Functional MRI activation of the nucleus tractus solitarius after taste stimuli at ultra-high field: a proof-of-concept single-subject study

Using ultra-high field (7 Tesla) functional MRI (fMRI), we conducted the first in-vivo functional neuroimaging study of the normal human brainstem specifically designed to examine neural signals in the Nucleus Tractus Solitarius (NTS) in response to all basic taste stimuli. NTS represents the first relay station along the mammalian taste processing pathway which originates at the taste buds in the oral cavity and passes through the thalamus before reaching the primary taste cortex in the brain. In our proof-of-concept study, we acquired data from one adult volunteer using fMRI at 1.2 mm isotropic resolution and performed a univariate general linear model analysis. During fMRI acquisition, three shuffled injections of sweet, bitter, salty, sour, and umami solutions were administered following an event-related design. We observed a statistically significant blood oxygen level-dependent (BOLD) response in the anatomically predicted location of the NTS for all five basic tastes. The results of this study appear statistically robust, even though they were obtained from a single volunteer. The information derived from a similar experimental strategy may inspire novel research aimed at clarifying important details of central nervous system involvement in eating disorders, at designing and monitoring tailored therapeutic strategies.

Effects of a health versus hedonic mindset on daily-life snacking behaviour

BACKGROUND

In today's obesogenic environment high-caloric palatable foods are omnipresent, making it hard for many to reach and maintain a healthy body weight. This study investigates the effects of a health versus hedonic mindset on daily-life snacking behaviour. The hypothesis is that a health mindset leads to reduced snacking behaviour compared to a hedonic mindset. This effect is expected to be most pronounced with high dietary restraint and least pronounced with high trait self-control.

METHODS

For 3 weeks, degree of craving and amount of snacks that were craved and consumed were assessed four times a day, using smartphone Ecological Momentary Assessment (EMA). A total of 111 female participants (body mass index range: 20-23.5) were randomly assigned to a 1-week health (n = 53) or hedonic (n = 58) mindset, occurring in week 2 of the EMA protocol. The mindset manipulations consisted of text messages, focusing either on the enjoyment of tasty food (hedonic) or on healthy living and eating (health).

RESULTS

contrary to our hypotheses, mindset did not affect snacking behaviour. Instead, degree of craving and intake of snacks reduced significantly over time, not moderated by mindset, dietary restraint (Restraint Scale) or trait self-control (Brief Self-Control Scale). Importantly, this was not due to reduced compliance. Possibly, the reduced craving and snacking behaviour were due to monitoring and/or socially desirable answering tendencies. Additional time point analyses showed that craving was strongest in the late afternoon (3:30-5:00 PM), and-across mindset conditions-degree of craving correlated negatively with trait self-control.

CONCLUSIONS

future studies could manipulate degree of monitoring and design individually tailored manipulations.

A smartphone application as a personalized treatment tool for adolescents with overweight: an explorative qualitative study

BACKGROUND

The present study is the first step of a 3-year European project in which a tailored smartphone application will be developed and tested as a potential tool in the personalized treatment of children and adolescents with overweight.

METHODS

In this study, 10 focus groups (n = 48 participants) were conducted in Belgium, The Netherlands and France with adolescents with overweight (12-16 years; n = 30) and parents of adolescents with overweight (n = 18) to investigate their perceptions on (un)healthy behavior, the drivers of these behaviors, and the needs of an eHealth application for weight loss. A thorough thematic analysis was performed using Nvivo12.

RESULTS

Results show that adolescents with overweight have a well-articulated perspective on (un)healthy behavior and their needs. Parents underestimate their own influence on the (un)healthy behavior of their children and report difficulties in healthy lifestyle parenting, which makes their role as a coach rather ambiguous. Concerning the needs of an eHealth application, both parents and adolescents formulated some challenging expectations regarding the content and the format including information, a monitoring feature and features that increase participants' motivation to behave healthy. The results of this analysis will form the basis for designing a personalized eHealth application, which will be tested in a next phase.

CONCLUSION

We can conclude that adolescents have a well-articulated perspective on healthy and unhealthy behavior and their needs, whereby a new app could be of great help. It could function as a day-by-day diary and as a supportive coach.

IT IS A MATTER OF PERSPECTIVE: ATTENTIONAL FOCUS RATHER THAN DIETARY RESTRAINT DRIVES BRAIN RESPONSES TO FOOD STIMULI

Brain responses to food are thought to reflect food's rewarding value and to fluctuate with dietary restraint. We propose that brain responses to food are dynamic and depend on attentional focus. Food pictures (high-caloric/low-caloric, palatable/unpalatable) were presented during fMRI-scanning, while attentional focus (hedonic/health/neutral) was induced in 52 female participants varying in dietary restraint. The level of brain activity was hardly different between palatable versus unpalatable foods or high-caloric versus low-caloric foods. Activity in several brain regions was higher in hedonic than in health or neutral attentional focus (p < 0.05, FWE-corrected). Palatability and calorie content could be decoded from multi-voxel activity patterns (p < 0.05, FDR-corrected). Dietary restraint did not significantly influence brain responses to food. So, level of brain activity in response to food stimuli depends on attentional focus, and may reflect salience, not reward value. Palatability and calorie content are reflected in patterns of brain activity.

More complex than you might think: Neural representations of food reward value in obesity

Obesity reached pandemic proportions and weight-loss treatments are mostly ineffective. The level of brain activity in the reward circuitry is proposed to be proportionate to the reward value of food stimuli, and stronger in people with obesity. However, empirical evidence is inconsistent. This may be due to the double-sided nature of high caloric palatable foods: at once highly palatable and high in calories (unhealthy). This study hypothesizes that, viewing high caloric palatable foods, a hedonic attentional focus compared to a health and a neutral attentional focus elicits more activity in reward-related brain regions, mostly in people with obesity. Moreover, caloric content and food palatability can be decoded from multivoxel patterns of activity most accurately in people with obesity and in the corresponding attentional focus. During one fMRI-session, attentional focus (hedonic, health, neutral) was manipulated using a one-back task with individually tailored food stimuli in 32 healthy-weight people and 29 people with obesity. Univariate analyses (p < 0.05, FWE-corrected) showed that brain activity was not different for palatable vs. unpalatable foods, nor for high vs. low caloric foods. Instead, this was higher in the hedonic compared to the health and neutral attentional focus. Multivariate analyses (MVPA) (p < 0.05, FDR-corrected) showed that palatability and caloric content could be decoded above chance level, independently of either BMI or attentional focus. Thus, brain activity to visual food stimuli is neither proportionate to the reward value (palatability and/or caloric content), nor significantly moderated by BMI. Instead, it depends on people's attentional focus, and may reflect motivational salience. Furthermore, food palatability and caloric content are represented as patterns of brain activity, independently of BMI and attentional focus. So, food reward value is reflected in patterns, not levels, of brain activity.

Effects of mindset on hormonal responding, neural representations, subjective experience and intake

A person can alternate between food-related mindsets, which in turn may depend on one's emotional state or situation. Being in a certain mindset can influence food-related thoughts, but interestingly it might also affect eating-related physiological responses. The current study investigates the influence of an induced 'loss of control' mindset as compared to an 'in control' mindset on hormonal, neural and behavioural responses to chocolate stimuli. Mindsets were induced by having female chocolate lovers view a short movie during two sessions in a within-subjects design. Neural responses to visual chocolate stimuli were measured using an ultra-high field (7T) scanner. Momentary ghrelin and glucagon-like peptide 1 (GLP-1) levels were determined on five moments and were simultaneously assessed with self-reports on perceptions of chocolate craving, hunger and feelings of control. Furthermore, chocolate intake was measured using a bogus chocolate taste test. It was hypothesized that the loss of control mindset would lead to hormonal, neural and behavioural responses that prepare for ongoing food intake, even after eating, while the control mindset would lead to responses reflecting satiety. Results show that neural activity in the mesocorticolimbic system was stronger for chocolate stimuli than for neutral stimuli and that ghrelin and GLP-1 levels responded to food intake, irrespective of mindset. Self-reported craving and actual chocolate intake were affected by mindset, in that cravings and intake were higher with a loss of control mindset than with a control mindset. Interestingly, these findings suggest that physiology on the one hand (hormonal and neural responses) and behavior and subjective experience (food intake and craving) on the other hand are not in sync, are not equally affected by mindset.

Fluctuations in attentional bias for food and the role of executive control

Research has shown repeatedly that overweight and obesity are associated with more fluctuations in attentional bias (AB), as reflected in trial-level bias scores (TL-BS). More specifically, people with a high BMI more frequently alternate their attention towards and away from food over time. The current study proposed and tested a model on the mechanism behind the positive association between variability of AB for food and BMI. It was hypothesized that poor executive control (poor response inhibition and lower sustained attention) would be related to both higher BMI and more fluctuations in AB for food and this would, at least partly, explain the significant relationship between variability of AB for food and BMI. To test our hypotheses, 99 female participants completed both an online food dot-probe task and an online stop-signal task. It was found that response inhibition was significantly related to BMI, whereas, contrary to our hypotheses, variability of AB for food was not related to BMI nor to executive control. In conclusion, this study revealed a relation between poor inhibitory control and higher BMI. However, a role of executive control in fluctuations in attention for food could not be established.

Food Palatability Directs Our Eyes Across Contexts

It is often believed that attentional bias (AB) for food is a stable trait of certain groups, like restrained eaters. However, empirical evidence from this domain is inconsistent. High-calorie foods are double-faceted, as they are both a source of reward and of weight/health concern. Their meaning might depend on the food-related context (i.e., focus on health or on enjoyment), which in turn could affect AB for food. This study primed 85 females with hedonic, healthy, and neutral contexts successively and examined whether food-related context affected AB for food and if effects were moderated by dietary restraint. Both the mean tendencies of AB for food and variability of AB for food were assessed in a food dot-probe task with a recording of both reaction times and eye movements. Contrary to our hypotheses, AB for food was not significantly affected by either context or the interaction between context and dietary restraint. Instead, liking of the presented food stimuli was related to longer initial fixations and longer dwell time on the food stimuli. In addition, in line with prior research, body mass index (BMI) was correlated with variability of AB for food instead of mean AB for food. In conclusion, this study did not find any support that AB for food is dependent on food-related context, but interestingly, reaction time-based variability of AB for food seems to relate to BMI, and eye movement-based mean AB seems to relate to appetitive motivation.

Neural Correlates of Food Cue Exposure Intervention for Obesity: A Case-Series Approach

Background

People with overweight have stronger reactivity (e.g., subjective craving) to food cues than lean people, and this reactivity is positively associated with food intake. Cue reactivity is a learned response that can be reduced with food cue exposure therapy.

Objectives

It was hypothesized that participants after food cue exposure therapy would show reduced neural activity in brain regions related to food cue reactivity and increased neural activity in brain regions related to inhibitory-control as compared to participants receiving a control lifestyle intervention.

Method

Neural activity of 10 women with overweight (BMI ≥ 27 kg/m²) in response to individually tailored visually presented palatable high-caloric food stimuli was examined before vs. after a cue exposure intervention (n = 5) or a control lifestyle (n = 5) intervention. Data were analyzed case-by-case.

Results

Neural responses to food stimuli were reduced in food-cue-reactivity-related brain regions after the lifestyle intervention in most participants, and generally not after the cue exposure therapy. Moreover, cue exposure did not lead to increased activity in inhibitory-control-related brain regions. However, decreased neural activity after cue exposure was found in most participants in the lateral occipital complex (LOC), which suggests a decreased visual salience of high-caloric food stimuli.

Conclusion

Receiving a cue exposure therapy did not lead to expected neural responses. As cue exposure relies on inhibitory learning mechanisms, differences in contexts (e.g., environments and food types) between the intervention setting and the scanning sessions may explain the general lack of effect of cue-exposure on neural activity.

Power of mind: Attentional focus rather than palatability dominates neural responding to visual food stimuli in females with overweight

Research investigating neural responses to visual food stimuli has produced inconsistent results. Crucially, high-caloric palatable foods have a double-sided nature - they are often craved but are also considered unhealthy - which may have contributed to the inconsistency in the literature. Taking this double-sided nature into account in the current study, neural responses to individually tailored palatable and unpalatable high caloric food stimuli were measured, while participants' (females with overweight: n = 23) attentional focus was manipulated to be either hedonic or neutral. Notably, results showed that the level of neural activity was not significantly different for palatable than for unpalatable food stimuli. Instead, independent of food palatability, several brain regions (including regions in the mesocorticolimbic system) responded more strongly when attentional focus was hedonic than when neutral (p < 0.05, cluster-based FWE corrected). Multivariate analyses showed that food palatability could be decoded from multi-voxel patterns of neural activity (p < 0.05, FDR corrected), mostly with a hedonic attentional focus. These findings illustrate that the level of neural activity might not be proportionate to the palatability of foods, but that food palatability can be decoded from multi-voxel patterns of neural activity. Moreover, they underline the importance of considering attentional focus when measuring food-related neural responses.

Reduced automatic approach tendencies towards task-relevant and task-irrelevant food pictures in Anorexia Nervosa

BACKGROUND AND OBJECTIVES

Anorexia Nervosa (AN) patients are characterized by an excessive restriction of their food-intake. Prior research using an Affective Simon Task (AST) with food as a task-irrelevant feature, provided evidence for the view that AN patients' ability to refrain from food is facilitated by reduced automatic approach tendencies towards food. However, because food was task-irrelevant (i.e., participants had to base their reaction on the perspective of the picture and not on its content), the findings may in fact reflect a relatively strong ability to ignore the content of the food stimuli rather than weakened approach towards food per se. Therefore, this study also included a Stimulus Response Compatibility (SRC) task with food as task-relevant feature that could not be ignored, because the required response depended on the [food vs non-food] content of the pictures.

METHODS

AN spectrum patients (n = 63), and a comparison group of adolescents without eating pathology (n = 57) completed both a SRC task with food as task-relevant feature, and an Affective Simon Task AST with food as task-irrelevant feature.

RESULTS

AN patients showed reduced approach tendencies for high caloric food. Only the SRC uniquely predicted the presence of AN.

LIMITATIONS

Comparison between tasks was hampered because the SRC only included high caloric food stimuli, whereas the AST included high and low caloric food stimuli.

CONCLUSION

Patients with AN are characterized by weakened automatic approach of high caloric food. This might 'help' restrict their food-intake even in a condition of starvation.

Food craving in daily life: comparison of overweight and normal-weight participants with ecological momentary assessment

Background

The present study examined food cravings in daily life by comparing overweight and normal‐weight participants right before eating events and at non‐eating moments. It was hypothesised that overweight participants would have (i) more frequent, (ii) stronger and (iii) a greater variety of high‐caloric palatable food cravings, and also would (iv) consume more high‐caloric palatable foods, than normal‐weight participants.

Methods

Ecological momentary assessment (EMA) was used to assess food craving strength and frequency, variety of specific food cravings, and food intake. Fifty‐seven overweight and 43 normal‐weight adult participants were assessed at eating events and at an average of eight random non‐eating moments per day for 2 weeks. Foods were categorised as: high‐caloric high palatable foods (HCHP), fruits and salads, staple food dishes and sandwiches, and soups and yoghurts.

Results

Overweight participants reported more frequent HCHP food cravings specifically at non‐eating moments than did normal‐weight participants. Normal‐weight participants reported more food cravings for staple foods, specifically at eating events. Moreover, overweight participants craved a greater variety of HCHP foods than normal‐weight participants at both eating events and random non‐eating moments. No other significant between‐group differences were found.

Conclusions

The results highlight the importance for obesity interventions (i) to specifically target high‐caloric palatable food cravings that are experienced during the day and are not tied to eating moments and (ii) to aim for a reduction in the variety of high‐caloric palatable food cravings. It might be fruitful to deliver treatment aimed at reducing cravings via mobile devices because this allows for easy individual tailoring and timing of interventions.

[Cognitive therapy and interpersonal psychotherapy for major depressive disorder: how do they work, how long, and for whom?]

Although the effectiveness of cognitive therapy (ct) and interpersonal psychotherapy (ipt) for depression has been well established, little is known about how, how long and for whom they work.<br/> AIM: To summarize findings from a large rct to the (differential) effects and mechanisms of change of ct/ipt for depression.<br/> METHOD: 182 adult depressed outpatients were randomized to ct (n = 76), ipt (n = 75), or a two-month wait-list-control condition (n = 31). Primary outcome was depression severity (bdi-ii). Other outcomes were quality of life, social and general psychological functioning and various potential process measures. Interventions were compared at the end of treatment, and up to 17 months follow-up.<br/> RESULTS: Overall, ct and ipt were both superior to the wait-list, but did not differ significantly from one another. However, the pathway through which therapeutic change occurred appeared to be different for ct and ipt, and many patients were predicted to have a clinically meaningful advantage in one of the two interventions. We did not find empirical support for the theoretical models of change.<br/> CONCLUSION: (Long-term) outcomes of ct and ipt appear to not differ significantly. The field would benefit from further refinement of research methods to disentangle mechanisms of change, and from advances in the field of personalized medicine.

The dynamic nature of food reward processing in the brain

PURPOSE OF REVIEW

The dominant view in the literature is that increased neural reactivity to high-caloric palatable foods in the mesocorticolimbic system is a stable-specific characteristic of obese people. In this review, we argue that this viewpoint may not be justified, and we propose that the neural response to food stimuli is dynamic, and in synchrony with the current motivational and cognitive state of an individual. We will further motivate why a clear mental task in the scanner is a necessity for drawing conclusions from neural activity, and why multivariate approaches to functional MRI (fMRI) data-analysis may carry the field forward.

RECENT FINDINGS

From the reviewed literature we draw the conclusions that: neural food-cue reactivity depends strongly on cognitive factors such as the use of cognitive regulation strategies, task demands, and focus of attention; neural activity in the mesocorticolimbic system is not proportionate to the hedonic value of presented food stimuli; and multivariate approaches to fMRI data-analysis have shown that hedonic value can be decoded from multivoxel patterns of neural activity.

SUMMARY

Future research should take the dynamic nature of food-reward processing into account and take advantage from state-of-the-art multivariate approaches to fMRI data-analysis.

Cue exposure therapy reduces overeating of exposed and non-exposed foods in obese adolescents

BACKGROUND AND OBJECTIVES

This study tested whether two sessions of food cue exposure therapy reduced eating in the absence of hunger (EAH), specified for exposed and non-exposed food, in overweight and obese adolescents, and whether habituation of food cue reactivity and reduced CS-US expectancies predicted a decrease in EAH.

METHODS

41 overweight adolescents (aged 12-18 years) were randomly assigned to a cue exposure intervention or a lifestyle intervention (control condition). Habituation of food cue reactivity (self-reported desire to eat and salivation) and CS-US expectancy were measured during both sessions, and EAH was measured at the end of session two.

RESULTS

Compared to the control condition, the cue exposure condition showed less EAH for the exposed food item as well as for the non-exposed food items. Larger within-session (WSH) and between-session habituation (BSH) of cue reactivity were not related to less EAH, change in CS-US expectancy was unrelated to EAH.

LIMITATIONS

The study was underpowered, and compliance to homework instructions between sessions was poor, intervention effects might have been larger when participants adhered to daily homework exercises.

CONCLUSIONS

Food cue exposure was effective to reduce EAH of exposed and non-exposed food items, indicating generalisability of the exposure effect. In line with exposure effects in anxiety disorders, habituation was not found to benefit outcome, though the present data do also not provide evidence that CS-US expectancy violation predicts EAH.

Automatic Approach Tendencies toward High and Low Caloric Food in Restrained Eaters: Influence of Task-Relevance and Mood

Objective: Although restrained eaters are motivated to control their weight by dieting, they are often unsuccessful in these attempts. Dual process models emphasize the importance of differentiating between controlled and automatic tendencies to approach food. This study investigated the hypothesis that heightened automatic approach tendencies in restrained eaters would be especially prominent in contexts where food is irrelevant for their current tasks. Additionally, we examined the influence of mood on the automatic tendency to approach food as a function of dietary restraint. Methods: An Affective Simon Task-manikin was administered to measure automatic approach tendencies where food is task-irrelevant, and a Stimulus Response Compatibility task (SRC) to measure automatic approach in contexts where food is task-relevant, in 92 female participants varying in dietary restraint. Prior to the task, sad, stressed, neutral, or positive mood was induced. Food intake was measured during a bogus taste task after the computer tasks. Results: Consistent with their diet goals, participants with a strong tendency to restrain their food intake showed a relatively weak approach bias toward food when food was task-relevant (SRC) and this effect was independent of mood. Restrained eaters showed a relatively strong approach bias toward food when food was task-irrelevant in the positive condition and a relatively weak approach in the sad mood. Conclusion: The weak approach bias in contexts where food is task-relevant may help high-restrained eaters to comply with their diet goal. However, the strong approach bias in contexts where food is task-irrelevant and when being in a positive mood may interfere with restrained eaters' goal of restricting food-intake.

Subjective craving and event-related brain response to olfactory and visual chocolate cues in binge-eating and healthy individuals

High-sugar/high-fat foods are related to binge-eating behaviour and especially people with low inhibitory control may encounter elevated difficulties to resist their intake. Incentive sensitization to food-related cues might lead to increased motivated attention towards these stimuli and to cue-induced craving. To investigate the combined influence of olfactory and visual stimuli on craving, inhibitory control and motivated attention, 20 healthy controls and 19 individuals with binge-eating viewed chocolate and neutral pictures, primed by chocolate or neutral odours. Subjective craving and electroencephalogram activity were recorded during the task. N2 and Late Positive Potential (LPP) amplitudes were analysed. Patients reported higher craving than controls. Subjective craving, N2 and LPP amplitudes were higher for chocolate versus neutral pictures. Patients showed a higher relative increase in N2 amplitudes to chocolate versus neutral pictures than controls. Chocolate images induced significant increases in craving, motivated attention and measures of cognitive control. Chocolate odour might potentiate the craving response to visual stimuli, especially in patients with binge-eating.

Brain dopamine and serotonin transporter binding are associated with visual attention bias for food in lean men

BACKGROUND

In rodents, the striatal dopamine (DA) system and the (hypo)thalamic serotonin (5-HT) system are involved in the regulation of feeding behavior. In lean humans, little is known about the relationship between these brain neurotransmitter systems and feeding. We studied the relationship between striatal DA transporters (DAT) and diencephalic 5-HT transporters (SERT), behavioral tasks and questionnaires, and food intake.

METHOD

We measured striatal DAT and diencephalic SERT binding with [123I]FP-CIT SPECT in 36 lean male subjects. Visual attention bias for food (detection speed and distraction time) and degree of impulsivity were measured using response-latency-based computer tasks. Craving and emotional eating were assessed with questionnaires and ratings of hunger by means of VAS scores. Food intake was assessed through a self-reported online diet journal.

RESULTS

Striatal DAT and diencephalic SERT binding negatively correlated with food detection speed (p = 0.008, r = -0.50 and p = 0.002, r = -0.57, respectively), but not with food distraction time, ratings of hunger, craving or impulsivity. Striatal DAT and diencephalic SERT binding did not correlate with free choice food intake, whereas food detection speed positively correlated with total caloric intake (p = 0.001, r = 0.60), protein intake (p = 0.01, r = 0.44), carbohydrate intake (p = 0.03, r = 0.39) and fat intake (p = 0.06, r = 0.35).

CONCLUSIONS

These results indicate a role for the central 5-HT and DA system in the regulation of visual attention bias for food, which contributes to the motivation to eat, in non-obese, healthy humans. In addition, this study confirms that food detection speed, measured with the latency-based computer task, positively correlates with total food and macronutrient intake.

A Cognitive Profile of Obesity and Its Translation into New Interventions

Change your lifestyle: decrease your energy intake and increase your energy expenditure, is what obesity experts tell people who need to lose weight. Though the advice might be correct, it appears to be extremely difficult to change one’s lifestyle. Unhealthy habits usually are ingrained and hard to change, especially for people with an “obese cognitive profile.” Knowledge of the cognitive mechanisms that maintain unhealthy eating habits is necessary for the development of interventions that can change behavior effectively. This paper discusses some cognitive processes that might maintain unhealthy eating habits and make healthier eating difficult, like increased food cue reactivity, weak executive skills and attention bias. An effort is also done to translate these basic scientific findings into new interventions which aim to tackle the sabotaging cognitive processes. Preliminary studies into the effectiveness of these interventions, if available, are presented.

Priming of conflicting motivational orientations in heavy drinkers: robust effects on self-report but not implicit measures

We report results from three experimental studies that investigated the independence of approach and avoidance motivational orientations for alcohol, both of which operate within controlled and automatic cognitive processes. In order to prime their approach or avoidance motivational orientations, participants watched brief videos, the content of which (positive or negative depictions of alcohol, or neutral) varied by experimental group. Immediately after watching the videos, participants completed self-report (Approach and Avoidance of Alcohol Questionnaire; all studies) and implicit (visual probe task in study 1, stimulus-response compatibility task in studies 2 and 3) measures of alcohol-related approach and avoidance. In study 3, we incorporated an additional experimental manipulation of thought suppression in an attempt to maximize the influence of the videos on implicit measures. Findings were consistent across all three studies: increases in self-reported approach inclinations were mirrored by decreases in avoidance inclinations, and vice versa. However, a combined analysis of data from all studies demonstrated that changes in approach inclinations were partially independent of changes in avoidance inclinations. There were no effects on implicit alcohol-related processing biases, although methodological issues may partially account for these findings. Our findings demonstrate that subjective approach and avoidance inclinations for alcohol tend to fluctuate in parallel, but changes in approach inclinations may be partially independent from changes in avoidance inclinations. We discuss methodological issues that may partially account for our findings.

Clinical effectiveness of cognitive therapy v. interpersonal psychotherapy for depression: results of a randomized controlled trial

BACKGROUND

Although both cognitive therapy (CT) and interpersonal psychotherapy (IPT) have been shown to be effective treatments for major depressive disorder (MDD), it is not clear yet whether one therapy outperforms the other with regard to severity and course of the disorder. This study examined the clinical effectiveness of CT v. IPT in a large sample of depressed patients seeking treatment in a Dutch outpatient mental health clinic. We tested whether one of the treatments was superior to the other at post-treatment and at 5 months follow-up. Furthermore, we tested whether active treatment was superior to no treatment. We also assessed whether initial depression severity moderated the effect of time and condition and tested for therapist differences.

METHOD

Depressed adults (n = 182) were randomized to either CT (n = 76), IPT (n = 75) or a 2-month waiting list control (WLC) condition (n = 31). Main outcome was depression severity, measured with the Beck Depression Inventory - II (BDI-II), assessed at baseline, 2, 3, and 7 months (treatment phase) and monthly up to 5 months follow-up (8-12 months).

RESULTS

No differential effects between CT and IPT were found. Both treatments exceeded response in the WLC condition, and led to considerable improvement in depression severity that was sustained up to 1 year. Baseline depression severity did not moderate the effect of time and condition.

CONCLUSIONS

Within our power and time ranges, CT and IPT appeared not to differ in the treatment of depression in the acute phase and beyond.

Picky eating and child weight status development: a longitudinal study

BACKGROUND

Children's picky eating behaviour has been linked both to being overweight and underweight. However, the role of parenting practices in this relationship has rarely been investigated. The present study aimed to clarify the direction of the association between picky eating and weight status and to examine the moderating role of food parenting practices.

METHODS

The present study comprised a longitudinal study on the effects of picky eating on child weight status within the KOALA Birth Cohort Study, the Netherlands. Mothers and their children were included in the analyses. Children's picky eating behaviour and food parenting practices were assessed at baseline (child age 5 years). Their weight status was assessed repeatedly until age 9 years. Mixed effects linear and logistic regressions were used to compare picky eaters (n = 403) and non-picky eaters (n = 621) on changes in weight status over the years.

RESULTS

At baseline of age 5 years, picky eaters were slightly shorter, more often underweight and less often overweight than non-picky eaters, whereas energy intake in relation to body weight (kJ kg(-1)) was similar. Picky eaters with a normal weight at baseline had no increased risk of becoming underweight during follow-up until age 9 years, and were less likely to become overweight compared to non-picky eaters. There were no interactions with food parenting practices. The parents of picky eaters more often reported pressuring their child to eat and restrict unhealthy food intake compared to parents of non-picky eaters.

CONCLUSIONS

The association between picky eating and child weight status was not influenced by parenting practices.

Neural predictors of chocolate intake following chocolate exposure

Previous studies have shown that one's brain response to high-calorie food cues can predict long-term weight gain or weight loss. The neural correlates that predict food intake in the short term have, however, hardly been investigated. This study examined which brain regions' activation predicts chocolate intake after participants had been either exposed to real chocolate or to control stimuli during approximately one hour, with interruptions for fMRI measurements. Further we investigated whether the variance in chocolate intake could be better explained by activated brain regions than by self-reported craving. In total, five brain regions correlated with subsequent chocolate intake. The activation of two reward regions (the right caudate and the left frontopolar cortex) correlated positively with intake in the exposure group. The activation of two regions associated with cognitive control (the left dorsolateral and left mid-dorsolateral PFC) correlated negatively with intake in the control group. When the regression analysis was conducted with the exposure and the control group together, an additional region's activation (the right anterior PFC) correlated positively with chocolate intake. In all analyses, the intake variance explained by neural correlates was above and beyond the variance explained by self-reported craving. These results are in line with neuroimaging research showing that brain responses are a better predictor of subsequent intake than self-reported craving. Therefore, our findings might provide for a missing link by associating brain activation, previously shown to predict weight change, with short-term intake.

Being impulsive and obese increases susceptibility to speeded detection of high-calorie foods

OBJECTIVE

Overeating and obesity are associated with impulsivity. In studies among patients with a substance use disorder, impulsivity was found to be associated with substance-related attentional bias. This study examined whether obesity, impulsivity and food craving are associated with an attentional bias for high-calorie food.

METHODS

Obese (n = 185, mean BMI = 38.18 ± 6.17) and matched healthy-weight (n = 134, mean BMI = 22.35 ± 1.63) men (27.9%) and women (72.1%), aged 18-45 years, took part in the study. Participants were tested on several self-report and behavioral measures of impulsivity (i.e., response inhibition and reward sensitivity) and self-reported trait craving. In addition, they performed a visual search task to measure attentional bias for high- and low-caloric foods.

RESULTS

Self-reported impulsivity influenced the relationship between weight status and detection speed of high- and low-caloric food items: High-impulsive participants with obesity were significantly faster than high-impulsive healthy-weight participants in detecting a high-caloric food item among neutral items, whereas no such difference was observed among low-impulsive participants. No significant effects were found on low-caloric food items, for trait craving or any of the behavioral measures of impulsivity.

CONCLUSION

Self-reported impulsivity, but not trait craving or behavioral measures of impulsivity, is associated with an attentional bias for high-caloric foods, but only in people with obesity. It is in particular the speedy detection of high-caloric foods in the environment that characterizes the impulsive person with obesity, which in turn may cause risky eating patterns in a society were high-caloric food is overly present.

Bits and pieces. Food texture influences food acceptance in young children

BACKGROUND

Picky or fussy eating is common in early childhood and associated with a decreased preference for a variety of foods. The aim of the current study was to test experimentally which sensory food feature influences food acceptance, which, in turn is an indication for fussy eating, in young children (32 - 48 months). Another aim was to evaluate if the behavioural measurement of food acceptance is related to parental reports of their child's fussy eating behaviour, parental feeding styles and children's BMI.

METHOD

In a repeated-measures-design, three sensory features were manipulated separately (i.e., colour, texture and taste) while keeping the other two features constant. The baseline measurement consisted of a well-liked yoghurt, which was presented before each manipulation variant. The number of spoons that children (N = 32) consumed from each variant were registered as behavioural indication for food acceptance. Parental reports of children's eating behaviour and parental feeding styles; and children's BMI were also measured.

RESULTS

The manipulation of food texture caused a significant decrease in intake. Colour and taste manipulations of the yoghurt did not affect children's intake. Parental reports of children's fussy eating behaviour and parental feeding styles were not related to the behavioural observation of food acceptance. The behavioural measurement of food acceptance and parental accounts of fussy eating were not related to children's BMI.

CONCLUSION

Food texture but not taste or colour alternations affected food acceptance, at least when consuming variations of a well-liked yoghurt. This knowledge is important for further research on picky-eating interventions. Parental reports of fussy eating did not concur with the behavioural observation of food acceptance. Further research is warranted to test whether these findings generalize to other food types.

Looking at food in sad mood: do attention biases lead emotional eaters into overeating after a negative mood induction?

BACKGROUND

Emotional eating is associated with overeating and the development of obesity. Yet, empirical evidence for individual (trait) differences in emotional eating and cognitive mechanisms that contribute to eating during sad mood remain equivocal.

AIM

The aim of this study was to test if attention bias for food moderates the effect of self-reported emotional eating during sad mood (vs neutral mood) on actual food intake. It was expected that emotional eating is predictive of elevated attention for food and higher food intake after an experimentally induced sad mood and that attentional maintenance on food predicts food intake during a sad versus a neutral mood.

METHOD

Participants (N = 85) were randomly assigned to one of the two experimental mood induction conditions (sad/neutral). Attentional biases for high caloric foods were measured by eye tracking during a visual probe task with pictorial food and neutral stimuli. Self-reported emotional eating was assessed with the Dutch Eating Behavior Questionnaire (DEBQ) and ad libitum food intake was tested by a disguised food offer.

RESULTS

Hierarchical multivariate regression modeling showed that self-reported emotional eating did not account for changes in attention allocation for food or food intake in either condition. Yet, attention maintenance on food cues was significantly related to increased intake specifically in the neutral condition, but not in the sad mood condition.

DISCUSSION

The current findings show that self-reported emotional eating (based on the DEBQ) might not validly predict who overeats when sad, at least not in a laboratory setting with healthy women. Results further suggest that attention maintenance on food relates to eating motivation when in a neutral affective state, and might therefore be a cognitive mechanism contributing to increased food intake in general, but maybe not during sad mood.

The value of an implicit self-associative measure specific to core beliefs of depression

BACKGROUND AND OBJECTIVES

The present study examined differences in explicit and implicit measures of self-esteem between depressed patients and healthy controls using an indirect measurement procedure especially adapted to measure self-esteem aspects of core beliefs of depression. Furthermore, we examined whether our implicit and explicit self-associative measures were associated with each other and with depressive symptoms, and investigated the effect of a discrepancy between the implicit and explicit measure on depression.

METHODS

Participants were 87 depressed patients and 30 healthy controls. The Self-Liking and Self-Competence Scale was administered as a measure of explicit self-esteem. A depression-specific variant of the Single Category Implicit Association Test served as a measure of implicit self-esteem.

RESULTS

Patients showed significantly lower levels of explicit self-esteem as compared to healthy controls. In spite of our adaptations, no differences were found on the implicit measure. The implicit measure of self-esteem was neither related to the explicit measure nor to depressive symptoms. Furthermore, although both the explicit measure of self-esteem and the difference score of the explicit and implicit measure were related to symptoms of depression, the relation between the explicit measure and depression was found to be significantly stronger.

LIMITATIONS

Results should be interpreted with caution because it is not clear yet to what extent these implicit measures really reflect self-esteem.

CONCLUSIONS

This study suggests that only the explicit measure of self-esteem - and not the implicit - is related to depression. Future research using well-designed measurement procedures for obtaining implicit and explicit measures could contribute to a better insight in the nature of these constructs.

Attention bias for chocolate increases chocolate consumption--an attention bias modification study

OBJECTIVE

The current study examined experimentally whether a manipulated attention bias for food cues increases craving, chocolate intake and motivation to search for hidden chocolates.

METHOD

To test the effect of attention for food on subsequent chocolate intake, attention for chocolate was experimentally modified by instructing participants to look at chocolate stimuli ("attend chocolate" group) or at non-food stimuli ("attend shoes" group) during a novel attention bias modification task (antisaccade task). Chocolate consumption, changes in craving and search time for hidden chocolates were assessed. Eye-movement recordings were used to monitor the accuracy during the experimental attention modification task as possible moderator of effects. Regression analyses were conducted to test the effect of attention modification and modification accuracy on chocolate intake, craving and motivation to search for hidden chocolates.

RESULTS

Results showed that participants with higher accuracy (+1 SD), ate more chocolate when they had to attend to chocolate and ate less chocolate when they had to attend to non-food stimuli. In contrast, for participants with lower accuracy (-1 SD), the results were exactly reversed. No effects of the experimental attention modification on craving or search time for hidden chocolates were found.

LIMITATION

We used chocolate as food stimuli so it remains unclear how our findings generalize to other types of food.

CONCLUSION

These findings demonstrate further evidence for a link between attention for food and food intake, and provide an indication about the direction of this relationship.

Attention bias for food is independent of restraint in healthy weight individuals-an eye tracking study

OBJECTIVE

Restrained eating style and weight status are highly correlated. Though both have been associated with an attentional bias for food cues, in prior research restraint and BMI were often confounded. The aim of the present study was to determine the existence and nature of an attention bias for food cues in healthy-weight female restrained and unrestrained eaters, when matching the two groups on BMI.

METHOD

Attention biases for food cues were measured by recordings of eye movements during a visual probe task with pictorial food versus non-food stimuli. Healthy weight high restrained (n = 24) and low restrained eaters (n = 21) were matched on BMI in an attempt to unconfound the effects of restraint and weight on attention allocation patterns.

RESULTS

All participants showed elevated attention biases for food stimuli in comparison to neutral stimuli, independent of restraint status.

DISCUSSION

These findings suggest that attention biases for food-related cues are common for healthy weight women and show that restrained eating (per se) is not related to biased processing of food stimuli, at least not in healthy weight participants.

Happy eating: the single target implicit association test predicts overeating after positive emotions

For many years, questionnaires have been considered the standard when examining emotional eating behavior. However, recently, some controversy has arisen about these questionnaires, and their usefulness in identifying emotional eaters has been questioned. The current study aimed to investigate the Single Target Implicit Association Test (ST-IAT) as a measure of emotional eating. Two ST-IATs (assessing food-positive and food-negative associations respectively) and the Dutch Eating Behaviour Questionnaire (DEBQ) were compared in undergraduate students. A positive, negative or neutral mood was induced by means of a film clip, and milkshake consumption was measured during and after the mood induction. It was hypothesized that participants with strong emotion-food associations on the ST-IATs (i.e., IAT-emotional eaters) would consume more food in the emotion induction condition corresponding to that emotion, as compared to those with weak emotion-food associations as well as to those in the neutral condition. Participants who scored high on both the positive and negative ST-IATs ate more during a positive mood induction than during a negative mood induction. This effect did not extend to milkshake consumption after the mood induction procedure. In addition, IAT-positive emotional eaters consumed more food than IAT-non-emotional eaters. No effects of the DEBQ on milkshake consumption were found. It is concluded that the ST-IAT has potential as a measure of emotional eating.

Happy eating: the underestimated role of overeating in a positive mood

Emotional eaters are often presumed to eat in response to negative emotions, while positive emotions have been largely neglected. The current study induced a positive, negative, or neutral mood in a student sample and subsequently measured food intake. In addition, the relation between caloric intake and mood improvement was assessed. It was expected that emotional eaters would consume more food than non-emotional eaters in the emotional conditions, and also more than in the neutral condition. Moderated regression analyses indeed showed a significant increase in food intake for emotional eaters in the positive compared to the neutral condition, and a trend towards higher food consumption than non-emotional eaters. No effects were found in the negative condition. With regard to mood changes during food intake, Pearson correlations demonstrated an association between amount of calories consumed and mood improvement after 5min of food consumption. However, there was no evidence for differences between emotional and non-emotional eaters. The current findings underline the importance of positive emotions in emotional eating, and provide new insights on the relationship between eating and mood melioration.

Measuring automatic associations: validation of algorithms for the Implicit Association Test (IAT) in a laboratory setting

BACKGROUND AND OBJECTIVES

In their paper, "Understanding and using the Implicit Association Test: I. An improved scoring algorithm", Greenwald, Nosek, and Banaji (2003) investigated different ways to calculate the IAT-effect. However, up to now, it remained unclear whether these findings - based on internet data - also generalize to laboratory settings. Therefore, the main goal of the present study was to cross-validate scoring algorithms for the IAT in a laboratory setting, specifically in the domain of psychopathology.

METHODS

Four known IAT algorithms and seven alternative IAT algorithms were evaluated on several performance criteria in the large-scale laboratory sample of the Netherlands Study of Depression and Anxiety (N = 2981) in which two IATs were included to obtain measurements of automatic self-anxious and automatic self-depressed associations.

RESULTS AND CONCLUSIONS

Results clearly demonstrated that the D(2SD)-measure and the D(600)-measure as well as an alternative algorithm based on the correct trials only (D(noEP)-measure) are suitable to be used in a laboratory setting for IATs with a fixed order of category combinations. It remains important to further replicate these findings, especially in studies that include outcome measures of more spontaneous kinds of behaviors.

The craving stops before you feel it: neural correlates of chocolate craving during cue exposure with response prevention

Cue reactivity and craving can be influenced by cue exposure with response prevention (CERP). This study investigated the neural correlates of CERP using functional magnetic resonance imaging, while participants smelled chocolate (17 participants) or a control object (17 participants). CERP was interrupted by 7 scanning sequences measuring the brain response to neutral and chocolate pictures. Chocolate craving was hypothesized to be mirrored by activation in brain reward regions. As expected, control group craving remained similar throughout the session. A short exposure (30 min) increased chocolate craving in the experimental group, which was mirrored by significant group differences in activation in brain reward regions. Unexpectedly, a long exposure (60 min) did not lead to craving extinction in the experimental group, although craving started to decrease at this point. On a neural level, however, activation in regions of interest in the experimental group seemed to have extinguished after the long exposure, as activation levels returned to or fell below control group levels. These results indicate that brain reward activation during CERP is linked to craving, at least for a short exposure. Regarding a longer exposure, the decline in brain reward activation in the experimental group may be a precursor of a decrease in craving.