latent components guided by affective and body composition indexes in healthy participants (N = 592) from the Healthy Brain Study. Next, general linear models were used to identify if any of the observed components were predictive of elevated unhealthy food valuation and choice in a food auction task. A multimodal component was predictive of both food valuation and choice. This component was characterized by co-occurring changes in several gut bacterial taxa at the genus level (e.g., UCG-010 and DTU089), specific connectivity between reward-related brain regions (e.g., nucleus accumbens, caudate), and was clearly linked to elevated anxiety sensitivity, life-event impact, and body mass index. These findings demonstrate the feasibility of supervised gut-brain integration for predicting behaviour and reveal a potential phenotype linking microbiota composition, brain function, and emotional state that should be further investigated

neuroscience↗

bioRxiv2026

A Multi-Omics Framework Reveals Phosphorylation-Dependent Control of Protein Interactions

Protein phosphorylation regulates nearly every cellular process, yet most of the hundreds of thousands of human phosphosites remain functionally uncharacterized. Rather than prioritising phosphosites by conservation or structural features, here we use the abundance of an interaction partner as a readout of whether a phosphosite affects that interaction. This idea exploits the fact that subunits of stable complexes are often degraded when unbound. Here, we apply a nested linear regression model to pan-cancer data from 1,006 tumours, while controlling for transcriptional and other covariates. We identified 6,160 associations between 3,038 phosphosites and the abundance of interacting proteins, including several known interaction-regulating sites. Mapping these onto AlphaFold-predicted complexes placed 239 sites at interaction interfaces, while another 402 were linked to compartment-specific localisation, indicating that phosphorylation can also tune interactions by relocating proteins between compartments. Affinity-purification mass spectrometry of NKAP and NUF2 phosphosite mutants experimentally supported some of these predictions. Together, this framework reveals a widespread coupling between phosphorylation and interaction-dependent protein abundance and provides a prioritized, structure-informed resource for characterizing the human phosphoproteome

bioinformatics↗

bioRxiv2026

Structure of the mammalian ciliary transition zone microtubule doublet

The ciliary transition zone gates bidirectional protein trafficking to maintain the specialized ciliary proteome using microtubule doublets as a scaffold. While ciliary axonemal doublets are well-characterized, the molecular architecture of the transition zone doublet remains elusive. Here, we report the structure of the mammalian transition zone doublet from bovine tracheal cilia using cryo-electron tomography at 4.7-5.0 [A] resolution. The transition zone doublet is a structurally independent segment defined by an 8 nm-periodic arrangement of unique microtubule-inner proteins (MIPs) and microtubule-associated proteins (MAPs). We identify the calcium-binding protein CAPSL as a lumenal MIP that forms a pseudo-helical spiral and stabilizes microtubules in vitro. Furthermore, a dense MAP network on the A-microtubule surface clashes with intraflagellar transport (IFT) motor binding sites, suggesting anterograde IFT is directed to the B-microtubule for potential regulation by MAP9. Our work provides a structural framework for understanding gated ciliary transport and transition zone-linked human ciliopathies.

Cell Biology↗

bioRxiv2026

Colon-delivered multivitamin supplementation enhances working memory-related fMRI responses in older adults: a randomized, placebo-controlled trial

BackgroundVitamins are important modulators of intestinal health and may affect the gut-brain axis through microbial metabolites such as short-chain fatty acids (SCFAs). However, the neurocognitive effects of colon-delivered vitamins in older adults remain unexplored - a critical gap given the gut-brain axiss emerging role in cognitive aging. ObjectiveWe investigated the effect of a colon-delivered multivitamin (CDMV) supplement on intestinal health and neurocognitive outcomes in older adults at risk of cognitive decline. MethodsWithin the double-blind randomized placebo-controlled trial COMBI (ClinicalTrials.govID: NCT05675007), we included 75 older adults (60-75 years) at risk of cognitive decline based on lifestyle-related factors. Participants consumed a colon-delivered capsule with vitamins B2, B3, B6, B9, C and D3, or a placebo, daily for six weeks. Pre- and post-intervention, we employed neuroimaging, feces- and blood collection. Primary outcomes were fecal SCFA concentrations, working memory (WM)-related fMRI responses, and WM performance measured with the n-back task. ResultsAfter adjusting for baseline values, we found no significant between-group differences in total fecal SCFA levels (p=0.30) and WM performance (p=0.50). Post-intervention WM-related fMRI responses in the hippocampus (p=0.01; p{superscript 2}=0.09) and dorsolateral prefrontal cortex (dlPFC) (p=0.06; p{superscript 2}=0.04), driven by the right dlPFC (p=0.02), were higher in the CDMV group compared to placebo. Independent of intervention group, post-pre increases in fecal SCFA levels were significantly correlated to increases in dlPFC fMRI responses ({rho}=0.31; p=0.02) and WM performance ({rho}=0.43; p=0.001). ConclusionsOur findings suggest that CDMV supplementation increases WM-related responses of the dlPFC and hippocampus in older adults, but this effect was not accompanied by changes in fecal SCFA levels or WM performance. The positive correlation of within-subject changes in fecal SCFAs with changes in WM dlPFC responses and performance across intervention groups provides human evidence for gut-brain communication in cognitive aging beyond cross-sectional associations.

neuroscience↗

bioRxiv2026

Unifying the genetic landscape of common and rare diseases via latent neighborhoods

Resolving disease mechanisms and identifying safer drug targets remains challenging due to difficulties in integrating inconsistent sources of genetic evidence. Here, we developed a deep-learning (DL) method for obtaining latent representations of human diseases and other terms by coupling a variational autoencoder (VAE) to network embeddings from graph representation learning on a protein interaction network. We apply this approach to map the landscape of human disease, by systematically integrating evidence for [~]42,000 traits and terms from sources such as clinical reports (ClinVar), genome-wide association studies (GWAS), mouse phenotypes and gene ontology. Similar diseases share their latent neighborhoods with the sources of evidence highlighting different aspects of the same cell biology for its role in disease. By decoding latent neighborhoods, we unify the sources of evidence and integrate across diseases to prioritize genes for common and rare diseases. Through examples for diabetes, hearing loss, and familial long QT syndrome, we illustrate how the methodology can be applied to develop hypotheses for disease mechanisms and to propose experimental models, measurements, targets and potential drugs that may improve diagnosis and treatments.

genetics↗

bioRxiv2026

Low-grade inflammation in obesity causes low-effort food choice

Inflammation relates to decreased effortful behaviour and altered effort-related responses in brain regions, such as the dorsomedial prefrontal cortex (dmPFC). Inflammation is prevalent in obesity, but its effects on effortful versus more convenient food choices are unknown. We investigated the role of low-grade inflammation in effortful food choice using functional MRI in a cross-sectional study (n=150 women, BMI>27 kg/m{superscript 2}) and a 12-week randomized controlled trial (n=59 women, BMI>30 kg/m{superscript 2}, CRP>3 mg/L; colchicine 0.5 mg/d vs. placebo). Inflammation was related to less high-effort choices (OR=0.27, p=0.004) and higher effort-related dmPFC signal ({beta}=0.23, p=0.025, Rpartial{superscript 2}=0.039), and mediated the association between BMI and dmPFC signal. Colchicine decreased systemic inflammation (i.e. INFLA-score) as expected ({beta}=-0.10 SD, p<0.001, Rpartial{superscript 2}=0.030), increased high-effort choices (OR=1.32, p=0.044), and marginally decreased effort-related dmPFC signal ({beta}=-0.13, p=0.053, Rpartial{superscript 2}=0.037). These findings show a causal role for inflammation in choosing convenience foods in obesity via increased effort aversion and associated dmPFC processing.

neuroscience↗

bioRxiv2025

Exhaled breath profiling for non-invasive monitoring of cognitive functioning in children

IntroductionChildhood is a critical period for the development of executive functioning skills, including selective attention and inhibitory control, which are essential for cognitive development. Optimal brain development during this time requires appropriate levels of macronutrient intake. Metabolomics can offer valuable insights into which metabolites cognitive functioning and the underlying gut-brain interactions. ObjectivesThis study aimed to explore to use of breathomics to investigate associations between exhaled metabolites and executive functioning in children. MethodsChildren (8-10 years; N = 31) were recruited via flyers at schools and after-school care. The assessment of executive functioning was done using Eriksen flanker task. Breath samples were collected in Tedlar(R) bags and analyzed with proton transfer reaction-mass spectrometry (PTR-MS). On-breath peaks were selected and subjected to partial least squares (PLS) regression. Significance multivariate correlation (sMC) was used afterwards to select metabolites bearing predictive power towards executive functioning. ResultsGut microbiome-related metabolites (methane, ethanol, and butyric acid) present in exhaled breath were associated with an improved executive functioning, whereas isoprene was linked to reduced executive functioning. Additionally, increased levels of inflammatory markers, ethylene and acetaldehyde, were associated with a higher compatibility effect in error rates, suggesting diminished cognitive control. These VOCs were putatively linked with specific gut microbial taxa; for instance, reduced Bacteroidetes abundance (associated with methane production) is associated with decreased inhibitory control, while Enterobacteriaceae were linked to lipopolysaccharide-induced inflammation which is also a process that causes increased ethylene production. ConclusionThis proof-of-concept study demonstrates that VOCs in exhaled breath could serve as a promising non-invasive tool for assessing gut-brain interactions related to executive functioning in children.

biochemistry↗

bioRxiv2024

Fatigue >12 weeks after coronavirus disease (COVID) is associated with reduced reward sensitivity during effort-based decision making

BackgroundFatigue and depressive mood is inherent to acute disease, but a substantial group of people report persisting disabling fatigue and depressive symptoms long after a COVID infection. Acute infections have shown to change decisions to engage in effortful and rewarding activities, but it is currently unclear whether fatigue and depressive symptoms similarly affect decision making during acute and persistent phases of a COVID infection. Here, we investigated whether fatigue and depressive mood are associated with altered weighting of effort and reward in decision-making during different timepoints after COVID infection. MethodsWe conducted an online cross-sectional study between March 2021 and March 2022. 242 Participants (18-65 years) with COVID <4 weeks ago (n=62), COVID >12 weeks ago (n=81), or no prior COVID (self-reported) (n=90) performed an effort-based decision-making task, in which they decided whether they wanted to exert physical effort (ticking boxes on screen, 5 levels) for reward (money to be gained in a voucher-lottery, 5 levels). State fatigue and depressive mood was measured by the Profile of Mood States (POMS) prior to the task. We used multilevel binomial regression analysis to test whether fatigue and depressive mood were related to acceptance rates for effort and reward levels and whether this differed between the groups. ResultsCompared with no COVID and COVID <4 weeks groups, the COVID >12 weeks group reported higher state fatigue scores (mean{+/-}SD: 20{+/-}7 vs. 14{+/-}7 and 12{+/-}6 POMS-score, respectively; both p<0.001) and was less sensitive to rewards (Reward*Group: OR: 0.35 (95%CI 0.20, 0.62), p<0.001 and OR: 0.38 (95%CI 0.20, 0.72), p=0.003). In the COVID >12 weeks group, fatigue was more negatively associated with reward sensitivity compared with the COVID <4 weeks group (Reward*Fatigue*Group: OR 0.47 (95%CI 0.25, 1.13), p=0.022) and the no COVID group (Reward*Fatigue*Group: OR 0.48 (95%CI 4.01, 0.92), p=0.029). No group differences were observed for the relationship between fatigue and effort sensitivity. No group differences were observed for the relationship between depressive mood and effort or reward sensitivity. Higher age, lower BMI, unhealthy lifestyle, and worrying during the acute phase of COVID each predicted decreased reward sensitivity in the >12 weeks group (Age*Reward: OR 0.30 (95%CI 0.19, 0.48), p<0.001; BMI*Reward: OR 1.43 (95%CI 1.01, 2.00), p=0.047); Lifestyle*Reward: OR 1.50 (95%CI 1.06, 2.14), p=0.022; Worrying*Reward: OR 0.59 (95%CI 0.38, 0.94), p=0.025, respectively). ConclusionThe finding that fatigue is related to lower reward sensitivity >12 weeks after COVID, suggesting potential reward deficits in post-covid fatigue. These findings are in line with previous observations that long-term inflammation can induce dysregulations in neural reward processing, which should be further investigated in future studies. HighlightsO_LIWe tested if fatigue and mood were related to altered decision making post-COVID C_LIO_LIParticipants post-COVID >12wks ago were more fatigued and less reward sensitive C_LIO_LIPost-COVID-related fatigue was associated with reduced reward sensitivity C_LIO_LIPost-COVID-related depressive mood was not associated with altered decision making C_LIO_LIHigher age, unhealthy lifestyle, and worrying predicted reward deficits C_LI

neuroscience↗

bioRxiv2023

Fatigue during acute systemic inflammation is associated with reduced mental effort expenditure while task accuracy is preserved

BackgroundEarlier work within the physical domain showed that acute inflammation changes motivational prioritization and effort allocation rather than physical abilities. It is currently unclear whether a similar motivational framework accounts for the mental fatigue and cognitive symptoms of acute sickness. Accordingly, this study aimed to assess the relationship between fatigue, cytokines and mental effort-based decision making during acute systemic inflammation. MethodsEighty-five participants (41 males; 18-30 years (M=23.0, SD=2.4)) performed a mental effort-based decision-making task before, 2 hours after, and 5 hours after intravenous administration of 1 ng/kg bacterial lipopolysaccharide (LPS) to induce systemic inflammation. Plasma concentrations of cytokines (interleukin (IL)-6, IL-8 and tumor necrosis factor (TNF)) and fatigue levels were assessed at similar timepoints. In the task, participants decided whether they wanted to perform (i.e., accepted) arithmetic calculations of varying difficulty (3 levels: easy, medium, hard) in order to obtain rewards (3 levels: 5, 6 or 7 points). Acceptance rates were analyzed using a binomial generalized estimated equation (GEE) approach with effort, reward and time as independent variables. Arithmetic performance was measured per effort level prior to the decisions and included as a covariate. Associations between acceptance rates, fatigue (self-reported) and cytokine concentrations levels were analyzed using partial correlation analyses. ResultsPlasma cytokine concentrations and fatigue were increased at 2 hours post-LPS compared to baseline and 5 hours post-LPS administration. Acceptance rates decreased for medium, but not for easy or hard effort levels at 2 hours post-LPS versus baseline and 5 hours post-LPS administration, irrespective of reward level. This reduction in acceptance rates occurred despite improved accuracy on the arithmetic calculations itself. Reduced acceptance rates for medium effort were associated with increased fatigue, but not with increased cytokines. ConclusionFatigue during acute systemic inflammation is associated with alterations in mental effort allocation, similarly as observed previously for physical effort-based choice. Specifically, willingness to exert mental effort depended on effort and not reward information, while task accuracy was preserved. These results extend the motivational account of inflammation to the mental domain and suggest that inflammation may not necessarily affect domain-specific mental abilities, but rather affects domain-general effort-allocation processes.

neuroscience↗

bioRxiv2022

Bayesian multilevel hidden Markov models identify stable state dynamics in longitudinal recordings from macaque primary motor cortex

Neural populations, rather than single neurons, may be the fundamental unit of cortical computation. Analyzing chronically recorded neural population activity is challenging not only because of the high dimensionality of activity in many neurons, but also because of changes in the recorded signal that may or may not be due to neural plasticity. Hidden Markov models (HMMs) are a promising technique for analyzing such data in terms of discrete, latent states, but previous approaches have either not considered the statistical properties of neural spiking data, have not been adaptable to longitudinal data, or have not modeled condition specific differences. We present a multilevel Bayesian HMM which addresses these shortcomings by incorporating multivariate Poisson log-normal emission probability distributions, multilevel parameter estimation, and trial-specific condition covariates. We applied this framework to multi-unit neural spiking data recorded using chronically implanted multi-electrode arrays from macaque primary motor cortex during a cued reaching, grasping, and placing task. We show that the model identifies latent neural population states which are tightly linked to behavioral events, despite the model being trained without any information about event timing. We show that these events represent specific spatiotemporal patterns of neural population activity and that their relationship to behavior is consistent over days of recording. The utility and stability of this approach is demonstrated using a previously learned task, but this multilevel Bayesian HMM framework would be especially suited for future studies of long-term plasticity in neural populations.

neuroscience↗

bioRxiv2020

The cognitive effects of a promised bonus do not depend on dopamine synthesis capacity

Reward motivation is known to enhance cognitive control. However, detrimental effects have also been observed, which have been attributed to overdosing of already high baseline dopamine levels by further dopamine increases elicited by reward cues. Aarts et al. (2014) indeed demonstrated, in 14 individuals, that reward effects depended on striatal dopamine synthesis capacity, measured with [18F]FMT-PET: promised reward improved Stroop control in low-dopamine individuals, while impairing it in high-dopamine individuals. Here, we aimed to assess this same effect in 44 new participants, who had previously undergone an [18F]DOPA-PET scan to quantify dopamine synthesis capacity. This sample performed the exact same rewarded Stroop paradigm as in the prior study. However, we did not find any correlation between reward effects on cognitive control and striatal dopamine synthesis capacity. The discrepancy between the current and our previous findings might reflect the use of different radiotracers for indexing dopamine synthesis capacity. STATEMENT OF RELEVANCEReward motivation is generally thought to enhance cognitive control, but paradoxical negative effects of rewards on cognitive control have also been observed. A previous PET study demonstrated that reward effects on Stroop control depended on baseline striatal dopamine synthesis capacity, indexed by uptake of the radiotracer [18F]FMT. The sample size is this study was very small for a between-subject correlational design. Replicating the exact same Stroop paradigm within a larger sample is therefore crucial to robustly establish the mechanistic link between incentive motivation and cognitive control and advancing our understanding of who chokes under pressure and why, a topic of great societal relevance today. The present study did not reveal any correlation between reward effects on cognitive control and striatal dopamine synthesis capacity, indexed with [18F]FDOPA-PET. Future studies might consider putative differential sensitivity of the radiotracer [18F]FMT and [18F]FDOPA, while also addressing other indices of dopamine transmission.

neuroscience↗

bioRxiv2020

Multivariate associative patterns between the gut microbiota and large-scale brain network connectivity

Research on the gut-brain axis has accelerated substantially over the course of the last years. Many reviews have outlined the important implications of understanding the relation of the gut microbiota with human brain function and behavior. One substantial drawback in integrating gut microbiome and brain data is the lack of integrative multivariate approaches that enable capturing variance in both modalities simultaneously. To address this issue, we applied a linked independent component analysis (LICA) to microbiota and brain connectivity data. We analyzed data from 58 healthy females (mean age = 21.5 years). Magnetic Resonance Imaging data were acquired using resting state functional imaging data. The assessment of gut microbial composition from feces was based on sequencing of the V4 16S rRNA gene region. We used the LICA model to simultaneously factorize the subjects large-scale brain networks and microbiome relative abundance data into 10 independent components of spatial and abundance variation. LICA decomposition resulted in four components with non-marginal contribution of the microbiota data. The default mode network featured strongly in three components, whereas the two-lateralized fronto-parietal attention networks contributed to one component. The executive-control (with the default mode) network was associated to another component. We found the abundance of Prevotella genus was associated to the strength of expression of all networks, whereas Bifidobacterium was associated with the default mode and frontoparietal-attention networks. We provide the first exploratory evidence for multivariate associative patterns between the gut microbiota and brain network connectivity in healthy humans, taking into account the complexity of both systems.

neuroscience↗

bioRxiv2020

Distraction attenuates goal-directed neural responses for food rewards

Distracted eating can lead to increased food intake, but it is unclear how. We hypothesized that distraction affects the change in motivated responses for food reward after satiation. To investigate this, 38 healthy normal-weight participants (28F, 10M) performed a detection task varying in attentional load (high or low distraction) during fMRI. Simultaneously, they exerted effort for food rewards (sweet or savory) by repeated button presses. Two fMRI runs were separated by outcome devaluation (satiation) of one of the reward outcomes, to assess outcome-sensitive, i.e. goal-directed, responses. Behavioral results showed no effect of distraction on effort for food reward following outcome devaluation. At an uncorrected threshold (p<0.001), distraction decreased goal-directed responses (devalued versus valued) in the right inferior frontal gyrus (rIFG). Importantly, these distraction-sensitive rIFG responses correlated negatively (r = - 0.40, p = 0.014) with the effect of distraction on the number of button presses. Specifically, decreased rIFG responses due to distraction related to increased button presses for food reward after satiation, in line with the rIFGs established role in response inhibition. Furthermore, distraction decreased functional connectivity between the rIFG (seed) and left putamen for valued versus devalued food rewards (pFWE(cluster)<0.05). Our results suggest that distraction attenuates the ability to inhibit responses for food reward after satiation by affecting the rIFG. Furthermore, distraction attenuated connectivity between two regions involved in response inhibition - rIFG and putamen - after outcome devaluation. These results may explain why distraction can lead to overeating in our current, distracting, environment. The study was preregistered at: https://osf.io/ad2qk.

neuroscience↗

bioRxiv2019

Effects of distraction on taste-related neural processing

Distracted eating is associated with increased food intake and overweight. However, the underlying neurocognitive mechanisms are unknown. To elucidate these mechanisms, 41 healthy normal-weight participants received sips of high- and low-sweet isocaloric chocolate milk, while performing a high- or low-distracting detection task during fMRI on two test days. Subsequently, we measured ad libitum food intake. As expected, a region in the primary taste cortex - located in the insula - responded more to the sweeter drink. Distraction did not affect this right insula sweetness response across the group, but did weaken sweetness-related connectivity of this region to a secondary taste region in the right orbitofrontal cortex. Moreover, distraction-related attenuation of taste processing in the insula predicted increased subsequent ad libitum food intake after distraction between subjects. These results reveal a previously unknown mechanism explaining how distraction during consumption attenuates neural taste processing and increases food intake. The study was preregistered at https://osf.io/vxdhg/register/5771ca429ad5a1020de2872e?view_only=e3207cd6567f41f0a1505e343a64b5aa.

neuroscience↗

bioRxiv2018

Stress matters: a double-blind, randomized controlled trial on the effects of a multispecies probiotic on neurocognition

Probiotics are microorganisms that can provide health benefits when consumed. Recent animal studies have demonstrated that probiotics can reverse gut microbiome-related alterations in anxiety and depression-like symptoms, in hormonal responses to stress, and in cognition. However, in humans, the effects of probiotics on neurocognition remain poorly understood and a causal understanding of the gut-brain link in emotion and cognition is lacking. We aimed to fill this gap by studying the effects of a probiotics intervention versus placebo on neurocognition in healthy human volunteers.\n\nWe set out to investigate the effects of a multispecies probiotic (Ecologic(R)Barrier) on specific neurocognitive measures of emotion reactivity, emotion regulation, and cognitive control using fMRI. Critically, we also tested whether the use of probiotics can buffer against the detrimental effects of acute stress on working memory. In a double blind, randomized, placebo-controlled, between-subjects intervention study, 58 healthy participants were tested twice, once before and once after 28 days of intervention with probiotics or placebo.\n\nProbiotics versus placebo did not affect emotion reactivity, emotion regulation, and cognitive control processes at brain or behavioral level, neither related self-report measures. However, relative to the placebo group, the probiotics group did show a significant stress-related increase in working memory performance after versus before supplementation (digit span backward, p=0.039, {eta}p2=.07). Interestingly, this change was associated with intervention-related neural changes in frontal cortex during cognitive control in the probiotics group, but not in the placebo group. Overall, our results show that neurocognitive effects of supplementation with a multispecies probiotic in healthy women become visible under challenging (stress) situations. Probiotics buffered against the detrimental effects of stress in terms of cognition, especially in those individuals with probiotics-induced changes in frontal brain regions during cognitive control.\n\nHighlightsO_LIWe ran a randomized placebo-controlled fMRI study with a multispecies probiotic\nC_LIO_LIProbiotics did not affect neurocognitive measures of emotion and cognitive control\nC_LIO_LIProbiotics did affect stress-related working memory and neural correlates\nC_LIO_LIProbiotics in healthy individuals can support cognition under stress\nC_LI

neuroscience↗

bioRxiv2017

Top-down expectation effects of food labels on motivation

When we buy our food, the information on the package informs us about the properties of the product, such as its taste and healthiness. These beliefs can influence the processing of food rewards and impact decision making beyond objective sensory properties. However, no studies, within or beyond the food domain, have assessed how written information, such as food labels, affect implicit motivation to obtain rewards, even though choices in daily life might be strongly driven by implicit motivational biases. We investigated how written information affects implicit motivation to obtain food rewards. We used food labels (high- and low-calorie), associated with an identical lemonade, to study motivation for food rewards during fMRI. In a joystick task, hungry participants (N=31) were instructed to make fast approach or avoid movements to earn the cued drinks. Behaviorally, we found a general approach bias, which was stronger for the drink that was most preferred during a subsequent choice test, i.e. the one labeled as low-calorie. This behavioral effect was accompanied by increased BOLD signal in the sensorimotor cortex during the response phase of the task for the preferred, low-calorie drink compared with the non-preferred, high-calorie drink. During the anticipation phase, the non-preferred, high-calorie drink label elicited stronger fMRI signal in the right ventral anterior insula, a region associated with aversion and taste intensity, than the preferred, low-calorie label. Together, these data suggest that high-calorie labeling can increase avoidance of drinks and reduce neural activity in brain regions associated with motor control. In conclusion, we show effects of food labeling on fMRI responses during anticipation and subsequent motivated action and on behavior, in the absence of objective taste differences, demonstrating the influence of written information on implicit biases. These findings contribute to our understanding of implicit biases in real-life eating behavior.

neuroscience↗

bioRxiv2017

Enhanced food-related responses in the ventral medial prefrontal cortex in orexin-deficient narcolepsy patients

BackgroundNarcolepsy Type 1 is a chronic sleep disorder caused by a deficiency of orexin (hypocretin). In addition to sleep regulation, orexin is important for motivated control processes. Weight gain and obesity are common in narcolepsy. However, the neurocognitive processes associated with food-related control and overeating in orexin-deficient patients are unknown. We explored the neural correlates of general and food-related attentional control in narcolepsy patients (n=23) and healthy BMI-matched controls (n=20). In secondary analyses, we included patients with idiopathic hypersomnia (n=15) to assess sleepiness-related influences.\n\nMethodsWe measured attentional bias to food words with a Food Stroop task and general executive control with a Classic Stroop task during fMRI. Moreover, with correlational analyses, we assessed the relative contribution of the neural findings on the Food Stroop and Classic Stroop tasks to spontaneous snack intake.\n\nResultsRelative to healthy controls, narcolepsy patients showed enhanced ventral medial prefrontal cortex responses and connectivity with motor cortex during the Food Stroop task, but attenuated dorsal medial prefrontal cortex responses during the Classic Stroop task. The ventral medial prefrontal cortex responses on the Food Stroop task, not the dorsal medial prefrontal cortex responses on the Classic Stroop task, were a significant predictor of snack intake. Comparing the narcolepsy patients with idiopathic hypersomnia patients revealed similar results.\n\nConclusionsThese findings demonstrate that orexin deficiency is associated with decreased dorsal medial prefrontal cortex responses during general executive control and enhanced ventral medial prefrontal cortex responses during food-driven attention, with the latter predicting increases in food intake.\n\nStatement of SignificancePatients with orexin (hypocretin) deficient narcolepsy type-1 often suffer from obesity as well as increased food craving, in addition to the sleep symptoms. However, whether and how orexin deficiency relates to neural differences in food-directed attention is unclear. We employed a Food Stroop task during fMRI and provide experimental evidence that the ventral medial prefrontal cortex responds more strongly to food words in narcolepsy patients than in controls. The hypothesis that this mechanism contributes to weight problems in narcolepsy is strengthened by the observation that ventral medial prefrontal cortex responses during the Food Stroop task were predictive of snack intake. These mechanistic data might thus advance the development of treatment targets for obesity in narcolepsy.

neuroscience↗

bioRxiv2017

The effect of an 8-week mindful eating intervention on anticipatory reward responses in the midbrain

Obesity is a highly prevalent disease, usually resulting from chronic overeating. Accumulating evidence suggests that increased neural responses during the anticipation of high-calorie food play an important role in overeating. A promising method for counteracting enhanced food anticipation in overeating might be mindfulness-based interventions (MBIs). However, the neural mechanisms by which MBIs can affect food reward anticipation are unclear. In this randomized, actively controlled study, the primary objective was to investigate the effect of an 8-week mindful eating intervention on reward anticipation. On the neural level, we hypothesized that mindful eating would decrease striatal reward anticipation responses. Additionally, responses in the midbrain - from which the reward pathways originate - were explored. Using functional magnetic resonance imaging (fMRI), we tested 58 healthy participants with a wide body mass index range (BMI: 19-35 kg/m2), motivated to change their eating behavior. During scanning they performed an incentive delay task, measuring neural reward anticipation responses to caloric and monetary cues before and after 8 weeks of mindful eating or educational cooking (active control). Compared with the educational cooking intervention, mindful eating affected neural reward anticipation responses, with relatively reduced caloric versus monetary reward responses. This effect was, however, not seen in the striatum, but only in the midbrain. The secondary objective was to assess temporary and long-lasting (one year follow-up) intervention effects on self-reported eating behavior and anthropometric measures (BMI, waist circumference, waist-to-hip-ratio (WHR)). We did not observe effects of the mindful eating intervention on eating behavior. Instead, the control intervention showed temporary beneficial effects on BMI, waist circumference, and diet quality, but not on WHR or self-reported eating behavior, as well as long-lasting increases in knowledge about healthy eating. These results suggest that an 8-week mindful eating intervention may have decreased the relative salience of food cues by affecting midbrain but not striatal reward responses. However, these exploratory results should be verified in confirmatory research. The primary and secondary objectives of the study were registered in the Dutch Trial Register (NTR): NL4923 (NTR5025).

neuroscience↗