Dietary tryptophan-rich protein hydrolysate can acutely impact physiological and psychological measures of mood and stress in healthy adults.

BACKGROUND: Tryptophan is the precursor to the mood regulating neurotransmitter serotonin. Its brain bioavailability from food can be dependent on the dietary source. Egg protein hydrolysate (EPH), a dietary supplement rich in tryptophan, has previously shown to acutely impact cognition, mood and stress benefits at 2 g dose. No data exist on the acute effects of lower doses in a food matrix. METHODS: This exploratory study tested the acute effects of low-doses EPH (0.5, 1 g) in a food matrix on cognition, mood and stress. The study employed a double-blinded randomized controlled parallel design in 45 participants with three arms. The effects of the interventions were measured after a multi-task cognitive stressor on blood biomarkers, self-reported mood states, performances of attention, autonomic parameters and, emotional reactivity responses from electroencephalographic recording. RESULTS: As compared to the reference, the 1 g EPH dose increased tryptophan bioavailability from baseline, and, both doses improved heart rate variability parameters related to parasympathetic activation while showing differences in the late neural response to negative versus neutral emotions. Post-hoc analyses indicated a gender difference in the baseline tryptophan bioavailability and further examination suggested the change in mood rating depends on the interaction between gender and change from baseline of tryptophan bioavailability. CONCLUSIONS: Overall, this study suggests that low levels of tryptophan rich EPH in a food matrix positively impact mood or stress in acute settings and adds to the body of evidence linking tryptophan and dietary sources thereof with these benefits. Confirmatory randomized controlled trials are needed to confirm these findings.Trial registration number: CER-VD N°2019-00218.

Effect of the dopamine D3 receptor antagonist GSK598809 on brain responses to rewarding food images in overweight and obese binge eaters.

The dopamine D(3) receptor is thought to be a potential target for treating compulsive disorders such as drug addiction and obesity. Here, we used functional Magnetic Resonance Imaging (fMRI) to investigate the effects the selective dopamine D(3) receptor antagonist GSK598809 on brain activation to food images in a sample of overweight and obese binge-eating subjects. Consistent with previous studies, processing of food images was associated with activation of a network of reward areas including the amygdala, striatum and insula. However, brain activation to food images was not modulated by GSK598809. The results demonstrate that D(3) receptor manipulation does not modulate brain responses to food images in overweight and obese subjects.

Soothing Effect of an Edible Teether: A Pilot Study in Children during Primary Dentition Age.

BACKGROUND: Irritability and discomfort are common symptoms during teething periods in infants and toddlers. Non-pharmacological remedies to relieve teething symptoms include teethers and food for chewing. However, the efficacy of such remedies for their soothing effect has been poorly investigated. MATERIALS AND METHODS: In this home-based pilot study, the soothing effect of a novel edible teether with a slowly dissolvable texture was investigated in 12 children aged 5 to 19 months old during primary dentition age. After parents observed their child getting irritable, the child received the edible teether for an exposure duration of 15 to 20 minutes. Parental ratings of children's mood states (crankiness, stress, happiness, and calmness) were collected using visual analog scales, and child cardiac measurements (heart rate and heart rate variability) were assessed using a wearable device. The soothing effect was quantified via mood ratings and physiological calming responses as a before-after comparison using Wilcoxon signed-rank tests. RESULTS: Parents perceived their child as significantly calmer and happier, less stressed, and marginally less cranky after edible teether exposure than before. The child cardiac variables showed no significant changes; however, exposure to the teether induced a marginal increase in HR within normal ranges, potentially indicating a stimulation effect. CONCLUSION: The pilot study provides the first insight on the soothing effect of a novel edible teether on parent-reported mood states in young children during primary dentition age. Further research is needed to understand the relative contribution of the different components of an edible teether to the observed effects, such as texture and exposure duration, and to demonstrate its efficacy against a control product. TRIAL REGISTRATION: Swiss registry of clinical trial: CER-VD 2019-02155. HOW TO CITE THIS ARTICLE: Lerond C, Hudry J, Zahar S, et al. Soothing Effect of an Edible Teether: A Pilot Study in Children during Primary Dentition Age. Int J Clin Pediatr Dent 2021;14(4):525-530.

Differential modulation of cognitive control networks by monetary reward and punishment.

Incentives are primary determinants of if and how well an organism will perform a given behavior. Here, we examined how incentive valence and magnitude influence task switching, a critical cognitive control process, and test the predictions that the anterior cingulate cortex (ACC) and the ventral striatum (vStr) function as key nodes linking motivation and control systems in the brain. Our results indicate that reward and punishment incentives have both common and distinct effects on cognitive control at the behavioral and neurobiological levels. For example, reward incentives led to greater activity in the ACC during the engagement of control relative to punishments. Furthermore, the neural responses to reward and punishment differed as a function of individual sensitivity to each incentive valence. Functional connectivity analyses suggest a role for vStr in signaling motivational value during cognitive control and as a potential link between motivation and control networks. Overall, our findings suggest that similar changes in observed behavior (e.g. response accuracy) under reward and punishment incentives are mediated by, at least partially, distinct neurobiological substrates.

A Neural Mechanism of Strategic Social Choice under Sanction-Induced Norm Compliance

In recent years, much has been learned about the representation of subjective value in simple, nonstrategic choices. However, a large fraction of our daily decisions are embedded in social interactions in which value guided decisions require balancing benefits for self against consequences imposed by others in response to our choices. Yet, despite their ubiquity, much less is known about how value computation takes place in strategic social contexts that include the possibility of retribution for norm violations. Here, we used functional magnetic resonance imaging (fMRI) to show that when human subjects face such a context connectivity increases between the temporoparietal junction (TPJ), implicated in the representation of other peoples' thoughts and intentions, and regions of ventromedial prefrontal cortex (vmPFC) that are associated with value computation. In contrast, we find no increase in connectivity between these regions in social nonstrategic cases where decision-makers are immune from retributive monetary punishments from a human partner. Moreover, there was also no increase in TPJ-vmPFC connectivity when the potential punishment was performed by a computer programmed to punish fairness norm violations in the same manner as a human would. Thus, TPJ-vmPFC connectivity is not simply a function of the social or norm enforcing nature of the decision, but rather occurs specifically in situations where subjects make decisions in a social context and strategically consider putative consequences imposed by others.

Acute Stress Impairs Self-Control in Goal-Directed Choice by Altering Multiple Functional Connections within the Brain's Decision Circuits.

Important decisions are often made under stressful circumstances that might compromise self-regulatory behavior. Yet the neural mechanisms by which stress influences self-control choices are unclear. We investigated these mechanisms in human participants who faced self-control dilemmas over food reward while undergoing fMRI following stress. We found that stress increased the influence of immediately rewarding taste attributes on choice and reduced self-control. This choice pattern was accompanied by increased functional connectivity between ventromedial prefrontal cortex (vmPFC) and amygdala and striatal regions encoding tastiness. Furthermore, stress was associated with reduced connectivity between the vmPFC and dorsolateral prefrontal cortex regions linked to self-control success. Notably, alterations in connectivity pathways could be dissociated by their differential relationships with cortisol and perceived stress. Our results indicate that stress may compromise self-control decisions by both enhancing the impact of immediately rewarding attributes and reducing the efficacy of regions promoting behaviors that are consistent with long-term goals.

Stop and be fair: DLPFC development contributes to social decision making.

In this issue of Neuron,Steinbeis et al. (2012) show that DLPFC structure and functions are associated with strategic social choices during an economic task and relate to impulse control abilities in both age dependent and independent manners.

The gut hormones PYY 3-36 and GLP-1 7-36 amide reduce food intake and modulate brain activity in appetite centers in humans.

Obesity is a major public health issue worldwide. Understanding how the brain controls appetite offers promising inroads toward new therapies for obesity. Peptide YY (PYY) and glucagon-like peptide 1 (GLP-1) are coreleased postprandially and reduce appetite and inhibit food intake when administered to humans. However, the effects of GLP-1 and the ways in which PYY and GLP-1 act together to modulate brain activity in humans are unknown. Here, we have used functional MRI to determine these effects in healthy, normal-weight human subjects and compared them to those seen physiologically following a meal. We provide a demonstration that the combined administration of PYY(3-36) and GLP-1(7-36 amide) to fasted human subjects leads to similar reductions in subsequent energy intake and brain activity, as observed physiologically following feeding.