Neurocognitive correlates of processing food-related stimuli in a Go/No-go paradigm

The processing of food stimuli in abnormal eating: a systematic review of electrophysiology

To update the knowledge about attentional processing of food stimuli, a systematic review of electrophysiological studies was conducted using PubMed, PsychInfo and Web of Knowledge (2000-2014). Twenty-one studies were included into a qualitative synthesis. Presentation of food and control pictures was used to analyze event-related potentials related to sensory processing and motivated attention. Results show consistent attentional bias towards food pictures compared with neutral pictures for patient and control groups. Group comparisons between individuals with abnormal-eating and healthy-eating participants were more inconsistent. Results suggest that temporal differences in the millisecond range are essential for the understanding of visual food processing. In obesity, early attention engagement to food is followed by relatice disengagement. Loss of control eating, as well as external and emotional eating, are associated with a sustained maintenance of attention towards high-caloric food. There is a lack of studies in anorexia nervosa, bulimia nervosa and binge eating disorder.

Inhibition ability of food cues between successful and unsuccessful restrained eaters: a two-choice oddball task

Background

Previous studies have presented mixed findings on the inhibition ability in restrained eaters (REs) due to the limited amount of neural evidence and limitations of behavioral measures. The current study explores the neural correlations of the specific inhibition ability among successful restrained eaters (S-REs), unsuccessful restrained eaters (US-REs), and unrestrained eaters (UREs).

Methodology and Principal Findings

Three groups of females (with 13 participants in each group) completed a two-choice Oddball task, while the event-related potentials (ERPs) are recorded synchronously. Results indicate that S-REs showed inhibition deficit in processing high-energy food cues whereas US-REs show inhibition deficit in processing both low- and high-energy food cues.

Conclusion

Results indicate that S-REs and US-REs differ in terms of specific inhibition ability and that enhanced inhibition is essential to a successful diet.

Patients lacking sustainable long-term weight loss after gastric bypass surgery show signs of decreased inhibitory control of prepotent responses

Background

A considerable number of bariatric patients report poor long-term weight loss after Roux-en-Y gastric bypass (RYGB) surgery. One possibility for an underlying cause is an impairment of cognitive control that impedes this patient group’s dietary efforts.

Objective

To investigate if patients having either poor or good weight loss response, ~12 years after RYGB-surgery, differ in their ability to inhibit prepotent responses when processing food cues during attentional operations—as measure of cognitive control.

Methods

In terms of weight loss following RYGB-surgery, 15 ‘poor responders’ and 15 ‘good responders’, matched for gender, age, education, preoperative body mass index, and years since surgery, were administered two tasks that measure sustained attention and response control: a go/no-go task and a Stroop interference task; both of which are associated with maladaptive eating behaviours.

Results

The poor responders (vs. good responders) needed significantly more time when conducting a go/no-go task (603±134 vs. 519±44 msec, p = 0.03), but the number of errors did not differ between groups. When conducting a Stroop interference task, poor responders read fewer inks than good responders (68±16 vs. 85±10 words, p = 0.002).

Conclusion

Patients lacking sustainable weight loss after RYGB-surgery showed poorer inhibitory control than patients that successfully lost weight. In the authors’ view, these results suggest that cognitive behavioral therapies post-RYGB-surgery may represent a promising behavioral adjuvant to achieve sustainable weight loss in patients undergoing this procedure. Future studies should examine whether these control deficits in poor responders are food-specific or not.

Increased impulsivity in response to food cues after sleep loss in healthy young men

OBJECTIVE

To investigate whether acute total sleep deprivation (TSD) leads to decreased cognitive control when food cues are presented during a task requiring active attention, by assessing the ability to cognitively inhibit prepotent responses.

METHODS

Fourteen males participated in the study on two separate occasions in a randomized, crossover within-subject design: one night of TSD versus normal sleep (8.5 hours). Following each nighttime intervention, hunger ratings and morning fasting plasma glucose concentrations were assessed before performing a go/no-go task.

RESULTS

Following TSD, participants made significantly more commission errors when they were presented "no-go" food words in the go/no-go task, as compared with their performance following sleep (+56%; P<0.05). In contrast, response time and omission errors to "go" non-food words did not differ between the conditions. Self-reported hunger after TSD was increased without changes in fasting plasma glucose. The increase in hunger did not correlate with the TSD-induced commission errors.

CONCLUSIONS

Our results suggest that TSD impairs cognitive control also in response to food stimuli in healthy young men. Whether such loss of inhibition or impulsiveness is food cue-specific as seen in obesity-thus providing a mechanism through which sleep disturbances may promote obesity development-warrants further investigation.